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
72 12.1 Disable specific versions
73 12.2 Provide mutex locking API
74 12.3 Evaluate SSL patches
75 12.4 Cache OpenSSL contexts
76 12.5 Export session ids
77 12.6 Provide callback for cert verification
78 12.7 improve configure --with-ssl
86 14.1 Other authentication mechanisms
87 14.2 Add QOP support to GSSAPI authentication
92 15.3 prevent file overwriting
93 15.4 simultaneous parallel transfers
94 15.5 provide formpost headers
95 15.6 warning when setting an option
102 17.2 nicer lacking perl message
103 17.3 more protocols supported
104 17.4 more platforms supported
105 17.5 Add support for concurrent connections
108 18.1 http-style HEAD output for FTP
109 18.2 combine error codes
110 18.3 extend CURLOPT_SOCKOPTFUNCTION prototype
112 19. Next major release
113 19.1 cleanup return codes
114 19.2 remove obsolete defines
116 19.4 remove several functions
117 19.5 remove CURLOPT_FAILONERROR
118 19.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
119 19.7 remove progress meter from libcurl
120 19.8 remove 'curl_httppost' from public
121 19.9 have form functions use CURL handle argument
122 19.10 Add CURLOPT_MAIL_CLIENT option
124 ==============================================================================
128 1.2 More data sharing
130 curl_share_* functions already exist and work, and they can be extended to
131 share more. For example, enable sharing of the ares channel and the
136 Use 'struct lifreq' and SIOCGLIFADDR instead of 'struct ifreq' and
137 SIOCGIFADDR on newer Solaris versions as they claim the latter is obsolete.
138 To support IPv6 interface addresses for network interfaces properly.
140 1.4 signal-based resolver timeouts
142 libcurl built without an asynchronous resolver library uses alarm() to time
143 out DNS lookups. When a timeout occurs, this causes libcurl to jump from the
144 signal handler back into the library with a sigsetjmp, which effectively
145 causes libcurl to continue running within the signal handler. This is
146 non-portable and could cause problems on some platforms. A discussion on the
147 problem is available at http://curl.haxx.se/mail/lib-2008-09/0197.html
149 Also, alarm() provides timeout resolution only to the nearest second. alarm
150 ought to be replaced by setitimer on systems that support it.
152 1.5 get rid of PATH_MAX
154 Having code use and rely on PATH_MAX is not nice:
155 http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
157 Currently the SSH based code uses it a bit, but to remove PATH_MAX from there
158 we need libssh2 to properly tell us when we pass in a too small buffer and
159 its current API (as of libssh2 1.2.7) doesn't.
161 1.6 Modified buffer size approach
163 Current libcurl allocates a fixed 16K size buffer for download and an
164 additional 16K for upload. They are always unconditionally part of the easy
165 handle. If CRLF translations are requested, an additional 32K "scratch
166 buffer" is allocated. A total of 64K transfer buffers in the worst case.
168 First, while the handles are not actually in use these buffers could be freed
169 so that lingering handles just kept in queues or whatever waste less memory.
171 Secondly, SFTP is a protocol that needs to handle many ~30K blocks at once
172 since each need to be individually acked and therefore libssh2 must be
173 allowed to send (or receive) many separate ones in parallel to achieve high
174 transfer speeds. A current libcurl build with a 16K buffer makes that
175 impossible, but one with a 512K buffer will reach MUCH faster transfers. But
176 allocating 512K unconditionally for all buffers just in case they would like
177 to do fast SFTP transfers at some point is not a good solution either.
179 Dynamically allocate buffer size depending on protocol in use in combination
180 with freeing it after each individual transfer? Other suggestions?
182 1.7 Detect when called from within callbacks
184 We should set a state variable before calling callbacks, so that we
185 subsequently can add code within libcurl that returns error if called within
186 callbacks for when that's not supported.
188 1.8 Allow SSL (HTTPS) to proxy
190 To prevent local users from snooping on your traffic to the proxy. Supported
192 http://www.chromium.org/developers/design-documents/secure-web-proxy
194 ...and by Firefox soon:
195 https://bugzilla.mozilla.org/show_bug.cgi?id=378637
197 1.9 Cache negative name resolves
199 A name resolve that has failed is likely to fail when made again within a
200 short period of time. Currently we only cache positive responses.
203 2. libcurl - multi interface
205 2.1 More non-blocking
207 Make sure we don't ever loop because of non-blocking sockets returning
208 EWOULDBLOCK or similar. Blocking cases include:
210 - Name resolves on non-windows unless c-ares is used
211 - NSS SSL connections
212 - HTTP proxy CONNECT operations
213 - SOCKS proxy handshakes
216 - The "DONE" operation (post transfer protocol-specific actions) for the
217 protocols SFTP, SMTP, FTP. Fixing Curl_done() for this is a worthy task.
219 2.2 Fix HTTP Pipelining for PUT
221 HTTP Pipelining can be a way to greatly enhance performance for multiple
222 serial requests and currently libcurl only supports that for HEAD and GET
223 requests but it should also be possible for PUT.
225 2.3 Better support for same name resolves
227 If a name resolve has been initiated for name NN and a second easy handle
228 wants to resolve that name as well, make it wait for the first resolve to end
229 up in the cache instead of doing a second separate resolve. This is
230 especially needed when adding many simultaneous handles using the same host
231 name when the DNS resolver can get flooded.
236 3.1 Update date and version in man pages
238 'maketgz' or another suitable script could update the .TH sections of the man
239 pages at release time to use the current date and curl/libcurl version
246 HOST is a command for a client to tell which host name to use, to offer FTP
247 servers named-based virtual hosting:
249 http://tools.ietf.org/html/rfc7151
251 4.2 Alter passive/active on failure and retry
253 When trying to connect passively to a server which only supports active
254 connections, libcurl returns CURLE_FTP_WEIRD_PASV_REPLY and closes the
255 connection. There could be a way to fallback to an active connection (and
256 vice versa). http://curl.haxx.se/bug/feature.cgi?id=1754793
258 4.3 Earlier bad letter detection
260 Make the detection of (bad) %0d and %0a codes in FTP URL parts earlier in the
261 process to avoid doing a resolve and connect in vain.
263 4.4 REST for large files
265 REST fix for servers not behaving well on >2GB requests. This should fail if
266 the server doesn't set the pointer to the requested index. The tricky
267 (impossible?) part is to figure out if the server did the right thing or not.
271 FTP ASCII transfers do not follow RFC959. They don't convert the data
274 4.6 GSSAPI via Windows SSPI
276 In addition to currently supporting the SASL GSSAPI mechanism (Kerberos V5)
277 via third-party GSS-API libraries, such as Heimdal or MIT Kerberos, also add
278 support for GSSAPI authentication via Windows SSPI.
280 4.7 STAT for LIST without data connection
282 Some FTP servers allow STAT for listing directories instead of using LIST, and
283 the response is then sent over the control connection instead of as the
284 otherwise usedw data connection: http://www.nsftools.com/tips/RawFTP.htm#STAT
286 This is not detailed in any FTP specification.
290 5.1 Better persistency for HTTP 1.0
292 "Better" support for persistent connections over HTTP 1.0
293 http://curl.haxx.se/bug/feature.cgi?id=1089001
295 5.2 support FF3 sqlite cookie files
297 Firefox 3 is changing from its former format to a a sqlite database instead.
298 We should consider how (lib)curl can/should support this.
299 http://curl.haxx.se/bug/feature.cgi?id=1871388
301 5.3 Rearrange request header order
303 Server implementors often make an effort to detect browser and to reject
304 clients it can detect to not match. One of the last details we cannot yet
305 control in libcurl's HTTP requests, which also can be exploited to detect
306 that libcurl is in fact used even when it tries to impersonate a browser, is
307 the order of the request headers. I propose that we introduce a new option in
308 which you give headers a value, and then when the HTTP request is built it
309 sorts the headers based on that number. We could then have internally created
310 headers use a default value so only headers that need to be moved have to be
315 Chrome and Firefox already support SPDY and lots of web services do. There's
316 a library for us to use for this (spdylay) that has a similar API and the
317 same author as nghttp2.
319 spdylay: https://github.com/tatsuhiro-t/spdylay
323 Add the ability to specify the preferred authentication mechanism to use by
324 using ;auth=<mech> in the login part of the URL.
328 http://test:pass;auth=NTLM@example.com would be equivalent to specifying --user
329 test:pass;auth=NTLM or --user test:pass --ntlm from the command line.
331 Additionally this should be implemented for proxy base URLs as well.
337 Reading input (to send to the remote server) on stdin is a crappy solution for
338 library purposes. We need to invent a good way for the application to be able
339 to provide the data to send.
341 6.2 ditch telnet-specific select
343 Move the telnet support's network select() loop go away and merge the code
344 into the main transfer loop. Until this is done, the multi interface won't
347 6.3 feature negotiation debug data
349 Add telnet feature negotiation data to the debug callback as header data.
351 6.4 send data in chunks
353 Currently, telnet sends data one byte at a time. This is fine for interactive
354 use, but inefficient for any other. Sent data should be sent in larger
361 Add support for pipelining emails.
363 7.2 Enhanced capability support
365 Add the ability, for an application that uses libcurl, to obtain the list of
366 capabilities returned from the EHLO command.
372 Add support for pipelining commands.
374 8.2 Enhanced capability support
376 Add the ability, for an application that uses libcurl, to obtain the list of
377 capabilities returned from the CAPA command.
381 9.1 Enhanced capability support
383 Add the ability, for an application that uses libcurl, to obtain the list of
384 capabilities returned from the CAPABILITY command.
388 10.1 SASL based authentication mechanisms
390 Currently the LDAP module only supports ldap_simple_bind_s() in order to bind
391 to an LDAP server. However, this function sends username and password details
392 using the simple authentication mechanism (as clear text). However, it should
393 be possible to use ldap_bind_s() instead specifying the security context
394 information ourselves.
400 There's no RFC for the protocol or an URI/URL format. An implementation
401 should most probably use an existing rsync library, such as librsync.
405 12.1 Disable specific versions
407 Provide an option that allows for disabling specific SSL versions, such as
408 SSLv2 http://curl.haxx.se/bug/feature.cgi?id=1767276
410 12.2 Provide mutex locking API
412 Provide a libcurl API for setting mutex callbacks in the underlying SSL
413 library, so that the same application code can use mutex-locking
414 independently of OpenSSL or GnutTLS being used.
416 12.3 Evaluate SSL patches
418 Evaluate/apply Gertjan van Wingerde's SSL patches:
419 http://curl.haxx.se/mail/lib-2004-03/0087.html
421 12.4 Cache OpenSSL contexts
423 "Look at SSL cafile - quick traces look to me like these are done on every
424 request as well, when they should only be necessary once per SSL context (or
425 once per handle)". The major improvement we can rather easily do is to make
426 sure we don't create and kill a new SSL "context" for every request, but
427 instead make one for every connection and re-use that SSL context in the same
428 style connections are re-used. It will make us use slightly more memory but
429 it will libcurl do less creations and deletions of SSL contexts.
431 12.5 Export session ids
433 Add an interface to libcurl that enables "session IDs" to get
434 exported/imported. Cris Bailiff said: "OpenSSL has functions which can
435 serialise the current SSL state to a buffer of your choice, and recover/reset
436 the state from such a buffer at a later date - this is used by mod_ssl for
437 apache to implement and SSL session ID cache".
439 12.6 Provide callback for cert verification
441 OpenSSL supports a callback for customised verification of the peer
442 certificate, but this doesn't seem to be exposed in the libcurl APIs. Could
443 it be? There's so much that could be done if it were!
445 12.7 improve configure --with-ssl
447 make the configure --with-ssl option first check for OpenSSL, then GnuTLS,
452 DNS-Based Authentication of Named Entities (DANE) is a way to provide SSL
453 keys and certs over DNS using DNSSEC as an alternative to the CA model.
454 http://www.rfc-editor.org/rfc/rfc6698.txt
456 An initial patch was posted by Suresh Krishnaswamy on March 7th 2013
457 (http://curl.haxx.se/mail/lib-2013-03/0075.html) but it was a too simple
458 approach. See Daniel's comments:
459 http://curl.haxx.se/mail/lib-2013-03/0103.html . libunbound may be the
460 correct library to base this development on.
464 13.1 SSL engine stuff
466 Is this even possible?
468 13.2 check connection
470 Add a way to check if the connection seems to be alive, to correspond to the
471 SSL_peak() way we use with OpenSSL.
475 14.1 Other authentication mechanisms
477 Add support for other authentication mechanisms such as EXTERNAL, OLP,
478 GSS-SPNEGO and others.
480 14.2 Add QOP support to GSSAPI authentication
482 Currently the GSSAPI authentication only supports the default QOP of auth
483 (Authentication), whilst Kerberos V5 supports both auth-int (Authentication
484 with integrity protection) and auth-conf (Authentication with integrity and
491 "curl --sync http://example.com/feed[1-100].rss" or
492 "curl --sync http://example.net/{index,calendar,history}.html"
494 Downloads a range or set of URLs using the remote name, but only if the
495 remote file is newer than the local file. A Last-Modified HTTP date header
496 should also be used to set the mod date on the downloaded file.
500 Globbing support for -d and -F, as in 'curl -d "name=foo[0-9]" URL'.
501 This is easily scripted though.
503 15.3 prevent file overwriting
505 Add an option that prevents cURL from overwriting existing local files. When
506 used, and there already is an existing file with the target file name
507 (either -O or -o), a number should be appended (and increased if already
508 existing). So that index.html becomes first index.html.1 and then
511 15.4 simultaneous parallel transfers
513 The client could be told to use maximum N simultaneous parallel transfers and
514 then just make sure that happens. It should of course not make more than one
515 connection to the same remote host. This would require the client to use the
516 multi interface. http://curl.haxx.se/bug/feature.cgi?id=1558595
518 15.5 provide formpost headers
520 Extending the capabilities of the multipart formposting. How about leaving
521 the ';type=foo' syntax as it is and adding an extra tag (headers) which
522 works like this: curl -F "coolfiles=@fil1.txt;headers=@fil1.hdr" where
523 fil1.hdr contains extra headers like
525 Content-Type: text/plain; charset=KOI8-R"
526 Content-Transfer-Encoding: base64
527 X-User-Comment: Please don't use browser specific HTML code
529 which should overwrite the program reasonable defaults (plain/text,
532 15.6 warning when setting an option
534 Display a warning when libcurl returns an error when setting an option.
535 This can be useful to tell when support for a particular feature hasn't been
536 compiled into the library.
542 Consider extending 'roffit' to produce decent ASCII output, and use that
543 instead of (g)nroff when building src/tool_hugehelp.c
549 Make our own version of stunnel for simple port forwarding to enable HTTPS
550 and FTP-SSL tests without the stunnel dependency, and it could allow us to
551 provide test tools built with either OpenSSL or GnuTLS
553 17.2 nicer lacking perl message
555 If perl wasn't found by the configure script, don't attempt to run the tests
556 but explain something nice why it doesn't.
558 17.3 more protocols supported
560 Extend the test suite to include more protocols. The telnet could just do FTP
561 or http operations (for which we have test servers).
563 17.4 more platforms supported
565 Make the test suite work on more platforms. OpenBSD and Mac OS. Remove
566 fork()s and it should become even more portable.
568 17.5 Add support for concurrent connections
570 Tests 836, 882 and 938 were designed to verify that separate connections aren't
571 used when using different login credentials in protocols that shouldn't re-use
572 a connection under such circumstances.
574 Unfortunately, ftpserver.pl doesn't appear to support multiple concurrent
575 connections. The read while() loop seems to loop until it receives a disconnect
576 from the client, where it then enters the waiting for connections loop. When
577 the client opens a second connection to the server, the first connection hasn't
578 been dropped (unless it has been forced - which we shouldn't do in these tests)
579 and thus the wait for connections loop is never entered to receive the second
584 18.1 http-style HEAD output for FTP
586 #undef CURL_FTP_HTTPSTYLE_HEAD in lib/ftp.c to remove the HTTP-style headers
587 from being output in NOBODY requests over FTP
589 18.2 combine error codes
591 Combine some of the error codes to remove duplicates. The original
592 numbering should not be changed, and the old identifiers would be
593 macroed to the new ones in an CURL_NO_OLDIES section to help with
594 backward compatibility.
596 Candidates for removal and their replacements:
598 CURLE_FILE_COULDNT_READ_FILE => CURLE_REMOTE_FILE_NOT_FOUND
600 CURLE_FTP_COULDNT_RETR_FILE => CURLE_REMOTE_FILE_NOT_FOUND
602 CURLE_FTP_COULDNT_USE_REST => CURLE_RANGE_ERROR
604 CURLE_FUNCTION_NOT_FOUND => CURLE_FAILED_INIT
606 CURLE_LDAP_INVALID_URL => CURLE_URL_MALFORMAT
608 CURLE_TFTP_NOSUCHUSER => CURLE_TFTP_ILLEGAL
610 CURLE_TFTP_NOTFOUND => CURLE_REMOTE_FILE_NOT_FOUND
612 CURLE_TFTP_PERM => CURLE_REMOTE_ACCESS_DENIED
614 18.3 extend CURLOPT_SOCKOPTFUNCTION prototype
616 The current prototype only provides 'purpose' that tells what the
617 connection/socket is for, but not any protocol or similar. It makes it hard
618 for applications to differentiate on TCP vs UDP and even HTTP vs FTP and
621 19. Next major release
623 19.1 cleanup return codes
625 curl_easy_cleanup() returns void, but curl_multi_cleanup() returns a
626 CURLMcode. These should be changed to be the same.
628 19.2 remove obsolete defines
630 remove obsolete defines from curl/curl.h
634 make several functions use size_t instead of int in their APIs
636 19.4 remove several functions
638 remove the following functions from the public API:
642 curl_mprintf (and variations)
648 They will instead become curlx_ - alternatives. That makes the curl app
649 still capable of using them, by building with them from source.
651 These functions have no purpose anymore:
655 curl_multi_socket_all
657 19.5 remove CURLOPT_FAILONERROR
659 Remove support for CURLOPT_FAILONERROR, it has gotten too kludgy and weird
660 internally. Let the app judge success or not for itself.
662 19.6 remove CURLOPT_DNS_USE_GLOBAL_CACHE
664 Remove support for a global DNS cache. Anything global is silly, and we
665 already offer the share interface for the same functionality but done
668 19.7 remove progress meter from libcurl
670 The internally provided progress meter output doesn't belong in the library.
671 Basically no application wants it (apart from curl) but instead applications
672 can and should do their own progress meters using the progress callback.
674 The progress callback should then be bumped as well to get proper 64bit
675 variable types passed to it instead of doubles so that big files work
678 19.8 remove 'curl_httppost' from public
680 curl_formadd() was made to fill in a public struct, but the fact that the
681 struct is public is never really used by application for their own advantage
682 but instead often restricts how the form functions can or can't be modified.
684 Changing them to return a private handle will benefit the implementation and
685 allow us much greater freedoms while still maintaining a solid API and ABI.
687 19.9 have form functions use CURL handle argument
689 curl_formadd() and curl_formget() both currently have no CURL handle
690 argument, but both can use a callback that is set in the easy handle, and
691 thus curl_formget() with callback cannot function without first having
692 curl_easy_perform() (or similar) called - which is hard to grasp and a design
695 19.10 Add CURLOPT_MAIL_CLIENT option
697 Rather than use the URL to specify the mail client string to present in the
698 HELO and EHLO commands, libcurl should support a new CURLOPT specifically for
699 specifying this data as the URL is non-standard and to be honest a bit of a
702 Please see the following thread for more information:
703 http://curl.haxx.se/mail/lib-2012-05/0178.html