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Christian Grothoff
f5d59eb3a7
I'm at the end of a long investigation and it's come down to that question
for post_process_urlencoded() in MHD.
MHD currently calls back with ("a&b", "1"). The app I'm working breaks
when it doesn't receive a callback for "b". The http client in this case
(that did the urlencoding) is google-http-java-client 1.23.0.
The client behavior may be questionable, but MHD's behavior doesn't seem
right either. Isn't there some principle, "clients should strive for
conformance, servers should strive for forgiveness".
I've attached a patch to MHD to add a failing test, but without a fix.
As for relevant standards, the W3C[1] is not detailed enough to cover it.
The WhatWG[2] is more specific and allows for empty values and even empty
keys. I'd like to callout uriparser[3], another C library I've patched in
as a work-around. Uriparser documents their handling of these cases well:
* NULL in the value member means there was no '=' in the item text as with
"?abc&def".
* An empty string in the value member means there was '=' in the item as
with "?abc=&def".
[1] https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1
[2] https://url.spec.whatwg.org/#urlencoded-parsing
[3] https://uriparser.github.io/doc/api/latest/#querystrings
commit aa0534af56d135e1b261d127af09c22015c1ff87
Author: Ethan Tuttle <ethan@ethantuttle.com>
Date: Tue Dec 24 03:50:59 2019 -0800
urlencoding post-processor: add failing tests for keys without values
About ===== GNU libmicrohttpd is a GNU package offering a C library that provides a compact API and implementation of an HTTP 1.1 web server (HTTP 1.0 is also supported). GNU libmicrohttpd only implements the HTTP 1.1 protocol. The main application must still provide the application logic to generate the content. GNU libmicrohttpd is dual-licensed under the GNU Lesser General Public License (LGPLv2.1+) and the eCos License. See COPYING for details. Installation ============ See INSTALL for generic installation instructions. If you are using Git, run "autoreconf -fi" to create configure. In order to run the testcases, you need a recent version of libcurl. libcurl is not required if you just want to install the library. Especially for development, do use the MHD_USE_ERROR_LOG option to get error messages. Configure options ================= If you are concerned about space, you should set "CFLAGS" to "-Os -fomit-frame-pointer" to have gcc generate tight code. You can use the following options to disable certain MHD features: --disable-https: no HTTPS / TLS / SSL support (significant reduction) --disable-messages: no error messages (they take space!) --disable-postprocessor: no MHD_PostProcessor API --disable-dauth: no digest authentication API --disable-epoll: no support for epoll, even on Linux The resulting binary should be about 30-40k depending on the platform. Portability =========== The latest version of libmicrohttpd will try to avoid SIGPIPE on its sockets. This should work on OS X, Linux and recent BSD systems (at least). On other systems that may trigger a SIGPIPE on send/recv, the main application should install a signal handler to handle SIGPIPE. libmicrohttpd should work well on GNU/Linux, W32, FreeBSD, Darwin, NetBSD, OpenBSD, Solaris/OpenIndiana, and z/OS. Note that HTTPS is not supported on z/OS (yet). We also have reports of users using it on vxWorks. Development Status ================== This is a beta release for libmicrohttpd. Before declaring the library stable, we should have testcases for the following features: - HTTP/1.1 pipelining (need to figure out how to ensure curl pipelines -- and it seems libcurl has issues with pipelining, see http://curl.haxx.se/mail/lib-2007-12/0248.html) - resource limit enforcement - client queuing early response, suppressing 100 CONTINUE - chunked encoding to validate handling of footers - more testing for SSL support - MHD basic and digest authentication In particular, the following functions are not covered by 'make check': - mhd_panic_std (daemon.c); special case (abort) - parse_options (daemon.c) - MHD_set_panic_func (daemon.c) - MHD_get_version (daemon.c) Note that the working library is in src/microhttpd/ with the API in src/include/microhttpd.h. An *experimental* (read: not yet working at all) newer implementation is in src/lib/, with the new API in src/include/microhttpd2.h. The experimental code will need MUCH more testing and development, you are strongly advised to stick to microhttpd.h unless you are a MHD developer!