| blob | 135dd74666ad4f21c23a17329a1105e39a840465 |
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2 .\" Copyright (c) 1998-2013 Dag-Erling Smørgrav
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27 .\" $FreeBSD: head/lib/libfetch/fetch.3 253805 2013-07-30 13:07:55Z des $
28 .\"
29 .Dd July 30, 2013
30 .Dt FETCH 3
31 .Os
32 .Sh NAME
33 .Nm fetchMakeURL ,
34 .Nm fetchParseURL ,
35 .Nm fetchFreeURL ,
36 .Nm fetchXGetURL ,
37 .Nm fetchGetURL ,
38 .Nm fetchPutURL ,
39 .Nm fetchStatURL ,
40 .Nm fetchListURL ,
41 .Nm fetchXGet ,
42 .Nm fetchGet ,
43 .Nm fetchPut ,
44 .Nm fetchStat ,
45 .Nm fetchList ,
46 .Nm fetchXGetFile ,
47 .Nm fetchGetFile ,
48 .Nm fetchPutFile ,
49 .Nm fetchStatFile ,
50 .Nm fetchListFile ,
51 .Nm fetchXGetHTTP ,
52 .Nm fetchGetHTTP ,
53 .Nm fetchPutHTTP ,
54 .Nm fetchStatHTTP ,
55 .Nm fetchListHTTP ,
56 .Nm fetchXGetFTP ,
57 .Nm fetchGetFTP ,
58 .Nm fetchPutFTP ,
59 .Nm fetchStatFTP ,
60 .Nm fetchListFTP
61 .Nd file transfer functions
62 .Sh LIBRARY
63 .Lb libfetch
64 .Sh SYNOPSIS
65 .In sys/param.h
66 .In stdio.h
67 .In fetch.h
68 .Ft struct url *
69 .Fn fetchMakeURL "const char *scheme" "const char *host" "int port" "const char *doc" "const char *user" "const char *pwd"
70 .Ft struct url *
71 .Fn fetchParseURL "const char *URL"
72 .Ft void
73 .Fn fetchFreeURL "struct url *u"
74 .Ft FILE *
75 .Fn fetchXGetURL "const char *URL" "struct url_stat *us" "const char *flags"
76 .Ft FILE *
77 .Fn fetchGetURL "const char *URL" "const char *flags"
78 .Ft FILE *
79 .Fn fetchPutURL "const char *URL" "const char *flags"
80 .Ft int
81 .Fn fetchStatURL "const char *URL" "struct url_stat *us" "const char *flags"
82 .Ft struct url_ent *
83 .Fn fetchListURL "const char *URL" "const char *flags"
84 .Ft FILE *
85 .Fn fetchXGet "struct url *u" "struct url_stat *us" "const char *flags"
86 .Ft FILE *
87 .Fn fetchGet "struct url *u" "const char *flags"
88 .Ft FILE *
89 .Fn fetchPut "struct url *u" "const char *flags"
90 .Ft int
91 .Fn fetchStat "struct url *u" "struct url_stat *us" "const char *flags"
92 .Ft struct url_ent *
93 .Fn fetchList "struct url *u" "const char *flags"
94 .Ft FILE *
95 .Fn fetchXGetFile "struct url *u" "struct url_stat *us" "const char *flags"
96 .Ft FILE *
97 .Fn fetchGetFile "struct url *u" "const char *flags"
98 .Ft FILE *
99 .Fn fetchPutFile "struct url *u" "const char *flags"
100 .Ft int
101 .Fn fetchStatFile "struct url *u" "struct url_stat *us" "const char *flags"
102 .Ft struct url_ent *
103 .Fn fetchListFile "struct url *u" "const char *flags"
104 .Ft FILE *
105 .Fn fetchXGetHTTP "struct url *u" "struct url_stat *us" "const char *flags"
106 .Ft FILE *
107 .Fn fetchGetHTTP "struct url *u" "const char *flags"
108 .Ft FILE *
109 .Fn fetchPutHTTP "struct url *u" "const char *flags"
110 .Ft int
111 .Fn fetchStatHTTP "struct url *u" "struct url_stat *us" "const char *flags"
112 .Ft struct url_ent *
113 .Fn fetchListHTTP "struct url *u" "const char *flags"
114 .Ft FILE *
115 .Fn fetchXGetFTP "struct url *u" "struct url_stat *us" "const char *flags"
116 .Ft FILE *
117 .Fn fetchGetFTP "struct url *u" "const char *flags"
118 .Ft FILE *
119 .Fn fetchPutFTP "struct url *u" "const char *flags"
120 .Ft int
121 .Fn fetchStatFTP "struct url *u" "struct url_stat *us" "const char *flags"
122 .Ft struct url_ent *
123 .Fn fetchListFTP "struct url *u" "const char *flags"
124 .Sh DESCRIPTION
125 These functions implement a high-level library for retrieving and
126 uploading files using Uniform Resource Locators (URLs).
127 .Pp
128 .Fn fetchParseURL
129 takes a URL in the form of a null-terminated string and splits it into
130 its components function according to the Common Internet Scheme Syntax
131 detailed in RFC1738.
132 A regular expression which produces this syntax is:
133 .Bd -literal
134 <scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
135 .Ed
136 .Pp
137 If the URL does not seem to begin with a scheme name, the following
138 syntax is assumed:
139 .Bd -literal
140 ((<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
141 .Ed
142 .Pp
143 Note that some components of the URL are not necessarily relevant to
144 all URL schemes.
145 For instance, the file scheme only needs the <scheme> and <document>
146 components.
147 .Pp
148 .Fn fetchMakeURL
149 and
150 .Fn fetchParseURL
151 return a pointer to a
152 .Vt url
153 structure, which is defined as follows in
154 .In fetch.h :
155 .Bd -literal
156 #define URL_SCHEMELEN 16
157 #define URL_USERLEN 256
158 #define URL_PWDLEN 256
160 struct url {
161 char scheme[URL_SCHEMELEN+1];
162 char user[URL_USERLEN+1];
163 char pwd[URL_PWDLEN+1];
164 char host[MAXHOSTNAMELEN+1];
165 int port;
166 char *doc;
167 off_t offset;
168 size_t length;
169 time_t ims_time;
170 };
171 .Ed
172 .Pp
173 The
174 .Va ims_time
175 field stores the time value for
176 .Li If-Modified-Since
177 HTTP requests.
178 .Pp
179 The pointer returned by
180 .Fn fetchMakeURL
181 or
182 .Fn fetchParseURL
183 should be freed using
184 .Fn fetchFreeURL .
185 .Pp
186 .Fn fetchXGetURL ,
187 .Fn fetchGetURL ,
188 and
189 .Fn fetchPutURL
190 constitute the recommended interface to the
191 .Nm fetch
192 library.
193 They examine the URL passed to them to determine the transfer
194 method, and call the appropriate lower-level functions to perform the
195 actual transfer.
196 .Fn fetchXGetURL
197 also returns the remote document's metadata in the
198 .Vt url_stat
199 structure pointed to by the
200 .Fa us
201 argument.
202 .Pp
203 The
204 .Fa flags
205 argument is a string of characters which specify transfer options.
206 The
207 meaning of the individual flags is scheme-dependent, and is detailed
208 in the appropriate section below.
209 .Pp
210 .Fn fetchStatURL
211 attempts to obtain the requested document's metadata and fill in the
212 structure pointed to by its second argument.
213 The
214 .Vt url_stat
215 structure is defined as follows in
216 .In fetch.h :
217 .Bd -literal
218 struct url_stat {
219 off_t size;
220 time_t atime;
221 time_t mtime;
222 };
223 .Ed
224 .Pp
225 If the size could not be obtained from the server, the
226 .Fa size
227 field is set to -1.
228 If the modification time could not be obtained from the server, the
229 .Fa mtime
230 field is set to the epoch.
231 If the access time could not be obtained from the server, the
232 .Fa atime
233 field is set to the modification time.
234 .Pp
235 .Fn fetchListURL
236 attempts to list the contents of the directory pointed to by the URL
237 provided.
238 If successful, it returns a malloced array of
239 .Vt url_ent
240 structures.
241 The
242 .Vt url_ent
243 structure is defined as follows in
244 .In fetch.h :
245 .Bd -literal
246 struct url_ent {
247 char name[PATH_MAX];
248 struct url_stat stat;
249 };
250 .Ed
251 .Pp
252 The list is terminated by an entry with an empty name.
253 .Pp
254 The pointer returned by
255 .Fn fetchListURL
256 should be freed using
257 .Fn free .
258 .Pp
259 .Fn fetchXGet ,
260 .Fn fetchGet ,
261 .Fn fetchPut
262 and
263 .Fn fetchStat
264 are similar to
265 .Fn fetchXGetURL ,
266 .Fn fetchGetURL ,
267 .Fn fetchPutURL
268 and
269 .Fn fetchStatURL ,
270 except that they expect a pre-parsed URL in the form of a pointer to
271 a
272 .Vt struct url
273 rather than a string.
274 .Pp
275 All of the
276 .Fn fetchXGetXXX ,
277 .Fn fetchGetXXX
278 and
279 .Fn fetchPutXXX
280 functions return a pointer to a stream which can be used to read or
281 write data from or to the requested document, respectively.
282 Note that
283 although the implementation details of the individual access methods
284 vary, it can generally be assumed that a stream returned by one of the
285 .Fn fetchXGetXXX
286 or
287 .Fn fetchGetXXX
288 functions is read-only, and that a stream returned by one of the
289 .Fn fetchPutXXX
290 functions is write-only.
291 .Sh FILE SCHEME
292 .Fn fetchXGetFile ,
293 .Fn fetchGetFile
294 and
295 .Fn fetchPutFile
296 provide access to documents which are files in a locally mounted file
297 system.
298 Only the <document> component of the URL is used.
299 .Pp
300 .Fn fetchXGetFile
301 and
302 .Fn fetchGetFile
303 do not accept any flags.
304 .Pp
305 .Fn fetchPutFile
306 accepts the
307 .Ql a
308 (append to file) flag.
309 If that flag is specified, the data written to
310 the stream returned by
311 .Fn fetchPutFile
312 will be appended to the previous contents of the file, instead of
313 replacing them.
314 .Sh FTP SCHEME
315 .Fn fetchXGetFTP ,
316 .Fn fetchGetFTP
317 and
318 .Fn fetchPutFTP
319 implement the FTP protocol as described in RFC959.
320 .Pp
321 If the
322 .Ql P
323 (not passive) flag is specified, an active (rather than passive)
324 connection will be attempted.
325 .Pp
326 The
327 .Ql p
328 flag is supported for compatibility with earlier versions where active
329 connections were the default.
330 It has precedence over the
331 .Ql P
332 flag, so if both are specified,
333 .Nm
334 will use a passive connection.
335 .Pp
336 If the
337 .Ql l
338 (low) flag is specified, data sockets will be allocated in the low (or
339 default) port range instead of the high port range (see
340 .Xr ip 4 ) .
341 .Pp
342 If the
343 .Ql d
344 (direct) flag is specified,
345 .Fn fetchXGetFTP ,
346 .Fn fetchGetFTP
347 and
348 .Fn fetchPutFTP
349 will use a direct connection even if a proxy server is defined.
350 .Pp
351 If no user name or password is given, the
352 .Nm fetch
353 library will attempt an anonymous login, with user name "anonymous"
354 and password "anonymous@<hostname>".
355 .Sh HTTP SCHEME
356 The
357 .Fn fetchXGetHTTP ,
358 .Fn fetchGetHTTP
359 and
360 .Fn fetchPutHTTP
361 functions implement the HTTP/1.1 protocol.
362 With a little luck, there is
363 even a chance that they comply with RFC2616 and RFC2617.
364 .Pp
365 If the
366 .Ql d
367 (direct) flag is specified,
368 .Fn fetchXGetHTTP ,
369 .Fn fetchGetHTTP
370 and
371 .Fn fetchPutHTTP
372 will use a direct connection even if a proxy server is defined.
373 .Pp
374 If the
375 .Ql i
376 (if-modified-since) flag is specified, and
377 the
378 .Va ims_time
379 field is set in
380 .Vt "struct url" ,
381 then
382 .Fn fetchXGetHTTP
383 and
384 .Fn fetchGetHTTP
385 will send a conditional
386 .Li If-Modified-Since
387 HTTP header to only fetch the content if it is newer than
388 .Va ims_time .
389 .Pp
390 Since there seems to be no good way of implementing the HTTP PUT
391 method in a manner consistent with the rest of the
392 .Nm fetch
393 library,
394 .Fn fetchPutHTTP
395 is currently unimplemented.
396 .Sh HTTPS SCHEME
397 Based on HTTP SCHEME.
398 By default the peer is verified using the CA bundle located in
399 .Pa /etc/ssl/cert.pem .
400 The file may contain multiple CA certificates.
401 A common source of a current CA bundle is
402 .Pa \%security/ca_root_nss .
403 .Pp
404 The CA bundle used for peer verification can be changed by setting the
405 environment variables
406 .Ev SSL_CA_CERT_FILE
407 to point to a concatenated bundle of trusted certificates and
408 .Ev SSL_CA_CERT_PATH
409 to point to a directory containing hashes of trusted CAs (see
410 .Xr verify 1 ) .
411 .Pp
412 A certificate revocation list (CRL) can be used by setting the
413 environment variable
414 .Ev SSL_CRL_FILE
415 (see
416 .Xr crl 1 ) .
417 .Pp
418 Peer verification can be disabled by setting the environment variable
419 .Ev SSL_NO_VERIFY_PEER .
420 Note that this also disables CRL checking.
421 .Pp
422 By default the service identity is verified according to the rules
423 detailed in RFC6125 (also known as hostname verification).
424 This feature can be disabled by setting the environment variable
425 .Ev SSL_NO_VERIFY_HOSTNAME .
426 .Pp
427 Client certificate based authentication is supported.
428 The environment variable
429 .Ev SSL_CLIENT_CERT_FILE
430 should be set to point to a file containing key and client certificate
431 to be used in PEM format. In case the key is stored in a separate
432 file, the environment variable
433 .Ev SSL_CLIENT_KEY_FILE
434 can be set to point to the key in PEM format.
435 In case the key uses a password, the user will be prompted on standard
436 input (see
437 .Xr PEM 3 ) .
438 .Pp
439 By default
440 .Nm libfetch
441 allows SSLv3 and TLSv1 when negotiating the connecting with the remote
442 peer.
443 You can change this behavior by setting the environment variable
444 .Ev SSL_ALLOW_SSL2
445 to allow SSLv2 (not recommended) and
446 .Ev SSL_NO_SSL3
447 or
448 .Ev SSL_NO_TLS1
449 to disable the respective methods.
450 .Sh AUTHENTICATION
451 Apart from setting the appropriate environment variables and
452 specifying the user name and password in the URL or the
453 .Vt struct url ,
454 the calling program has the option of defining an authentication
455 function with the following prototype:
456 .Pp
457 .Ft int
458 .Fn myAuthMethod "struct url *u"
459 .Pp
460 The callback function should fill in the
461 .Fa user
462 and
463 .Fa pwd
464 fields in the provided
465 .Vt struct url
466 and return 0 on success, or any other value to indicate failure.
467 .Pp
468 To register the authentication callback, simply set
469 .Va fetchAuthMethod
470 to point at it.
471 The callback will be used whenever a site requires authentication and
472 the appropriate environment variables are not set.
473 .Pp
474 This interface is experimental and may be subject to change.
475 .Sh RETURN VALUES
476 .Fn fetchParseURL
477 returns a pointer to a
478 .Vt struct url
479 containing the individual components of the URL.
480 If it is
481 unable to allocate memory, or the URL is syntactically incorrect,
482 .Fn fetchParseURL
483 returns a NULL pointer.
484 .Pp
485 The
486 .Fn fetchStat
487 functions return 0 on success and -1 on failure.
488 .Pp
489 All other functions return a stream pointer which may be used to
490 access the requested document, or NULL if an error occurred.
491 .Pp
492 The following error codes are defined in
493 .In fetch.h :
494 .Bl -tag -width 18n
495 .It Bq Er FETCH_ABORT
496 Operation aborted
497 .It Bq Er FETCH_AUTH
498 Authentication failed
499 .It Bq Er FETCH_DOWN
500 Service unavailable
501 .It Bq Er FETCH_EXISTS
502 File exists
503 .It Bq Er FETCH_FULL
504 File system full
505 .It Bq Er FETCH_INFO
506 Informational response
507 .It Bq Er FETCH_MEMORY
508 Insufficient memory
509 .It Bq Er FETCH_MOVED
510 File has moved
511 .It Bq Er FETCH_NETWORK
512 Network error
513 .It Bq Er FETCH_OK
514 No error
515 .It Bq Er FETCH_PROTO
516 Protocol error
517 .It Bq Er FETCH_RESOLV
518 Resolver error
519 .It Bq Er FETCH_SERVER
520 Server error
521 .It Bq Er FETCH_TEMP
522 Temporary error
523 .It Bq Er FETCH_TIMEOUT
524 Operation timed out
525 .It Bq Er FETCH_UNAVAIL
526 File is not available
527 .It Bq Er FETCH_UNKNOWN
528 Unknown error
529 .It Bq Er FETCH_URL
530 Invalid URL
531 .El
532 .Pp
533 The accompanying error message includes a protocol-specific error code
534 and message, e.g.\& "File is not available (404 Not Found)"
535 .Sh ENVIRONMENT
536 .Bl -tag -width ".Ev FETCH_BIND_ADDRESS"
537 .It Ev FETCH_BIND_ADDRESS
538 Specifies a hostname or IP address to which sockets used for outgoing
539 connections will be bound.
540 .It Ev FTP_LOGIN
541 Default FTP login if none was provided in the URL.
542 .It Ev FTP_PASSIVE_MODE
543 If set to
544 .Ql no ,
545 forces the FTP code to use active mode.
546 If set to any other value, forces passive mode even if the application
547 requested active mode.
548 .It Ev FTP_PASSWORD
549 Default FTP password if the remote server requests one and none was
550 provided in the URL.
551 .It Ev FTP_PROXY
552 URL of the proxy to use for FTP requests.
553 The document part is ignored.
554 FTP and HTTP proxies are supported; if no scheme is specified, FTP is
555 assumed.
556 If the proxy is an FTP proxy,
557 .Nm libfetch
558 will send
559 .Ql user@host
560 as user name to the proxy, where
561 .Ql user
562 is the real user name, and
563 .Ql host
564 is the name of the FTP server.
565 .Pp
566 If this variable is set to an empty string, no proxy will be used for
567 FTP requests, even if the
568 .Ev HTTP_PROXY
569 variable is set.
570 .It Ev ftp_proxy
571 Same as
572 .Ev FTP_PROXY ,
573 for compatibility.
574 .It Ev HTTP_ACCEPT
575 Specifies the value of the
576 .Va Accept
577 header for HTTP requests.
578 If empty, no
579 .Va Accept
580 header is sent.
581 The default is
582 .Dq */* .
583 .It Ev HTTP_AUTH
584 Specifies HTTP authorization parameters as a colon-separated list of
585 items.
586 The first and second item are the authorization scheme and realm
587 respectively; further items are scheme-dependent.
588 Currently, the
589 .Dq basic
590 and
591 .Dq digest
592 authorization methods are supported.
593 .Pp
594 Both methods require two parameters: the user name and
595 password, in that order.
596 .Pp
597 This variable is only used if the server requires authorization and
598 no user name or password was specified in the URL.
599 .It Ev HTTP_PROXY
600 URL of the proxy to use for HTTP requests.
601 The document part is ignored.
602 Only HTTP proxies are supported for HTTP requests.
603 If no port number is specified, the default is 3128.
604 .Pp
605 Note that this proxy will also be used for FTP documents, unless the
606 .Ev FTP_PROXY
607 variable is set.
608 .It Ev http_proxy
609 Same as
610 .Ev HTTP_PROXY ,
611 for compatibility.
612 .It Ev HTTP_PROXY_AUTH
613 Specifies authorization parameters for the HTTP proxy in the same
614 format as the
615 .Ev HTTP_AUTH
616 variable.
617 .Pp
618 This variable is used if and only if connected to an HTTP proxy, and
619 is ignored if a user and/or a password were specified in the proxy
620 URL.
621 .It Ev HTTP_REFERER
622 Specifies the referrer URL to use for HTTP requests.
623 If set to
624 .Dq auto ,
625 the document URL will be used as referrer URL.
626 .It Ev HTTP_USER_AGENT
627 Specifies the User-Agent string to use for HTTP requests.
628 This can be useful when working with HTTP origin or proxy servers that
629 differentiate between user agents.
630 .It Ev NETRC
631 Specifies a file to use instead of
632 .Pa ~/.netrc
633 to look up login names and passwords for FTP sites.
634 See
635 .Xr ftp 1
636 for a description of the file format.
637 This feature is experimental.
638 .It Ev NO_PROXY
639 Either a single asterisk, which disables the use of proxies
640 altogether, or a comma- or whitespace-separated list of hosts for
641 which proxies should not be used.
642 .It Ev no_proxy
643 Same as
644 .Ev NO_PROXY ,
645 for compatibility.
646 .It Ev SSL_ALLOW_SSL2
647 Allow SSL version 2 when negotiating the connection (not recommended).
648 .It Ev SSL_CA_CERT_FILE
649 CA certificate bundle containing trusted CA certificates.
650 Default value:
651 .Pa /etc/ssl/cert.pem .
652 .It Ev SSL_CA_CERT_PATH
653 Path containing trusted CA hashes.
654 .It Ev SSL_CLIENT_CERT_FILE
655 PEM encoded client certificate/key which will be used in
656 client certificate authentication.
657 .It Ev SSL_CLIENT_KEY_FILE
658 PEM encoded client key in case key and client certificate
659 are stored separately.
660 .It Ev SSL_CRL_FILE
661 File containing certificate revocation list.
662 .It Ev SSL_NO_SSL3
663 Don't allow SSL version 3 when negotiating the connection.
664 .It Ev SSL_NO_TLS1
665 Don't allow TLV version 1 when negotiating the connection.
666 .It Ev SSL_NO_VERIFY_HOSTNAME
667 If set, do not verify that the hostname matches the subject of the
668 certificate presented by the server.
669 .It Ev SSL_NO_VERIFY_PEER
670 If set, do not verify the peer certificate against trusted CAs.
671 .El
672 .Sh EXAMPLES
673 To access a proxy server on
674 .Pa proxy.example.com
675 port 8080, set the
676 .Ev HTTP_PROXY
677 environment variable in a manner similar to this:
678 .Pp
679 .Dl HTTP_PROXY=http://proxy.example.com:8080
680 .Pp
681 If the proxy server requires authentication, there are
682 two options available for passing the authentication data.
683 The first method is by using the proxy URL:
684 .Pp
685 .Dl HTTP_PROXY=http://<user>:<pwd>@proxy.example.com:8080
686 .Pp
687 The second method is by using the
688 .Ev HTTP_PROXY_AUTH
689 environment variable:
690 .Bd -literal -offset indent
691 HTTP_PROXY=http://proxy.example.com:8080
692 HTTP_PROXY_AUTH=basic:*:<user>:<pwd>
693 .Ed
694 .Pp
695 To disable the use of a proxy for an HTTP server running on the local
696 host, define
697 .Ev NO_PROXY
698 as follows:
699 .Bd -literal -offset indent
700 NO_PROXY=localhost,127.0.0.1
701 .Ed
702 .Pp
703 Access HTTPS website without any certificate verification whatsoever:
704 .Bd -literal -offset indent
705 SSL_NO_VERIFY_PEER=1
706 SSL_NO_VERIFY_HOSTNAME=1
707 .Ed
708 .Pp
709 Access HTTPS website using client certificate based authentication
710 and a private CA:
711 .Bd -literal -offset indent
712 SSL_CLIENT_CERT_FILE=/path/to/client.pem
713 SSL_CA_CERT_FILE=/path/to/myca.pem
714 .Ed
715 .Sh SEE ALSO
716 .Xr fetch 1 ,
717 .Xr ftpio 3 ,
718 .Xr ip 4
719 .Rs
720 .%A J. Postel
721 .%A J. K. Reynolds
722 .%D October 1985
723 .%B File Transfer Protocol
724 .%O RFC959
725 .Re
726 .Rs
727 .%A P. Deutsch
728 .%A A. Emtage
729 .%A A. Marine.
730 .%D May 1994
731 .%T How to Use Anonymous FTP
732 .%O RFC1635
733 .Re
734 .Rs
735 .%A T. Berners-Lee
736 .%A L. Masinter
737 .%A M. McCahill
738 .%D December 1994
739 .%T Uniform Resource Locators (URL)
740 .%O RFC1738
741 .Re
742 .Rs
743 .%A R. Fielding
744 .%A J. Gettys
745 .%A J. Mogul
746 .%A H. Frystyk
747 .%A L. Masinter
748 .%A P. Leach
749 .%A T. Berners-Lee
750 .%D January 1999
751 .%B Hypertext Transfer Protocol -- HTTP/1.1
752 .%O RFC2616
753 .Re
754 .Rs
755 .%A J. Franks
756 .%A P. Hallam-Baker
757 .%A J. Hostetler
758 .%A S. Lawrence
759 .%A P. Leach
760 .%A A. Luotonen
761 .%A L. Stewart
762 .%D June 1999
763 .%B HTTP Authentication: Basic and Digest Access Authentication
764 .%O RFC2617
765 .Re
766 .Sh HISTORY
767 The
768 .Nm fetch
769 library first appeared in
770 .Fx 3.0 .
771 .Sh AUTHORS
772 .An -nosplit
773 The
774 .Nm fetch
775 library was mostly written by
776 .An Dag-Erling Sm\(/orgrav Aq Mt des@FreeBSD.org
777 with numerous suggestions and contributions from
778 .An Jordan K. Hubbard Aq Mt jkh@FreeBSD.org ,
779 .An Eugene Skepner Aq Mt eu@qub.com ,
780 .An Hajimu Umemoto Aq Mt ume@FreeBSD.org ,
781 .An Henry Whincup Aq Mt henry@techiebod.com ,
782 .An Jukka A. Ukkonen Aq Mt jau@iki.fi ,
783 .An Jean-Fran\(,cois Dockes Aq Mt jf@dockes.org ,
784 .An Michael Gmelin Aq Mt freebsd@grem.de
785 and others.
786 It replaces the older
787 .Nm ftpio
788 library written by
789 .An Poul-Henning Kamp Aq Mt phk@FreeBSD.org
790 and
791 .An Jordan K. Hubbard Aq Mt jkh@FreeBSD.org .
792 .Pp
793 This manual page was written by
794 .An Dag-Erling Sm\(/orgrav Aq Mt des@FreeBSD.org
795 and
796 .An Michael Gmelin Aq Mt freebsd@grem.de .
797 .Sh BUGS
798 Some parts of the library are not yet implemented.
799 The most notable
800 examples of this are
801 .Fn fetchPutHTTP ,
802 .Fn fetchListHTTP ,
803 .Fn fetchListFTP
804 and FTP proxy support.
805 .Pp
806 There is no way to select a proxy at run-time other than setting the
807 .Ev HTTP_PROXY
808 or
809 .Ev FTP_PROXY
810 environment variables as appropriate.
811 .Pp
812 .Nm libfetch
813 does not understand or obey 305 (Use Proxy) replies.
814 .Pp
815 Error numbers are unique only within a certain context; the error
816 codes used for FTP and HTTP overlap, as do those used for resolver and
817 system errors.
818 For instance, error code 202 means "Command not
819 implemented, superfluous at this site" in an FTP context and
820 "Accepted" in an HTTP context.
821 .Pp
822 .Fn fetchStatFTP
823 does not check that the result of an MDTM command is a valid date.
824 .Pp
825 In case password protected keys are used for client certificate based
826 authentication the user is prompted for the password on each and every
827 fetch operation.
828 .Pp
829 The man page is incomplete, poorly written and produces badly
830 formatted text.
831 .Pp
832 The error reporting mechanism is unsatisfactory.
833 .Pp
834 Some parts of the code are not fully reentrant.