Nokogiri installation fails -libxml2 is missing

First, install the dependencies:

sudo apt-get install libxslt-dev libxml2-dev

If you still receive the error, you may be missing a compiler toolchain:

sudo apt-get install build-essential

You'll get the "libxml2 is missing" error if you're missing a build toolchain (at least I ran into this issue on Debian Lenny).

The Nokogiri build test-compiles a libxml2 header file to verify that it is present, however, it doesn't differentiate between "libxml2 is missing" and "a compiler to test libxml2 is missing".

You may actually need to install both of these packages

sudo apt-get install libxslt-dev libxml2-dev

In Mac OS X (Mavericks), installing the libraries with brew and setting NOKOGIRI_USE_SYSTEM_LIBRARIES=1 before installing the gem did the trick for me.

Summarising:

• If previously installed, uninstall the gem:

  gem uninstall nokogiri
  

• Use Homebrew to install libxml2, libxslt and libiconv:

  brew install libxml2 libxslt libiconv
  

• Install the gem specifying the paths to the libraries to be linked against:

  NOKOGIRI_USE_SYSTEM_LIBRARIES=1 gem install nokogiri -- --use-system-libraries --with-iconv-dir="$(brew --prefix libiconv)" --with-xml2-config="$(brew --prefix libxml2)/bin/xml2-config" --with-xslt-config="$(brew --prefix libxslt)/bin/xslt-config"