Installing Nokogiri

Because Nokogiri needs to be compiled and dynamically linked against both libxml2 and libxslt, it has gained a reputation for being complicated to install.

Let’s wrassle this little myth to the ground, shall we?

Mac OS X

The following should work on both Leopard and Snow Leopard:

sudo port install libxml2 libxslt
sudo gem install nokogiri

Please note that Leopard comes bundled with libxml 2.6.16. Someone in Cupertino is having some fun at our expense, because this MUST be somebody’s idea of a bad joke. 2.6.16 was released Nov 2004 and is really quite buggy. We here at Nokogiri HQ advise strongly that you do not use this version.

Sensibly, Snow Leopard comes packaged with libxml 2.7.3.

Ubuntu / Debian

Ubuntu doesn’t come with the Ruby development packages that are required for building gems with C extensions. Here are the commands to install everything you might need:

# ruby developer packages
sudo apt-get install ruby1.8-dev ruby1.8 ri1.8 rdoc1.8 irb1.8
sudo apt-get install libreadline-ruby1.8 libruby1.8 libopenssl-ruby

# nokogiri requirements
sudo apt-get install libxslt-dev libxml2-dev
sudo gem install nokogiri

Although, if you’re using Hardy (8.04) or earlier, you’ll need to install slightly different packages:

# nokogiri requirements for Hardy (8.04) and earlier
sudo apt-get install libxslt1-dev libxml2-dev

As John Barnette once said, “Isn’t package management convenient? :)”

Red Hat / CentOS

In theory, this is easy peasy:

sudo yum install -y libxml2 libxml2-devel libxslt libxslt-devel
sudo gem install nokogiri

In practice, though, CentOS 5 (and RHEL5) come installed with libxml 2.6.26 which, while not as offensively out-of-date as Mac Leopard, is still pretty damn old (released June 2006) and has known issues.

If you’re affected by any known bugs or are seeing odd behavior, you may want to consider uninstalling the RPMs for libxml2 and libxslt, and building them from source.

1. sudo yum remove -y libxml2-devel libxslt-devel
2. download the most recent libxml2 and libxslt from ftp://xmlsoft.org/libxml2/
3. ./configure ; make ; sudo make install

Then install nokogiri specifying the libxml2 and libxslt install directories:

sudo gem install nokogiri -- --with-xml2-lib=/usr/local/lib 
                             --with-xml2-include=/usr/local/include/libxml2 
                             --with-xslt-lib=/usr/local/lib
                             --with-xslt-include=/usr/local/include/libxslt`

Or, you know, whatever directories into which you installed libxml and libxslt. Good luck.

Nonstandard libxml2 / libxslt installations

If you’ve got libxml2 and/or libxslt installed in a nonstandard place (read as “not /opt/local, /usr/local, /usr or the standard Ruby directories”), you can use command-line parameters to the gem install command to grease the wheels:

gem install nokogiri -- --with-xml2-dir=/home/joe/builds --with-xslt-dir=/home/joe/builds

Or, you can specify include and library directories separately:

gem install nokogiri -- --with-xml2-lib=/home/joe/builds/lib \
                        --with-xml2-include=/home/joe/builds/include/libxml2 \
                        --with-xslt-lib=/home/joe/builds/lib \
                        --with-xslt-include=/home/joe/builds/include/libxslt

Windows

Luckily for you, building on Windows is so difficult that we’ve done it for you: Nokogiri comes bundled with all the DLLs you need to be NOKOGIRIFIED!

gem install nokogiri