1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // HTTP server. See RFC 2616.
31 "golang_org/x/net/lex/httplex"
34 // Errors used by the HTTP server.
36 // ErrBodyNotAllowed is returned by ResponseWriter.Write calls
37 // when the HTTP method or response code does not permit a
39 ErrBodyNotAllowed
= errors
.New("http: request method or response status code does not allow body")
41 // ErrHijacked is returned by ResponseWriter.Write calls when
42 // the underlying connection has been hijacked using the
43 // Hijacker interface. A zero-byte write on a hijacked
44 // connection will return ErrHijacked without any other side
46 ErrHijacked
= errors
.New("http: connection has been hijacked")
48 // ErrContentLength is returned by ResponseWriter.Write calls
49 // when a Handler set a Content-Length response header with a
50 // declared size and then attempted to write more bytes than
52 ErrContentLength
= errors
.New("http: wrote more than the declared Content-Length")
54 // Deprecated: ErrWriteAfterFlush is no longer used.
55 ErrWriteAfterFlush
= errors
.New("unused")
58 // A Handler responds to an HTTP request.
60 // ServeHTTP should write reply headers and data to the ResponseWriter
61 // and then return. Returning signals that the request is finished; it
62 // is not valid to use the ResponseWriter or read from the
63 // Request.Body after or concurrently with the completion of the
66 // Depending on the HTTP client software, HTTP protocol version, and
67 // any intermediaries between the client and the Go server, it may not
68 // be possible to read from the Request.Body after writing to the
69 // ResponseWriter. Cautious handlers should read the Request.Body
70 // first, and then reply.
72 // Except for reading the body, handlers should not modify the
75 // If ServeHTTP panics, the server (the caller of ServeHTTP) assumes
76 // that the effect of the panic was isolated to the active request.
77 // It recovers the panic, logs a stack trace to the server error log,
78 // and either closes the network connection or sends an HTTP/2
79 // RST_STREAM, depending on the HTTP protocol. To abort a handler so
80 // the client sees an interrupted response but the server doesn't log
81 // an error, panic with the value ErrAbortHandler.
82 type Handler
interface {
83 ServeHTTP(ResponseWriter
, *Request
)
86 // A ResponseWriter interface is used by an HTTP handler to
87 // construct an HTTP response.
89 // A ResponseWriter may not be used after the Handler.ServeHTTP method
91 type ResponseWriter
interface {
92 // Header returns the header map that will be sent by
93 // WriteHeader. The Header map also is the mechanism with which
94 // Handlers can set HTTP trailers.
96 // Changing the header map after a call to WriteHeader (or
97 // Write) has no effect unless the modified headers are
100 // There are two ways to set Trailers. The preferred way is to
101 // predeclare in the headers which trailers you will later
102 // send by setting the "Trailer" header to the names of the
103 // trailer keys which will come later. In this case, those
104 // keys of the Header map are treated as if they were
105 // trailers. See the example. The second way, for trailer
106 // keys not known to the Handler until after the first Write,
107 // is to prefix the Header map keys with the TrailerPrefix
108 // constant value. See TrailerPrefix.
110 // To suppress implicit response headers (such as "Date"), set
111 // their value to nil.
114 // Write writes the data to the connection as part of an HTTP reply.
116 // If WriteHeader has not yet been called, Write calls
117 // WriteHeader(http.StatusOK) before writing the data. If the Header
118 // does not contain a Content-Type line, Write adds a Content-Type set
119 // to the result of passing the initial 512 bytes of written data to
120 // DetectContentType.
122 // Depending on the HTTP protocol version and the client, calling
123 // Write or WriteHeader may prevent future reads on the
124 // Request.Body. For HTTP/1.x requests, handlers should read any
125 // needed request body data before writing the response. Once the
126 // headers have been flushed (due to either an explicit Flusher.Flush
127 // call or writing enough data to trigger a flush), the request body
128 // may be unavailable. For HTTP/2 requests, the Go HTTP server permits
129 // handlers to continue to read the request body while concurrently
130 // writing the response. However, such behavior may not be supported
131 // by all HTTP/2 clients. Handlers should read before writing if
132 // possible to maximize compatibility.
133 Write([]byte) (int, error
)
135 // WriteHeader sends an HTTP response header with status code.
136 // If WriteHeader is not called explicitly, the first call to Write
137 // will trigger an implicit WriteHeader(http.StatusOK).
138 // Thus explicit calls to WriteHeader are mainly used to
143 // The Flusher interface is implemented by ResponseWriters that allow
144 // an HTTP handler to flush buffered data to the client.
146 // The default HTTP/1.x and HTTP/2 ResponseWriter implementations
147 // support Flusher, but ResponseWriter wrappers may not. Handlers
148 // should always test for this ability at runtime.
150 // Note that even for ResponseWriters that support Flush,
151 // if the client is connected through an HTTP proxy,
152 // the buffered data may not reach the client until the response
154 type Flusher
interface {
155 // Flush sends any buffered data to the client.
159 // The Hijacker interface is implemented by ResponseWriters that allow
160 // an HTTP handler to take over the connection.
162 // The default ResponseWriter for HTTP/1.x connections supports
163 // Hijacker, but HTTP/2 connections intentionally do not.
164 // ResponseWriter wrappers may also not support Hijacker. Handlers
165 // should always test for this ability at runtime.
166 type Hijacker
interface {
167 // Hijack lets the caller take over the connection.
168 // After a call to Hijack the HTTP server library
169 // will not do anything else with the connection.
171 // It becomes the caller's responsibility to manage
172 // and close the connection.
174 // The returned net.Conn may have read or write deadlines
175 // already set, depending on the configuration of the
176 // Server. It is the caller's responsibility to set
177 // or clear those deadlines as needed.
179 // The returned bufio.Reader may contain unprocessed buffered
180 // data from the client.
182 // After a call to Hijack, the original Request.Body should
184 Hijack() (net
.Conn
, *bufio
.ReadWriter
, error
)
187 // The CloseNotifier interface is implemented by ResponseWriters which
188 // allow detecting when the underlying connection has gone away.
190 // This mechanism can be used to cancel long operations on the server
191 // if the client has disconnected before the response is ready.
192 type CloseNotifier
interface {
193 // CloseNotify returns a channel that receives at most a
194 // single value (true) when the client connection has gone
197 // CloseNotify may wait to notify until Request.Body has been
200 // After the Handler has returned, there is no guarantee
201 // that the channel receives a value.
203 // If the protocol is HTTP/1.1 and CloseNotify is called while
204 // processing an idempotent request (such a GET) while
205 // HTTP/1.1 pipelining is in use, the arrival of a subsequent
206 // pipelined request may cause a value to be sent on the
207 // returned channel. In practice HTTP/1.1 pipelining is not
208 // enabled in browsers and not seen often in the wild. If this
209 // is a problem, use HTTP/2 or only use CloseNotify on methods
211 CloseNotify() <-chan bool
215 // ServerContextKey is a context key. It can be used in HTTP
216 // handlers with context.WithValue to access the server that
217 // started the handler. The associated value will be of
219 ServerContextKey
= &contextKey
{"http-server"}
221 // LocalAddrContextKey is a context key. It can be used in
222 // HTTP handlers with context.WithValue to access the address
223 // the local address the connection arrived on.
224 // The associated value will be of type net.Addr.
225 LocalAddrContextKey
= &contextKey
{"local-addr"}
228 // A conn represents the server side of an HTTP connection.
230 // server is the server on which the connection arrived.
231 // Immutable; never nil.
234 // cancelCtx cancels the connection-level context.
235 cancelCtx context
.CancelFunc
237 // rwc is the underlying network connection.
238 // This is never wrapped by other types and is the value given out
239 // to CloseNotifier callers. It is usually of type *net.TCPConn or
243 // remoteAddr is rwc.RemoteAddr().String(). It is not populated synchronously
244 // inside the Listener's Accept goroutine, as some implementations block.
245 // It is populated immediately inside the (*conn).serve goroutine.
246 // This is the value of a Handler's (*Request).RemoteAddr.
249 // tlsState is the TLS connection state when using TLS.
250 // nil means not TLS.
251 tlsState
*tls
.ConnectionState
253 // werr is set to the first write error to rwc.
254 // It is set via checkConnErrorWriter{w}, where bufw writes.
257 // r is bufr's read source. It's a wrapper around rwc that provides
258 // io.LimitedReader-style limiting (while reading request headers)
259 // and functionality to support CloseNotifier. See *connReader docs.
262 // bufr reads from r.
265 // bufw writes to checkConnErrorWriter{c}, which populates werr on error.
268 // lastMethod is the method of the most recent request
269 // on this connection, if any.
272 curReq atomic
.Value
// of *response (which has a Request in it)
274 curState atomic
.Value
// of ConnState
276 // mu guards hijackedv
279 // hijackedv is whether this connection has been hijacked
280 // by a Handler with the Hijacker interface.
281 // It is guarded by mu.
285 func (c
*conn
) hijacked() bool {
291 // c.mu must be held.
292 func (c
*conn
) hijackLocked() (rwc net
.Conn
, buf
*bufio
.ReadWriter
, err error
) {
294 return nil, nil, ErrHijacked
296 c
.r
.abortPendingRead()
300 rwc
.SetDeadline(time
.Time
{})
302 buf
= bufio
.NewReadWriter(c
.bufr
, bufio
.NewWriter(rwc
))
304 if _
, err
:= c
.bufr
.Peek(c
.bufr
.Buffered() + 1); err
!= nil {
305 return nil, nil, fmt
.Errorf("unexpected Peek failure reading buffered byte: %v", err
)
308 c
.setState(rwc
, StateHijacked
)
312 // This should be >= 512 bytes for DetectContentType,
313 // but otherwise it's somewhat arbitrary.
314 const bufferBeforeChunkingSize
= 2048
316 // chunkWriter writes to a response's conn buffer, and is the writer
317 // wrapped by the response.bufw buffered writer.
319 // chunkWriter also is responsible for finalizing the Header, including
320 // conditionally setting the Content-Type and setting a Content-Length
321 // in cases where the handler's final output is smaller than the buffer
322 // size. It also conditionally adds chunk headers, when in chunking mode.
324 // See the comment above (*response).Write for the entire write flow.
325 type chunkWriter
struct {
328 // header is either nil or a deep clone of res.handlerHeader
329 // at the time of res.WriteHeader, if res.WriteHeader is
330 // called and extra buffering is being done to calculate
331 // Content-Type and/or Content-Length.
334 // wroteHeader tells whether the header's been written to "the
335 // wire" (or rather: w.conn.buf). this is unlike
336 // (*response).wroteHeader, which tells only whether it was
337 // logically written.
340 // set by the writeHeader method:
341 chunking
bool // using chunked transfer encoding for reply body
345 crlf
= []byte("\r\n")
346 colonSpace
= []byte(": ")
349 func (cw
*chunkWriter
) Write(p
[]byte) (n
int, err error
) {
353 if cw
.res
.req
.Method
== "HEAD" {
358 _
, err
= fmt
.Fprintf(cw
.res
.conn
.bufw
, "%x\r\n", len(p
))
360 cw
.res
.conn
.rwc
.Close()
364 n
, err
= cw
.res
.conn
.bufw
.Write(p
)
365 if cw
.chunking
&& err
== nil {
366 _
, err
= cw
.res
.conn
.bufw
.Write(crlf
)
369 cw
.res
.conn
.rwc
.Close()
374 func (cw
*chunkWriter
) flush() {
378 cw
.res
.conn
.bufw
.Flush()
381 func (cw
*chunkWriter
) close() {
386 bw
:= cw
.res
.conn
.bufw
// conn's bufio writer
387 // zero chunk to mark EOF
388 bw
.WriteString("0\r\n")
389 if trailers
:= cw
.res
.finalTrailers(); trailers
!= nil {
390 trailers
.Write(bw
) // the writer handles noting errors
392 // final blank line after the trailers (whether
394 bw
.WriteString("\r\n")
398 // A response represents the server side of an HTTP response.
399 type response
struct {
401 req
*Request
// request for this response
402 reqBody io
.ReadCloser
403 cancelCtx context
.CancelFunc
// when ServeHTTP exits
404 wroteHeader
bool // reply header has been (logically) written
405 wroteContinue
bool // 100 Continue response was written
406 wants10KeepAlive
bool // HTTP/1.0 w/ Connection "keep-alive"
407 wantsClose
bool // HTTP request has Connection "close"
409 w
*bufio
.Writer
// buffers output in chunks to chunkWriter
412 // handlerHeader is the Header that Handlers get access to,
413 // which may be retained and mutated even after WriteHeader.
414 // handlerHeader is copied into cw.header at WriteHeader
415 // time, and privately mutated thereafter.
417 calledHeader
bool // handler accessed handlerHeader via Header
419 written
int64 // number of bytes written in body
420 contentLength
int64 // explicitly-declared Content-Length; or -1
421 status
int // status code passed to WriteHeader
423 // close connection after this reply. set on request and
424 // updated after response from handler if there's a
425 // "Connection: keep-alive" response header and a
429 // requestBodyLimitHit is set by requestTooLarge when
430 // maxBytesReader hits its max size. It is checked in
431 // WriteHeader, to make sure we don't consume the
432 // remaining request body to try to advance to the next HTTP
433 // request. Instead, when this is set, we stop reading
434 // subsequent requests on this connection and stop reading
436 requestBodyLimitHit
bool
438 // trailers are the headers to be sent after the handler
439 // finishes writing the body. This field is initialized from
440 // the Trailer response header when the response header is
444 handlerDone atomicBool
// set true when the handler exits
446 // Buffers for Date, Content-Length, and status code
447 dateBuf
[len(TimeFormat
)]byte
451 // closeNotifyCh is the channel returned by CloseNotify.
452 // TODO(bradfitz): this is currently (for Go 1.8) always
453 // non-nil. Make this lazily-created again as it used to be?
454 closeNotifyCh
chan bool
455 didCloseNotify
int32 // atomic (only 0->1 winner should send)
458 // TrailerPrefix is a magic prefix for ResponseWriter.Header map keys
459 // that, if present, signals that the map entry is actually for
460 // the response trailers, and not the response headers. The prefix
461 // is stripped after the ServeHTTP call finishes and the values are
462 // sent in the trailers.
464 // This mechanism is intended only for trailers that are not known
465 // prior to the headers being written. If the set of trailers is fixed
466 // or known before the header is written, the normal Go trailers mechanism
468 // https://golang.org/pkg/net/http/#ResponseWriter
469 // https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
470 const TrailerPrefix
= "Trailer:"
472 // finalTrailers is called after the Handler exits and returns a non-nil
473 // value if the Handler set any trailers.
474 func (w
*response
) finalTrailers() Header
{
476 for k
, vv
:= range w
.handlerHeader
{
477 if strings
.HasPrefix(k
, TrailerPrefix
) {
481 t
[strings
.TrimPrefix(k
, TrailerPrefix
)] = vv
484 for _
, k
:= range w
.trailers
{
488 for _
, v
:= range w
.handlerHeader
[k
] {
495 type atomicBool
int32
497 func (b
*atomicBool
) isSet() bool { return atomic
.LoadInt32((*int32)(b
)) != 0 }
498 func (b
*atomicBool
) setTrue() { atomic
.StoreInt32((*int32)(b
), 1) }
500 // declareTrailer is called for each Trailer header when the
501 // response header is written. It notes that a header will need to be
502 // written in the trailers at the end of the response.
503 func (w
*response
) declareTrailer(k
string) {
504 k
= CanonicalHeaderKey(k
)
506 case "Transfer-Encoding", "Content-Length", "Trailer":
507 // Forbidden by RFC 2616 14.40.
510 w
.trailers
= append(w
.trailers
, k
)
513 // requestTooLarge is called by maxBytesReader when too much input has
514 // been read from the client.
515 func (w
*response
) requestTooLarge() {
516 w
.closeAfterReply
= true
517 w
.requestBodyLimitHit
= true
519 w
.Header().Set("Connection", "close")
523 // needsSniff reports whether a Content-Type still needs to be sniffed.
524 func (w
*response
) needsSniff() bool {
525 _
, haveType
:= w
.handlerHeader
["Content-Type"]
526 return !w
.cw
.wroteHeader
&& !haveType
&& w
.written
< sniffLen
529 // writerOnly hides an io.Writer value's optional ReadFrom method
531 type writerOnly
struct {
535 func srcIsRegularFile(src io
.Reader
) (isRegular
bool, err error
) {
536 switch v
:= src
.(type) {
542 return fi
.Mode().IsRegular(), nil
543 case *io
.LimitedReader
:
544 return srcIsRegularFile(v
.R
)
550 // ReadFrom is here to optimize copying from an *os.File regular file
551 // to a *net.TCPConn with sendfile.
552 func (w
*response
) ReadFrom(src io
.Reader
) (n
int64, err error
) {
553 // Our underlying w.conn.rwc is usually a *TCPConn (with its
554 // own ReadFrom method). If not, or if our src isn't a regular
555 // file, just fall back to the normal copy method.
556 rf
, ok
:= w
.conn
.rwc
.(io
.ReaderFrom
)
557 regFile
, err
:= srcIsRegularFile(src
)
562 bufp
:= copyBufPool
.Get().(*[]byte)
563 defer copyBufPool
.Put(bufp
)
564 return io
.CopyBuffer(writerOnly
{w
}, src
, *bufp
)
570 w
.WriteHeader(StatusOK
)
574 n0
, err
:= io
.Copy(writerOnly
{w
}, io
.LimitReader(src
, sniffLen
))
581 w
.w
.Flush() // get rid of any previous writes
582 w
.cw
.flush() // make sure Header is written; flush data to rwc
584 // Now that cw has been flushed, its chunking field is guaranteed initialized.
585 if !w
.cw
.chunking
&& w
.bodyAllowed() {
586 n0
, err
:= rf
.ReadFrom(src
)
592 n0
, err
:= io
.Copy(writerOnly
{w
}, src
)
597 // debugServerConnections controls whether all server connections are wrapped
598 // with a verbose logging wrapper.
599 const debugServerConnections
= false
601 // Create new connection from rwc.
602 func (srv
*Server
) newConn(rwc net
.Conn
) *conn
{
607 if debugServerConnections
{
608 c
.rwc
= newLoggingConn("server", c
.rwc
)
613 type readResult
struct {
616 b
byte // byte read, if n == 1
619 // connReader is the io.Reader wrapper used by *conn. It combines a
620 // selectively-activated io.LimitedReader (to bound request header
621 // read sizes) with support for selectively keeping an io.Reader.Read
622 // call blocked in a background goroutine to wait for activity and
623 // trigger a CloseNotifier channel.
624 type connReader
struct {
627 mu sync
.Mutex
// guards following
632 aborted
bool // set true before conn.rwc deadline is set to past
633 remain
int64 // bytes remaining
636 func (cr
*connReader
) lock() {
639 cr
.cond
= sync
.NewCond(&cr
.mu
)
643 func (cr
*connReader
) unlock() { cr
.mu
.Unlock() }
645 func (cr
*connReader
) startBackgroundRead() {
649 panic("invalid concurrent Body.Read call")
655 cr
.conn
.rwc
.SetReadDeadline(time
.Time
{})
656 go cr
.backgroundRead()
659 func (cr
*connReader
) backgroundRead() {
660 n
, err
:= cr
.conn
.rwc
.Read(cr
.byteBuf
[:])
664 // We were at EOF already (since we wouldn't be in a
665 // background read otherwise), so this is a pipelined
667 cr
.closeNotifyFromPipelinedRequest()
669 if ne
, ok
:= err
.(net
.Error
); ok
&& cr
.aborted
&& ne
.Timeout() {
670 // Ignore this error. It's the expected error from
671 // another goroutine calling abortPendingRead.
672 } else if err
!= nil {
673 cr
.handleReadError(err
)
681 func (cr
*connReader
) abortPendingRead() {
688 cr
.conn
.rwc
.SetReadDeadline(aLongTimeAgo
)
692 cr
.conn
.rwc
.SetReadDeadline(time
.Time
{})
695 func (cr
*connReader
) setReadLimit(remain
int64) { cr
.remain
= remain
}
696 func (cr
*connReader
) setInfiniteReadLimit() { cr
.remain
= maxInt64
}
697 func (cr
*connReader
) hitReadLimit() bool { return cr
.remain
<= 0 }
699 // may be called from multiple goroutines.
700 func (cr
*connReader
) handleReadError(err error
) {
705 // closeNotifyFromPipelinedRequest simply calls closeNotify.
707 // This method wrapper is here for documentation. The callers are the
708 // cases where we send on the closenotify channel because of a
709 // pipelined HTTP request, per the previous Go behavior and
710 // documentation (that this "MAY" happen).
712 // TODO: consider changing this behavior and making context
713 // cancelation and closenotify work the same.
714 func (cr
*connReader
) closeNotifyFromPipelinedRequest() {
718 // may be called from multiple goroutines.
719 func (cr
*connReader
) closeNotify() {
720 res
, _
:= cr
.conn
.curReq
.Load().(*response
)
722 if atomic
.CompareAndSwapInt32(&res
.didCloseNotify
, 0, 1) {
723 res
.closeNotifyCh
<- true
728 func (cr
*connReader
) Read(p
[]byte) (n
int, err error
) {
732 panic("invalid concurrent Body.Read call")
734 if cr
.hitReadLimit() {
742 if int64(len(p
)) > cr
.remain
{
753 n
, err
= cr
.conn
.rwc
.Read(p
)
758 cr
.handleReadError(err
)
760 cr
.remain
-= int64(n
)
768 bufioReaderPool sync
.Pool
769 bufioWriter2kPool sync
.Pool
770 bufioWriter4kPool sync
.Pool
773 var copyBufPool
= sync
.Pool
{
774 New
: func() interface{} {
775 b
:= make([]byte, 32*1024)
780 func bufioWriterPool(size
int) *sync
.Pool
{
783 return &bufioWriter2kPool
785 return &bufioWriter4kPool
790 func newBufioReader(r io
.Reader
) *bufio
.Reader
{
791 if v
:= bufioReaderPool
.Get(); v
!= nil {
792 br
:= v
.(*bufio
.Reader
)
796 // Note: if this reader size is ever changed, update
797 // TestHandlerBodyClose's assumptions.
798 return bufio
.NewReader(r
)
801 func putBufioReader(br
*bufio
.Reader
) {
803 bufioReaderPool
.Put(br
)
806 func newBufioWriterSize(w io
.Writer
, size
int) *bufio
.Writer
{
807 pool
:= bufioWriterPool(size
)
809 if v
:= pool
.Get(); v
!= nil {
810 bw
:= v
.(*bufio
.Writer
)
815 return bufio
.NewWriterSize(w
, size
)
818 func putBufioWriter(bw
*bufio
.Writer
) {
820 if pool
:= bufioWriterPool(bw
.Available()); pool
!= nil {
825 // DefaultMaxHeaderBytes is the maximum permitted size of the headers
826 // in an HTTP request.
827 // This can be overridden by setting Server.MaxHeaderBytes.
828 const DefaultMaxHeaderBytes
= 1 << 20 // 1 MB
830 func (srv
*Server
) maxHeaderBytes() int {
831 if srv
.MaxHeaderBytes
> 0 {
832 return srv
.MaxHeaderBytes
834 return DefaultMaxHeaderBytes
837 func (srv
*Server
) initialReadLimitSize() int64 {
838 return int64(srv
.maxHeaderBytes()) + 4096 // bufio slop
841 // wrapper around io.ReadCloser which on first read, sends an
842 // HTTP/1.1 100 Continue header
843 type expectContinueReader
struct {
845 readCloser io
.ReadCloser
850 func (ecr
*expectContinueReader
) Read(p
[]byte) (n
int, err error
) {
852 return 0, ErrBodyReadAfterClose
854 if !ecr
.resp
.wroteContinue
&& !ecr
.resp
.conn
.hijacked() {
855 ecr
.resp
.wroteContinue
= true
856 ecr
.resp
.conn
.bufw
.WriteString("HTTP/1.1 100 Continue\r\n\r\n")
857 ecr
.resp
.conn
.bufw
.Flush()
859 n
, err
= ecr
.readCloser
.Read(p
)
866 func (ecr
*expectContinueReader
) Close() error
{
868 return ecr
.readCloser
.Close()
871 // TimeFormat is the time format to use when generating times in HTTP
872 // headers. It is like time.RFC1123 but hard-codes GMT as the time
873 // zone. The time being formatted must be in UTC for Format to
874 // generate the correct format.
876 // For parsing this time format, see ParseTime.
877 const TimeFormat
= "Mon, 02 Jan 2006 15:04:05 GMT"
879 // appendTime is a non-allocating version of []byte(t.UTC().Format(TimeFormat))
880 func appendTime(b
[]byte, t time
.Time
) []byte {
881 const days
= "SunMonTueWedThuFriSat"
882 const months
= "JanFebMarAprMayJunJulAugSepOctNovDec"
885 yy
, mm
, dd
:= t
.Date()
886 hh
, mn
, ss
:= t
.Clock()
887 day
:= days
[3*t
.Weekday():]
888 mon
:= months
[3*(mm
-1):]
891 day
[0], day
[1], day
[2], ',', ' ',
892 byte('0'+dd
/10), byte('0'+dd%10
), ' ',
893 mon
[0], mon
[1], mon
[2], ' ',
894 byte('0'+yy
/1000), byte('0'+(yy
/100)%10
), byte('0'+(yy
/10)%10
), byte('0'+yy%10
), ' ',
895 byte('0'+hh
/10), byte('0'+hh%10
), ':',
896 byte('0'+mn
/10), byte('0'+mn%10
), ':',
897 byte('0'+ss
/10), byte('0'+ss%10
), ' ',
901 var errTooLarge
= errors
.New("http: request too large")
903 // Read next request from connection.
904 func (c
*conn
) readRequest(ctx context
.Context
) (w
*response
, err error
) {
906 return nil, ErrHijacked
910 wholeReqDeadline time
.Time
// or zero if none
911 hdrDeadline time
.Time
// or zero if none
914 if d
:= c
.server
.readHeaderTimeout(); d
!= 0 {
915 hdrDeadline
= t0
.Add(d
)
917 if d
:= c
.server
.ReadTimeout
; d
!= 0 {
918 wholeReqDeadline
= t0
.Add(d
)
920 c
.rwc
.SetReadDeadline(hdrDeadline
)
921 if d
:= c
.server
.WriteTimeout
; d
!= 0 {
923 c
.rwc
.SetWriteDeadline(time
.Now().Add(d
))
927 c
.r
.setReadLimit(c
.server
.initialReadLimitSize())
928 if c
.lastMethod
== "POST" {
929 // RFC 2616 section 4.1 tolerance for old buggy clients.
930 peek
, _
:= c
.bufr
.Peek(4) // ReadRequest will get err below
931 c
.bufr
.Discard(numLeadingCRorLF(peek
))
933 req
, err
:= readRequest(c
.bufr
, keepHostHeader
)
935 if c
.r
.hitReadLimit() {
936 return nil, errTooLarge
941 if !http1ServerSupportsRequest(req
) {
942 return nil, badRequestError("unsupported protocol version")
945 c
.lastMethod
= req
.Method
946 c
.r
.setInfiniteReadLimit()
948 hosts
, haveHost
:= req
.Header
["Host"]
949 isH2Upgrade
:= req
.isH2Upgrade()
950 if req
.ProtoAtLeast(1, 1) && (!haveHost ||
len(hosts
) == 0) && !isH2Upgrade
&& req
.Method
!= "CONNECT" {
951 return nil, badRequestError("missing required Host header")
954 return nil, badRequestError("too many Host headers")
956 if len(hosts
) == 1 && !httplex
.ValidHostHeader(hosts
[0]) {
957 return nil, badRequestError("malformed Host header")
959 for k
, vv
:= range req
.Header
{
960 if !httplex
.ValidHeaderFieldName(k
) {
961 return nil, badRequestError("invalid header name")
963 for _
, v
:= range vv
{
964 if !httplex
.ValidHeaderFieldValue(v
) {
965 return nil, badRequestError("invalid header value")
969 delete(req
.Header
, "Host")
971 ctx
, cancelCtx
:= context
.WithCancel(ctx
)
973 req
.RemoteAddr
= c
.remoteAddr
975 if body
, ok
:= req
.Body
.(*body
); ok
{
976 body
.doEarlyClose
= true
979 // Adjust the read deadline if necessary.
980 if !hdrDeadline
.Equal(wholeReqDeadline
) {
981 c
.rwc
.SetReadDeadline(wholeReqDeadline
)
986 cancelCtx
: cancelCtx
,
989 handlerHeader
: make(Header
),
991 closeNotifyCh
: make(chan bool, 1),
993 // We populate these ahead of time so we're not
994 // reading from req.Header after their Handler starts
995 // and maybe mutates it (Issue 14940)
996 wants10KeepAlive
: req
.wantsHttp10KeepAlive(),
997 wantsClose
: req
.wantsClose(),
1000 w
.closeAfterReply
= true
1003 w
.w
= newBufioWriterSize(&w
.cw
, bufferBeforeChunkingSize
)
1007 // http1ServerSupportsRequest reports whether Go's HTTP/1.x server
1008 // supports the given request.
1009 func http1ServerSupportsRequest(req
*Request
) bool {
1010 if req
.ProtoMajor
== 1 {
1013 // Accept "PRI * HTTP/2.0" upgrade requests, so Handlers can
1014 // wire up their own HTTP/2 upgrades.
1015 if req
.ProtoMajor
== 2 && req
.ProtoMinor
== 0 &&
1016 req
.Method
== "PRI" && req
.RequestURI
== "*" {
1019 // Reject HTTP/0.x, and all other HTTP/2+ requests (which
1020 // aren't encoded in ASCII anyway).
1024 func (w
*response
) Header() Header
{
1025 if w
.cw
.header
== nil && w
.wroteHeader
&& !w
.cw
.wroteHeader
{
1026 // Accessing the header between logically writing it
1027 // and physically writing it means we need to allocate
1028 // a clone to snapshot the logically written state.
1029 w
.cw
.header
= w
.handlerHeader
.clone()
1031 w
.calledHeader
= true
1032 return w
.handlerHeader
1035 // maxPostHandlerReadBytes is the max number of Request.Body bytes not
1036 // consumed by a handler that the server will read from the client
1037 // in order to keep a connection alive. If there are more bytes than
1038 // this then the server to be paranoid instead sends a "Connection:
1041 // This number is approximately what a typical machine's TCP buffer
1042 // size is anyway. (if we have the bytes on the machine, we might as
1044 const maxPostHandlerReadBytes
= 256 << 10
1046 func (w
*response
) WriteHeader(code
int) {
1047 if w
.conn
.hijacked() {
1048 w
.conn
.server
.logf("http: response.WriteHeader on hijacked connection")
1052 w
.conn
.server
.logf("http: multiple response.WriteHeader calls")
1055 w
.wroteHeader
= true
1058 if w
.calledHeader
&& w
.cw
.header
== nil {
1059 w
.cw
.header
= w
.handlerHeader
.clone()
1062 if cl
:= w
.handlerHeader
.get("Content-Length"); cl
!= "" {
1063 v
, err
:= strconv
.ParseInt(cl
, 10, 64)
1064 if err
== nil && v
>= 0 {
1067 w
.conn
.server
.logf("http: invalid Content-Length of %q", cl
)
1068 w
.handlerHeader
.Del("Content-Length")
1073 // extraHeader is the set of headers sometimes added by chunkWriter.writeHeader.
1074 // This type is used to avoid extra allocations from cloning and/or populating
1075 // the response Header map and all its 1-element slices.
1076 type extraHeader
struct {
1079 transferEncoding
string
1080 date
[]byte // written if not nil
1081 contentLength
[]byte // written if not nil
1084 // Sorted the same as extraHeader.Write's loop.
1085 var extraHeaderKeys
= [][]byte{
1086 []byte("Content-Type"),
1087 []byte("Connection"),
1088 []byte("Transfer-Encoding"),
1092 headerContentLength
= []byte("Content-Length: ")
1093 headerDate
= []byte("Date: ")
1096 // Write writes the headers described in h to w.
1098 // This method has a value receiver, despite the somewhat large size
1099 // of h, because it prevents an allocation. The escape analysis isn't
1100 // smart enough to realize this function doesn't mutate h.
1101 func (h extraHeader
) Write(w
*bufio
.Writer
) {
1107 if h
.contentLength
!= nil {
1108 w
.Write(headerContentLength
)
1109 w
.Write(h
.contentLength
)
1112 for i
, v
:= range []string{h
.contentType
, h
.connection
, h
.transferEncoding
} {
1114 w
.Write(extraHeaderKeys
[i
])
1122 // writeHeader finalizes the header sent to the client and writes it
1123 // to cw.res.conn.bufw.
1125 // p is not written by writeHeader, but is the first chunk of the body
1126 // that will be written. It is sniffed for a Content-Type if none is
1127 // set explicitly. It's also used to set the Content-Length, if the
1128 // total body size was small and the handler has already finished
1130 func (cw
*chunkWriter
) writeHeader(p
[]byte) {
1134 cw
.wroteHeader
= true
1137 keepAlivesEnabled
:= w
.conn
.server
.doKeepAlives()
1138 isHEAD
:= w
.req
.Method
== "HEAD"
1140 // header is written out to w.conn.buf below. Depending on the
1141 // state of the handler, we either own the map or not. If we
1142 // don't own it, the exclude map is created lazily for
1143 // WriteSubset to remove headers. The setHeader struct holds
1144 // headers we need to add.
1146 owned
:= header
!= nil
1148 header
= w
.handlerHeader
1150 var excludeHeader
map[string]bool
1151 delHeader
:= func(key
string) {
1156 if _
, ok
:= header
[key
]; !ok
{
1159 if excludeHeader
== nil {
1160 excludeHeader
= make(map[string]bool)
1162 excludeHeader
[key
] = true
1164 var setHeader extraHeader
1166 // Don't write out the fake "Trailer:foo" keys. See TrailerPrefix.
1168 for k
:= range cw
.header
{
1169 if strings
.HasPrefix(k
, TrailerPrefix
) {
1170 if excludeHeader
== nil {
1171 excludeHeader
= make(map[string]bool)
1173 excludeHeader
[k
] = true
1177 for _
, v
:= range cw
.header
["Trailer"] {
1179 foreachHeaderElement(v
, cw
.res
.declareTrailer
)
1182 te
:= header
.get("Transfer-Encoding")
1185 // If the handler is done but never sent a Content-Length
1186 // response header and this is our first (and last) write, set
1187 // it, even to zero. This helps HTTP/1.0 clients keep their
1188 // "keep-alive" connections alive.
1189 // Exceptions: 304/204/1xx responses never get Content-Length, and if
1190 // it was a HEAD request, we don't know the difference between
1191 // 0 actual bytes and 0 bytes because the handler noticed it
1192 // was a HEAD request and chose not to write anything. So for
1193 // HEAD, the handler should either write the Content-Length or
1194 // write non-zero bytes. If it's actually 0 bytes and the
1195 // handler never looked at the Request.Method, we just don't
1196 // send a Content-Length header.
1197 // Further, we don't send an automatic Content-Length if they
1198 // set a Transfer-Encoding, because they're generally incompatible.
1199 if w
.handlerDone
.isSet() && !trailers
&& !hasTE
&& bodyAllowedForStatus(w
.status
) && header
.get("Content-Length") == "" && (!isHEAD ||
len(p
) > 0) {
1200 w
.contentLength
= int64(len(p
))
1201 setHeader
.contentLength
= strconv
.AppendInt(cw
.res
.clenBuf
[:0], int64(len(p
)), 10)
1204 // If this was an HTTP/1.0 request with keep-alive and we sent a
1205 // Content-Length back, we can make this a keep-alive response ...
1206 if w
.wants10KeepAlive
&& keepAlivesEnabled
{
1207 sentLength
:= header
.get("Content-Length") != ""
1208 if sentLength
&& header
.get("Connection") == "keep-alive" {
1209 w
.closeAfterReply
= false
1213 // Check for a explicit (and valid) Content-Length header.
1214 hasCL
:= w
.contentLength
!= -1
1216 if w
.wants10KeepAlive
&& (isHEAD || hasCL ||
!bodyAllowedForStatus(w
.status
)) {
1217 _
, connectionHeaderSet
:= header
["Connection"]
1218 if !connectionHeaderSet
{
1219 setHeader
.connection
= "keep-alive"
1221 } else if !w
.req
.ProtoAtLeast(1, 1) || w
.wantsClose
{
1222 w
.closeAfterReply
= true
1225 if header
.get("Connection") == "close" ||
!keepAlivesEnabled
{
1226 w
.closeAfterReply
= true
1229 // If the client wanted a 100-continue but we never sent it to
1230 // them (or, more strictly: we never finished reading their
1231 // request body), don't reuse this connection because it's now
1232 // in an unknown state: we might be sending this response at
1233 // the same time the client is now sending its request body
1234 // after a timeout. (Some HTTP clients send Expect:
1235 // 100-continue but knowing that some servers don't support
1236 // it, the clients set a timer and send the body later anyway)
1237 // If we haven't seen EOF, we can't skip over the unread body
1238 // because we don't know if the next bytes on the wire will be
1239 // the body-following-the-timer or the subsequent request.
1241 if ecr
, ok
:= w
.req
.Body
.(*expectContinueReader
); ok
&& !ecr
.sawEOF
{
1242 w
.closeAfterReply
= true
1245 // Per RFC 2616, we should consume the request body before
1246 // replying, if the handler hasn't already done so. But we
1247 // don't want to do an unbounded amount of reading here for
1248 // DoS reasons, so we only try up to a threshold.
1249 // TODO(bradfitz): where does RFC 2616 say that? See Issue 15527
1250 // about HTTP/1.x Handlers concurrently reading and writing, like
1251 // HTTP/2 handlers can do. Maybe this code should be relaxed?
1252 if w
.req
.ContentLength
!= 0 && !w
.closeAfterReply
{
1253 var discard
, tooBig
bool
1255 switch bdy
:= w
.req
.Body
.(type) {
1256 case *expectContinueReader
:
1257 if bdy
.resp
.wroteContinue
{
1265 // Body was closed in handler with non-EOF error.
1266 w
.closeAfterReply
= true
1268 case bdy
.unreadDataSizeLocked() >= maxPostHandlerReadBytes
:
1279 _
, err
:= io
.CopyN(ioutil
.Discard
, w
.reqBody
, maxPostHandlerReadBytes
+1)
1282 // There must be even more data left over.
1284 case ErrBodyReadAfterClose
:
1285 // Body was already consumed and closed.
1287 // The remaining body was just consumed, close it.
1288 err
= w
.reqBody
.Close()
1290 w
.closeAfterReply
= true
1293 // Some other kind of error occurred, like a read timeout, or
1294 // corrupt chunked encoding. In any case, whatever remains
1295 // on the wire must not be parsed as another HTTP request.
1296 w
.closeAfterReply
= true
1302 delHeader("Connection")
1303 setHeader
.connection
= "close"
1308 if bodyAllowedForStatus(code
) {
1309 // If no content type, apply sniffing algorithm to body.
1310 _
, haveType
:= header
["Content-Type"]
1311 if !haveType
&& !hasTE
{
1312 setHeader
.contentType
= DetectContentType(p
)
1315 for _
, k
:= range suppressedHeaders(code
) {
1320 if _
, ok
:= header
["Date"]; !ok
{
1321 setHeader
.date
= appendTime(cw
.res
.dateBuf
[:0], time
.Now())
1324 if hasCL
&& hasTE
&& te
!= "identity" {
1325 // TODO: return an error if WriteHeader gets a return parameter
1326 // For now just ignore the Content-Length.
1327 w
.conn
.server
.logf("http: WriteHeader called with both Transfer-Encoding of %q and a Content-Length of %d",
1328 te
, w
.contentLength
)
1329 delHeader("Content-Length")
1333 if w
.req
.Method
== "HEAD" ||
!bodyAllowedForStatus(code
) {
1335 } else if code
== StatusNoContent
{
1336 delHeader("Transfer-Encoding")
1338 delHeader("Transfer-Encoding")
1339 } else if w
.req
.ProtoAtLeast(1, 1) {
1340 // HTTP/1.1 or greater: Transfer-Encoding has been set to identity, and no
1341 // content-length has been provided. The connection must be closed after the
1342 // reply is written, and no chunking is to be done. This is the setup
1343 // recommended in the Server-Sent Events candidate recommendation 11,
1345 if hasTE
&& te
== "identity" {
1347 w
.closeAfterReply
= true
1349 // HTTP/1.1 or greater: use chunked transfer encoding
1350 // to avoid closing the connection at EOF.
1352 setHeader
.transferEncoding
= "chunked"
1353 if hasTE
&& te
== "chunked" {
1354 // We will send the chunked Transfer-Encoding header later.
1355 delHeader("Transfer-Encoding")
1359 // HTTP version < 1.1: cannot do chunked transfer
1360 // encoding and we don't know the Content-Length so
1361 // signal EOF by closing connection.
1362 w
.closeAfterReply
= true
1363 delHeader("Transfer-Encoding") // in case already set
1366 // Cannot use Content-Length with non-identity Transfer-Encoding.
1368 delHeader("Content-Length")
1370 if !w
.req
.ProtoAtLeast(1, 0) {
1374 if w
.closeAfterReply
&& (!keepAlivesEnabled ||
!hasToken(cw
.header
.get("Connection"), "close")) {
1375 delHeader("Connection")
1376 if w
.req
.ProtoAtLeast(1, 1) {
1377 setHeader
.connection
= "close"
1381 writeStatusLine(w
.conn
.bufw
, w
.req
.ProtoAtLeast(1, 1), code
, w
.statusBuf
[:])
1382 cw
.header
.WriteSubset(w
.conn
.bufw
, excludeHeader
)
1383 setHeader
.Write(w
.conn
.bufw
)
1384 w
.conn
.bufw
.Write(crlf
)
1387 // foreachHeaderElement splits v according to the "#rule" construction
1388 // in RFC 2616 section 2.1 and calls fn for each non-empty element.
1389 func foreachHeaderElement(v
string, fn
func(string)) {
1390 v
= textproto
.TrimString(v
)
1394 if !strings
.Contains(v
, ",") {
1398 for _
, f
:= range strings
.Split(v
, ",") {
1399 if f
= textproto
.TrimString(f
); f
!= "" {
1405 // writeStatusLine writes an HTTP/1.x Status-Line (RFC 2616 Section 6.1)
1406 // to bw. is11 is whether the HTTP request is HTTP/1.1. false means HTTP/1.0.
1407 // code is the response status code.
1408 // scratch is an optional scratch buffer. If it has at least capacity 3, it's used.
1409 func writeStatusLine(bw
*bufio
.Writer
, is11
bool, code
int, scratch
[]byte) {
1411 bw
.WriteString("HTTP/1.1 ")
1413 bw
.WriteString("HTTP/1.0 ")
1415 if text
, ok
:= statusText
[code
]; ok
{
1416 bw
.Write(strconv
.AppendInt(scratch
[:0], int64(code
), 10))
1418 bw
.WriteString(text
)
1419 bw
.WriteString("\r\n")
1421 // don't worry about performance
1422 fmt
.Fprintf(bw
, "%03d status code %d\r\n", code
, code
)
1426 // bodyAllowed reports whether a Write is allowed for this response type.
1427 // It's illegal to call this before the header has been flushed.
1428 func (w
*response
) bodyAllowed() bool {
1432 return bodyAllowedForStatus(w
.status
)
1435 // The Life Of A Write is like this:
1437 // Handler starts. No header has been sent. The handler can either
1438 // write a header, or just start writing. Writing before sending a header
1439 // sends an implicitly empty 200 OK header.
1441 // If the handler didn't declare a Content-Length up front, we either
1442 // go into chunking mode or, if the handler finishes running before
1443 // the chunking buffer size, we compute a Content-Length and send that
1444 // in the header instead.
1446 // Likewise, if the handler didn't set a Content-Type, we sniff that
1447 // from the initial chunk of output.
1449 // The Writers are wired together like:
1451 // 1. *response (the ResponseWriter) ->
1452 // 2. (*response).w, a *bufio.Writer of bufferBeforeChunkingSize bytes
1453 // 3. chunkWriter.Writer (whose writeHeader finalizes Content-Length/Type)
1454 // and which writes the chunk headers, if needed.
1455 // 4. conn.buf, a bufio.Writer of default (4kB) bytes, writing to ->
1456 // 5. checkConnErrorWriter{c}, which notes any non-nil error on Write
1457 // and populates c.werr with it if so. but otherwise writes to:
1458 // 6. the rwc, the net.Conn.
1460 // TODO(bradfitz): short-circuit some of the buffering when the
1461 // initial header contains both a Content-Type and Content-Length.
1462 // Also short-circuit in (1) when the header's been sent and not in
1463 // chunking mode, writing directly to (4) instead, if (2) has no
1464 // buffered data. More generally, we could short-circuit from (1) to
1465 // (3) even in chunking mode if the write size from (1) is over some
1466 // threshold and nothing is in (2). The answer might be mostly making
1467 // bufferBeforeChunkingSize smaller and having bufio's fast-paths deal
1468 // with this instead.
1469 func (w
*response
) Write(data
[]byte) (n
int, err error
) {
1470 return w
.write(len(data
), data
, "")
1473 func (w
*response
) WriteString(data
string) (n
int, err error
) {
1474 return w
.write(len(data
), nil, data
)
1477 // either dataB or dataS is non-zero.
1478 func (w
*response
) write(lenData
int, dataB
[]byte, dataS
string) (n
int, err error
) {
1479 if w
.conn
.hijacked() {
1481 w
.conn
.server
.logf("http: response.Write on hijacked connection")
1483 return 0, ErrHijacked
1486 w
.WriteHeader(StatusOK
)
1491 if !w
.bodyAllowed() {
1492 return 0, ErrBodyNotAllowed
1495 w
.written
+= int64(lenData
) // ignoring errors, for errorKludge
1496 if w
.contentLength
!= -1 && w
.written
> w
.contentLength
{
1497 return 0, ErrContentLength
1500 return w
.w
.Write(dataB
)
1502 return w
.w
.WriteString(dataS
)
1506 func (w
*response
) finishRequest() {
1507 w
.handlerDone
.setTrue()
1510 w
.WriteHeader(StatusOK
)
1518 w
.conn
.r
.abortPendingRead()
1520 // Close the body (regardless of w.closeAfterReply) so we can
1521 // re-use its bufio.Reader later safely.
1524 if w
.req
.MultipartForm
!= nil {
1525 w
.req
.MultipartForm
.RemoveAll()
1529 // shouldReuseConnection reports whether the underlying TCP connection can be reused.
1530 // It must only be called after the handler is done executing.
1531 func (w
*response
) shouldReuseConnection() bool {
1532 if w
.closeAfterReply
{
1533 // The request or something set while executing the
1534 // handler indicated we shouldn't reuse this
1539 if w
.req
.Method
!= "HEAD" && w
.contentLength
!= -1 && w
.bodyAllowed() && w
.contentLength
!= w
.written
{
1540 // Did not write enough. Avoid getting out of sync.
1544 // There was some error writing to the underlying connection
1545 // during the request, so don't re-use this conn.
1546 if w
.conn
.werr
!= nil {
1550 if w
.closedRequestBodyEarly() {
1557 func (w
*response
) closedRequestBodyEarly() bool {
1558 body
, ok
:= w
.req
.Body
.(*body
)
1559 return ok
&& body
.didEarlyClose()
1562 func (w
*response
) Flush() {
1564 w
.WriteHeader(StatusOK
)
1570 func (c
*conn
) finalFlush() {
1572 // Steal the bufio.Reader (~4KB worth of memory) and its associated
1573 // reader for a future connection.
1574 putBufioReader(c
.bufr
)
1580 // Steal the bufio.Writer (~4KB worth of memory) and its associated
1581 // writer for a future connection.
1582 putBufioWriter(c
.bufw
)
1587 // Close the connection.
1588 func (c
*conn
) close() {
1593 // rstAvoidanceDelay is the amount of time we sleep after closing the
1594 // write side of a TCP connection before closing the entire socket.
1595 // By sleeping, we increase the chances that the client sees our FIN
1596 // and processes its final data before they process the subsequent RST
1597 // from closing a connection with known unread data.
1598 // This RST seems to occur mostly on BSD systems. (And Windows?)
1599 // This timeout is somewhat arbitrary (~latency around the planet).
1600 const rstAvoidanceDelay
= 500 * time
.Millisecond
1602 type closeWriter
interface {
1606 var _ closeWriter
= (*net
.TCPConn
)(nil)
1608 // closeWrite flushes any outstanding data and sends a FIN packet (if
1609 // client is connected via TCP), signalling that we're done. We then
1610 // pause for a bit, hoping the client processes it before any
1613 // See https://golang.org/issue/3595
1614 func (c
*conn
) closeWriteAndWait() {
1616 if tcp
, ok
:= c
.rwc
.(closeWriter
); ok
{
1619 time
.Sleep(rstAvoidanceDelay
)
1622 // validNPN reports whether the proto is not a blacklisted Next
1623 // Protocol Negotiation protocol. Empty and built-in protocol types
1624 // are blacklisted and can't be overridden with alternate
1626 func validNPN(proto
string) bool {
1628 case "", "http/1.1", "http/1.0":
1634 func (c
*conn
) setState(nc net
.Conn
, state ConnState
) {
1638 srv
.trackConn(c
, true)
1639 case StateHijacked
, StateClosed
:
1640 srv
.trackConn(c
, false)
1642 c
.curState
.Store(connStateInterface
[state
])
1643 if hook
:= srv
.ConnState
; hook
!= nil {
1648 // connStateInterface is an array of the interface{} versions of
1649 // ConnState values, so we can use them in atomic.Values later without
1650 // paying the cost of shoving their integers in an interface{}.
1651 var connStateInterface
= [...]interface{}{
1653 StateActive
: StateActive
,
1654 StateIdle
: StateIdle
,
1655 StateHijacked
: StateHijacked
,
1656 StateClosed
: StateClosed
,
1659 // badRequestError is a literal string (used by in the server in HTML,
1660 // unescaped) to tell the user why their request was bad. It should
1661 // be plain text without user info or other embedded errors.
1662 type badRequestError
string
1664 func (e badRequestError
) Error() string { return "Bad Request: " + string(e
) }
1666 // ErrAbortHandler is a sentinel panic value to abort a handler.
1667 // While any panic from ServeHTTP aborts the response to the client,
1668 // panicking with ErrAbortHandler also suppresses logging of a stack
1669 // trace to the server's error log.
1670 var ErrAbortHandler
= errors
.New("net/http: abort Handler")
1672 // isCommonNetReadError reports whether err is a common error
1673 // encountered during reading a request off the network when the
1674 // client has gone away or had its read fail somehow. This is used to
1675 // determine which logs are interesting enough to log about.
1676 func isCommonNetReadError(err error
) bool {
1680 if neterr
, ok
:= err
.(net
.Error
); ok
&& neterr
.Timeout() {
1683 if oe
, ok
:= err
.(*net
.OpError
); ok
&& oe
.Op
== "read" {
1689 // Serve a new connection.
1690 func (c
*conn
) serve(ctx context
.Context
) {
1691 c
.remoteAddr
= c
.rwc
.RemoteAddr().String()
1692 ctx
= context
.WithValue(ctx
, LocalAddrContextKey
, c
.rwc
.LocalAddr())
1694 if err
:= recover(); err
!= nil && err
!= ErrAbortHandler
{
1695 const size
= 64 << 10
1696 buf
:= make([]byte, size
)
1697 buf
= buf
[:runtime
.Stack(buf
, false)]
1698 c
.server
.logf("http: panic serving %v: %v\n%s", c
.remoteAddr
, err
, buf
)
1702 c
.setState(c
.rwc
, StateClosed
)
1706 if tlsConn
, ok
:= c
.rwc
.(*tls
.Conn
); ok
{
1707 if d
:= c
.server
.ReadTimeout
; d
!= 0 {
1708 c
.rwc
.SetReadDeadline(time
.Now().Add(d
))
1710 if d
:= c
.server
.WriteTimeout
; d
!= 0 {
1711 c
.rwc
.SetWriteDeadline(time
.Now().Add(d
))
1713 if err
:= tlsConn
.Handshake(); err
!= nil {
1714 c
.server
.logf("http: TLS handshake error from %s: %v", c
.rwc
.RemoteAddr(), err
)
1717 c
.tlsState
= new(tls
.ConnectionState
)
1718 *c
.tlsState
= tlsConn
.ConnectionState()
1719 if proto
:= c
.tlsState
.NegotiatedProtocol
; validNPN(proto
) {
1720 if fn
:= c
.server
.TLSNextProto
[proto
]; fn
!= nil {
1721 h
:= initNPNRequest
{tlsConn
, serverHandler
{c
.server
}}
1722 fn(c
.server
, tlsConn
, h
)
1728 // HTTP/1.x from here on.
1730 ctx
, cancelCtx
:= context
.WithCancel(ctx
)
1731 c
.cancelCtx
= cancelCtx
1734 c
.r
= &connReader
{conn
: c
}
1735 c
.bufr
= newBufioReader(c
.r
)
1736 c
.bufw
= newBufioWriterSize(checkConnErrorWriter
{c
}, 4<<10)
1739 w
, err
:= c
.readRequest(ctx
)
1740 if c
.r
.remain
!= c
.server
.initialReadLimitSize() {
1741 // If we read any bytes off the wire, we're active.
1742 c
.setState(c
.rwc
, StateActive
)
1745 const errorHeaders
= "\r\nContent-Type: text/plain; charset=utf-8\r\nConnection: close\r\n\r\n"
1747 if err
== errTooLarge
{
1748 // Their HTTP client may or may not be
1749 // able to read this if we're
1750 // responding to them and hanging up
1751 // while they're still writing their
1752 // request. Undefined behavior.
1753 const publicErr
= "431 Request Header Fields Too Large"
1754 fmt
.Fprintf(c
.rwc
, "HTTP/1.1 "+publicErr
+errorHeaders
+publicErr
)
1755 c
.closeWriteAndWait()
1758 if isCommonNetReadError(err
) {
1759 return // don't reply
1762 publicErr
:= "400 Bad Request"
1763 if v
, ok
:= err
.(badRequestError
); ok
{
1764 publicErr
= publicErr
+ ": " + string(v
)
1767 fmt
.Fprintf(c
.rwc
, "HTTP/1.1 "+publicErr
+errorHeaders
+publicErr
)
1771 // Expect 100 Continue support
1773 if req
.expectsContinue() {
1774 if req
.ProtoAtLeast(1, 1) && req
.ContentLength
!= 0 {
1775 // Wrap the Body reader with one that replies on the connection
1776 req
.Body
= &expectContinueReader
{readCloser
: req
.Body
, resp
: w
}
1778 } else if req
.Header
.get("Expect") != "" {
1779 w
.sendExpectationFailed()
1785 if requestBodyRemains(req
.Body
) {
1786 registerOnHitEOF(req
.Body
, w
.conn
.r
.startBackgroundRead
)
1788 if w
.conn
.bufr
.Buffered() > 0 {
1789 w
.conn
.r
.closeNotifyFromPipelinedRequest()
1791 w
.conn
.r
.startBackgroundRead()
1794 // HTTP cannot have multiple simultaneous active requests.[*]
1795 // Until the server replies to this request, it can't read another,
1796 // so we might as well run the handler in this goroutine.
1797 // [*] Not strictly true: HTTP pipelining. We could let them all process
1798 // in parallel even if their responses need to be serialized.
1799 // But we're not going to implement HTTP pipelining because it
1800 // was never deployed in the wild and the answer is HTTP/2.
1801 serverHandler
{c
.server
}.ServeHTTP(w
, w
.req
)
1807 if !w
.shouldReuseConnection() {
1808 if w
.requestBodyLimitHit || w
.closedRequestBodyEarly() {
1809 c
.closeWriteAndWait()
1813 c
.setState(c
.rwc
, StateIdle
)
1814 c
.curReq
.Store((*response
)(nil))
1816 if !w
.conn
.server
.doKeepAlives() {
1817 // We're in shutdown mode. We might've replied
1818 // to the user without "Connection: close" and
1819 // they might think they can send another
1820 // request, but such is life with HTTP/1.1.
1824 if d
:= c
.server
.idleTimeout(); d
!= 0 {
1825 c
.rwc
.SetReadDeadline(time
.Now().Add(d
))
1826 if _
, err
:= c
.bufr
.Peek(4); err
!= nil {
1830 c
.rwc
.SetReadDeadline(time
.Time
{})
1834 func (w
*response
) sendExpectationFailed() {
1835 // TODO(bradfitz): let ServeHTTP handlers handle
1836 // requests with non-standard expectation[s]? Seems
1837 // theoretical at best, and doesn't fit into the
1838 // current ServeHTTP model anyway. We'd need to
1839 // make the ResponseWriter an optional
1840 // "ExpectReplier" interface or something.
1842 // For now we'll just obey RFC 2616 14.20 which says
1843 // "If a server receives a request containing an
1844 // Expect field that includes an expectation-
1845 // extension that it does not support, it MUST
1846 // respond with a 417 (Expectation Failed) status."
1847 w
.Header().Set("Connection", "close")
1848 w
.WriteHeader(StatusExpectationFailed
)
1852 // Hijack implements the Hijacker.Hijack method. Our response is both a ResponseWriter
1854 func (w
*response
) Hijack() (rwc net
.Conn
, buf
*bufio
.ReadWriter
, err error
) {
1855 if w
.handlerDone
.isSet() {
1856 panic("net/http: Hijack called after ServeHTTP finished")
1866 // Release the bufioWriter that writes to the chunk writer, it is not
1867 // used after a connection has been hijacked.
1868 rwc
, buf
, err
= c
.hijackLocked()
1873 return rwc
, buf
, err
1876 func (w
*response
) CloseNotify() <-chan bool {
1877 if w
.handlerDone
.isSet() {
1878 panic("net/http: CloseNotify called after ServeHTTP finished")
1880 return w
.closeNotifyCh
1883 func registerOnHitEOF(rc io
.ReadCloser
, fn
func()) {
1884 switch v
:= rc
.(type) {
1885 case *expectContinueReader
:
1886 registerOnHitEOF(v
.readCloser
, fn
)
1888 v
.registerOnHitEOF(fn
)
1890 panic("unexpected type " + fmt
.Sprintf("%T", rc
))
1894 // requestBodyRemains reports whether future calls to Read
1895 // on rc might yield more data.
1896 func requestBodyRemains(rc io
.ReadCloser
) bool {
1900 switch v
:= rc
.(type) {
1901 case *expectContinueReader
:
1902 return requestBodyRemains(v
.readCloser
)
1904 return v
.bodyRemains()
1906 panic("unexpected type " + fmt
.Sprintf("%T", rc
))
1910 // The HandlerFunc type is an adapter to allow the use of
1911 // ordinary functions as HTTP handlers. If f is a function
1912 // with the appropriate signature, HandlerFunc(f) is a
1913 // Handler that calls f.
1914 type HandlerFunc
func(ResponseWriter
, *Request
)
1916 // ServeHTTP calls f(w, r).
1917 func (f HandlerFunc
) ServeHTTP(w ResponseWriter
, r
*Request
) {
1923 // Error replies to the request with the specified error message and HTTP code.
1924 // It does not otherwise end the request; the caller should ensure no further
1925 // writes are done to w.
1926 // The error message should be plain text.
1927 func Error(w ResponseWriter
, error
string, code
int) {
1928 w
.Header().Set("Content-Type", "text/plain; charset=utf-8")
1929 w
.Header().Set("X-Content-Type-Options", "nosniff")
1931 fmt
.Fprintln(w
, error
)
1934 // NotFound replies to the request with an HTTP 404 not found error.
1935 func NotFound(w ResponseWriter
, r
*Request
) { Error(w
, "404 page not found", StatusNotFound
) }
1937 // NotFoundHandler returns a simple request handler
1938 // that replies to each request with a ``404 page not found'' reply.
1939 func NotFoundHandler() Handler
{ return HandlerFunc(NotFound
) }
1941 // StripPrefix returns a handler that serves HTTP requests
1942 // by removing the given prefix from the request URL's Path
1943 // and invoking the handler h. StripPrefix handles a
1944 // request for a path that doesn't begin with prefix by
1945 // replying with an HTTP 404 not found error.
1946 func StripPrefix(prefix
string, h Handler
) Handler
{
1950 return HandlerFunc(func(w ResponseWriter
, r
*Request
) {
1951 if p
:= strings
.TrimPrefix(r
.URL
.Path
, prefix
); len(p
) < len(r
.URL
.Path
) {
1954 r2
.URL
= new(url
.URL
)
1964 // Redirect replies to the request with a redirect to url,
1965 // which may be a path relative to the request path.
1967 // The provided code should be in the 3xx range and is usually
1968 // StatusMovedPermanently, StatusFound or StatusSeeOther.
1969 func Redirect(w ResponseWriter
, r
*Request
, url
string, code
int) {
1970 // parseURL is just url.Parse (url is shadowed for godoc).
1971 if u
, err
:= parseURL(url
); err
== nil {
1972 // If url was relative, make absolute by
1973 // combining with request path.
1974 // The browser would probably do this for us,
1975 // but doing it ourselves is more reliable.
1977 // NOTE(rsc): RFC 2616 says that the Location
1978 // line must be an absolute URI, like
1979 // "http://www.google.com/redirect/",
1980 // not a path like "/redirect/".
1981 // Unfortunately, we don't know what to
1982 // put in the host name section to get the
1983 // client to connect to us again, so we can't
1984 // know the right absolute URI to send back.
1985 // Because of this problem, no one pays attention
1986 // to the RFC; they all send back just a new path.
1988 if u
.Scheme
== "" && u
.Host
== "" {
1989 oldpath
:= r
.URL
.Path
1990 if oldpath
== "" { // should not happen, but avoid a crash if it does
1994 // no leading http://server
1995 if url
== "" || url
[0] != '/' {
1996 // make relative path absolute
1997 olddir
, _
:= path
.Split(oldpath
)
2002 if i
:= strings
.Index(url
, "?"); i
!= -1 {
2003 url
, query
= url
[:i
], url
[i
:]
2006 // clean up but preserve trailing slash
2007 trailing
:= strings
.HasSuffix(url
, "/")
2008 url
= path
.Clean(url
)
2009 if trailing
&& !strings
.HasSuffix(url
, "/") {
2016 w
.Header().Set("Location", hexEscapeNonASCII(url
))
2019 // RFC 2616 recommends that a short note "SHOULD" be included in the
2020 // response because older user agents may not understand 301/307.
2021 // Shouldn't send the response for POST or HEAD; that leaves GET.
2022 if r
.Method
== "GET" {
2023 note
:= "<a href=\"" + htmlEscape(url
) + "\">" + statusText
[code
] + "</a>.\n"
2024 fmt
.Fprintln(w
, note
)
2028 // parseURL is just url.Parse. It exists only so that url.Parse can be called
2029 // in places where url is shadowed for godoc. See https://golang.org/cl/49930.
2030 var parseURL
= url
.Parse
2032 var htmlReplacer
= strings
.NewReplacer(
2036 // """ is shorter than """.
2038 // "'" is shorter than "'" and apos was not in HTML until HTML5.
2042 func htmlEscape(s
string) string {
2043 return htmlReplacer
.Replace(s
)
2046 // Redirect to a fixed URL
2047 type redirectHandler
struct {
2052 func (rh
*redirectHandler
) ServeHTTP(w ResponseWriter
, r
*Request
) {
2053 Redirect(w
, r
, rh
.url
, rh
.code
)
2056 // RedirectHandler returns a request handler that redirects
2057 // each request it receives to the given url using the given
2060 // The provided code should be in the 3xx range and is usually
2061 // StatusMovedPermanently, StatusFound or StatusSeeOther.
2062 func RedirectHandler(url
string, code
int) Handler
{
2063 return &redirectHandler
{url
, code
}
2066 // ServeMux is an HTTP request multiplexer.
2067 // It matches the URL of each incoming request against a list of registered
2068 // patterns and calls the handler for the pattern that
2069 // most closely matches the URL.
2071 // Patterns name fixed, rooted paths, like "/favicon.ico",
2072 // or rooted subtrees, like "/images/" (note the trailing slash).
2073 // Longer patterns take precedence over shorter ones, so that
2074 // if there are handlers registered for both "/images/"
2075 // and "/images/thumbnails/", the latter handler will be
2076 // called for paths beginning "/images/thumbnails/" and the
2077 // former will receive requests for any other paths in the
2078 // "/images/" subtree.
2080 // Note that since a pattern ending in a slash names a rooted subtree,
2081 // the pattern "/" matches all paths not matched by other registered
2082 // patterns, not just the URL with Path == "/".
2084 // If a subtree has been registered and a request is received naming the
2085 // subtree root without its trailing slash, ServeMux redirects that
2086 // request to the subtree root (adding the trailing slash). This behavior can
2087 // be overridden with a separate registration for the path without
2088 // the trailing slash. For example, registering "/images/" causes ServeMux
2089 // to redirect a request for "/images" to "/images/", unless "/images" has
2090 // been registered separately.
2092 // Patterns may optionally begin with a host name, restricting matches to
2093 // URLs on that host only. Host-specific patterns take precedence over
2094 // general patterns, so that a handler might register for the two patterns
2095 // "/codesearch" and "codesearch.google.com/" without also taking over
2096 // requests for "http://www.google.com/".
2098 // ServeMux also takes care of sanitizing the URL request path,
2099 // redirecting any request containing . or .. elements or repeated slashes
2100 // to an equivalent, cleaner URL.
2101 type ServeMux
struct {
2103 m
map[string]muxEntry
2104 hosts
bool // whether any patterns contain hostnames
2107 type muxEntry
struct {
2113 // NewServeMux allocates and returns a new ServeMux.
2114 func NewServeMux() *ServeMux
{ return new(ServeMux
) }
2116 // DefaultServeMux is the default ServeMux used by Serve.
2117 var DefaultServeMux
= &defaultServeMux
2119 var defaultServeMux ServeMux
2121 // Does path match pattern?
2122 func pathMatch(pattern
, path
string) bool {
2123 if len(pattern
) == 0 {
2124 // should not happen
2128 if pattern
[n
-1] != '/' {
2129 return pattern
== path
2131 return len(path
) >= n
&& path
[0:n
] == pattern
2134 // Return the canonical path for p, eliminating . and .. elements.
2135 func cleanPath(p
string) string {
2143 // path.Clean removes trailing slash except for root;
2144 // put the trailing slash back if necessary.
2145 if p
[len(p
)-1] == '/' && np
!= "/" {
2151 // stripHostPort returns h without any trailing ":<port>".
2152 func stripHostPort(h
string) string {
2153 // If no port on host, return unchanged
2154 if strings
.IndexByte(h
, ':') == -1 {
2157 host
, _
, err
:= net
.SplitHostPort(h
)
2159 return h
// on error, return unchanged
2164 // Find a handler on a handler map given a path string.
2165 // Most-specific (longest) pattern wins.
2166 func (mux
*ServeMux
) match(path
string) (h Handler
, pattern
string) {
2167 // Check for exact match first.
2168 v
, ok
:= mux
.m
[path
]
2170 return v
.h
, v
.pattern
2173 // Check for longest valid match.
2175 for k
, v
:= range mux
.m
{
2176 if !pathMatch(k
, path
) {
2179 if h
== nil ||
len(k
) > n
{
2188 // Handler returns the handler to use for the given request,
2189 // consulting r.Method, r.Host, and r.URL.Path. It always returns
2190 // a non-nil handler. If the path is not in its canonical form, the
2191 // handler will be an internally-generated handler that redirects
2192 // to the canonical path. If the host contains a port, it is ignored
2193 // when matching handlers.
2195 // The path and host are used unchanged for CONNECT requests.
2197 // Handler also returns the registered pattern that matches the
2198 // request or, in the case of internally-generated redirects,
2199 // the pattern that will match after following the redirect.
2201 // If there is no registered handler that applies to the request,
2202 // Handler returns a ``page not found'' handler and an empty pattern.
2203 func (mux
*ServeMux
) Handler(r
*Request
) (h Handler
, pattern
string) {
2205 // CONNECT requests are not canonicalized.
2206 if r
.Method
== "CONNECT" {
2207 return mux
.handler(r
.Host
, r
.URL
.Path
)
2210 // All other requests have any port stripped and path cleaned
2211 // before passing to mux.handler.
2212 host
:= stripHostPort(r
.Host
)
2213 path
:= cleanPath(r
.URL
.Path
)
2214 if path
!= r
.URL
.Path
{
2215 _
, pattern
= mux
.handler(host
, path
)
2218 return RedirectHandler(url
.String(), StatusMovedPermanently
), pattern
2221 return mux
.handler(host
, r
.URL
.Path
)
2224 // handler is the main implementation of Handler.
2225 // The path is known to be in canonical form, except for CONNECT methods.
2226 func (mux
*ServeMux
) handler(host
, path
string) (h Handler
, pattern
string) {
2228 defer mux
.mu
.RUnlock()
2230 // Host-specific pattern takes precedence over generic ones
2232 h
, pattern
= mux
.match(host
+ path
)
2235 h
, pattern
= mux
.match(path
)
2238 h
, pattern
= NotFoundHandler(), ""
2243 // ServeHTTP dispatches the request to the handler whose
2244 // pattern most closely matches the request URL.
2245 func (mux
*ServeMux
) ServeHTTP(w ResponseWriter
, r
*Request
) {
2246 if r
.RequestURI
== "*" {
2247 if r
.ProtoAtLeast(1, 1) {
2248 w
.Header().Set("Connection", "close")
2250 w
.WriteHeader(StatusBadRequest
)
2253 h
, _
:= mux
.Handler(r
)
2257 // Handle registers the handler for the given pattern.
2258 // If a handler already exists for pattern, Handle panics.
2259 func (mux
*ServeMux
) Handle(pattern
string, handler Handler
) {
2261 defer mux
.mu
.Unlock()
2264 panic("http: invalid pattern " + pattern
)
2267 panic("http: nil handler")
2269 if mux
.m
[pattern
].explicit
{
2270 panic("http: multiple registrations for " + pattern
)
2274 mux
.m
= make(map[string]muxEntry
)
2276 mux
.m
[pattern
] = muxEntry
{explicit
: true, h
: handler
, pattern
: pattern
}
2278 if pattern
[0] != '/' {
2282 // Helpful behavior:
2283 // If pattern is /tree/, insert an implicit permanent redirect for /tree.
2284 // It can be overridden by an explicit registration.
2286 if n
> 0 && pattern
[n
-1] == '/' && !mux
.m
[pattern
[0:n
-1]].explicit
{
2287 // If pattern contains a host name, strip it and use remaining
2288 // path for redirect.
2290 if pattern
[0] != '/' {
2291 // In pattern, at least the last character is a '/', so
2292 // strings.Index can't be -1.
2293 path
= pattern
[strings
.Index(pattern
, "/"):]
2295 url
:= &url
.URL
{Path
: path
}
2296 mux
.m
[pattern
[0:n
-1]] = muxEntry
{h
: RedirectHandler(url
.String(), StatusMovedPermanently
), pattern
: pattern
}
2300 // HandleFunc registers the handler function for the given pattern.
2301 func (mux
*ServeMux
) HandleFunc(pattern
string, handler
func(ResponseWriter
, *Request
)) {
2302 mux
.Handle(pattern
, HandlerFunc(handler
))
2305 // Handle registers the handler for the given pattern
2306 // in the DefaultServeMux.
2307 // The documentation for ServeMux explains how patterns are matched.
2308 func Handle(pattern
string, handler Handler
) { DefaultServeMux
.Handle(pattern
, handler
) }
2310 // HandleFunc registers the handler function for the given pattern
2311 // in the DefaultServeMux.
2312 // The documentation for ServeMux explains how patterns are matched.
2313 func HandleFunc(pattern
string, handler
func(ResponseWriter
, *Request
)) {
2314 DefaultServeMux
.HandleFunc(pattern
, handler
)
2317 // Serve accepts incoming HTTP connections on the listener l,
2318 // creating a new service goroutine for each. The service goroutines
2319 // read requests and then call handler to reply to them.
2320 // Handler is typically nil, in which case the DefaultServeMux is used.
2321 func Serve(l net
.Listener
, handler Handler
) error
{
2322 srv
:= &Server
{Handler
: handler
}
2326 // Serve accepts incoming HTTPS connections on the listener l,
2327 // creating a new service goroutine for each. The service goroutines
2328 // read requests and then call handler to reply to them.
2330 // Handler is typically nil, in which case the DefaultServeMux is used.
2332 // Additionally, files containing a certificate and matching private key
2333 // for the server must be provided. If the certificate is signed by a
2334 // certificate authority, the certFile should be the concatenation
2335 // of the server's certificate, any intermediates, and the CA's certificate.
2336 func ServeTLS(l net
.Listener
, handler Handler
, certFile
, keyFile
string) error
{
2337 srv
:= &Server
{Handler
: handler
}
2338 return srv
.ServeTLS(l
, certFile
, keyFile
)
2341 // A Server defines parameters for running an HTTP server.
2342 // The zero value for Server is a valid configuration.
2343 type Server
struct {
2344 Addr
string // TCP address to listen on, ":http" if empty
2345 Handler Handler
// handler to invoke, http.DefaultServeMux if nil
2346 TLSConfig
*tls
.Config
// optional TLS config, used by ServeTLS and ListenAndServeTLS
2348 // ReadTimeout is the maximum duration for reading the entire
2349 // request, including the body.
2351 // Because ReadTimeout does not let Handlers make per-request
2352 // decisions on each request body's acceptable deadline or
2353 // upload rate, most users will prefer to use
2354 // ReadHeaderTimeout. It is valid to use them both.
2355 ReadTimeout time
.Duration
2357 // ReadHeaderTimeout is the amount of time allowed to read
2358 // request headers. The connection's read deadline is reset
2359 // after reading the headers and the Handler can decide what
2360 // is considered too slow for the body.
2361 ReadHeaderTimeout time
.Duration
2363 // WriteTimeout is the maximum duration before timing out
2364 // writes of the response. It is reset whenever a new
2365 // request's header is read. Like ReadTimeout, it does not
2366 // let Handlers make decisions on a per-request basis.
2367 WriteTimeout time
.Duration
2369 // IdleTimeout is the maximum amount of time to wait for the
2370 // next request when keep-alives are enabled. If IdleTimeout
2371 // is zero, the value of ReadTimeout is used. If both are
2372 // zero, ReadHeaderTimeout is used.
2373 IdleTimeout time
.Duration
2375 // MaxHeaderBytes controls the maximum number of bytes the
2376 // server will read parsing the request header's keys and
2377 // values, including the request line. It does not limit the
2378 // size of the request body.
2379 // If zero, DefaultMaxHeaderBytes is used.
2382 // TLSNextProto optionally specifies a function to take over
2383 // ownership of the provided TLS connection when an NPN/ALPN
2384 // protocol upgrade has occurred. The map key is the protocol
2385 // name negotiated. The Handler argument should be used to
2386 // handle HTTP requests and will initialize the Request's TLS
2387 // and RemoteAddr if not already set. The connection is
2388 // automatically closed when the function returns.
2389 // If TLSNextProto is not nil, HTTP/2 support is not enabled
2391 TLSNextProto
map[string]func(*Server
, *tls
.Conn
, Handler
)
2393 // ConnState specifies an optional callback function that is
2394 // called when a client connection changes state. See the
2395 // ConnState type and associated constants for details.
2396 ConnState
func(net
.Conn
, ConnState
)
2398 // ErrorLog specifies an optional logger for errors accepting
2399 // connections and unexpected behavior from handlers.
2400 // If nil, logging goes to os.Stderr via the log package's
2402 ErrorLog
*log
.Logger
2404 disableKeepAlives
int32 // accessed atomically.
2405 inShutdown
int32 // accessed atomically (non-zero means we're in Shutdown)
2406 nextProtoOnce sync
.Once
// guards setupHTTP2_* init
2407 nextProtoErr error
// result of http2.ConfigureServer if used
2410 listeners
map[net
.Listener
]struct{}
2411 activeConn
map[*conn
]struct{}
2412 doneChan
chan struct{}
2416 func (s
*Server
) getDoneChan() <-chan struct{} {
2419 return s
.getDoneChanLocked()
2422 func (s
*Server
) getDoneChanLocked() chan struct{} {
2423 if s
.doneChan
== nil {
2424 s
.doneChan
= make(chan struct{})
2429 func (s
*Server
) closeDoneChanLocked() {
2430 ch
:= s
.getDoneChanLocked()
2433 // Already closed. Don't close again.
2435 // Safe to close here. We're the only closer, guarded
2441 // Close immediately closes all active net.Listeners and any
2442 // connections in state StateNew, StateActive, or StateIdle. For a
2443 // graceful shutdown, use Shutdown.
2445 // Close does not attempt to close (and does not even know about)
2446 // any hijacked connections, such as WebSockets.
2448 // Close returns any error returned from closing the Server's
2449 // underlying Listener(s).
2450 func (srv
*Server
) Close() error
{
2452 defer srv
.mu
.Unlock()
2453 srv
.closeDoneChanLocked()
2454 err
:= srv
.closeListenersLocked()
2455 for c
:= range srv
.activeConn
{
2457 delete(srv
.activeConn
, c
)
2462 // shutdownPollInterval is how often we poll for quiescence
2463 // during Server.Shutdown. This is lower during tests, to
2465 // Ideally we could find a solution that doesn't involve polling,
2466 // but which also doesn't have a high runtime cost (and doesn't
2467 // involve any contentious mutexes), but that is left as an
2468 // exercise for the reader.
2469 var shutdownPollInterval
= 500 * time
.Millisecond
2471 // Shutdown gracefully shuts down the server without interrupting any
2472 // active connections. Shutdown works by first closing all open
2473 // listeners, then closing all idle connections, and then waiting
2474 // indefinitely for connections to return to idle and then shut down.
2475 // If the provided context expires before the shutdown is complete,
2476 // Shutdown returns the context's error, otherwise it returns any
2477 // error returned from closing the Server's underlying Listener(s).
2479 // When Shutdown is called, Serve, ListenAndServe, and
2480 // ListenAndServeTLS immediately return ErrServerClosed. Make sure the
2481 // program doesn't exit and waits instead for Shutdown to return.
2483 // Shutdown does not attempt to close nor wait for hijacked
2484 // connections such as WebSockets. The caller of Shutdown should
2485 // separately notify such long-lived connections of shutdown and wait
2486 // for them to close, if desired.
2487 func (srv
*Server
) Shutdown(ctx context
.Context
) error
{
2488 atomic
.AddInt32(&srv
.inShutdown
, 1)
2489 defer atomic
.AddInt32(&srv
.inShutdown
, -1)
2492 lnerr
:= srv
.closeListenersLocked()
2493 srv
.closeDoneChanLocked()
2494 for _
, f
:= range srv
.onShutdown
{
2499 ticker
:= time
.NewTicker(shutdownPollInterval
)
2502 if srv
.closeIdleConns() {
2513 // RegisterOnShutdown registers a function to call on Shutdown.
2514 // This can be used to gracefully shutdown connections that have
2515 // undergone NPN/ALPN protocol upgrade or that have been hijacked.
2516 // This function should start protocol-specific graceful shutdown,
2517 // but should not wait for shutdown to complete.
2518 func (srv
*Server
) RegisterOnShutdown(f
func()) {
2520 srv
.onShutdown
= append(srv
.onShutdown
, f
)
2524 // closeIdleConns closes all idle connections and reports whether the
2525 // server is quiescent.
2526 func (s
*Server
) closeIdleConns() bool {
2530 for c
:= range s
.activeConn
{
2531 st
, ok
:= c
.curState
.Load().(ConnState
)
2532 if !ok || st
!= StateIdle
{
2537 delete(s
.activeConn
, c
)
2542 func (s
*Server
) closeListenersLocked() error
{
2544 for ln
:= range s
.listeners
{
2545 if cerr
:= ln
.Close(); cerr
!= nil && err
== nil {
2548 delete(s
.listeners
, ln
)
2553 // A ConnState represents the state of a client connection to a server.
2554 // It's used by the optional Server.ConnState hook.
2558 // StateNew represents a new connection that is expected to
2559 // send a request immediately. Connections begin at this
2560 // state and then transition to either StateActive or
2562 StateNew ConnState
= iota
2564 // StateActive represents a connection that has read 1 or more
2565 // bytes of a request. The Server.ConnState hook for
2566 // StateActive fires before the request has entered a handler
2567 // and doesn't fire again until the request has been
2568 // handled. After the request is handled, the state
2569 // transitions to StateClosed, StateHijacked, or StateIdle.
2570 // For HTTP/2, StateActive fires on the transition from zero
2571 // to one active request, and only transitions away once all
2572 // active requests are complete. That means that ConnState
2573 // cannot be used to do per-request work; ConnState only notes
2574 // the overall state of the connection.
2577 // StateIdle represents a connection that has finished
2578 // handling a request and is in the keep-alive state, waiting
2579 // for a new request. Connections transition from StateIdle
2580 // to either StateActive or StateClosed.
2583 // StateHijacked represents a hijacked connection.
2584 // This is a terminal state. It does not transition to StateClosed.
2587 // StateClosed represents a closed connection.
2588 // This is a terminal state. Hijacked connections do not
2589 // transition to StateClosed.
2593 var stateName
= map[ConnState
]string{
2595 StateActive
: "active",
2597 StateHijacked
: "hijacked",
2598 StateClosed
: "closed",
2601 func (c ConnState
) String() string {
2605 // serverHandler delegates to either the server's Handler or
2606 // DefaultServeMux and also handles "OPTIONS *" requests.
2607 type serverHandler
struct {
2611 func (sh serverHandler
) ServeHTTP(rw ResponseWriter
, req
*Request
) {
2612 handler
:= sh
.srv
.Handler
2614 handler
= DefaultServeMux
2616 if req
.RequestURI
== "*" && req
.Method
== "OPTIONS" {
2617 handler
= globalOptionsHandler
{}
2619 handler
.ServeHTTP(rw
, req
)
2622 // ListenAndServe listens on the TCP network address srv.Addr and then
2623 // calls Serve to handle requests on incoming connections.
2624 // Accepted connections are configured to enable TCP keep-alives.
2625 // If srv.Addr is blank, ":http" is used.
2626 // ListenAndServe always returns a non-nil error.
2627 func (srv
*Server
) ListenAndServe() error
{
2632 ln
, err
:= net
.Listen("tcp", addr
)
2636 return srv
.Serve(tcpKeepAliveListener
{ln
.(*net
.TCPListener
)})
2639 var testHookServerServe
func(*Server
, net
.Listener
) // used if non-nil
2641 // shouldDoServeHTTP2 reports whether Server.Serve should configure
2642 // automatic HTTP/2. (which sets up the srv.TLSNextProto map)
2643 func (srv
*Server
) shouldConfigureHTTP2ForServe() bool {
2644 if srv
.TLSConfig
== nil {
2645 // Compatibility with Go 1.6:
2646 // If there's no TLSConfig, it's possible that the user just
2647 // didn't set it on the http.Server, but did pass it to
2648 // tls.NewListener and passed that listener to Serve.
2649 // So we should configure HTTP/2 (to set up srv.TLSNextProto)
2650 // in case the listener returns an "h2" *tls.Conn.
2653 // The user specified a TLSConfig on their http.Server.
2654 // In this, case, only configure HTTP/2 if their tls.Config
2655 // explicitly mentions "h2". Otherwise http2.ConfigureServer
2656 // would modify the tls.Config to add it, but they probably already
2657 // passed this tls.Config to tls.NewListener. And if they did,
2658 // it's too late anyway to fix it. It would only be potentially racy.
2660 return strSliceContains(srv
.TLSConfig
.NextProtos
, http2NextProtoTLS
)
2663 // ErrServerClosed is returned by the Server's Serve, ServeTLS, ListenAndServe,
2664 // and ListenAndServeTLS methods after a call to Shutdown or Close.
2665 var ErrServerClosed
= errors
.New("http: Server closed")
2667 // Serve accepts incoming connections on the Listener l, creating a
2668 // new service goroutine for each. The service goroutines read requests and
2669 // then call srv.Handler to reply to them.
2671 // For HTTP/2 support, srv.TLSConfig should be initialized to the
2672 // provided listener's TLS Config before calling Serve. If
2673 // srv.TLSConfig is non-nil and doesn't include the string "h2" in
2674 // Config.NextProtos, HTTP/2 support is not enabled.
2676 // Serve always returns a non-nil error. After Shutdown or Close, the
2677 // returned error is ErrServerClosed.
2678 func (srv
*Server
) Serve(l net
.Listener
) error
{
2680 if fn
:= testHookServerServe
; fn
!= nil {
2683 var tempDelay time
.Duration
// how long to sleep on accept failure
2685 if err
:= srv
.setupHTTP2_Serve(); err
!= nil {
2689 srv
.trackListener(l
, true)
2690 defer srv
.trackListener(l
, false)
2692 baseCtx
:= context
.Background() // base is always background, per Issue 16220
2693 ctx
:= context
.WithValue(baseCtx
, ServerContextKey
, srv
)
2698 case <-srv
.getDoneChan():
2699 return ErrServerClosed
2702 if ne
, ok
:= e
.(net
.Error
); ok
&& ne
.Temporary() {
2704 tempDelay
= 5 * time
.Millisecond
2708 if max
:= 1 * time
.Second
; tempDelay
> max
{
2711 srv
.logf("http: Accept error: %v; retrying in %v", e
, tempDelay
)
2712 time
.Sleep(tempDelay
)
2718 c
:= srv
.newConn(rw
)
2719 c
.setState(c
.rwc
, StateNew
) // before Serve can return
2724 // ServeTLS accepts incoming connections on the Listener l, creating a
2725 // new service goroutine for each. The service goroutines read requests and
2726 // then call srv.Handler to reply to them.
2728 // Additionally, files containing a certificate and matching private key for
2729 // the server must be provided if neither the Server's TLSConfig.Certificates
2730 // nor TLSConfig.GetCertificate are populated.. If the certificate is signed by
2731 // a certificate authority, the certFile should be the concatenation of the
2732 // server's certificate, any intermediates, and the CA's certificate.
2734 // For HTTP/2 support, srv.TLSConfig should be initialized to the
2735 // provided listener's TLS Config before calling Serve. If
2736 // srv.TLSConfig is non-nil and doesn't include the string "h2" in
2737 // Config.NextProtos, HTTP/2 support is not enabled.
2739 // ServeTLS always returns a non-nil error. After Shutdown or Close, the
2740 // returned error is ErrServerClosed.
2741 func (srv
*Server
) ServeTLS(l net
.Listener
, certFile
, keyFile
string) error
{
2742 // Setup HTTP/2 before srv.Serve, to initialize srv.TLSConfig
2743 // before we clone it and create the TLS Listener.
2744 if err
:= srv
.setupHTTP2_ServeTLS(); err
!= nil {
2748 config
:= cloneTLSConfig(srv
.TLSConfig
)
2749 if !strSliceContains(config
.NextProtos
, "http/1.1") {
2750 config
.NextProtos
= append(config
.NextProtos
, "http/1.1")
2753 configHasCert
:= len(config
.Certificates
) > 0 || config
.GetCertificate
!= nil
2754 if !configHasCert || certFile
!= "" || keyFile
!= "" {
2756 config
.Certificates
= make([]tls
.Certificate
, 1)
2757 config
.Certificates
[0], err
= tls
.LoadX509KeyPair(certFile
, keyFile
)
2763 tlsListener
:= tls
.NewListener(l
, config
)
2764 return srv
.Serve(tlsListener
)
2767 func (s
*Server
) trackListener(ln net
.Listener
, add
bool) {
2770 if s
.listeners
== nil {
2771 s
.listeners
= make(map[net
.Listener
]struct{})
2774 // If the *Server is being reused after a previous
2775 // Close or Shutdown, reset its doneChan:
2776 if len(s
.listeners
) == 0 && len(s
.activeConn
) == 0 {
2779 s
.listeners
[ln
] = struct{}{}
2781 delete(s
.listeners
, ln
)
2785 func (s
*Server
) trackConn(c
*conn
, add
bool) {
2788 if s
.activeConn
== nil {
2789 s
.activeConn
= make(map[*conn
]struct{})
2792 s
.activeConn
[c
] = struct{}{}
2794 delete(s
.activeConn
, c
)
2798 func (s
*Server
) idleTimeout() time
.Duration
{
2799 if s
.IdleTimeout
!= 0 {
2800 return s
.IdleTimeout
2802 return s
.ReadTimeout
2805 func (s
*Server
) readHeaderTimeout() time
.Duration
{
2806 if s
.ReadHeaderTimeout
!= 0 {
2807 return s
.ReadHeaderTimeout
2809 return s
.ReadTimeout
2812 func (s
*Server
) doKeepAlives() bool {
2813 return atomic
.LoadInt32(&s
.disableKeepAlives
) == 0 && !s
.shuttingDown()
2816 func (s
*Server
) shuttingDown() bool {
2817 return atomic
.LoadInt32(&s
.inShutdown
) != 0
2820 // SetKeepAlivesEnabled controls whether HTTP keep-alives are enabled.
2821 // By default, keep-alives are always enabled. Only very
2822 // resource-constrained environments or servers in the process of
2823 // shutting down should disable them.
2824 func (srv
*Server
) SetKeepAlivesEnabled(v
bool) {
2826 atomic
.StoreInt32(&srv
.disableKeepAlives
, 0)
2829 atomic
.StoreInt32(&srv
.disableKeepAlives
, 1)
2831 // Close idle HTTP/1 conns:
2832 srv
.closeIdleConns()
2834 // Close HTTP/2 conns, as soon as they become idle, but reset
2835 // the chan so future conns (if the listener is still active)
2836 // still work and don't get a GOAWAY immediately, before their
2839 defer srv
.mu
.Unlock()
2840 srv
.closeDoneChanLocked() // closes http2 conns
2844 func (s
*Server
) logf(format
string, args
...interface{}) {
2845 if s
.ErrorLog
!= nil {
2846 s
.ErrorLog
.Printf(format
, args
...)
2848 log
.Printf(format
, args
...)
2852 // ListenAndServe listens on the TCP network address addr
2853 // and then calls Serve with handler to handle requests
2854 // on incoming connections.
2855 // Accepted connections are configured to enable TCP keep-alives.
2856 // Handler is typically nil, in which case the DefaultServeMux is
2859 // A trivial example server is:
2869 // // hello world, the web server
2870 // func HelloServer(w http.ResponseWriter, req *http.Request) {
2871 // io.WriteString(w, "hello, world!\n")
2875 // http.HandleFunc("/hello", HelloServer)
2876 // log.Fatal(http.ListenAndServe(":12345", nil))
2879 // ListenAndServe always returns a non-nil error.
2880 func ListenAndServe(addr
string, handler Handler
) error
{
2881 server
:= &Server
{Addr
: addr
, Handler
: handler
}
2882 return server
.ListenAndServe()
2885 // ListenAndServeTLS acts identically to ListenAndServe, except that it
2886 // expects HTTPS connections. Additionally, files containing a certificate and
2887 // matching private key for the server must be provided. If the certificate
2888 // is signed by a certificate authority, the certFile should be the concatenation
2889 // of the server's certificate, any intermediates, and the CA's certificate.
2891 // A trivial example server is:
2898 // func handler(w http.ResponseWriter, req *http.Request) {
2899 // w.Header().Set("Content-Type", "text/plain")
2900 // w.Write([]byte("This is an example server.\n"))
2904 // http.HandleFunc("/", handler)
2905 // log.Printf("About to listen on 10443. Go to https://127.0.0.1:10443/")
2906 // err := http.ListenAndServeTLS(":10443", "cert.pem", "key.pem", nil)
2910 // One can use generate_cert.go in crypto/tls to generate cert.pem and key.pem.
2912 // ListenAndServeTLS always returns a non-nil error.
2913 func ListenAndServeTLS(addr
, certFile
, keyFile
string, handler Handler
) error
{
2914 server
:= &Server
{Addr
: addr
, Handler
: handler
}
2915 return server
.ListenAndServeTLS(certFile
, keyFile
)
2918 // ListenAndServeTLS listens on the TCP network address srv.Addr and
2919 // then calls Serve to handle requests on incoming TLS connections.
2920 // Accepted connections are configured to enable TCP keep-alives.
2922 // Filenames containing a certificate and matching private key for the
2923 // server must be provided if neither the Server's TLSConfig.Certificates
2924 // nor TLSConfig.GetCertificate are populated. If the certificate is
2925 // signed by a certificate authority, the certFile should be the
2926 // concatenation of the server's certificate, any intermediates, and
2927 // the CA's certificate.
2929 // If srv.Addr is blank, ":https" is used.
2931 // ListenAndServeTLS always returns a non-nil error.
2932 func (srv
*Server
) ListenAndServeTLS(certFile
, keyFile
string) error
{
2938 ln
, err
:= net
.Listen("tcp", addr
)
2943 return srv
.ServeTLS(tcpKeepAliveListener
{ln
.(*net
.TCPListener
)}, certFile
, keyFile
)
2946 // setupHTTP2_ServeTLS conditionally configures HTTP/2 on
2947 // srv and returns whether there was an error setting it up. If it is
2948 // not configured for policy reasons, nil is returned.
2949 func (srv
*Server
) setupHTTP2_ServeTLS() error
{
2950 srv
.nextProtoOnce
.Do(srv
.onceSetNextProtoDefaults
)
2951 return srv
.nextProtoErr
2954 // setupHTTP2_Serve is called from (*Server).Serve and conditionally
2955 // configures HTTP/2 on srv using a more conservative policy than
2956 // setupHTTP2_ServeTLS because Serve may be called
2959 // The tests named TestTransportAutomaticHTTP2* and
2960 // TestConcurrentServerServe in server_test.go demonstrate some
2961 // of the supported use cases and motivations.
2962 func (srv
*Server
) setupHTTP2_Serve() error
{
2963 srv
.nextProtoOnce
.Do(srv
.onceSetNextProtoDefaults_Serve
)
2964 return srv
.nextProtoErr
2967 func (srv
*Server
) onceSetNextProtoDefaults_Serve() {
2968 if srv
.shouldConfigureHTTP2ForServe() {
2969 srv
.onceSetNextProtoDefaults()
2973 // onceSetNextProtoDefaults configures HTTP/2, if the user hasn't
2974 // configured otherwise. (by setting srv.TLSNextProto non-nil)
2975 // It must only be called via srv.nextProtoOnce (use srv.setupHTTP2_*).
2976 func (srv
*Server
) onceSetNextProtoDefaults() {
2977 if strings
.Contains(os
.Getenv("GODEBUG"), "http2server=0") {
2980 // Enable HTTP/2 by default if the user hasn't otherwise
2981 // configured their TLSNextProto map.
2982 if srv
.TLSNextProto
== nil {
2983 conf
:= &http2Server
{
2984 NewWriteScheduler
: func() http2WriteScheduler
{ return http2NewPriorityWriteScheduler(nil) },
2986 srv
.nextProtoErr
= http2ConfigureServer(srv
, conf
)
2990 // TimeoutHandler returns a Handler that runs h with the given time limit.
2992 // The new Handler calls h.ServeHTTP to handle each request, but if a
2993 // call runs for longer than its time limit, the handler responds with
2994 // a 503 Service Unavailable error and the given message in its body.
2995 // (If msg is empty, a suitable default message will be sent.)
2996 // After such a timeout, writes by h to its ResponseWriter will return
2997 // ErrHandlerTimeout.
2999 // TimeoutHandler buffers all Handler writes to memory and does not
3000 // support the Hijacker or Flusher interfaces.
3001 func TimeoutHandler(h Handler
, dt time
.Duration
, msg
string) Handler
{
3002 return &timeoutHandler
{
3009 // ErrHandlerTimeout is returned on ResponseWriter Write calls
3010 // in handlers which have timed out.
3011 var ErrHandlerTimeout
= errors
.New("http: Handler timeout")
3013 type timeoutHandler
struct {
3018 // When set, no timer will be created and this channel will
3020 testTimeout
<-chan time
.Time
3023 func (h
*timeoutHandler
) errorBody() string {
3027 return "<html><head><title>Timeout</title></head><body><h1>Timeout</h1></body></html>"
3030 func (h
*timeoutHandler
) ServeHTTP(w ResponseWriter
, r
*Request
) {
3032 timeout
:= h
.testTimeout
3034 t
= time
.NewTimer(h
.dt
)
3037 done
:= make(chan struct{})
3038 tw
:= &timeoutWriter
{
3043 h
.handler
.ServeHTTP(tw
, r
)
3049 defer tw
.mu
.Unlock()
3051 for k
, vv
:= range tw
.h
{
3054 if !tw
.wroteHeader
{
3057 w
.WriteHeader(tw
.code
)
3058 w
.Write(tw
.wbuf
.Bytes())
3064 defer tw
.mu
.Unlock()
3065 w
.WriteHeader(StatusServiceUnavailable
)
3066 io
.WriteString(w
, h
.errorBody())
3072 type timeoutWriter
struct {
3083 func (tw
*timeoutWriter
) Header() Header
{ return tw
.h
}
3085 func (tw
*timeoutWriter
) Write(p
[]byte) (int, error
) {
3087 defer tw
.mu
.Unlock()
3089 return 0, ErrHandlerTimeout
3091 if !tw
.wroteHeader
{
3092 tw
.writeHeader(StatusOK
)
3094 return tw
.wbuf
.Write(p
)
3097 func (tw
*timeoutWriter
) WriteHeader(code
int) {
3099 defer tw
.mu
.Unlock()
3100 if tw
.timedOut || tw
.wroteHeader
{
3103 tw
.writeHeader(code
)
3106 func (tw
*timeoutWriter
) writeHeader(code
int) {
3107 tw
.wroteHeader
= true
3111 // tcpKeepAliveListener sets TCP keep-alive timeouts on accepted
3112 // connections. It's used by ListenAndServe and ListenAndServeTLS so
3113 // dead TCP connections (e.g. closing laptop mid-download) eventually
3115 type tcpKeepAliveListener
struct {
3119 func (ln tcpKeepAliveListener
) Accept() (c net
.Conn
, err error
) {
3120 tc
, err
:= ln
.AcceptTCP()
3124 tc
.SetKeepAlive(true)
3125 tc
.SetKeepAlivePeriod(3 * time
.Minute
)
3129 // globalOptionsHandler responds to "OPTIONS *" requests.
3130 type globalOptionsHandler
struct{}
3132 func (globalOptionsHandler
) ServeHTTP(w ResponseWriter
, r
*Request
) {
3133 w
.Header().Set("Content-Length", "0")
3134 if r
.ContentLength
!= 0 {
3135 // Read up to 4KB of OPTIONS body (as mentioned in the
3136 // spec as being reserved for future use), but anything
3137 // over that is considered a waste of server resources
3138 // (or an attack) and we abort and close the connection,
3139 // courtesy of MaxBytesReader's EOF behavior.
3140 mb
:= MaxBytesReader(w
, r
.Body
, 4<<10)
3141 io
.Copy(ioutil
.Discard
, mb
)
3145 // initNPNRequest is an HTTP handler that initializes certain
3146 // uninitialized fields in its *Request. Such partially-initialized
3147 // Requests come from NPN protocol handlers.
3148 type initNPNRequest
struct {
3153 func (h initNPNRequest
) ServeHTTP(rw ResponseWriter
, req
*Request
) {
3155 req
.TLS
= &tls
.ConnectionState
{}
3156 *req
.TLS
= h
.c
.ConnectionState()
3158 if req
.Body
== nil {
3161 if req
.RemoteAddr
== "" {
3162 req
.RemoteAddr
= h
.c
.RemoteAddr().String()
3164 h
.h
.ServeHTTP(rw
, req
)
3167 // loggingConn is used for debugging.
3168 type loggingConn
struct {
3174 uniqNameMu sync
.Mutex
3175 uniqNameNext
= make(map[string]int)
3178 func newLoggingConn(baseName
string, c net
.Conn
) net
.Conn
{
3180 defer uniqNameMu
.Unlock()
3181 uniqNameNext
[baseName
]++
3182 return &loggingConn
{
3183 name
: fmt
.Sprintf("%s-%d", baseName
, uniqNameNext
[baseName
]),
3188 func (c
*loggingConn
) Write(p
[]byte) (n
int, err error
) {
3189 log
.Printf("%s.Write(%d) = ....", c
.name
, len(p
))
3190 n
, err
= c
.Conn
.Write(p
)
3191 log
.Printf("%s.Write(%d) = %d, %v", c
.name
, len(p
), n
, err
)
3195 func (c
*loggingConn
) Read(p
[]byte) (n
int, err error
) {
3196 log
.Printf("%s.Read(%d) = ....", c
.name
, len(p
))
3197 n
, err
= c
.Conn
.Read(p
)
3198 log
.Printf("%s.Read(%d) = %d, %v", c
.name
, len(p
), n
, err
)
3202 func (c
*loggingConn
) Close() (err error
) {
3203 log
.Printf("%s.Close() = ...", c
.name
)
3204 err
= c
.Conn
.Close()
3205 log
.Printf("%s.Close() = %v", c
.name
, err
)
3209 // checkConnErrorWriter writes to c.rwc and records any write errors to c.werr.
3210 // It only contains one field (and a pointer field at that), so it
3211 // fits in an interface value without an extra allocation.
3212 type checkConnErrorWriter
struct {
3216 func (w checkConnErrorWriter
) Write(p
[]byte) (n
int, err error
) {
3217 n
, err
= w
.c
.rwc
.Write(p
)
3218 if err
!= nil && w
.c
.werr
== nil {
3225 func numLeadingCRorLF(v
[]byte) (n
int) {
3226 for _
, b
:= range v
{
3227 if b
== '\r' || b
== '\n' {
3237 func strSliceContains(ss
[]string, s
string) bool {
3238 for _
, v
:= range ss
{