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 within callbacks
21 1.8 Allow SSL (HTTPS) to proxy
22 1.9 Cache negative name resolves
24 2. libcurl - multi interface
26 2.2 Fix HTTP Pipelining for PUT
27 2.3 Better support for same name resolves
30 3.1 Update date and version in man pages
34 4.2 Alter passive/active on failure and retry
35 4.3 Earlier bad letter detection
36 4.4 REST for large files
38 4.6 GSSAPI via Windows SSPI
39 4.7 STAT for LIST without data connection
42 5.1 Better persistency for HTTP 1.0
43 5.2 support FF3 sqlite cookie files
44 5.3 Rearrange request header order
50 6.2 ditch telnet-specific select
51 6.3 feature negotiation debug data
52 6.4 send data in chunks
56 7.2 Enhanced capability support
60 8.2 Enhanced capability support
63 9.1 Enhanced capability support
66 10.1 SASL based authentication mechanisms
69 11.1 File listing support
70 11.2 Honor file timestamps
77 13.1 Disable specific versions
78 13.2 Provide mutex locking API
79 13.3 Evaluate SSL patches
80 13.4 Cache OpenSSL contexts
81 13.5 Export session ids
82 13.6 Provide callback for cert verification
83 13.7 improve configure --with-ssl
91 15.1 Other authentication mechanisms
92 15.2 Add QOP support to GSSAPI authentication
97 16.3 prevent file overwriting
98 16.4 simultaneous parallel transfers
99 16.5 provide formpost headers
100 16.6 warning when setting an option
107 18.2 nicer lacking perl message
108 18.3 more protocols supported
109 18.4 more platforms supported
110 18.5 Add support for concurrent connections
113 19.1 http-style HEAD output for FTP
114 19.2 combine error codes
115 19.3 extend CURLOPT_SOCKOPTFUNCTION prototype
117 20. Next major release
118 20.1 cleanup return codes
119 20.2 remove obsolete defines
121 20.4 remove several functions
122 20.5 remove CURLOPT_FAILONERROR
123 20.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
124 20.7 remove progress meter from libcurl
125 20.8 remove 'curl_httppost' from public
126 20.9 have form functions use CURL handle argument
127 20.10 Add CURLOPT_MAIL_CLIENT option
129 ==============================================================================
133 1.2 More data sharing
135 curl_share_* functions already exist and work, and they can be extended to
136 share more. For example, enable sharing of the ares channel and the
141 Use 'struct lifreq' and SIOCGLIFADDR instead of 'struct ifreq' and
142 SIOCGIFADDR on newer Solaris versions as they claim the latter is obsolete.
143 To support IPv6 interface addresses for network interfaces properly.
145 1.4 signal-based resolver timeouts
147 libcurl built without an asynchronous resolver library uses alarm() to time
148 out DNS lookups. When a timeout occurs, this causes libcurl to jump from the
149 signal handler back into the library with a sigsetjmp, which effectively
150 causes libcurl to continue running within the signal handler. This is
151 non-portable and could cause problems on some platforms. A discussion on the
152 problem is available at http://curl.haxx.se/mail/lib-2008-09/0197.html
154 Also, alarm() provides timeout resolution only to the nearest second. alarm
155 ought to be replaced by setitimer on systems that support it.
157 1.5 get rid of PATH_MAX
159 Having code use and rely on PATH_MAX is not nice:
160 http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
162 Currently the SSH based code uses it a bit, but to remove PATH_MAX from there
163 we need libssh2 to properly tell us when we pass in a too small buffer and
164 its current API (as of libssh2 1.2.7) doesn't.
166 1.6 Modified buffer size approach
168 Current libcurl allocates a fixed 16K size buffer for download and an
169 additional 16K for upload. They are always unconditionally part of the easy
170 handle. If CRLF translations are requested, an additional 32K "scratch
171 buffer" is allocated. A total of 64K transfer buffers in the worst case.
173 First, while the handles are not actually in use these buffers could be freed
174 so that lingering handles just kept in queues or whatever waste less memory.
176 Secondly, SFTP is a protocol that needs to handle many ~30K blocks at once
177 since each need to be individually acked and therefore libssh2 must be
178 allowed to send (or receive) many separate ones in parallel to achieve high
179 transfer speeds. A current libcurl build with a 16K buffer makes that
180 impossible, but one with a 512K buffer will reach MUCH faster transfers. But
181 allocating 512K unconditionally for all buffers just in case they would like
182 to do fast SFTP transfers at some point is not a good solution either.
184 Dynamically allocate buffer size depending on protocol in use in combination
185 with freeing it after each individual transfer? Other suggestions?
187 1.7 Detect when called from within callbacks
189 We should set a state variable before calling callbacks, so that we
190 subsequently can add code within libcurl that returns error if called within
191 callbacks for when that's not supported.
193 1.8 Allow SSL (HTTPS) to proxy
195 To prevent local users from snooping on your traffic to the proxy. Supported
197 http://www.chromium.org/developers/design-documents/secure-web-proxy
199 ...and by Firefox soon:
200 https://bugzilla.mozilla.org/show_bug.cgi?id=378637
202 1.9 Cache negative name resolves
204 A name resolve that has failed is likely to fail when made again within a
205 short period of time. Currently we only cache positive responses.
208 2. libcurl - multi interface
210 2.1 More non-blocking
212 Make sure we don't ever loop because of non-blocking sockets returning
213 EWOULDBLOCK or similar. Blocking cases include:
215 - Name resolves on non-windows unless c-ares is used
216 - NSS SSL connections
217 - HTTP proxy CONNECT operations
218 - SOCKS proxy handshakes
221 - The "DONE" operation (post transfer protocol-specific actions) for the
222 protocols SFTP, SMTP, FTP. Fixing Curl_done() for this is a worthy task.
224 2.2 Fix HTTP Pipelining for PUT
226 HTTP Pipelining can be a way to greatly enhance performance for multiple
227 serial requests and currently libcurl only supports that for HEAD and GET
228 requests but it should also be possible for PUT.
230 2.3 Better support for same name resolves
232 If a name resolve has been initiated for name NN and a second easy handle
233 wants to resolve that name as well, make it wait for the first resolve to end
234 up in the cache instead of doing a second separate resolve. This is
235 especially needed when adding many simultaneous handles using the same host
236 name when the DNS resolver can get flooded.
241 3.1 Update date and version in man pages
243 'maketgz' or another suitable script could update the .TH sections of the man
244 pages at release time to use the current date and curl/libcurl version
251 HOST is a command for a client to tell which host name to use, to offer FTP
252 servers named-based virtual hosting:
254 http://tools.ietf.org/html/rfc7151
256 4.2 Alter passive/active on failure and retry
258 When trying to connect passively to a server which only supports active
259 connections, libcurl returns CURLE_FTP_WEIRD_PASV_REPLY and closes the
260 connection. There could be a way to fallback to an active connection (and
261 vice versa). http://curl.haxx.se/bug/feature.cgi?id=1754793
263 4.3 Earlier bad letter detection
265 Make the detection of (bad) %0d and %0a codes in FTP URL parts earlier in the
266 process to avoid doing a resolve and connect in vain.
268 4.4 REST for large files
270 REST fix for servers not behaving well on >2GB requests. This should fail if
271 the server doesn't set the pointer to the requested index. The tricky
272 (impossible?) part is to figure out if the server did the right thing or not.
276 FTP ASCII transfers do not follow RFC959. They don't convert the data
279 4.6 GSSAPI via Windows SSPI
281 In addition to currently supporting the SASL GSSAPI mechanism (Kerberos V5)
282 via third-party GSS-API libraries, such as Heimdal or MIT Kerberos, also add
283 support for GSSAPI authentication via Windows SSPI.
285 4.7 STAT for LIST without data connection
287 Some FTP servers allow STAT for listing directories instead of using LIST, and
288 the response is then sent over the control connection instead of as the
289 otherwise usedw data connection: http://www.nsftools.com/tips/RawFTP.htm#STAT
291 This is not detailed in any FTP specification.
295 5.1 Better persistency for HTTP 1.0
297 "Better" support for persistent connections over HTTP 1.0
298 http://curl.haxx.se/bug/feature.cgi?id=1089001
300 5.2 support FF3 sqlite cookie files
302 Firefox 3 is changing from its former format to a a sqlite database instead.
303 We should consider how (lib)curl can/should support this.
304 http://curl.haxx.se/bug/feature.cgi?id=1871388
306 5.3 Rearrange request header order
308 Server implementors often make an effort to detect browser and to reject
309 clients it can detect to not match. One of the last details we cannot yet
310 control in libcurl's HTTP requests, which also can be exploited to detect
311 that libcurl is in fact used even when it tries to impersonate a browser, is
312 the order of the request headers. I propose that we introduce a new option in
313 which you give headers a value, and then when the HTTP request is built it
314 sorts the headers based on that number. We could then have internally created
315 headers use a default value so only headers that need to be moved have to be
320 Chrome and Firefox already support SPDY and lots of web services do. There's
321 a library for us to use for this (spdylay) that has a similar API and the
322 same author as nghttp2.
324 spdylay: https://github.com/tatsuhiro-t/spdylay
328 Add the ability to specify the preferred authentication mechanism to use by
329 using ;auth=<mech> in the login part of the URL.
333 http://test:pass;auth=NTLM@example.com would be equivalent to specifying --user
334 test:pass;auth=NTLM or --user test:pass --ntlm from the command line.
336 Additionally this should be implemented for proxy base URLs as well.
342 Reading input (to send to the remote server) on stdin is a crappy solution for
343 library purposes. We need to invent a good way for the application to be able
344 to provide the data to send.
346 6.2 ditch telnet-specific select
348 Move the telnet support's network select() loop go away and merge the code
349 into the main transfer loop. Until this is done, the multi interface won't
352 6.3 feature negotiation debug data
354 Add telnet feature negotiation data to the debug callback as header data.
356 6.4 send data in chunks
358 Currently, telnet sends data one byte at a time. This is fine for interactive
359 use, but inefficient for any other. Sent data should be sent in larger
366 Add support for pipelining emails.
368 7.2 Enhanced capability support
370 Add the ability, for an application that uses libcurl, to obtain the list of
371 capabilities returned from the EHLO command.
377 Add support for pipelining commands.
379 8.2 Enhanced capability support
381 Add the ability, for an application that uses libcurl, to obtain the list of
382 capabilities returned from the CAPA command.
386 9.1 Enhanced capability support
388 Add the ability, for an application that uses libcurl, to obtain the list of
389 capabilities returned from the CAPABILITY command.
393 10.1 SASL based authentication mechanisms
395 Currently the LDAP module only supports ldap_simple_bind_s() in order to bind
396 to an LDAP server. However, this function sends username and password details
397 using the simple authentication mechanism (as clear text). However, it should
398 be possible to use ldap_bind_s() instead specifying the security context
399 information ourselves.
403 11.1 File listing support
405 Add support for listing the contents of a SMB share. The output should probably
406 be the same as/similar to FTP.
408 11.2 Honor file timestamps
410 The timestamp of the transfered file should reflect that of the original file.
414 Currently the SMB authentication uses NTLMv1.
420 There's no RFC for the protocol or an URI/URL format. An implementation
421 should most probably use an existing rsync library, such as librsync.
425 13.1 Disable specific versions
427 Provide an option that allows for disabling specific SSL versions, such as
428 SSLv2 http://curl.haxx.se/bug/feature.cgi?id=1767276
430 13.2 Provide mutex locking API
432 Provide a libcurl API for setting mutex callbacks in the underlying SSL
433 library, so that the same application code can use mutex-locking
434 independently of OpenSSL or GnutTLS being used.
436 13.3 Evaluate SSL patches
438 Evaluate/apply Gertjan van Wingerde's SSL patches:
439 http://curl.haxx.se/mail/lib-2004-03/0087.html
441 13.4 Cache OpenSSL contexts
443 "Look at SSL cafile - quick traces look to me like these are done on every
444 request as well, when they should only be necessary once per SSL context (or
445 once per handle)". The major improvement we can rather easily do is to make
446 sure we don't create and kill a new SSL "context" for every request, but
447 instead make one for every connection and re-use that SSL context in the same
448 style connections are re-used. It will make us use slightly more memory but
449 it will libcurl do less creations and deletions of SSL contexts.
451 13.5 Export session ids
453 Add an interface to libcurl that enables "session IDs" to get
454 exported/imported. Cris Bailiff said: "OpenSSL has functions which can
455 serialise the current SSL state to a buffer of your choice, and recover/reset
456 the state from such a buffer at a later date - this is used by mod_ssl for
457 apache to implement and SSL session ID cache".
459 13.6 Provide callback for cert verification
461 OpenSSL supports a callback for customised verification of the peer
462 certificate, but this doesn't seem to be exposed in the libcurl APIs. Could
463 it be? There's so much that could be done if it were!
465 13.7 improve configure --with-ssl
467 make the configure --with-ssl option first check for OpenSSL, then GnuTLS,
472 DNS-Based Authentication of Named Entities (DANE) is a way to provide SSL
473 keys and certs over DNS using DNSSEC as an alternative to the CA model.
474 http://www.rfc-editor.org/rfc/rfc6698.txt
476 An initial patch was posted by Suresh Krishnaswamy on March 7th 2013
477 (http://curl.haxx.se/mail/lib-2013-03/0075.html) but it was a too simple
478 approach. See Daniel's comments:
479 http://curl.haxx.se/mail/lib-2013-03/0103.html . libunbound may be the
480 correct library to base this development on.
484 14.1 SSL engine stuff
486 Is this even possible?
488 14.2 check connection
490 Add a way to check if the connection seems to be alive, to correspond to the
491 SSL_peak() way we use with OpenSSL.
495 15.1 Other authentication mechanisms
497 Add support for other authentication mechanisms such as EXTERNAL, OLP,
498 GSS-SPNEGO and others.
500 15.2 Add QOP support to GSSAPI authentication
502 Currently the GSSAPI authentication only supports the default QOP of auth
503 (Authentication), whilst Kerberos V5 supports both auth-int (Authentication
504 with integrity protection) and auth-conf (Authentication with integrity and
511 "curl --sync http://example.com/feed[1-100].rss" or
512 "curl --sync http://example.net/{index,calendar,history}.html"
514 Downloads a range or set of URLs using the remote name, but only if the
515 remote file is newer than the local file. A Last-Modified HTTP date header
516 should also be used to set the mod date on the downloaded file.
520 Globbing support for -d and -F, as in 'curl -d "name=foo[0-9]" URL'.
521 This is easily scripted though.
523 16.3 prevent file overwriting
525 Add an option that prevents cURL from overwriting existing local files. When
526 used, and there already is an existing file with the target file name
527 (either -O or -o), a number should be appended (and increased if already
528 existing). So that index.html becomes first index.html.1 and then
531 16.4 simultaneous parallel transfers
533 The client could be told to use maximum N simultaneous parallel transfers and
534 then just make sure that happens. It should of course not make more than one
535 connection to the same remote host. This would require the client to use the
536 multi interface. http://curl.haxx.se/bug/feature.cgi?id=1558595
538 16.5 provide formpost headers
540 Extending the capabilities of the multipart formposting. How about leaving
541 the ';type=foo' syntax as it is and adding an extra tag (headers) which
542 works like this: curl -F "coolfiles=@fil1.txt;headers=@fil1.hdr" where
543 fil1.hdr contains extra headers like
545 Content-Type: text/plain; charset=KOI8-R"
546 Content-Transfer-Encoding: base64
547 X-User-Comment: Please don't use browser specific HTML code
549 which should overwrite the program reasonable defaults (plain/text,
552 16.6 warning when setting an option
554 Display a warning when libcurl returns an error when setting an option.
555 This can be useful to tell when support for a particular feature hasn't been
556 compiled into the library.
562 Consider extending 'roffit' to produce decent ASCII output, and use that
563 instead of (g)nroff when building src/tool_hugehelp.c
569 Make our own version of stunnel for simple port forwarding to enable HTTPS
570 and FTP-SSL tests without the stunnel dependency, and it could allow us to
571 provide test tools built with either OpenSSL or GnuTLS
573 18.2 nicer lacking perl message
575 If perl wasn't found by the configure script, don't attempt to run the tests
576 but explain something nice why it doesn't.
578 18.3 more protocols supported
580 Extend the test suite to include more protocols. The telnet could just do FTP
581 or http operations (for which we have test servers).
583 18.4 more platforms supported
585 Make the test suite work on more platforms. OpenBSD and Mac OS. Remove
586 fork()s and it should become even more portable.
588 18.5 Add support for concurrent connections
590 Tests 836, 882 and 938 were designed to verify that separate connections aren't
591 used when using different login credentials in protocols that shouldn't re-use
592 a connection under such circumstances.
594 Unfortunately, ftpserver.pl doesn't appear to support multiple concurrent
595 connections. The read while() loop seems to loop until it receives a disconnect
596 from the client, where it then enters the waiting for connections loop. When
597 the client opens a second connection to the server, the first connection hasn't
598 been dropped (unless it has been forced - which we shouldn't do in these tests)
599 and thus the wait for connections loop is never entered to receive the second
604 19.1 http-style HEAD output for FTP
606 #undef CURL_FTP_HTTPSTYLE_HEAD in lib/ftp.c to remove the HTTP-style headers
607 from being output in NOBODY requests over FTP
609 19.2 combine error codes
611 Combine some of the error codes to remove duplicates. The original
612 numbering should not be changed, and the old identifiers would be
613 macroed to the new ones in an CURL_NO_OLDIES section to help with
614 backward compatibility.
616 Candidates for removal and their replacements:
618 CURLE_FILE_COULDNT_READ_FILE => CURLE_REMOTE_FILE_NOT_FOUND
620 CURLE_FTP_COULDNT_RETR_FILE => CURLE_REMOTE_FILE_NOT_FOUND
622 CURLE_FTP_COULDNT_USE_REST => CURLE_RANGE_ERROR
624 CURLE_FUNCTION_NOT_FOUND => CURLE_FAILED_INIT
626 CURLE_LDAP_INVALID_URL => CURLE_URL_MALFORMAT
628 CURLE_TFTP_NOSUCHUSER => CURLE_TFTP_ILLEGAL
630 CURLE_TFTP_NOTFOUND => CURLE_REMOTE_FILE_NOT_FOUND
632 CURLE_TFTP_PERM => CURLE_REMOTE_ACCESS_DENIED
634 19.3 extend CURLOPT_SOCKOPTFUNCTION prototype
636 The current prototype only provides 'purpose' that tells what the
637 connection/socket is for, but not any protocol or similar. It makes it hard
638 for applications to differentiate on TCP vs UDP and even HTTP vs FTP and
641 20. Next major release
643 20.1 cleanup return codes
645 curl_easy_cleanup() returns void, but curl_multi_cleanup() returns a
646 CURLMcode. These should be changed to be the same.
648 20.2 remove obsolete defines
650 remove obsolete defines from curl/curl.h
654 make several functions use size_t instead of int in their APIs
656 20.4 remove several functions
658 remove the following functions from the public API:
662 curl_mprintf (and variations)
668 They will instead become curlx_ - alternatives. That makes the curl app
669 still capable of using them, by building with them from source.
671 These functions have no purpose anymore:
675 curl_multi_socket_all
677 20.5 remove CURLOPT_FAILONERROR
679 Remove support for CURLOPT_FAILONERROR, it has gotten too kludgy and weird
680 internally. Let the app judge success or not for itself.
682 20.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
684 Remove support for a global DNS cache. Anything global is silly, and we
685 already offer the share interface for the same functionality but done
688 20.7 remove progress meter from libcurl
690 The internally provided progress meter output doesn't belong in the library.
691 Basically no application wants it (apart from curl) but instead applications
692 can and should do their own progress meters using the progress callback.
694 The progress callback should then be bumped as well to get proper 64bit
695 variable types passed to it instead of doubles so that big files work
698 20.8 remove 'curl_httppost' from public
700 curl_formadd() was made to fill in a public struct, but the fact that the
701 struct is public is never really used by application for their own advantage
702 but instead often restricts how the form functions can or can't be modified.
704 Changing them to return a private handle will benefit the implementation and
705 allow us much greater freedoms while still maintaining a solid API and ABI.
707 20.9 have form functions use CURL handle argument
709 curl_formadd() and curl_formget() both currently have no CURL handle
710 argument, but both can use a callback that is set in the easy handle, and
711 thus curl_formget() with callback cannot function without first having
712 curl_easy_perform() (or similar) called - which is hard to grasp and a design
715 20.10 Add CURLOPT_MAIL_CLIENT option
717 Rather than use the URL to specify the mail client string to present in the
718 HELO and EHLO commands, libcurl should support a new CURLOPT specifically for
719 specifying this data as the URL is non-standard and to be honest a bit of a
722 Please see the following thread for more information:
723 http://curl.haxx.se/mail/lib-2012-05/0178.html