Install
sudo gem install nokogiri
Contribute
github.com/sparklemotion/nokogiri

An HTML, XML, SAX, & Reader parser with the ability to search documents via XPath or CSS3 selectors… and much more

Nokogiri

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?

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? :)”

Mac OS X

Please note that Leopard comes bundled with libxml 2.6.16. Someone in Cupertino MUST be having some fun at our expense, because this is clearly 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, but you’re probably using either macports or homebrew to manage your dev packages, so Read On, True Believer!

macports

sudo port install libxml2 libxslt
sudo gem install nokogiri

And if you have problems, try:

sudo port upgrade outdated

homebrew 0.9

Apparently some people have had problems getting libiconv to install under homebrew 0.9 (see issue #442). Here’s what reportedly works:

brew install libxml2 libxslt
brew link libxml2 libxslt

Then install libiconv from source:

wget http://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.13.1.tar.gz
tar xvfz libiconv-1.13.1.tar.gz
cd libiconv-1.13.1
./configure --prefix=/usr/local/Cellar/libiconv/1.13.1
make
sudo make install

Then (finally) install nokogiri:

gem install nokogiri -- --with-xml2-include=/usr/local/Cellar/libxml2/2.7.8/include/libxml2 
                        --with-xml2-lib=/usr/local/Cellar/libxml2/2.7.8/lib 
                        --with-xslt-dir=/usr/local/Cellar/libxslt/1.1.26 
                        --with-iconv-include=/usr/local/Cellar/libiconv/1.13.1/include 
                        --with-iconv-lib=/usr/local/Cellar/libiconv/1.13.1/lib

Well played, homebrew. That certainly was “the easiest and most flexible way to install the UNIX tools Apple didn’t include with OS X.” </sarcasm>

homebrew 0.8

brew install libxml2 libxslt libiconv
brew link libxml2 libxslt libiconv
gem install nokogiri

homebrew 0.7

# the rest of this snippet assumes installation of libxml 2.7.7. YMMV.
brew install libxml2
brew link libxml2

# install libxslt from source
wget ftp://xmlsoft.org/libxml2/libxslt-1.1.26.tar.gz
tar -zxvf libxslt-1.1.26.tar.gz
cd libxslt-1.1.26
./configure --prefix=/usr/local/Cellar/libxslt/1.1.26 
            --with-libxml-prefix=/usr/local/Cellar/libxml2/2.7.7
make
sudo make install

gem install nokogiri -- --with-xslt-dir=/usr/local/Cellar/libxslt/1.1.26

Red Hat / CentOS

The easiest way to get Nokogiri installed on CentOS and RHEL seems to be the EPEL repository which contains a prebuilt nokogiri package. To use it, install the appropriate epel-release package for your OS, then run:

sudo yum install -y rubygem-nokogiri

To install using gem install is somewhat more complicated because of the age of the packages available from the central repositories. If you have rubygems installed, you may be able to install nokogiri via gem install. If you run intro problems, try installing these packages as well.

sudo yum install -y gcc ruby-devel libxml2 libxml2-devel libxslt libxslt-devel

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

(Note that, by default, libxslt header files are installed into the root include directory, but libxml2 header files are installed into a subdirectory thereof named libxml2.)

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

Note that, by default, libxslt header files are installed into the root include directory, but libxml2 header files are installed into a subdirectory thereof named libxml2.

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