Lighttpd

Chapter 1. Introduction to Lighttpd

In this chapter, we will learn:

What Lighttpd is
How to install Lighttpd
How to build Lighttpd using:
- Autotools
- CMake

What is Lighttpd? Lighttpd, or Lighty, as it is affectionately called, is an extensible, modular, low-footprint, single-threaded, high performance, web server that will happily run on small servers, and outperform an Apache server or Microsoft IIS in most settings. Lighttpd powers many large sites, such as the YouTube video download servers and the image upload server of Wikipedia. At the time of this writing, Lighttpd has the fifth place in the netcraft web server top ten. The plugin architecture encourages developing custom modules and trying new ideas. The development community around Lighttpd is friendly, helpful and pragmatic, and the documentation, though a little scattered, is quite thorough, if you know where to look.

Installing Lighttpd

Lighttpd has very little dependencies considering the wealth of functionalities it provides. For most systems, getting Lighttpd is just a matter of downloading and installing a package. Before we go out and get one, we better know what we want. There are two branches of Lighttpd: a stable branch and a development branch.

The stable branch is very solid and changes at the most once every two months (if bug fixes are not counted, then about once a year), allowing the developers to concentrate on bug fixes. The development branch moves faster, with a new release every four to six weeks. The development snapshots contain new shiny features, but can also contain hidden bugs, break old features and can generally be less stable.

At the time of writing, version 1.4.19 is deemed to be the stable version, while pre-releases of the upcoming 1.5.0 version are distributed for more testing before the final release. Some systems might have packages of older versions, but anything older than the stable branch many contain known security holes.

For a live server, or if we want the latest versions, we usually compile Lighttpd from sources. For a development server, we might take the easy route and install a precompiled package to leave the worries about dependencies to whoever maintains the package database.

The last question is, on which system we should use Lighttpd? My pragmatic advice is to use what you have. For a development system, take the platform you currently work on. For integration and production platforms, this advice needs to be constrained a little—apart from Windows, which allows too little connections to be open in parallel, most operating systems are suitable for production use—the POSIX-implementing ones (Linux, every BSD, Solaris, Mac OS X, and so on) also benefit from numerous optimizations.

Now, without further ado, here is a list of binary packages per system:

System	Download address or command
Debian GNU/Linux, Ubuntu, Knoppix, other Derivatives	`apt-get install libpcre3` `apt-get install zlib1g` `apt-get install mysql-common libmysqlclient12` `apt-get install lighttpd lighttpd-doc`
Fedora / Red Hat Novell / SuSE Linux other RPM-based distributions	`yum install pcre` `yum install zlib` wget http://www.kevindustries.com`/media/kw/files/linux/lighttpd/RPMS/lighttpd-1.4.13-3.KWEL4.i386.rpm`
Gentoo Linux	`emerge lighttpd`
Windows	http://www.kevinworthington.com:8181/?cat=20

To compile Lighttpd from source, download the latest source package from http://lighttpd.net/download/. Between Lighttpd versions 1.4.19 and 1.5.0, the build system has changed from Autotools to CMake. Before we can install it, we need the following:

A compiler and toolchain—most systems have gcc make and a libc (usually glibc) providing the usual functions. For some embedded platforms, the need to define some constants by hand before cross-compiling has been observed.
PCRE—the libpcre package (http://www.pcre.org) supplies PERL-compatible regular expressions to Lighttpd. Lighttpd will run without it, but won't do anything more complex than serving web pages directly under only one hostname and path, without any rewriting or redirecting.

Apart from these, there are some optional packages that expand the capabilities of Lighttpd:

OpenSSL (http://openssl.org) or any other SSL library (but OpenSSL is the most-tested one) is needed for transport layer encryption, so our site can be accessed via https.
zlib (http://www.zlib.org) is required for mod_compress to supply on-the-fly gzip compression for static content. As virtually every system has zlib available, this should not concern us.
bzip2 (http://www.bzip.org) can also be used by mod_compress static content for clients who allow bzip2 compression. It is a little slower than zlib, but achieves higher compression rates.
Lua (http://www.lua.org) is a small, fast, powerful scripting language, which is a perfect match for Lighttpd and can be embedded as mod_magnet.
MySQL (http://www.mysql.org) is a product by the company that employs the author of Lighttpd. Therefore, it is no surprise that Lighttpd uses MySQL for database-backed virtual hosting. Also, under Debian, a binary install depends on MySQL.
pkg-config (http://pkgconfig.freedesktop.org) is not strictly necessary, but it will make the installation easier. Especially for Lua, the Lighttpd installation process relies on it unless given explicit library paths.

Installing Lighttpd

Now, without further ado, here is a list of binary packages per system:

System	Download address or command
Debian GNU/Linux, Ubuntu, Knoppix, other Derivatives	`apt-get install libpcre3` `apt-get install zlib1g` `apt-get install mysql-common libmysqlclient12` `apt-get install lighttpd lighttpd-doc`
Fedora / Red Hat Novell / SuSE Linux other RPM-based distributions	`yum install pcre` `yum install zlib` wget http://www.kevindustries.com`/media/kw/files/linux/lighttpd/RPMS/lighttpd-1.4.13-3.KWEL4.i386.rpm`
Gentoo Linux	`emerge lighttpd`
Windows	http://www.kevinworthington.com:8181/?cat=20

A compiler and toolchain—most systems have gcc make and a libc (usually glibc) providing the usual functions. For some embedded platforms, the need to define some constants by hand before cross-compiling has been observed.
PCRE—the libpcre package (http://www.pcre.org) supplies PERL-compatible regular expressions to Lighttpd. Lighttpd will run without it, but won't do anything more complex than serving web pages directly under only one hostname and path, without any rewriting or redirecting.

Apart from these, there are some optional packages that expand the capabilities of Lighttpd:

OpenSSL (http://openssl.org) or any other SSL library (but OpenSSL is the most-tested one) is needed for transport layer encryption, so our site can be accessed via https.
zlib (http://www.zlib.org) is required for mod_compress to supply on-the-fly gzip compression for static content. As virtually every system has zlib available, this should not concern us.
bzip2 (http://www.bzip.org) can also be used by mod_compress static content for clients who allow bzip2 compression. It is a little slower than zlib, but achieves higher compression rates.
Lua (http://www.lua.org) is a small, fast, powerful scripting language, which is a perfect match for Lighttpd and can be embedded as mod_magnet.
MySQL (http://www.mysql.org) is a product by the company that employs the author of Lighttpd. Therefore, it is no surprise that Lighttpd uses MySQL for database-backed virtual hosting. Also, under Debian, a binary install depends on MySQL.
pkg-config (http://pkgconfig.freedesktop.org) is not strictly necessary, but it will make the installation easier. Especially for Lua, the Lighttpd installation process relies on it unless given explicit library paths.

Building Lighttpd using Autotools

Lighttpd was built using Autotools until version 1.5.0, in which the authors experimented with CMake (and other build systems). The Autotools build system has been around for some time. So, almost every system that has a sufficient toolchain can build Lighttpd.

Note that the building can and should be done as a normal user, while the installation must usually be done as a superuser, unless the target directory is owned by the normal user. The easiest way (provided we have sudo) is:

configure && make && sudo make install

Before we enter this command line, we can set a few environment variables that will affect the build process. We can do this in a bash compatible shell using:

export SOME_VAR=X

This will set the variable SOME_VAR to X and export it to the shell. Alternatively, we can just omit the export if we write the variable declarations at the beginning of our command, as in:

SOME_VAR=X; OTHER_VAR=Y; configure

Here are the most important variables:

Variable name	Useful value	Description
CC	arm-gcc icc	Specify an alternate compiler if you cross-compile Lighttpd or have a more optimizing compiler compared to gcc.
CFLAGS LDFLAGS	-g -Os -L/usr/local/lib	These options go to the gcc compiler. Read up on gcc for further information.
PKG_CONFIG	/opt/pkg_config	We may need to specify where pkg-config is, if configure cannot find it.
FAM_CFLAGS FAM_LIBS	-I/opt/fam/include -L/opt/fam/lib	We can specify alternate C Flags and linker settings (for example, paths) for FAM.
LUA_CFLAGS LUA_LIBS	-I/usr/include/lua/ -llua	This tells configure where to find Lua (for example, if pkg-config is missing)

configure takes some options to select features. These options are usually expressed as:

configure --with-lua=/usr/src/lua-5.1 --with-pcre

Note that for every "with-something" option, there also is a "without-something" option that does the exact opposite. Here are the most important options:

Parameter (example)	Description
--help	This makes configure print a help screen and exit.
--prefix=/usr/ --prefix=/opt/lighttpd/	Specify your installation directory if you want to install Lighttpd at a location different from `default/usr/local/`.
--bindir=... --sbindir=... --datadir=... --libdir=... --sysconfdir=...	We can also set each directory individually for the installation process.
--host=PLATFORM --target=PLATFORM --build=PLATFORM	If we want to cross-compile Lighttpd or have different platforms to compile Lighttpd against, we can specify them here. Usually, we can leave these settings alone.
--enable-static --enable-shared	Makes configure build static or shared libraries to link to the Lighttpd executable. The same default is shared.
--enable-lfs	This option enables large files (above 2Gig). Set it if you host HD-movies or large genome sequence files.
--disable-ipv6	Lighttpd by default can use IPv6 in addition to the usual IPv4. Disabling it may reduce the size a little bit and quell our fears of possible bugs in the IPv6 implementation, but may leave out all users of next-gen Internet technologies in the cold.
--with-pcre	This is on by default if PCRE is available. You probably want it anyway, unless your target system is embedded.
--with-openssl	This enables SSL (usually using OpenSSL).
--with-kerberos5	This makes configure use the kerberos5 support supplied by OpenSSL.
--with-zlib --with-zlib=/usr/local/lib/	This adds libgz compression to Lighttpd (via mod_compress). If the path is omitted, configure will try to infer it.
--with-bzip --with-bzip=/opt/lib/	This adds bzip2 compression to Lighttpd (via mod_compress). See --with-zlib.
--with-fam --with-fam=/opt/fam/	This activates the use of the FAM/gamin stat cache which speeds up Lighttpd considerably on repeated requests for the same file.
--with-ldap	This allows Lighttpd to authenticate users (in mod_auth) against an LDAP directory.
--with-webdav-props --with-webdav-locks	These options enable properties and locks in WebDAV (mod_webdav).
--with-gdbm --with-memcache	These options enables the use of GDBM or memcached storage in mod_trigger_b4_dl, respectively.
--with-atttr	This makes Lighttpd support XFS' extended attributes to get the MIME type for a file (by mimetype.use-xattr).
--with-mysql --with-mysql=/opt/mysql/	This option adds MySQL support by mod_mysql_vhost. The optional path should contain mysql_config.
--with-lua --with-lua=/usr/src/lua	This enables the use of the Lua programming language to be embedded into lightTPD as mod_magnet.
--with-valgrind	This adds internal valgrind support. We only need this if we want to debug Lighttpd memory usage.

The make utility will use the Makefile that configure has generated to build and install Lighttpd. Configure Lighttpd to your needs, but the defaults will take care of most of them.