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.
24 "golang_org/x/net/http/httpguts"
27 // ErrLineTooLong is returned when reading request or response bodies
28 // with malformed chunked encoding.
29 var ErrLineTooLong
= internal
.ErrLineTooLong
31 type errorReader
struct {
35 func (r errorReader
) Read(p
[]byte) (n
int, err error
) {
39 type byteReader
struct {
44 func (br
*byteReader
) Read(p
[]byte) (n
int, err error
) {
56 // transferBodyReader is an io.Reader that reads from tw.Body
57 // and records any non-EOF error in tw.bodyReadError.
58 // It is exactly 1 pointer wide to avoid allocations into interfaces.
59 type transferBodyReader
struct{ tw
*transferWriter
}
61 func (br transferBodyReader
) Read(p
[]byte) (n
int, err error
) {
62 n
, err
= br
.tw
.Body
.Read(p
)
63 if err
!= nil && err
!= io
.EOF
{
64 br
.tw
.bodyReadError
= err
69 // transferWriter inspects the fields of a user-supplied Request or Response,
70 // sanitizes them without changing the user object and provides methods for
71 // writing the respective header, body and trailer in wire format.
72 type transferWriter
struct {
77 ContentLength
int64 // -1 means unknown, 0 means exactly none
79 TransferEncoding
[]string
83 bodyReadError error
// any non-EOF error from reading Body
85 FlushHeaders
bool // flush headers to network before body
86 ByteReadCh
chan readResult
// non-nil if probeRequestBody called
89 func newTransferWriter(r
interface{}) (t
*transferWriter
, err error
) {
92 // Extract relevant fields
93 atLeastHTTP11
:= false
94 switch rr
:= r
.(type) {
96 if rr
.ContentLength
!= 0 && rr
.Body
== nil {
97 return nil, fmt
.Errorf("http: Request.ContentLength=%d with nil Body", rr
.ContentLength
)
99 t
.Method
= valueOrDefault(rr
.Method
, "GET")
101 t
.TransferEncoding
= rr
.TransferEncoding
103 t
.Trailer
= rr
.Trailer
105 t
.BodyCloser
= rr
.Body
106 t
.ContentLength
= rr
.outgoingLength()
107 if t
.ContentLength
< 0 && len(t
.TransferEncoding
) == 0 && t
.shouldSendChunkedRequestBody() {
108 t
.TransferEncoding
= []string{"chunked"}
110 // If there's a body, conservatively flush the headers
111 // to any bufio.Writer we're writing to, just in case
112 // the server needs the headers early, before we copy
113 // the body and possibly block. We make an exception
114 // for the common standard library in-memory types,
115 // though, to avoid unnecessary TCP packets on the
116 // wire. (Issue 22088.)
117 if t
.ContentLength
!= 0 && !isKnownInMemoryReader(t
.Body
) {
118 t
.FlushHeaders
= true
121 atLeastHTTP11
= true // Transport requests are always 1.1 or 2.0
124 if rr
.Request
!= nil {
125 t
.Method
= rr
.Request
.Method
128 t
.BodyCloser
= rr
.Body
129 t
.ContentLength
= rr
.ContentLength
131 t
.TransferEncoding
= rr
.TransferEncoding
133 t
.Trailer
= rr
.Trailer
134 atLeastHTTP11
= rr
.ProtoAtLeast(1, 1)
135 t
.ResponseToHEAD
= noResponseBodyExpected(t
.Method
)
138 // Sanitize Body,ContentLength,TransferEncoding
139 if t
.ResponseToHEAD
{
141 if chunked(t
.TransferEncoding
) {
145 if !atLeastHTTP11 || t
.Body
== nil {
146 t
.TransferEncoding
= nil
148 if chunked(t
.TransferEncoding
) {
150 } else if t
.Body
== nil { // no chunking, no body
156 if !chunked(t
.TransferEncoding
) {
163 // shouldSendChunkedRequestBody reports whether we should try to send a
164 // chunked request body to the server. In particular, the case we really
165 // want to prevent is sending a GET or other typically-bodyless request to a
166 // server with a chunked body when the body has zero bytes, since GETs with
167 // bodies (while acceptable according to specs), even zero-byte chunked
168 // bodies, are approximately never seen in the wild and confuse most
169 // servers. See Issue 18257, as one example.
171 // The only reason we'd send such a request is if the user set the Body to a
172 // non-nil value (say, ioutil.NopCloser(bytes.NewReader(nil))) and didn't
173 // set ContentLength, or NewRequest set it to -1 (unknown), so then we assume
174 // there's bytes to send.
176 // This code tries to read a byte from the Request.Body in such cases to see
177 // whether the body actually has content (super rare) or is actually just
178 // a non-nil content-less ReadCloser (the more common case). In that more
179 // common case, we act as if their Body were nil instead, and don't send
181 func (t
*transferWriter
) shouldSendChunkedRequestBody() bool {
182 // Note that t.ContentLength is the corrected content length
183 // from rr.outgoingLength, so 0 actually means zero, not unknown.
184 if t
.ContentLength
>= 0 || t
.Body
== nil { // redundant checks; caller did them
187 if requestMethodUsuallyLacksBody(t
.Method
) {
188 // Only probe the Request.Body for GET/HEAD/DELETE/etc
189 // requests, because it's only those types of requests
190 // that confuse servers.
191 t
.probeRequestBody() // adjusts t.Body, t.ContentLength
194 // For all other request types (PUT, POST, PATCH, or anything
195 // made-up we've never heard of), assume it's normal and the server
196 // can deal with a chunked request body. Maybe we'll adjust this
201 // probeRequestBody reads a byte from t.Body to see whether it's empty
202 // (returns io.EOF right away).
204 // But because we've had problems with this blocking users in the past
205 // (issue 17480) when the body is a pipe (perhaps waiting on the response
206 // headers before the pipe is fed data), we need to be careful and bound how
207 // long we wait for it. This delay will only affect users if all the following
209 // * the request body blocks
210 // * the content length is not set (or set to -1)
211 // * the method doesn't usually have a body (GET, HEAD, DELETE, ...)
212 // * there is no transfer-encoding=chunked already set.
213 // In other words, this delay will not normally affect anybody, and there
214 // are workarounds if it does.
215 func (t
*transferWriter
) probeRequestBody() {
216 t
.ByteReadCh
= make(chan readResult
, 1)
217 go func(body io
.Reader
) {
220 rres
.n
, rres
.err
= body
.Read(buf
[:])
226 timer
:= time
.NewTimer(200 * time
.Millisecond
)
228 case rres
:= <-t
.ByteReadCh
:
230 if rres
.n
== 0 && rres
.err
== io
.EOF
{
234 } else if rres
.n
== 1 {
236 t
.Body
= io
.MultiReader(&byteReader
{b
: rres
.b
}, errorReader
{rres
.err
})
238 t
.Body
= io
.MultiReader(&byteReader
{b
: rres
.b
}, t
.Body
)
240 } else if rres
.err
!= nil {
241 t
.Body
= errorReader
{rres
.err
}
244 // Too slow. Don't wait. Read it later, and keep
245 // assuming that this is ContentLength == -1
246 // (unknown), which means we'll send a
247 // "Transfer-Encoding: chunked" header.
248 t
.Body
= io
.MultiReader(finishAsyncByteRead
{t
}, t
.Body
)
249 // Request that Request.Write flush the headers to the
250 // network before writing the body, since our body may not
251 // become readable until it's seen the response headers.
252 t
.FlushHeaders
= true
256 func noResponseBodyExpected(requestMethod
string) bool {
257 return requestMethod
== "HEAD"
260 func (t
*transferWriter
) shouldSendContentLength() bool {
261 if chunked(t
.TransferEncoding
) {
264 if t
.ContentLength
> 0 {
267 if t
.ContentLength
< 0 {
270 // Many servers expect a Content-Length for these methods
271 if t
.Method
== "POST" || t
.Method
== "PUT" {
274 if t
.ContentLength
== 0 && isIdentity(t
.TransferEncoding
) {
275 if t
.Method
== "GET" || t
.Method
== "HEAD" {
284 func (t
*transferWriter
) writeHeader(w io
.Writer
, trace
*httptrace
.ClientTrace
) error
{
285 if t
.Close
&& !hasToken(t
.Header
.get("Connection"), "close") {
286 if _
, err
:= io
.WriteString(w
, "Connection: close\r\n"); err
!= nil {
289 if trace
!= nil && trace
.WroteHeaderField
!= nil {
290 trace
.WroteHeaderField("Connection", []string{"close"})
294 // Write Content-Length and/or Transfer-Encoding whose values are a
295 // function of the sanitized field triple (Body, ContentLength,
297 if t
.shouldSendContentLength() {
298 if _
, err
:= io
.WriteString(w
, "Content-Length: "); err
!= nil {
301 if _
, err
:= io
.WriteString(w
, strconv
.FormatInt(t
.ContentLength
, 10)+"\r\n"); err
!= nil {
304 if trace
!= nil && trace
.WroteHeaderField
!= nil {
305 trace
.WroteHeaderField("Content-Length", []string{strconv
.FormatInt(t
.ContentLength
, 10)})
307 } else if chunked(t
.TransferEncoding
) {
308 if _
, err
:= io
.WriteString(w
, "Transfer-Encoding: chunked\r\n"); err
!= nil {
311 if trace
!= nil && trace
.WroteHeaderField
!= nil {
312 trace
.WroteHeaderField("Transfer-Encoding", []string{"chunked"})
316 // Write Trailer header
317 if t
.Trailer
!= nil {
318 keys
:= make([]string, 0, len(t
.Trailer
))
319 for k
:= range t
.Trailer
{
320 k
= CanonicalHeaderKey(k
)
322 case "Transfer-Encoding", "Trailer", "Content-Length":
323 return &badStringError
{"invalid Trailer key", k
}
325 keys
= append(keys
, k
)
329 // TODO: could do better allocation-wise here, but trailers are rare,
330 // so being lazy for now.
331 if _
, err
:= io
.WriteString(w
, "Trailer: "+strings
.Join(keys
, ",")+"\r\n"); err
!= nil {
334 if trace
!= nil && trace
.WroteHeaderField
!= nil {
335 trace
.WroteHeaderField("Trailer", keys
)
343 func (t
*transferWriter
) writeBody(w io
.Writer
) error
{
349 var body
= transferBodyReader
{t
}
350 if chunked(t
.TransferEncoding
) {
351 if bw
, ok
:= w
.(*bufio
.Writer
); ok
&& !t
.IsResponse
{
352 w
= &internal
.FlushAfterChunkWriter
{Writer
: bw
}
354 cw
:= internal
.NewChunkedWriter(w
)
355 _
, err
= io
.Copy(cw
, body
)
359 } else if t
.ContentLength
== -1 {
360 ncopy
, err
= io
.Copy(w
, body
)
362 ncopy
, err
= io
.Copy(w
, io
.LimitReader(body
, t
.ContentLength
))
367 nextra
, err
= io
.Copy(ioutil
.Discard
, body
)
374 if t
.BodyCloser
!= nil {
375 if err
:= t
.BodyCloser
.Close(); err
!= nil {
380 if !t
.ResponseToHEAD
&& t
.ContentLength
!= -1 && t
.ContentLength
!= ncopy
{
381 return fmt
.Errorf("http: ContentLength=%d with Body length %d",
382 t
.ContentLength
, ncopy
)
385 if chunked(t
.TransferEncoding
) {
386 // Write Trailer header
387 if t
.Trailer
!= nil {
388 if err
:= t
.Trailer
.Write(w
); err
!= nil {
392 // Last chunk, empty trailer
393 _
, err
= io
.WriteString(w
, "\r\n")
398 type transferReader
struct {
408 TransferEncoding
[]string
413 func (t
*transferReader
) protoAtLeast(m
, n
int) bool {
414 return t
.ProtoMajor
> m ||
(t
.ProtoMajor
== m
&& t
.ProtoMinor
>= n
)
417 // bodyAllowedForStatus reports whether a given response status code
418 // permits a body. See RFC 7230, section 3.3.
419 func bodyAllowedForStatus(status
int) bool {
421 case status
>= 100 && status
<= 199:
432 suppressedHeaders304
= []string{"Content-Type", "Content-Length", "Transfer-Encoding"}
433 suppressedHeadersNoBody
= []string{"Content-Length", "Transfer-Encoding"}
436 func suppressedHeaders(status
int) []string {
439 // RFC 7232 section 4.1
440 return suppressedHeaders304
441 case !bodyAllowedForStatus(status
):
442 return suppressedHeadersNoBody
447 // msg is *Request or *Response.
448 func readTransfer(msg
interface{}, r
*bufio
.Reader
) (err error
) {
449 t
:= &transferReader
{RequestMethod
: "GET"}
453 switch rr
:= msg
.(type) {
456 t
.StatusCode
= rr
.StatusCode
457 t
.ProtoMajor
= rr
.ProtoMajor
458 t
.ProtoMinor
= rr
.ProtoMinor
459 t
.Close
= shouldClose(t
.ProtoMajor
, t
.ProtoMinor
, t
.Header
, true)
461 if rr
.Request
!= nil {
462 t
.RequestMethod
= rr
.Request
.Method
466 t
.RequestMethod
= rr
.Method
467 t
.ProtoMajor
= rr
.ProtoMajor
468 t
.ProtoMinor
= rr
.ProtoMinor
469 // Transfer semantics for Requests are exactly like those for
470 // Responses with status code 200, responding to a GET method
474 panic("unexpected type")
477 // Default to HTTP/1.1
478 if t
.ProtoMajor
== 0 && t
.ProtoMinor
== 0 {
479 t
.ProtoMajor
, t
.ProtoMinor
= 1, 1
482 // Transfer encoding, content length
483 err
= t
.fixTransferEncoding()
488 realLength
, err
:= fixLength(isResponse
, t
.StatusCode
, t
.RequestMethod
, t
.Header
, t
.TransferEncoding
)
492 if isResponse
&& t
.RequestMethod
== "HEAD" {
493 if n
, err
:= parseContentLength(t
.Header
.get("Content-Length")); err
!= nil {
499 t
.ContentLength
= realLength
503 t
.Trailer
, err
= fixTrailer(t
.Header
, t
.TransferEncoding
)
508 // If there is no Content-Length or chunked Transfer-Encoding on a *Response
509 // and the status is not 1xx, 204 or 304, then the body is unbounded.
510 // See RFC 7230, section 3.3.
513 if realLength
== -1 &&
514 !chunked(t
.TransferEncoding
) &&
515 bodyAllowedForStatus(t
.StatusCode
) {
521 // Prepare body reader. ContentLength < 0 means chunked encoding
522 // or close connection when finished, since multipart is not supported yet
524 case chunked(t
.TransferEncoding
):
525 if noResponseBodyExpected(t
.RequestMethod
) ||
!bodyAllowedForStatus(t
.StatusCode
) {
528 t
.Body
= &body
{src
: internal
.NewChunkedReader(r
), hdr
: msg
, r
: r
, closing
: t
.Close
}
530 case realLength
== 0:
533 t
.Body
= &body
{src
: io
.LimitReader(r
, realLength
), closing
: t
.Close
}
535 // realLength < 0, i.e. "Content-Length" not mentioned in header
537 // Close semantics (i.e. HTTP/1.0)
538 t
.Body
= &body
{src
: r
, closing
: t
.Close
}
540 // Persistent connection (i.e. HTTP/1.1)
546 switch rr
:= msg
.(type) {
549 rr
.ContentLength
= t
.ContentLength
550 rr
.TransferEncoding
= t
.TransferEncoding
552 rr
.Trailer
= t
.Trailer
555 rr
.ContentLength
= t
.ContentLength
556 rr
.TransferEncoding
= t
.TransferEncoding
558 rr
.Trailer
= t
.Trailer
564 // Checks whether chunked is part of the encodings stack
565 func chunked(te
[]string) bool { return len(te
) > 0 && te
[0] == "chunked" }
567 // Checks whether the encoding is explicitly "identity".
568 func isIdentity(te
[]string) bool { return len(te
) == 1 && te
[0] == "identity" }
570 // fixTransferEncoding sanitizes t.TransferEncoding, if needed.
571 func (t
*transferReader
) fixTransferEncoding() error
{
572 raw
, present
:= t
.Header
["Transfer-Encoding"]
576 delete(t
.Header
, "Transfer-Encoding")
578 // Issue 12785; ignore Transfer-Encoding on HTTP/1.0 requests.
579 if !t
.protoAtLeast(1, 1) {
583 encodings
:= strings
.Split(raw
[0], ",")
584 te
:= make([]string, 0, len(encodings
))
585 // TODO: Even though we only support "identity" and "chunked"
586 // encodings, the loop below is designed with foresight. One
587 // invariant that must be maintained is that, if present,
588 // chunked encoding must always come first.
589 for _
, encoding
:= range encodings
{
590 encoding
= strings
.ToLower(strings
.TrimSpace(encoding
))
591 // "identity" encoding is not recorded
592 if encoding
== "identity" {
595 if encoding
!= "chunked" {
596 return &badStringError
{"unsupported transfer encoding", encoding
}
598 te
= te
[0 : len(te
)+1]
599 te
[len(te
)-1] = encoding
602 return &badStringError
{"too many transfer encodings", strings
.Join(te
, ",")}
605 // RFC 7230 3.3.2 says "A sender MUST NOT send a
606 // Content-Length header field in any message that
607 // contains a Transfer-Encoding header field."
610 // "If a message is received with both a
611 // Transfer-Encoding and a Content-Length header
612 // field, the Transfer-Encoding overrides the
613 // Content-Length. Such a message might indicate an
614 // attempt to perform request smuggling (Section 9.5)
615 // or response splitting (Section 9.4) and ought to be
616 // handled as an error. A sender MUST remove the
617 // received Content-Length field prior to forwarding
618 // such a message downstream."
620 // Reportedly, these appear in the wild.
621 delete(t
.Header
, "Content-Length")
622 t
.TransferEncoding
= te
629 // Determine the expected body length, using RFC 7230 Section 3.3. This
630 // function is not a method, because ultimately it should be shared by
631 // ReadResponse and ReadRequest.
632 func fixLength(isResponse
bool, status
int, requestMethod
string, header Header
, te
[]string) (int64, error
) {
633 isRequest
:= !isResponse
634 contentLens
:= header
["Content-Length"]
636 // Hardening against HTTP request smuggling
637 if len(contentLens
) > 1 {
638 // Per RFC 7230 Section 3.3.2, prevent multiple
639 // Content-Length headers if they differ in value.
640 // If there are dups of the value, remove the dups.
642 first
:= strings
.TrimSpace(contentLens
[0])
643 for _
, ct
:= range contentLens
[1:] {
644 if first
!= strings
.TrimSpace(ct
) {
645 return 0, fmt
.Errorf("http: message cannot contain multiple Content-Length headers; got %q", contentLens
)
649 // deduplicate Content-Length
650 header
.Del("Content-Length")
651 header
.Add("Content-Length", first
)
653 contentLens
= header
["Content-Length"]
656 // Logic based on response type or status
657 if noResponseBodyExpected(requestMethod
) {
658 // For HTTP requests, as part of hardening against request
659 // smuggling (RFC 7230), don't allow a Content-Length header for
660 // methods which don't permit bodies. As an exception, allow
661 // exactly one Content-Length header if its value is "0".
662 if isRequest
&& len(contentLens
) > 0 && !(len(contentLens
) == 1 && contentLens
[0] == "0") {
663 return 0, fmt
.Errorf("http: method cannot contain a Content-Length; got %q", contentLens
)
675 // Logic based on Transfer-Encoding
680 // Logic based on Content-Length
682 if len(contentLens
) == 1 {
683 cl
= strings
.TrimSpace(contentLens
[0])
686 n
, err
:= parseContentLength(cl
)
692 header
.Del("Content-Length")
695 // RFC 7230 neither explicitly permits nor forbids an
696 // entity-body on a GET request so we permit one if
697 // declared, but we default to 0 here (not -1 below)
698 // if there's no mention of a body.
699 // Likewise, all other request methods are assumed to have
700 // no body if neither Transfer-Encoding chunked nor a
701 // Content-Length are set.
705 // Body-EOF logic based on other methods (like closing, or chunked coding)
709 // Determine whether to hang up after sending a request and body, or
710 // receiving a response and body
711 // 'header' is the request headers
712 func shouldClose(major
, minor
int, header Header
, removeCloseHeader
bool) bool {
717 conv
:= header
["Connection"]
718 hasClose
:= httpguts
.HeaderValuesContainsToken(conv
, "close")
719 if major
== 1 && minor
== 0 {
720 return hasClose ||
!httpguts
.HeaderValuesContainsToken(conv
, "keep-alive")
723 if hasClose
&& removeCloseHeader
{
724 header
.Del("Connection")
730 // Parse the trailer header
731 func fixTrailer(header Header
, te
[]string) (Header
, error
) {
732 vv
, ok
:= header
["Trailer"]
736 header
.Del("Trailer")
738 trailer
:= make(Header
)
740 for _
, v
:= range vv
{
741 foreachHeaderElement(v
, func(key
string) {
742 key
= CanonicalHeaderKey(key
)
744 case "Transfer-Encoding", "Trailer", "Content-Length":
746 err
= &badStringError
{"bad trailer key", key
}
756 if len(trailer
) == 0 {
760 // Trailer and no chunking
761 return nil, ErrUnexpectedTrailer
766 // body turns a Reader into a ReadCloser.
767 // Close ensures that the body has been fully read
768 // and then reads the trailer if necessary.
771 hdr
interface{} // non-nil (Response or Request) value means read trailer
772 r
*bufio
.Reader
// underlying wire-format reader for the trailer
773 closing
bool // is the connection to be closed after reading body?
774 doEarlyClose
bool // whether Close should stop early
776 mu sync
.Mutex
// guards following, and calls to Read and Close
779 earlyClose
bool // Close called and we didn't read to the end of src
780 onHitEOF
func() // if non-nil, func to call when EOF is Read
783 // ErrBodyReadAfterClose is returned when reading a Request or Response
784 // Body after the body has been closed. This typically happens when the body is
785 // read after an HTTP Handler calls WriteHeader or Write on its
787 var ErrBodyReadAfterClose
= errors
.New("http: invalid Read on closed Body")
789 func (b
*body
) Read(p
[]byte) (n
int, err error
) {
793 return 0, ErrBodyReadAfterClose
795 return b
.readLocked(p
)
799 func (b
*body
) readLocked(p
[]byte) (n
int, err error
) {
803 n
, err
= b
.src
.Read(p
)
807 // Chunked case. Read the trailer.
809 if e
:= b
.readTrailer(); e
!= nil {
811 // Something went wrong in the trailer, we must not allow any
812 // further reads of any kind to succeed from body, nor any
813 // subsequent requests on the server connection. See
814 // golang.org/issue/12027
820 // If the server declared the Content-Length, our body is a LimitedReader
821 // and we need to check whether this EOF arrived early.
822 if lr
, ok
:= b
.src
.(*io
.LimitedReader
); ok
&& lr
.N
> 0 {
823 err
= io
.ErrUnexpectedEOF
828 // If we can return an EOF here along with the read data, do
829 // so. This is optional per the io.Reader contract, but doing
830 // so helps the HTTP transport code recycle its connection
831 // earlier (since it will see this EOF itself), even if the
832 // client doesn't do future reads or Close.
833 if err
== nil && n
> 0 {
834 if lr
, ok
:= b
.src
.(*io
.LimitedReader
); ok
&& lr
.N
== 0 {
840 if b
.sawEOF
&& b
.onHitEOF
!= nil {
848 singleCRLF
= []byte("\r\n")
849 doubleCRLF
= []byte("\r\n\r\n")
852 func seeUpcomingDoubleCRLF(r
*bufio
.Reader
) bool {
853 for peekSize
:= 4; ; peekSize
++ {
854 // This loop stops when Peek returns an error,
855 // which it does when r's buffer has been filled.
856 buf
, err
:= r
.Peek(peekSize
)
857 if bytes
.HasSuffix(buf
, doubleCRLF
) {
867 var errTrailerEOF
= errors
.New("http: unexpected EOF reading trailer")
869 func (b
*body
) readTrailer() error
{
870 // The common case, since nobody uses trailers.
871 buf
, err
:= b
.r
.Peek(2)
872 if bytes
.Equal(buf
, singleCRLF
) {
883 // Make sure there's a header terminator coming up, to prevent
884 // a DoS with an unbounded size Trailer. It's not easy to
885 // slip in a LimitReader here, as textproto.NewReader requires
886 // a concrete *bufio.Reader. Also, we can't get all the way
887 // back up to our conn's LimitedReader that *might* be backing
888 // this bufio.Reader. Instead, a hack: we iteratively Peek up
889 // to the bufio.Reader's max size, looking for a double CRLF.
890 // This limits the trailer to the underlying buffer size, typically 4kB.
891 if !seeUpcomingDoubleCRLF(b
.r
) {
892 return errors
.New("http: suspiciously long trailer after chunked body")
895 hdr
, err
:= textproto
.NewReader(b
.r
).ReadMIMEHeader()
902 switch rr
:= b
.hdr
.(type) {
904 mergeSetHeader(&rr
.Trailer
, Header(hdr
))
906 mergeSetHeader(&rr
.Trailer
, Header(hdr
))
911 func mergeSetHeader(dst
*Header
, src Header
) {
916 for k
, vv
:= range src
{
921 // unreadDataSizeLocked returns the number of bytes of unread input.
922 // It returns -1 if unknown.
923 // b.mu must be held.
924 func (b
*body
) unreadDataSizeLocked() int64 {
925 if lr
, ok
:= b
.src
.(*io
.LimitedReader
); ok
{
931 func (b
*body
) Close() error
{
940 // Already saw EOF, so no need going to look for it.
941 case b
.hdr
== nil && b
.closing
:
942 // no trailer and closing the connection next.
943 // no point in reading to EOF.
945 // Read up to maxPostHandlerReadBytes bytes of the body, looking for
946 // for EOF (and trailers), so we can re-use this connection.
947 if lr
, ok
:= b
.src
.(*io
.LimitedReader
); ok
&& lr
.N
> maxPostHandlerReadBytes
{
948 // There was a declared Content-Length, and we have more bytes remaining
949 // than our maxPostHandlerReadBytes tolerance. So, give up.
953 // Consume the body, or, which will also lead to us reading
954 // the trailer headers after the body, if present.
955 n
, err
= io
.CopyN(ioutil
.Discard
, bodyLocked
{b
}, maxPostHandlerReadBytes
)
959 if n
== maxPostHandlerReadBytes
{
964 // Fully consume the body, which will also lead to us reading
965 // the trailer headers after the body, if present.
966 _
, err
= io
.Copy(ioutil
.Discard
, bodyLocked
{b
})
972 func (b
*body
) didEarlyClose() bool {
978 // bodyRemains reports whether future Read calls might
980 func (b
*body
) bodyRemains() bool {
986 func (b
*body
) registerOnHitEOF(fn
func()) {
992 // bodyLocked is a io.Reader reading from a *body when its mutex is
994 type bodyLocked
struct {
998 func (bl bodyLocked
) Read(p
[]byte) (n
int, err error
) {
1000 return 0, ErrBodyReadAfterClose
1002 return bl
.b
.readLocked(p
)
1005 // parseContentLength trims whitespace from s and returns -1 if no value
1006 // is set, or the value if it's >= 0.
1007 func parseContentLength(cl
string) (int64, error
) {
1008 cl
= strings
.TrimSpace(cl
)
1012 n
, err
:= strconv
.ParseInt(cl
, 10, 64)
1013 if err
!= nil || n
< 0 {
1014 return 0, &badStringError
{"bad Content-Length", cl
}
1020 // finishAsyncByteRead finishes reading the 1-byte sniff
1021 // from the ContentLength==0, Body!=nil case.
1022 type finishAsyncByteRead
struct {
1026 func (fr finishAsyncByteRead
) Read(p
[]byte) (n
int, err error
) {
1030 rres
:= <-fr
.tw
.ByteReadCh
1031 n
, err
= rres
.n
, rres
.err
1038 var nopCloserType
= reflect
.TypeOf(ioutil
.NopCloser(nil))
1040 // isKnownInMemoryReader reports whether r is a type known to not
1041 // block on Read. Its caller uses this as an optional optimization to
1042 // send fewer TCP packets.
1043 func isKnownInMemoryReader(r io
.Reader
) bool {
1045 case *bytes
.Reader
, *bytes
.Buffer
, *strings
.Reader
:
1048 if reflect
.TypeOf(r
) == nopCloserType
{
1049 return isKnownInMemoryReader(reflect
.ValueOf(r
).Field(0).Interface().(io
.Reader
))