5 \___|\___/|_| \_\_____|
7 Things that could be nice to do in the future
9 Things to do in project cURL. Please tell us what you think, contribute and
10 send us patches that improve things!
12 All bugs documented in the KNOWN_BUGS document are subject for fixing!
17 1.4 signal-based resolver timeouts
18 1.5 get rid of PATH_MAX
19 1.6 progress callback without doubles
20 1.7 Happy Eyeball dual stack connect
22 2. libcurl - multi interface
24 2.2 Fix HTTP Pipelining for PUT
31 4.2 Alter passive/active on failure and retry
32 4.3 Earlier bad letter detection
33 4.4 REST for large files
38 5.1 Better persistency for HTTP 1.0
39 5.2 support FF3 sqlite cookie files
40 5.3 Rearrange request header order
45 6.2 ditch telnet-specific select
46 6.3 feature negotiation debug data
47 6.4 send data in chunks
51 7.2 Graceful base64 decoding failure
52 7.3 Enhanced capability support
56 8.2 Graceful base64 decoding failure
57 8.3 Enhanced capability support
60 9.1 Graceful base64 decoding failure
61 9.2 Enhanced capability support
64 10.1 SASL based authentication mechanisms
70 12.1 Disable specific versions
71 12.2 Provide mutex locking API
72 12.3 Evaluate SSL patches
73 12.4 Cache OpenSSL contexts
74 12.5 Export session ids
75 12.6 Provide callback for cert verification
76 12.7 Support other SSL libraries
77 12.8 improve configure --with-ssl
85 14.1 Other authentication mechanisms
90 15.3 prevent file overwriting
91 15.4 simultaneous parallel transfers
92 15.5 provide formpost headers
93 15.6 url-specific options
94 15.7 warning when setting an option
95 15.8 IPv6 addresses with globbing
102 17.2 nicer lacking perl message
103 17.3 more protocols supported
104 17.4 more platforms supported
107 18.1 http-style HEAD output for ftp
108 18.2 combine error codes
109 18.3 extend CURLOPT_SOCKOPTFUNCTION prototype
111 19. Next major release
112 19.1 cleanup return codes
113 19.2 remove obsolete defines
115 19.4 remove several functions
116 19.5 remove CURLOPT_FAILONERROR
117 19.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
118 19.7 remove progress meter from libcurl
119 19.8 remove 'curl_httppost' from public
120 19.9 have form functions use CURL handle argument
121 19.10 Add CURLOPT_MAIL_CLIENT option
123 ==============================================================================
127 1.2 More data sharing
129 curl_share_* functions already exist and work, and they can be extended to
130 share more. For example, enable sharing of the ares channel and the
135 Use 'struct lifreq' and SIOCGLIFADDR instead of 'struct ifreq' and
136 SIOCGIFADDR on newer Solaris versions as they claim the latter is obsolete.
137 To support ipv6 interface addresses for network interfaces properly.
139 1.4 signal-based resolver timeouts
141 libcurl built without an asynchronous resolver library uses alarm() to time
142 out DNS lookups. When a timeout occurs, this causes libcurl to jump from the
143 signal handler back into the library with a sigsetjmp, which effectively
144 causes libcurl to continue running within the signal handler. This is
145 non-portable and could cause problems on some platforms. A discussion on the
146 problem is available at http://curl.haxx.se/mail/lib-2008-09/0197.html
148 Also, alarm() provides timeout resolution only to the nearest second. alarm
149 ought to be replaced by setitimer on systems that support it.
151 1.5 get rid of PATH_MAX
153 Having code use and rely on PATH_MAX is not nice:
154 http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
156 Currently the SSH based code uses it a bit, but to remove PATH_MAX from there
157 we need libssh2 to properly tell us when we pass in a too small buffer and
158 its current API (as of libssh2 1.2.7) doesn't.
160 1.6 progress callback without doubles
162 The progress callback was introduced way back in the days and the choice to
163 use doubles in the arguments was possibly good at the time. Today the doubles
164 only confuse users and make the amounts less precise. We should introduce
165 another progress callback option that take precedence over the old one and
166 have both co-exist for a forseeable time until we can remove the double-using
169 1.7 Happy Eyeball dual stack connect
171 In order to make alternative technologies not suffer when transitioning, like
172 when introducing IPv6 as an alternative to IPv4 and there are more than one
173 option existing simultaneously there are reasons to reconsider internal
176 To make libcurl do blazing fast IPv6 in a dual-stack configuration, this needs
179 http://tools.ietf.org/html/rfc6555
181 2. libcurl - multi interface
183 2.1 More non-blocking
185 Make sure we don't ever loop because of non-blocking sockets returning
186 EWOULDBLOCK or similar. Blocking cases include:
188 - Name resolves on non-windows unless c-ares is used
189 - NSS SSL connections
190 - HTTP proxy CONNECT operations
191 - SOCKS proxy handshakes
194 - The "DONE" operation (post transfer protocol-specific actions) for the
195 protocols SFTP, SMTP, FTP. Fixing Curl_done() for this is a worthy task.
197 2.2 Fix HTTP Pipelining for PUT
199 HTTP Pipelining can be a way to greatly enhance performance for multiple
200 serial requests and currently libcurl only supports that for HEAD and GET
201 requests but it should also be possible for PUT.
213 HOST is a suggested command in the works for a client to tell which host name
214 to use, to offer FTP servers named-based virtual hosting:
216 http://tools.ietf.org/html/draft-hethmon-mcmurray-ftp-hosts-11
218 4.2 Alter passive/active on failure and retry
220 When trying to connect passively to a server which only supports active
221 connections, libcurl returns CURLE_FTP_WEIRD_PASV_REPLY and closes the
222 connection. There could be a way to fallback to an active connection (and
223 vice versa). http://curl.haxx.se/bug/feature.cgi?id=1754793
225 4.3 Earlier bad letter detection
227 Make the detection of (bad) %0d and %0a codes in FTP url parts earlier in the
228 process to avoid doing a resolve and connect in vain.
230 4.4 REST for large files
232 REST fix for servers not behaving well on >2GB requests. This should fail if
233 the server doesn't set the pointer to the requested index. The tricky
234 (impossible?) part is to figure out if the server did the right thing or not.
236 4.5 FTP proxy support
238 Support the most common FTP proxies, Philip Newton provided a list allegedly
239 from ncftp. This is not a subject without debate, and is probably not really
240 suitable for libcurl. http://curl.haxx.se/mail/archive-2003-04/0126.html
244 FTP ASCII transfers do not follow RFC959. They don't convert the data
249 5.1 Better persistency for HTTP 1.0
251 "Better" support for persistent connections over HTTP 1.0
252 http://curl.haxx.se/bug/feature.cgi?id=1089001
254 5.2 support FF3 sqlite cookie files
256 Firefox 3 is changing from its former format to a a sqlite database instead.
257 We should consider how (lib)curl can/should support this.
258 http://curl.haxx.se/bug/feature.cgi?id=1871388
260 5.3 Rearrange request header order
262 Server implementors often make an effort to detect browser and to reject
263 clients it can detect to not match. One of the last details we cannot yet
264 control in libcurl's HTTP requests, which also can be exploited to detect
265 that libcurl is in fact used even when it tries to impersonate a browser, is
266 the order of the request headers. I propose that we introduce a new option in
267 which you give headers a value, and then when the HTTP request is built it
268 sorts the headers based on that number. We could then have internally created
269 headers use a default value so only headers that need to be moved have to be
274 The first drafts for HTTP2 have been published
275 (http://tools.ietf.org/html/draft-ietf-httpbis-http2-03) and is so far based
276 on SPDY (http://www.chromium.org/spdy) designs and experiences. Chances are
277 it will end up in that style. Chrome and Firefox already support SPDY and
278 lots of web services do.
280 It would make sense to implement SPDY support now and later transition into
281 or add HTTP2 support as well.
283 We should base or HTTP2/SPDY work on a 3rd party library for the protocol
284 fiddling. The Spindy library (http://spindly.haxx.se/) was an attempt to make
285 such a library with an API suitable for use by libcurl but that effort has
286 more or less stalled. spdylay (https://github.com/tatsuhiro-t/spdylay) may
287 be a better option, either used directly or wrapped with a more spindly-like
295 Reading input (to send to the remote server) on stdin is a crappy solution for
296 library purposes. We need to invent a good way for the application to be able
297 to provide the data to send.
299 6.2 ditch telnet-specific select
301 Move the telnet support's network select() loop go away and merge the code
302 into the main transfer loop. Until this is done, the multi interface won't
305 6.3 feature negotiation debug data
307 Add telnet feature negotiation data to the debug callback as header data.
309 6.4 send data in chunks
311 Currently, telnet sends data one byte at a time. This is fine for interactive
312 use, but inefficient for any other. Sent data should be sent in larger
319 Add support for pipelining emails.
321 7.2 Graceful base64 decoding failure
323 Rather than shutting down the session and returning an error when the
324 decoding of a base64 encoded authentication response fails, we should
325 gracefully shutdown the authentication process by sending a * response to the
326 server as per RFC4954.
328 7.3 Enhanced capability support
330 Add the ability, for an application that uses libcurl, to obtain the list of
331 capabilities returned from the EHLO command.
337 Add support for pipelining commands.
339 8.2 Graceful base64 decoding failure
341 Rather than shutting down the session and returning an error when the
342 decoding of a base64 encoded authentication response fails, we should
343 gracefully shutdown the authentication process by sending a * response to the
344 server as per RFC5034.
346 8.3 Enhanced capability support
348 Add the ability, for an application that uses libcurl, to obtain the list of
349 capabilities returned from the CAPA command.
353 9.1 Graceful base64 decoding failure
355 Rather than shutting down the session and returning an error when the
356 decoding of a base64 encoded authentication response fails, we should
357 gracefully shutdown the authentication process by sending a * response to the
358 server as per RFC3501.
360 9.2 Enhanced capability support
362 Add the ability, for an application that uses libcurl, to obtain the list of
363 capabilities returned from the CAPABILITY command.
367 10.1 SASL based authentication mechanisms
369 Currently the LDAP module only supports ldap_simple_bind_s() in order to bind
370 to an LDAP server. However, this function sends username and password details
371 using the simple authentication mechanism (as clear text). However, it should
372 be possible to use ldap_bind_s() instead specifing the security context
373 information ourselves.
379 There's no RFC for the protocol or an URI/URL format. An implementation
380 should most probably use an existing rsync library, such as librsync.
384 12.1 Disable specific versions
386 Provide an option that allows for disabling specific SSL versions, such as
387 SSLv2 http://curl.haxx.se/bug/feature.cgi?id=1767276
389 12.2 Provide mutex locking API
391 Provide a libcurl API for setting mutex callbacks in the underlying SSL
392 library, so that the same application code can use mutex-locking
393 independently of OpenSSL or GnutTLS being used.
395 12.3 Evaluate SSL patches
397 Evaluate/apply Gertjan van Wingerde's SSL patches:
398 http://curl.haxx.se/mail/lib-2004-03/0087.html
400 12.4 Cache OpenSSL contexts
402 "Look at SSL cafile - quick traces look to me like these are done on every
403 request as well, when they should only be necessary once per ssl context (or
404 once per handle)". The major improvement we can rather easily do is to make
405 sure we don't create and kill a new SSL "context" for every request, but
406 instead make one for every connection and re-use that SSL context in the same
407 style connections are re-used. It will make us use slightly more memory but
408 it will libcurl do less creations and deletions of SSL contexts.
410 12.5 Export session ids
412 Add an interface to libcurl that enables "session IDs" to get
413 exported/imported. Cris Bailiff said: "OpenSSL has functions which can
414 serialise the current SSL state to a buffer of your choice, and recover/reset
415 the state from such a buffer at a later date - this is used by mod_ssl for
416 apache to implement and SSL session ID cache".
418 12.6 Provide callback for cert verification
420 OpenSSL supports a callback for customised verification of the peer
421 certificate, but this doesn't seem to be exposed in the libcurl APIs. Could
422 it be? There's so much that could be done if it were!
424 12.7 Support other SSL libraries
426 Make curl's SSL layer capable of using other free SSL libraries. Such as
427 MatrixSSL (http://www.matrixssl.org/).
429 12.8 improve configure --with-ssl
431 make the configure --with-ssl option first check for OpenSSL, then GnuTLS,
436 DNS-Based Authentication of Named Entities (DANE) is a way to provide SSL
437 keys and certs over DNS using DNSSEC as an alternative to the CA model.
438 http://www.rfc-editor.org/rfc/rfc6698.txt
440 An initial patch was posted by Suresh Krishnaswamy on March 7th 2013
441 (http://curl.haxx.se/mail/lib-2013-03/0075.html) but it was a too simple
442 approach. See Daniel's comments:
443 http://curl.haxx.se/mail/lib-2013-03/0103.html . libunbound may be the
444 correct library to base this development on.
448 13.1 SSL engine stuff
450 Is this even possible?
452 13.2 check connection
454 Add a way to check if the connection seems to be alive, to correspond to the
455 SSL_peak() way we use with OpenSSL.
459 14.1 Other authentication mechanisms
461 Add support for GSSAPI to SMTP, POP3 and IMAP.
467 "curl --sync http://example.com/feed[1-100].rss" or
468 "curl --sync http://example.net/{index,calendar,history}.html"
470 Downloads a range or set of URLs using the remote name, but only if the
471 remote file is newer than the local file. A Last-Modified HTTP date header
472 should also be used to set the mod date on the downloaded file.
476 Globbing support for -d and -F, as in 'curl -d "name=foo[0-9]" URL'.
477 This is easily scripted though.
479 15.3 prevent file overwriting
481 Add an option that prevents cURL from overwriting existing local files. When
482 used, and there already is an existing file with the target file name
483 (either -O or -o), a number should be appended (and increased if already
484 existing). So that index.html becomes first index.html.1 and then
487 15.4 simultaneous parallel transfers
489 The client could be told to use maximum N simultaneous parallel transfers and
490 then just make sure that happens. It should of course not make more than one
491 connection to the same remote host. This would require the client to use the
492 multi interface. http://curl.haxx.se/bug/feature.cgi?id=1558595
494 15.5 provide formpost headers
496 Extending the capabilities of the multipart formposting. How about leaving
497 the ';type=foo' syntax as it is and adding an extra tag (headers) which
498 works like this: curl -F "coolfiles=@fil1.txt;headers=@fil1.hdr" where
499 fil1.hdr contains extra headers like
501 Content-Type: text/plain; charset=KOI8-R"
502 Content-Transfer-Encoding: base64
503 X-User-Comment: Please don't use browser specific HTML code
505 which should overwrite the program reasonable defaults (plain/text,
508 15.6 url-specific options
510 Provide a way to make options bound to a specific URL among several on the
511 command line. Possibly by letting ':' separate options between URLs,
514 curl --data foo --url url.com : \
516 --url url3.com --data foo3
518 (More details: http://curl.haxx.se/mail/archive-2004-07/0133.html)
520 The example would do a POST-GET-POST combination on a single command line.
522 15.7 warning when setting an option
524 Display a warning when libcurl returns an error when setting an option.
525 This can be useful to tell when support for a particular feature hasn't been
526 compiled into the library.
528 15.8 IPv6 addresses with globbing
530 Currently the command line client needs to get url globbing disabled (with
531 -g) for it to support IPv6 numerical addresses. This is a rather silly flaw
532 that should be corrected. It probably involves a smarter detection of the
539 Consider extending 'roffit' to produce decent ASCII output, and use that
540 instead of (g)nroff when building src/tool_hugehelp.c
546 Make our own version of stunnel for simple port forwarding to enable HTTPS
547 and FTP-SSL tests without the stunnel dependency, and it could allow us to
548 provide test tools built with either OpenSSL or GnuTLS
550 17.2 nicer lacking perl message
552 If perl wasn't found by the configure script, don't attempt to run the tests
553 but explain something nice why it doesn't.
555 17.3 more protocols supported
557 Extend the test suite to include more protocols. The telnet could just do ftp
558 or http operations (for which we have test servers).
560 17.4 more platforms supported
562 Make the test suite work on more platforms. OpenBSD and Mac OS. Remove
563 fork()s and it should become even more portable.
567 18.1 http-style HEAD output for ftp
569 #undef CURL_FTP_HTTPSTYLE_HEAD in lib/ftp.c to remove the HTTP-style headers
570 from being output in NOBODY requests over ftp
572 18.2 combine error codes
574 Combine some of the error codes to remove duplicates. The original
575 numbering should not be changed, and the old identifiers would be
576 macroed to the new ones in an CURL_NO_OLDIES section to help with
577 backward compatibility.
579 Candidates for removal and their replacements:
581 CURLE_FILE_COULDNT_READ_FILE => CURLE_REMOTE_FILE_NOT_FOUND
583 CURLE_FTP_COULDNT_RETR_FILE => CURLE_REMOTE_FILE_NOT_FOUND
585 CURLE_FTP_COULDNT_USE_REST => CURLE_RANGE_ERROR
587 CURLE_FUNCTION_NOT_FOUND => CURLE_FAILED_INIT
589 CURLE_LDAP_INVALID_URL => CURLE_URL_MALFORMAT
591 CURLE_TFTP_NOSUCHUSER => CURLE_TFTP_ILLEGAL
593 CURLE_TFTP_NOTFOUND => CURLE_REMOTE_FILE_NOT_FOUND
595 CURLE_TFTP_PERM => CURLE_REMOTE_ACCESS_DENIED
597 18.3 extend CURLOPT_SOCKOPTFUNCTION prototype
599 The current prototype only provides 'purpose' that tells what the
600 connection/socket is for, but not any protocol or similar. It makes it hard
601 for applications to differentiate on TCP vs UDP and even HTTP vs FTP and
604 10. Next major release
606 19.1 cleanup return codes
608 curl_easy_cleanup() returns void, but curl_multi_cleanup() returns a
609 CURLMcode. These should be changed to be the same.
611 19.2 remove obsolete defines
613 remove obsolete defines from curl/curl.h
617 make several functions use size_t instead of int in their APIs
619 19.4 remove several functions
621 remove the following functions from the public API:
625 curl_mprintf (and variations)
631 They will instead become curlx_ - alternatives. That makes the curl app
632 still capable of using them, by building with them from source.
634 These functions have no purpose anymore:
638 curl_multi_socket_all
640 19.5 remove CURLOPT_FAILONERROR
642 Remove support for CURLOPT_FAILONERROR, it has gotten too kludgy and weird
643 internally. Let the app judge success or not for itself.
645 19.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
647 Remove support for a global DNS cache. Anything global is silly, and we
648 already offer the share interface for the same functionality but done
651 19.7 remove progress meter from libcurl
653 The internally provided progress meter output doesn't belong in the library.
654 Basically no application wants it (apart from curl) but instead applications
655 can and should do their own progress meters using the progress callback.
657 The progress callback should then be bumped as well to get proper 64bit
658 variable types passed to it instead of doubles so that big files work
661 19.8 remove 'curl_httppost' from public
663 curl_formadd() was made to fill in a public struct, but the fact that the
664 struct is public is never really used by application for their own advantage
665 but instead often restricts how the form functions can or can't be modified.
667 Changing them to return a private handle will benefit the implementation and
668 allow us much greater freedoms while still maintining a solid API and ABI.
670 19.9 have form functions use CURL handle argument
672 curl_formadd() and curl_formget() both currently have no CURL handle
673 argument, but both can use a callback that is set in the easy handle, and
674 thus curl_formget() with callback cannot function without first having
675 curl_easy_perform() (or similar) called - which is hard to grasp and a design
678 19.10 Add CURLOPT_MAIL_CLIENT option
680 Rather than use the URL to specify the mail client string to present in the
681 HELO and EHLO commands, libcurl should support a new CURLOPT specifically for
682 specifing this data as the URL is non-standard and to be honest a bit of a
685 Please see the following thread for more information:
686 http://curl.haxx.se/mail/lib-2012-05/0178.html