curl/docs/TODO

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TODO

 Things to do in project cURL. Please tell me what you think, contribute and
 send me patches that improve things! Also check the http://curl.haxx.se/dev
 web section for various development notes.

 LIBCURL

 * Consider an interface to libcurl that allows applications to easier get to
   know what cookies that are sent back in the response headers.

 * Make content encoding/decoding internally be made using a filter system.

 * The new 'multi' interface is being designed. Work out the details, start
   implementing and write test applications!
   [http://curl.haxx.se/lxr/source/lib/multi.h]

 * Introduce another callback interface for upload/download that makes one
   less copy of data and thus a faster operation.
   [http://curl.haxx.se/dev/no_copy_callbacks.txt]

 * Add configure options that disables certain protocols in libcurl to
   decrease footprint.  '--disable-[protocol]' where protocol is http, ftp,
   telnet, ldap, dict or file.

 * Add asynchronous name resolving. http://curl.haxx.se/dev/async-resolver.txt
   This should be made to work on most of the supported platforms, or
   otherwise it isn't really interesting.

 * Data sharing. Tell which easy handles within a multi handle that should
   share cookies, connection cache, dns cache, ssl session cache.

 * Mutexes. By adding mutex callback support, the 'data sharing' mentioned
   above can be made between several easy handles running in different threads
   too. The actual mutex implementations will be left for the application to
   implement, libcurl will merely call 'getmutex' and 'leavemutex' callbacks.

 * No-faster-then-this transfers. Many people have limited bandwidth and they
   want the ability to make sure their transfers never use more bandwith than
   they think is good.

 * Set the SO_KEEPALIVE socket option to make libcurl notice and disconnect
   very long time idle connections.

 * Make sure we don't ever loop because of non-blocking sockets return
   EWOULDBLOCK or similar. This concerns the HTTP request sending (and
   especially regular HTTP POST), the FTP command sending etc.

 * Go through the code and verify that libcurl deals with big files >2GB and
   >4GB all over. Bug reports indicate that it doesn't currently work
   properly.

 DOCUMENTATION

 * Document all CURLcode error codes, why they happen and what most likely
   will make them not happen again. In a libcurl point of view.

 FTP

 * FTP ASCII upload does not follow RFC959 section 3.1.1.1: "The sender
   converts the data from an internal character representation to the standard
   8-bit NVT-ASCII representation (see the Telnet specification).  The
   receiver will convert the data from the standard form to his own internal
   form."

 * An option to only download remote FTP files if they're newer than the local
   one is a good idea, and it would fit right into the same syntax as the
   already working http dito works. It of course requires that 'MDTM' works,
   and it isn't a standard FTP command.

 * Add FTPS support with SSL for the data connection too.

 HTTP

 * Make it possible to supply normal POST data through the ordinary read data
   callback.

 * HTTP PUT for files passed on stdin *OR* when the --crlf option is
   used. Requires libcurl to send the file with chunked content
   encoding. [http://curl.haxx.se/dev/HTTP-PUT-stdin.txt] When the filter
   system mentioned above gets real, it'll be a piece of cake to add.

 * Pass a list of host name to libcurl to which we allow the user name and
   password to get sent to. Currently, it only get sent to the host name that
   the first URL uses (to prevent others from being able to read it), but this
   also prevents the authentication info from getting sent when following
   locations to legitimate other host names.

 * "Content-Encoding: compress/gzip/zlib" HTTP 1.1 clearly defines how to get
   and decode compressed documents. There is the zlib that is pretty good at
   decompressing stuff. This work was started in October 1999 but halted again
   since it proved more work than we thought. It is still a good idea to
   implement though. This requires the filter system mentioned above.

 * Authentication: NTLM. Support for that MS crap called NTLM
   authentication. MS proxies and servers sometime require that. Since that
   protocol is a proprietary one, it involves reverse engineering and network
   sniffing. This should however be a library-based functionality. There are a
   few different efforts "out there" to make open source HTTP clients support
   this and it should be possible to take advantage of other people's hard
   work. http://modntlm.sourceforge.net/ is one. There's a web page at
   http://www.innovation.ch/java/ntlm.html that contains detailed reverse-
   engineered info.

 * RFC2617 compliance, "Digest Access Authentication" A valid test page seem
   to exist at: http://hopf.math.nwu.edu/testpage/digest/ And some friendly
   person's server source code is available at
   http://hopf.math.nwu.edu/digestauth/index.html Then there's the Apache
   mod_digest source code too of course.  It seems as if Netscape doesn't
   support this, and not many servers do. Although this is a lot better
   authentication method than the more common "Basic". Basic sends the
   password in cleartext over the network, this "Digest" method uses a
   challange-response protocol which increases security quite a lot.

 * Pipelining. Sending multiple requests before the previous one(s) are done.
   This could possibly be implemented using the multi interface to queue
   requests and the response data.

 TELNET

 * Make TELNET work on windows98!

 * Reading input (to send to the remote server) on stdin is a crappy solution
   for library purposes. We need to invent a good way for the application to
   be able to provide the data to send.

 * Move the telnet support's network select() loop go away and merge the code
   into the main transfer loop. Until this is done, the multi interface won't
   work for telnet.

 SSL

 * If you really want to improve the SSL situation, you should probably have a
   look at SSL cafile loading as well - quick traces look to me like these are
   done on every request as well, when they should only be necessary once per
   ssl context (or once per handle). Even better would be to support the SSL
   CAdir option - instead of loading all of the root CA certs for every
   request, this option allows you to only read the CA chain that is actually
   required (into the cache)...

 * Add an interface to libcurl that enables "session IDs" to get
   exported/imported. Cris Bailiff said: "OpenSSL has functions which can
   serialise the current SSL state to a buffer of your choice, and
   recover/reset the state from such a buffer at a later date - this is used
   by mod_ssl for apache to implement and SSL session ID cache". This whole
   idea might become moot if we enable the 'data sharing' as mentioned in the
   LIBCURL label above.

 * OpenSSL supports a callback for customised verification of the peer
   certificate, but this doesn't seem to be exposed in the libcurl APIs. Could
   it be? There's so much that could be done if it were! (brought by Chris
   Clark)

 * Make curl's SSL layer option capable of using other free SSL libraries.
   Such as the Mozilla Security Services
   (http://www.mozilla.org/projects/security/pki/nss/) and GNUTLS
   (http://gnutls.hellug.gr/)

 LDAP

 * Look over the implementation. The looping will have to "go away" from the
   lib/ldap.c source file and get moved to the main network code so that the
   multi interface and friends will work for LDAP as well.

 CLIENT

 * "curl ftp://site.com/*.txt"

 * Several URLs can be specified to get downloaded. We should be able to use
   the same syntax to specify several files to get uploaded (using the same
   persistant connection), using -T.

 * When the multi interface has been implemented and proved to work, the
   client could be told to use maximum N simultaneous transfers and then just
   make sure that happens. It should of course not make more than one
   connection to the same remote host.

 * Extending the capabilities of the multipart formposting. How about leaving
   the ';type=foo' syntax as it is and adding an extra tag (headers) which
   works like this: curl -F "coolfiles=@fil1.txt;headers=@fil1.hdr" where
   fil1.hdr contains extra headers like

     Content-Type: text/plain; charset=KOI8-R"
     Content-Transfer-Encoding: base64
     X-User-Comment: Please don't use browser specific HTML code

   which should overwrite the program reasonable defaults (plain/text,
   8bit...) (Idea brough to us by kromJx)

 TEST SUITE

 * Extend the test suite to include more protocols. The telnet could just do
   ftp or http operations (for which we have test servers).

 * Make the test suite work on more platforms. OpenBSD and Mac OS. Remove
   fork()s and it should become even more portable.

 * Introduce a test suite that tests libcurl better and more explicitly.