1 .\" Copyright (c) 1998 Dag-Erling Coïdan Smørgrav
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59 .Nd file transfer functions
63 .Fd #include <sys/param.h>
64 .Fd #include <stdio.h>
65 .Fd #include <fetch.h>
67 .Fn fetchMakeURL "const char *scheme" "const char *host" "int port" "const char *doc" "const char *user" "const char *pwd"
69 .Fn fetchParseURL "const char *URL"
71 .Fn fetchFreeURL "struct url *u"
73 .Fn fetchXGetURL "const char *URL" "struct url_stat *us" "const char *flags"
75 .Fn fetchGetURL "const char *URL" "const char *flags"
77 .Fn fetchPutURL "const char *URL" "const char *flags"
79 .Fn fetchStatURL "const char *URL" "struct url_stat *us" "const char *flags"
81 .Fn fetchListURL "const char *URL" "const char *flags"
83 .Fn fetchXGet "struct url *u" "struct url_stat *us" "const char *flags"
85 .Fn fetchGet "struct url *u" "const char *flags"
87 .Fn fetchPut "struct url *u" "const char *flags"
89 .Fn fetchStat "struct url *u" "struct url_stat *us" "const char *flags"
91 .Fn fetchList "struct url *u" "const char *flags"
93 .Fn fetchXGetFile "struct url *u" "struct url_stat *us" "const char *flags"
95 .Fn fetchGetFile "struct url *u" "const char *flags"
97 .Fn fetchPutFile "struct url *u" "const char *flags"
99 .Fn fetchStatFile "struct url *u" "struct url_stat *us" "const char *flags"
101 .Fn fetchListFile "struct url *u" "const char *flags"
103 .Fn fetchXGetHTTP "struct url *u" "struct url_stat *us" "const char *flags"
105 .Fn fetchGetHTTP "struct url *u" "const char *flags"
107 .Fn fetchPutHTTP "struct url *u" "const char *flags"
109 .Fn fetchStatHTTP "struct url *u" "struct url_stat *us" "const char *flags"
111 .Fn fetchListHTTP "struct url *u" "const char *flags"
113 .Fn fetchXGetFTP "struct url *u" "struct url_stat *us" "const char *flags"
115 .Fn fetchGetFTP "struct url *u" "const char *flags"
117 .Fn fetchPutFTP "struct url *u" "const char *flags"
119 .Fn fetchStatFTP "struct url *u" "struct url_stat *us" "const char *flags"
121 .Fn fetchListFTP "struct url *u" "const char *flags"
124 These functions implement a high-level library for retrieving and
125 uploading files using Uniform Resource Locators (URLs).
128 takes a URL in the form of a null-terminated string and splits it into
129 its components function according to the Common Internet Scheme Syntax
131 A regular expression which produces this syntax is:
133 <scheme>:(//(<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
136 If the URL does not seem to begin with a scheme name, the following
139 ((<user>(:<pwd>)?@)?<host>(:<port>)?)?/(<document>)?
142 Note that some components of the URL are not necessarily relevant to
144 For instance, the file scheme only needs the <scheme> and <document>
150 return a pointer to a
152 structure, which is defined as follows in
155 #define URL_SCHEMELEN 16
156 #define URL_USERLEN 256
157 #define URL_PWDLEN 256
160 char scheme[URL_SCHEMELEN+1];
161 char user[URL_USERLEN+1];
162 char pwd[URL_PWDLEN+1];
163 char host[MAXHOSTNAMELEN+1];
171 The pointer returned by
175 should be freed using
182 constitute the recommended interface to the
185 They examine the URL passed to them to determine the transfer
186 method, and call the appropriate lower-level functions to perform the
189 also returns the remote document's metadata in the
191 structure pointed to by the
197 argument is a string of characters which specify transfer options.
199 meaning of the individual flags is scheme-dependent, and is detailed
200 in the appropriate section below.
203 attempts to obtain the requested document's metadata and fill in the
204 structure pointed to by its second argument.
207 structure is defined as follows in
217 If the size could not be obtained from the server, the
220 If the modification time could not be obtained from the server, the
222 field is set to the epoch.
223 If the access time could not be obtained from the server, the
225 field is set to the modification time.
228 attempts to list the contents of the directory pointed to by the URL
230 If successful, it returns a malloced array of
235 structure is defined as follows in
239 char name[MAXPATHLEN];
240 struct url_stat stat;
244 The list is terminated by an entry with an empty name.
246 The pointer returned by
248 should be freed using
262 except that they expect a pre-parsed URL in the form of a pointer to
265 rather than a string.
272 functions return a pointer to a stream which can be used to read or
273 write data from or to the requested document, respectively.
275 although the implementation details of the individual access methods
276 vary, it can generally be assumed that a stream returned by one of the
280 functions is read-only, and that a stream returned by one of the
282 functions is write-only.
288 provide access to documents which are files in a locally mounted file
290 Only the <document> component of the URL is used.
295 do not accept any flags.
300 (append to file) flag.
301 If that flag is specified, the data written to
302 the stream returned by
304 will be appended to the previous contents of the file, instead of
311 implement the FTP protocol as described in RFC959.
315 (passive) flag is specified, a passive (rather than active) connection
320 (low) flag is specified, data sockets will be allocated in the low (or
321 default) port range instead of the hifh port range (see
326 (direct) flag is specified,
331 will use a direct connection even if a proxy server is defined.
333 If no user name or password is given, the
335 library will attempt an anonymous login, with user name "anonymous"
336 and password "anonymous@<hostname>".
343 functions implement the HTTP/1.1 protocol.
344 With a little luck, there's
345 even a chance that they comply with RFC2616 and RFC2617.
349 (direct) flag is specified,
354 will use a direct connection even if a proxy server is defined.
356 Since there seems to be no good way of implementing the HTTP PUT
357 method in a manner consistent with the rest of the
361 is currently unimplemented.
363 Apart from setting the appropriate environment variables and
364 specifying the user name and password in the URL or the
366 the calling program has the option of defining an authentication
367 function with the following prototype:
370 .Fn myAuthMethod "struct url *u"
372 The callback function should fill in the
376 fields in the provided
378 and return 0 on success, or any other value to indicate failure.
380 To register the authentication callback, simply set
383 The callback will be used whenever a site requires authentication and
384 the appropriate environment variables aren't set.
386 This interface is experimental and may be subject to change.
389 returns a pointer to a
391 containing the individual components of the URL.
393 unable to allocate memory, or the URL is syntactically incorrect,
395 returns a NULL pointer.
399 functions return 0 on success and -1 on failure.
401 All other functions return a stream pointer which may be used to
402 access the requested document, or NULL if an error occurred.
404 The following error codes are defined in
407 .It Bq Er FETCH_ABORT
410 Authentication failed
413 .It Bq Er FETCH_EXISTS
418 Informational response
419 .It Bq Er FETCH_MEMORY
421 .It Bq Er FETCH_MOVED
423 .It Bq Er FETCH_NETWORK
427 .It Bq Er FETCH_PROTO
429 .It Bq Er FETCH_RESOLV
431 .It Bq Er FETCH_SERVER
435 .It Bq Er FETCH_TIMEOUT
437 .It Bq Er FETCH_UNAVAIL
438 File is not available
439 .It Bq Er FETCH_UNKNOWN
445 The accompanying error message includes a protocol-specific error code
446 and message, e.g. "File is not available (404 Not Found)"
448 .Bl -tag -width FTP_PASSIVE_MODE
450 Default FTP login if none was provided in the URL.
451 .It Ev FTP_PASSIVE_MODE
452 If set to anything but
454 forces the FTP code to use passive mode.
456 Default FTP password if the remote server requests one and none was
459 URL of the proxy to use for FTP requests.
460 The document part is ignored.
461 FTP and HTTP proxies are supported; if no scheme is specified, FTP is
463 If the proxy is an FTP proxy,
467 as user name to the proxy, where
469 is the real user name, and
471 is the name of the FTP server.
473 If this variable is set to an empty string, no proxy will be used for
474 FTP requests, even if the
482 Specifies HTTP authorization parameters as a colon-separated list of
484 The first and second item are the authorization scheme and realm
485 respectively; further items are scheme-dependent.
486 Currently, only basic authorization is supported.
488 Basic authorization requires two parameters: the user name and
489 password, in that order.
491 This variable is only used if the server requires authorization and
492 no user name or password was specified in the URL.
494 URL of the proxy to use for HTTP requests.
495 The document part is ignored.
496 Only HTTP proxies are supported for HTTP requests.
497 If no port number is specified, the default is 3128.
499 Note that this proxy will also be used for FTP documents, unless the
506 .It Ev HTTP_PROXY_AUTH
507 Specifies authorization parameters for the HTTP proxy in the same
512 This variable is used if and only if connected to an HTTP proxy, and
513 is ignored if a user and/or a password were specified in the proxy
515 .It Ev HTTP_USER_AGENT
516 Specifies the User-Agent string to use for HTTP requests.
517 This can be useful when working with HTTP origin or proxy servers that
518 differentiate between usder agents.
528 .%B File Transfer Protocol
536 .%T How to Use Anonymous FTP
544 .%T Uniform Resource Locators (URL)
556 .%B Hypertext Transfer Protocol -- HTTP/1.1
568 .%B HTTP Authentication: Basic and Digest Access Authentication
574 library first appeared in
580 library was mostly written by
581 .An Dag-Erling Co\(:idan Sm\(/orgrav Aq des@FreeBSD.org
582 with numerous suggestions from
583 .An Jordan K. Hubbard Aq jkh@FreeBSD.org ,
584 .An Eugene Skepner Aq eu@qub.com
588 It replaces the older
591 .An Poul-Henning Kamp Aq pkh@FreeBSD.org
593 .An Jordan K. Hubbard Aq jkh@FreeBSD.org .
595 This manual page was written by
596 .An Dag-Erling Co\(:idan Sm\(/orgrav Aq des@FreeBSD.org .
598 Some parts of the library are not yet implemented.
604 and FTP proxy support.
606 There's no way to select a proxy at run-time other than setting the
610 environment variables as appropriate.
613 does not understand or obey 305 (Use Proxy) replies.
615 Error numbers are unique only within a certain context; the error
616 codes used for FTP and HTTP overlap, as do those used for resolver and
618 For instance, error code 202 means "Command not
619 implemented, superfluous at this site" in an FTP context and
620 "Accepted" in an HTTP context.
623 does not check that the result of an MDTM command is a valid date.
625 The man page is incomplete, poorly written and produces badly
628 The error reporting mechanism is unsatisfactory.
630 Some parts of the code are not fully reentrant.