• official website: http://xzero.io/ (work in progress)
• github: http://github.com/xzero/x0
• ohloh: http://www.ohloh.net/p/x0
• travis-ci: https://travis-ci.org/xzero/x0

x0 is a thin low-latency scalable HTTP web server and web service framework written in modern C++.

• HTTP/1.1, including pipelining
• thin and clean core API with powerful plugin system
• fully asynchronous response content generation support
• response output filter API
• zero-copy networking optimization through sendfile() system call
• transmitting of static files with partial response support and cache-friendly
• instant mode (configuration-less basic HTTP serving)
• flow-based configuration system, just-in-time compiled into native CPU instructions
• automatic directory indexing
• customizable error pages
• on-the-fly executable upgrade with gracefully finishing currently active requests.
• CGI/1.1 support (plugin)
• FastCGI support (plugin)
• HTTP reverse proxy support (plugin)
• name based virtual hosting (plugin)
• SSL connection encryption (plugin)
  • SSL Server Name Indication (SNI) extension
• dynamic content compression (plugin)
• basic authentication (plugin)
• advanced dynamic load balancer (plugin)
  • supporting different backend transports (TCP/IP, and UNIX Domain Sockets).
  • supporting different backend protocols (HTTP and FastCGI)
  • supporting different backend acceleration strategies (memory, disk)
  • advanced health monitoring
  • JSON API for retrieving state, stats, and reconfiguring clusters (including adding/updating/removing backends).
  • client side routing support
  • sticky offline mode
  • X-Sendfile support, full static file transmission acceleration
  • HAproxy compatible CSV output
  • Object Cache
    • fully runtime configurable
    • client-cache aware
    • life JSON stats
    • supports serving stale objects when no backend is available
    • Vary-response support.
    • multiple update strategies (locked, shadowed)
• request path aliasing (plugin)
• automatic directory listing generation (plugin)
• apache-style access log (plugin)
• user-directory support (plugin)
• browser match support (plugin)
• customized Expires and Cache-Control response header control (plugin)

• gcc >= 4.6.0 (for building only)
• libev >= 4.0
• cmake (for building only)
• tbb, Threading Building Blocks (required)
• zlib (optional & recommended, for compression)
• bzip2 (optional & recommended, for compression)
• gnutls (optional & recommended, for SSL/TLS encryption)
• gtest (optional, for unit testing)

# Install git and clone repository
apt-get install git
git clone git://github.com/xzero/x0.git && cd x0

# Installs required dependencies
sudo apt-get install make cmake gcc g++ libcppunit-dev libgnutls28-dev libgcrypt11-dev \
    libmysqlclient-dev libev-dev zlib1g-dev libbz2-dev pkg-config \
    libpcre3-dev libfcgi-dev libgoogle-perftools0 libtbb-dev libpam-dev

# Installs optional requirements
sudo apt-get install libmagickwand-dev librrd-dev

# If you want to built the tests, you must install libgtest-dev and then built it yourself
sudo apt-get install libgtest-dev
cd /usr/src/gtest && sudo cmake . && sudo make && sudo cp -vpi libgtest*.a /usr/local/lib/

# Now run cmake to bootstrap build
cmake -DCMAKE_BUILD_TYPE=debug -DCMAKE_INSTALL_PREFIX=$HOME/local

# Ensure installation target prefix
mkdir $HOME/local

# Now compiling should just work.
make && make install

# Run web server on port 8080
`pwd`/x0d/src/x0d --instant=`pwd`/www/htdocs,8080

# or try its CLI help
`pwd`/x0d/src/x0d -h

# have fun hacking.

You can built x0 with the very latest Clang/LLVM 3.4. I tested this against the libstdc++ of GCC 4.8 and not yet libc++.