Yaws webserver
Erlang Shell C Makefile JavaScript M4 Other
Latest commit 1208b68 Aug 22, 2016 @ofavre ofavre committed with vinoski Fix #283: FastCGI protocol error for empty HTTP body requests
In my setup I receive the following 500 error when POSTing an empty
request to any PHP script.

  CGI failure: {"recv from application server failed",closed}

My investigations showed that the FCGI_STDIN <<>> frame was sent twice
and the FastCGI server closes the connection right away, (most of the
time) before having time to anwser.

The FastCGI protocol describes the end of a stream as an empty record
for that stream. What Yaws does is it basically closes the stream
twice. Moreover, a stream is described as zero or more non-empty
records, followed by an empty record.


  "A stream record is part of a stream, i.e. a series of zero or more
  non-empty records (length != 0) of the stream type, followed by an
  empty record (length == 0) of the stream type."


  "Furthermore, it will forward any POST data it receives from the
  client to the application via the STDIN stream. Once all data have
  been forwarded, an empty STDIN packet is sent to close the stream."

Though the specification is not as precise as an RFC, sending two
empty records is not in the spirit of the spec.

Add special handling for empty body requests to
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applications Manage modules/functions deprecated in Erlang/OTP 19.0 Jun 30, 2016
c_src add check for have_sendfile Aug 23, 2015
contrib Use binary:compile_pattern for multipart messages Oct 3, 2015
doc Fix #274: remove doc ref to is_default Jul 2, 2016
ebin Massive autotools refactoring & cleanup Jul 7, 2014
examples Add yaws_api:websocket_send for ws_state records May 7, 2016
include Move username/password tuples from server state to an ETS table Apr 27, 2016
m4 Massive autotools refactoring & cleanup Jul 7, 2014
man Fix incomplete and outdated documentation of .yaws_auth Apr 27, 2016
munin README.munin Jun 12, 2009
priv Massive autotools refactoring & cleanup Jul 7, 2014
rebar-templates Remove very old use_old_ssl directive Apr 13, 2016
rel Exclude hipe application in reltool.config Sep 10, 2014
scripts Remove very old use_old_ssl directive Apr 13, 2016
src Fix #283: FastCGI protocol error for empty HTTP body requests Aug 22, 2016
ssl Add SNI support Apr 13, 2016
test Fix the UTF-8 handling for directories and files in yaws_ls Jul 1, 2016
win32 Use id to build the command line in the windows startup script Apr 13, 2016
www Fix typos in shopcart.erl Jul 10, 2016
.gitignore Ignore emacs backup files in .gitignore Jan 19, 2015
.travis.yml Manage modules/functions deprecated in Erlang/OTP 19.0 Jun 30, 2016
ChangeLog whitespace cleanup Oct 31, 2011
LICENSE whitespace cleanup Oct 31, 2011
Makefile.am New ssl option for yaws.conf: dhfile Aug 5, 2015
README.cygwin Massive autotools refactoring & cleanup Jul 7, 2014
README.md Fix link of the travis status image in README.md Aug 27, 2015
README.osx Add README.osx for instructions on installing on OSX using Homebrew Oct 7, 2013
README.pkg-config whitespace cleanup Oct 31, 2011
_build.cfg Adding files for Erlware. A very rough packaging of 1.76 has been rel… May 15, 2008
configure.ac Move Erlang compatibily checks from the configure to a module Apr 13, 2016
erlang_deps.mk Massive autotools refactoring & cleanup Jul 7, 2014
include.mk Move Erlang compatibily checks from the configure to a module Apr 13, 2016
known_dialyzer_warnings Update known dialyzer warnings Jul 10, 2016
rebar.config Update rebar.config to require Erlang/OTP R14B02 or higher to compile… May 7, 2015
rebar.config.script Move Erlang compatibily checks from the configure to a module Apr 13, 2016
two-mode-mode.el updates to make two-mode-mode work with emacs 23 May 31, 2010
vsn.mk Preparing for rel 2.0.3 Jun 30, 2016
yaws.pc.in add pkg-config support contributed by Olivier Girondel Jan 29, 2009


This is Yaws, a webserver for dynamic content written in Erlang.

Travis build Status

Prepare build

Get and install an Erlang system (http://www.erlang.org).

To compile Yaws, Erlang/OTP R14B02 or higher is required.

For SSL-enabled instances, Erlang/OTP R16B01 or higher is required in order to allow only specific protocol versions.

If you've cloned the source from github and you want to build using autotools, note there is no ./configure script in the source, so create one:

$> autoreconf -fi

Install build dependencies. Required packages to compile Yaws are (based on debian packages):

  • build-essential
  • autoconf/automake/libtool
  • erlang - Required apps:
    • erlang-{kernel/stdlib/sasl/erts}
    • erlang-compiler
    • erlang-crypto
    • erlang-xmerl
  • libpam0g-dev

To build the documentation (optional), you also need to install:

  • texlive-latex-base
  • texlive-latex-recommended
  • texlive-fonts-recommended
  • texlive-font-utils
  • texlive-extra-utils
  • ghostscript

On Ubuntu/debian this is pretty much equal to:

$> apt-get build-dep yaws

Finally, to run the testsuites, yaws need to install:

  • git
  • wget
  • curl
  • erlang-eunit
  • erlang-inets
  • erlang-mnesia
  • erlang-ssl
  • cadaver


You can build using rebar:

$> rebar get-deps compile

or via autotools:

$> ./configure --prefix=/usr/local

If using rebar, you'll get a "local installation" with Yaws script in ./bin and the Yaws configuration file in ./etc/yaws.

If using autotools, the build will be configured by default for installation under /usr/local. For more information about installation directories and other supported options, see the configure help. Useful options are:

--with-defaultcharset=CHARSET specify default charset, i.e UTF-8
--with-extrainclude=DIR       dir to include if e.g. pam is installed in some odd place
--with-erlang=PREFIX          prefix where Erlang is installed (optional)

Note to packagers (rpm, deb ...) All install targets support the DESTDIR variable. Thus, if we do

$> ./configure --prefix=/usr; make

we can subsequently do:

$> make install DESTDIR=/foo/bar

All Yaws files will be installed under DESTDIR, but all code will assume Yaws should be installed under /usr.

Main make targets:

  • all : compile Yaws
  • debug : compile Yaws with debug flags
  • clean : remove files produced by all or debug target
  • install : do a proper install of Yaws
  • doc or docs : build the documentation
  • check or test : launch tests
  • cleantest : remove files produced by check target
  • dialyzer : run dialyzer on Yaws
  • mkinstaller : build an installer for windows
  • cleaninstaller: remove files produced by mkinstaller target
  • apps : compile Yaws applications (chat,mail,wiki,yapp)
  • cleanapps : remove files produced by apps target
  • installapps : install Yaws applications
  • fullinstall : install + installapps
  • fullclean : clean + cleantest + cleanapps + cleaninstaller

Test your build

With autotools, to test the build, you should install it somewhere:

$> ./configure --prefix=$PWD/_inst && make install
$> $PWD/_inst/bin/yaws -i

If you used rebar to compile Yaws, you can alternatively start Yaws with

$> ./bin/yaws -i

Either approach will start a webserver at Terminate through ^C, or ^G followed by q, or

> init:stop()

NOTE: If you've used rebar to build the system, none of the following directions apply. With rebar only "local installations" are supported.

Install and run

NOTE: following commands may require root privileges, depending of the installation prefix.

Just run:

$> make install

Then, to run Yaws, you should use its script:

$> ${bindir}/yaws -i

This starts an interactive system.

With the default yaws.conf file, this will create a webserver at http://${host} and one at https://${host}.

You can adapt Yaws configuration by editing '${sysconfig}/yaws/yaws.conf'.

Daemonize Yaws

Start it using '--daemon' and '--heart' options:

$> ${bindir}/yaws --daemon --heart

This will start a daemon (--daemon) which will be autorestarted when/if it crashes or hangs (--heart). Also, for most unices, we create proper start scripts in ${sysconfdir}/init.d

Example: Here is how I compile/start the yaws system that runs at http://yaws.hyber.org (Ubuntu server system)

$> autoreconf -fi
$> ./configure --sysconfdir=/etc
$> make && make install
$> /etc/init.d/yaws start