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 Modified buffer size approach
20 1.7 Detect when called from witin callbacks
21 1.8 Allow SSL (HTTPS) to proxy
23 2. libcurl - multi interface
25 2.2 Fix HTTP Pipelining for PUT
32 4.2 Alter passive/active on failure and retry
33 4.3 Earlier bad letter detection
34 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
46 6.2 ditch telnet-specific select
47 6.3 feature negotiation debug data
48 6.4 send data in chunks
52 7.2 Enhanced capability support
56 8.2 Enhanced capability support
59 9.1 Enhanced capability support
62 10.1 SASL based authentication mechanisms
68 12.1 Disable specific versions
69 12.2 Provide mutex locking API
70 12.3 Evaluate SSL patches
71 12.4 Cache OpenSSL contexts
72 12.5 Export session ids
73 12.6 Provide callback for cert verification
74 12.7 improve configure --with-ssl
82 14.1 Other authentication mechanisms
87 15.3 prevent file overwriting
88 15.4 simultaneous parallel transfers
89 15.5 provide formpost headers
90 15.6 warning when setting an option
91 15.7 IPv6 addresses with globbing
98 17.2 nicer lacking perl message
99 17.3 more protocols supported
100 17.4 more platforms supported
103 18.1 http-style HEAD output for ftp
104 18.2 combine error codes
105 18.3 extend CURLOPT_SOCKOPTFUNCTION prototype
107 19. Next major release
108 19.1 cleanup return codes
109 19.2 remove obsolete defines
111 19.4 remove several functions
112 19.5 remove CURLOPT_FAILONERROR
113 19.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
114 19.7 remove progress meter from libcurl
115 19.8 remove 'curl_httppost' from public
116 19.9 have form functions use CURL handle argument
117 19.10 Add CURLOPT_MAIL_CLIENT option
119 ==============================================================================
123 1.2 More data sharing
125 curl_share_* functions already exist and work, and they can be extended to
126 share more. For example, enable sharing of the ares channel and the
131 Use 'struct lifreq' and SIOCGLIFADDR instead of 'struct ifreq' and
132 SIOCGIFADDR on newer Solaris versions as they claim the latter is obsolete.
133 To support ipv6 interface addresses for network interfaces properly.
135 1.4 signal-based resolver timeouts
137 libcurl built without an asynchronous resolver library uses alarm() to time
138 out DNS lookups. When a timeout occurs, this causes libcurl to jump from the
139 signal handler back into the library with a sigsetjmp, which effectively
140 causes libcurl to continue running within the signal handler. This is
141 non-portable and could cause problems on some platforms. A discussion on the
142 problem is available at http://curl.haxx.se/mail/lib-2008-09/0197.html
144 Also, alarm() provides timeout resolution only to the nearest second. alarm
145 ought to be replaced by setitimer on systems that support it.
147 1.5 get rid of PATH_MAX
149 Having code use and rely on PATH_MAX is not nice:
150 http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
152 Currently the SSH based code uses it a bit, but to remove PATH_MAX from there
153 we need libssh2 to properly tell us when we pass in a too small buffer and
154 its current API (as of libssh2 1.2.7) doesn't.
156 1.6 Modified buffer size approach
158 Current libcurl allocates a fixed 16K size buffer for download and an
159 additional 16K for upload. They are always unconditionally part of the easy
160 handle. If CRLF translations are requested, an additional 32K "scratch
161 buffer" is allocated. A total of 64K transfer buffers in the worst case.
163 First, while the handles are not actually in use these buffers could be freed
164 so that lingering handles just kept in queues or whatever waste less memory.
166 Secondly, SFTP is a protocol that needs to handle many ~30K blocks at once
167 since each need to be individually acked and therefore libssh2 must be
168 allowed to send (or receive) many separate ones in parallel to achieve high
169 transfer speeds. A current libcurl build with a 16K buffer makes that
170 impossible, but one with a 512K buffer will reach MUCH faster transfers. But
171 allocating 512K unconditionally for all buffers just in case they would like
172 to do fast SFTP transfers at some point is not a good solution either.
174 Dynamically allocate buffer size depending on protocol in use in combination
175 with freeing it after each individual transfer? Other suggestions?
177 1.7 Detect when called from witin callbacks
179 We should set a state variable before calling callbacks, so that we
180 subsequently can add code within libcurl that returns error if called within
181 callbacks for when that's not supported.
183 1.8 Allow SSL (HTTPS) to proxy
185 To prevent local users from snooping on your traffic to the proxy. Supported
187 http://www.chromium.org/developers/design-documents/secure-web-proxy
190 2. libcurl - multi interface
192 2.1 More non-blocking
194 Make sure we don't ever loop because of non-blocking sockets returning
195 EWOULDBLOCK or similar. Blocking cases include:
197 - Name resolves on non-windows unless c-ares is used
198 - NSS SSL connections
199 - HTTP proxy CONNECT operations
200 - SOCKS proxy handshakes
203 - The "DONE" operation (post transfer protocol-specific actions) for the
204 protocols SFTP, SMTP, FTP. Fixing Curl_done() for this is a worthy task.
206 2.2 Fix HTTP Pipelining for PUT
208 HTTP Pipelining can be a way to greatly enhance performance for multiple
209 serial requests and currently libcurl only supports that for HEAD and GET
210 requests but it should also be possible for PUT.
222 HOST is a suggested command in the works for a client to tell which host name
223 to use, to offer FTP servers named-based virtual hosting:
225 http://tools.ietf.org/html/draft-hethmon-mcmurray-ftp-hosts-11
227 4.2 Alter passive/active on failure and retry
229 When trying to connect passively to a server which only supports active
230 connections, libcurl returns CURLE_FTP_WEIRD_PASV_REPLY and closes the
231 connection. There could be a way to fallback to an active connection (and
232 vice versa). http://curl.haxx.se/bug/feature.cgi?id=1754793
234 4.3 Earlier bad letter detection
236 Make the detection of (bad) %0d and %0a codes in FTP url parts earlier in the
237 process to avoid doing a resolve and connect in vain.
239 4.4 REST for large files
241 REST fix for servers not behaving well on >2GB requests. This should fail if
242 the server doesn't set the pointer to the requested index. The tricky
243 (impossible?) part is to figure out if the server did the right thing or not.
247 FTP ASCII transfers do not follow RFC959. They don't convert the data
252 5.1 Better persistency for HTTP 1.0
254 "Better" support for persistent connections over HTTP 1.0
255 http://curl.haxx.se/bug/feature.cgi?id=1089001
257 5.2 support FF3 sqlite cookie files
259 Firefox 3 is changing from its former format to a a sqlite database instead.
260 We should consider how (lib)curl can/should support this.
261 http://curl.haxx.se/bug/feature.cgi?id=1871388
263 5.3 Rearrange request header order
265 Server implementors often make an effort to detect browser and to reject
266 clients it can detect to not match. One of the last details we cannot yet
267 control in libcurl's HTTP requests, which also can be exploited to detect
268 that libcurl is in fact used even when it tries to impersonate a browser, is
269 the order of the request headers. I propose that we introduce a new option in
270 which you give headers a value, and then when the HTTP request is built it
271 sorts the headers based on that number. We could then have internally created
272 headers use a default value so only headers that need to be moved have to be
277 The first drafts for HTTP2 have been published
278 (http://tools.ietf.org/html/draft-ietf-httpbis-http2-03) and is so far based
279 on SPDY (http://www.chromium.org/spdy) designs and experiences. Chances are
280 it will end up in that style. Chrome and Firefox already support SPDY and
281 lots of web services do.
283 It would make sense to implement SPDY support now and later transition into
284 or add HTTP2 support as well.
286 We should base or HTTP2/SPDY work on a 3rd party library for the protocol
287 fiddling. The Spindy library (http://spindly.haxx.se/) was an attempt to make
288 such a library with an API suitable for use by libcurl but that effort has
289 more or less stalled. spdylay (https://github.com/tatsuhiro-t/spdylay) may
290 be a better option, either used directly or wrapped with a more spindly-like
295 Add the ability to specify the preferred authentication mechanism to use by
296 using ;auth=<mech> in the login part of the URL.
300 http://test:pass;auth=NTLM@example.com would be equivalent to specifing --user
301 test:pass;auth=NTLM or --user test:pass --ntlm from the command line.
303 Additionally this should be implemented for proxy base URLs as well.
309 Reading input (to send to the remote server) on stdin is a crappy solution for
310 library purposes. We need to invent a good way for the application to be able
311 to provide the data to send.
313 6.2 ditch telnet-specific select
315 Move the telnet support's network select() loop go away and merge the code
316 into the main transfer loop. Until this is done, the multi interface won't
319 6.3 feature negotiation debug data
321 Add telnet feature negotiation data to the debug callback as header data.
323 6.4 send data in chunks
325 Currently, telnet sends data one byte at a time. This is fine for interactive
326 use, but inefficient for any other. Sent data should be sent in larger
333 Add support for pipelining emails.
335 7.2 Enhanced capability support
337 Add the ability, for an application that uses libcurl, to obtain the list of
338 capabilities returned from the EHLO command.
344 Add support for pipelining commands.
346 8.2 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 Enhanced capability support
355 Add the ability, for an application that uses libcurl, to obtain the list of
356 capabilities returned from the CAPABILITY command.
360 10.1 SASL based authentication mechanisms
362 Currently the LDAP module only supports ldap_simple_bind_s() in order to bind
363 to an LDAP server. However, this function sends username and password details
364 using the simple authentication mechanism (as clear text). However, it should
365 be possible to use ldap_bind_s() instead specifing the security context
366 information ourselves.
372 There's no RFC for the protocol or an URI/URL format. An implementation
373 should most probably use an existing rsync library, such as librsync.
377 12.1 Disable specific versions
379 Provide an option that allows for disabling specific SSL versions, such as
380 SSLv2 http://curl.haxx.se/bug/feature.cgi?id=1767276
382 12.2 Provide mutex locking API
384 Provide a libcurl API for setting mutex callbacks in the underlying SSL
385 library, so that the same application code can use mutex-locking
386 independently of OpenSSL or GnutTLS being used.
388 12.3 Evaluate SSL patches
390 Evaluate/apply Gertjan van Wingerde's SSL patches:
391 http://curl.haxx.se/mail/lib-2004-03/0087.html
393 12.4 Cache OpenSSL contexts
395 "Look at SSL cafile - quick traces look to me like these are done on every
396 request as well, when they should only be necessary once per ssl context (or
397 once per handle)". The major improvement we can rather easily do is to make
398 sure we don't create and kill a new SSL "context" for every request, but
399 instead make one for every connection and re-use that SSL context in the same
400 style connections are re-used. It will make us use slightly more memory but
401 it will libcurl do less creations and deletions of SSL contexts.
403 12.5 Export session ids
405 Add an interface to libcurl that enables "session IDs" to get
406 exported/imported. Cris Bailiff said: "OpenSSL has functions which can
407 serialise the current SSL state to a buffer of your choice, and recover/reset
408 the state from such a buffer at a later date - this is used by mod_ssl for
409 apache to implement and SSL session ID cache".
411 12.6 Provide callback for cert verification
413 OpenSSL supports a callback for customised verification of the peer
414 certificate, but this doesn't seem to be exposed in the libcurl APIs. Could
415 it be? There's so much that could be done if it were!
417 12.7 improve configure --with-ssl
419 make the configure --with-ssl option first check for OpenSSL, then GnuTLS,
424 DNS-Based Authentication of Named Entities (DANE) is a way to provide SSL
425 keys and certs over DNS using DNSSEC as an alternative to the CA model.
426 http://www.rfc-editor.org/rfc/rfc6698.txt
428 An initial patch was posted by Suresh Krishnaswamy on March 7th 2013
429 (http://curl.haxx.se/mail/lib-2013-03/0075.html) but it was a too simple
430 approach. See Daniel's comments:
431 http://curl.haxx.se/mail/lib-2013-03/0103.html . libunbound may be the
432 correct library to base this development on.
436 13.1 SSL engine stuff
438 Is this even possible?
440 13.2 check connection
442 Add a way to check if the connection seems to be alive, to correspond to the
443 SSL_peak() way we use with OpenSSL.
447 14.1 Other authentication mechanisms
449 Add support for GSSAPI to SMTP, POP3 and IMAP.
455 "curl --sync http://example.com/feed[1-100].rss" or
456 "curl --sync http://example.net/{index,calendar,history}.html"
458 Downloads a range or set of URLs using the remote name, but only if the
459 remote file is newer than the local file. A Last-Modified HTTP date header
460 should also be used to set the mod date on the downloaded file.
464 Globbing support for -d and -F, as in 'curl -d "name=foo[0-9]" URL'.
465 This is easily scripted though.
467 15.3 prevent file overwriting
469 Add an option that prevents cURL from overwriting existing local files. When
470 used, and there already is an existing file with the target file name
471 (either -O or -o), a number should be appended (and increased if already
472 existing). So that index.html becomes first index.html.1 and then
475 15.4 simultaneous parallel transfers
477 The client could be told to use maximum N simultaneous parallel transfers and
478 then just make sure that happens. It should of course not make more than one
479 connection to the same remote host. This would require the client to use the
480 multi interface. http://curl.haxx.se/bug/feature.cgi?id=1558595
482 15.5 provide formpost headers
484 Extending the capabilities of the multipart formposting. How about leaving
485 the ';type=foo' syntax as it is and adding an extra tag (headers) which
486 works like this: curl -F "coolfiles=@fil1.txt;headers=@fil1.hdr" where
487 fil1.hdr contains extra headers like
489 Content-Type: text/plain; charset=KOI8-R"
490 Content-Transfer-Encoding: base64
491 X-User-Comment: Please don't use browser specific HTML code
493 which should overwrite the program reasonable defaults (plain/text,
496 15.6 warning when setting an option
498 Display a warning when libcurl returns an error when setting an option.
499 This can be useful to tell when support for a particular feature hasn't been
500 compiled into the library.
502 15.7 IPv6 addresses with globbing
504 Currently the command line client needs to get url globbing disabled (with
505 -g) for it to support IPv6 numerical addresses. This is a rather silly flaw
506 that should be corrected. It probably involves a smarter detection of the
513 Consider extending 'roffit' to produce decent ASCII output, and use that
514 instead of (g)nroff when building src/tool_hugehelp.c
520 Make our own version of stunnel for simple port forwarding to enable HTTPS
521 and FTP-SSL tests without the stunnel dependency, and it could allow us to
522 provide test tools built with either OpenSSL or GnuTLS
524 17.2 nicer lacking perl message
526 If perl wasn't found by the configure script, don't attempt to run the tests
527 but explain something nice why it doesn't.
529 17.3 more protocols supported
531 Extend the test suite to include more protocols. The telnet could just do ftp
532 or http operations (for which we have test servers).
534 17.4 more platforms supported
536 Make the test suite work on more platforms. OpenBSD and Mac OS. Remove
537 fork()s and it should become even more portable.
541 18.1 http-style HEAD output for ftp
543 #undef CURL_FTP_HTTPSTYLE_HEAD in lib/ftp.c to remove the HTTP-style headers
544 from being output in NOBODY requests over ftp
546 18.2 combine error codes
548 Combine some of the error codes to remove duplicates. The original
549 numbering should not be changed, and the old identifiers would be
550 macroed to the new ones in an CURL_NO_OLDIES section to help with
551 backward compatibility.
553 Candidates for removal and their replacements:
555 CURLE_FILE_COULDNT_READ_FILE => CURLE_REMOTE_FILE_NOT_FOUND
557 CURLE_FTP_COULDNT_RETR_FILE => CURLE_REMOTE_FILE_NOT_FOUND
559 CURLE_FTP_COULDNT_USE_REST => CURLE_RANGE_ERROR
561 CURLE_FUNCTION_NOT_FOUND => CURLE_FAILED_INIT
563 CURLE_LDAP_INVALID_URL => CURLE_URL_MALFORMAT
565 CURLE_TFTP_NOSUCHUSER => CURLE_TFTP_ILLEGAL
567 CURLE_TFTP_NOTFOUND => CURLE_REMOTE_FILE_NOT_FOUND
569 CURLE_TFTP_PERM => CURLE_REMOTE_ACCESS_DENIED
571 18.3 extend CURLOPT_SOCKOPTFUNCTION prototype
573 The current prototype only provides 'purpose' that tells what the
574 connection/socket is for, but not any protocol or similar. It makes it hard
575 for applications to differentiate on TCP vs UDP and even HTTP vs FTP and
578 19. Next major release
580 19.1 cleanup return codes
582 curl_easy_cleanup() returns void, but curl_multi_cleanup() returns a
583 CURLMcode. These should be changed to be the same.
585 19.2 remove obsolete defines
587 remove obsolete defines from curl/curl.h
591 make several functions use size_t instead of int in their APIs
593 19.4 remove several functions
595 remove the following functions from the public API:
599 curl_mprintf (and variations)
605 They will instead become curlx_ - alternatives. That makes the curl app
606 still capable of using them, by building with them from source.
608 These functions have no purpose anymore:
612 curl_multi_socket_all
614 19.5 remove CURLOPT_FAILONERROR
616 Remove support for CURLOPT_FAILONERROR, it has gotten too kludgy and weird
617 internally. Let the app judge success or not for itself.
619 19.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
621 Remove support for a global DNS cache. Anything global is silly, and we
622 already offer the share interface for the same functionality but done
625 19.7 remove progress meter from libcurl
627 The internally provided progress meter output doesn't belong in the library.
628 Basically no application wants it (apart from curl) but instead applications
629 can and should do their own progress meters using the progress callback.
631 The progress callback should then be bumped as well to get proper 64bit
632 variable types passed to it instead of doubles so that big files work
635 19.8 remove 'curl_httppost' from public
637 curl_formadd() was made to fill in a public struct, but the fact that the
638 struct is public is never really used by application for their own advantage
639 but instead often restricts how the form functions can or can't be modified.
641 Changing them to return a private handle will benefit the implementation and
642 allow us much greater freedoms while still maintining a solid API and ABI.
644 19.9 have form functions use CURL handle argument
646 curl_formadd() and curl_formget() both currently have no CURL handle
647 argument, but both can use a callback that is set in the easy handle, and
648 thus curl_formget() with callback cannot function without first having
649 curl_easy_perform() (or similar) called - which is hard to grasp and a design
652 19.10 Add CURLOPT_MAIL_CLIENT option
654 Rather than use the URL to specify the mail client string to present in the
655 HELO and EHLO commands, libcurl should support a new CURLOPT specifically for
656 specifing this data as the URL is non-standard and to be honest a bit of a
659 Please see the following thread for more information:
660 http://curl.haxx.se/mail/lib-2012-05/0178.html