Parsing an HTML/XML document →

Installing Nokogiri

  1. Install with included libraries (RECOMMENDED)
  2. Install with system libraries
  3. Install with custom / non-standard libraries

Installing Nokogiri

Nokogiri includes its own updated and patched copies of libxml2 and libxslt libraries. By default, installation of Nokogiri will use these copies. Alternatively, you may install using your operating system’s built-in libraries or other custom versions of these libraries.

This document also helps with common problems we’ve heard. If you have an issue not discussed here, please open an issue.

For earlier versions of Nokogiri, find instructions in the git history for this document.

For other platforms, please send pull requests to sparklemotion/nokogiri.org-tutorials.

Install with included libraries (RECOMMENDED)

Ubuntu / Debian

Install Nokogiri on a brand new Ubuntu system with these commands:

1
2

sudo apt-get install build-essential patch ruby-dev zlib1g-dev liblzma-dev
gem install nokogiri

Note for RVM users: you may require libgmp, consider running sudo apt-get install libgmp-dev.

FreeBSD / OpenBSD >= 6.2

Install Nokogiri on a brand new FreeBSD system with these commands:

1

gem install nokogiri

OpenBSD < 6.2

Use gcc from ports in order to compile the included libraries:

1
2

pkg_add -v gcc
gem install nokogiri

Windows

Use Rubyinstaller to install our binary distribution in a flash!

1

gem install nokogiri

Or build using DevKit. This is an advanced option you should only try if you know what you’re doing. You MUST use Rubygems 2.4.5 or later.

Also see more details on this advanced procedure on this nokogiri-talk thread.

Red Hat / CentOS

Install Nokogiri on a brand new Red Had / CentOS system with these commands:

1
2
3

sudo yum install -y gcc ruby-devel zlib-devel
# sudo dnf install -y rpm-build # This may be required
gem install nokogiri

Alternatively, you may install the appropriate epel-release and get the Nokogiri package from EPEL using:

1

sudo yum install -y rubygem-nokogiri

GNU Guix

Install on any Linux distribution using GNU Guix, a reproducible binary software package management and distribution system.

Use this command:

1

guix package -i ruby-nokogiri

Note: source code is available here. A short description of how Nokogiri was packaged can be found here.

macOS

First, make sure you have the latest version of RubyGems and xcode commandline tools:

1
2

gem update --system
xcode-select --install # Then agree to the terms, even if you have done this before!

Then install nokogiri:

1

gem install nokogiri

This is verified working on maxOS 10.9 w/ Xcode’s clang compiler. (Many thanks to @allaire and others for helping!)

xcode-select errors with a ‘network problem’

If, you see this dialog when you run the above commands:

xcode-select-network-problem

Then run this command to turn off forced-authentication with Apple Software Update:

1

sudo defaults delete /Library/Preferences/com.apple.SoftwareUpdate CatalogURL

Error Message About Undeclared Identifier LZMA_OK

A more recent error mentions an undeclared identifier LZMA_OK:

1
2
3
4

xmlIO.c:1450:52: error: use of undeclared identifier 'LZMA_OK'
    ret =  (__libxml2_xzclose((xzFile) context) == LZMA_OK ) ? 0 : -1;
                                                   ^
1 error generated.

The solution for this is a little more subtle and can be fixed in a couple of ways.

  1. When using Homebrew, there are several libraries that use a formula called xz (including the_silver_searcher and imagemagick), which by default install a version of liblzma that is incompatible with most Ruby builds. (Homebrew installs only the 64-bit version of the library, but most Ruby builds are universal.) This can be fixed in a couple of ways:

    1. The most reliable way appears to be temporarily unlinking xz and relinking it during an install of nokogiri:

      brew unlink xz
gem install nokogiri # or bundle install
brew link xz

    2. The third way is to use a Homebrew-installed libxml2, as suggested in using your system libraries.

      brew install libxml2
# If installing directly
gem install nokogiri -- --use-system-libraries \
  --with-xml2-include=$(brew --prefix libxml2)/include/libxml2
# If using Bundle
bundle config build.nokogiri --use-system-libraries \
  --with-xml2-include=$(brew --prefix libxml2)/include/libxml2
bundle install

      When working with this, be certain to use $(brew --prefix libxml2) because it will use the correct location for your Homebrew install.

Other macOS Tips

  • Make sure ruby is compiled with the latest clang compiler.
  • Binary gems and ruby should be compiled with the same compiler/environment.
  • If you have multiple versions of Xcode installed, make sure you use the right xcode-select.
  • Try installing with system libraries.

If reporting an issue about the macOS installation instructions, please mention @zenspider.

Install with system libraries

Nokogiri will refuse to build against certain versions of libxml2, libxslt supplied with your operating system, and certain versions will cause mysterious problems. The compile scripts will warn you if you try to do this.

Step 1: Install pkg-config

On Debian/Ubuntu:

1

sudo apt-get install pkg-config

On FreeBSD:

1

sudo pkg install pkgconf

Step 2: Build Nokogiri

Using gem:

1

gem install nokogiri -- --use-system-libraries

Or, use Bundler:

1
2

bundle config build.nokogiri --use-system-libraries
bundle install

Install with custom / non-standard libraries

If:

  • you’ve got libxml2 and/or libxslt installed in a nonstandard place,
  • and you don’t have pkg-config installed

you can use command-line parameters to the gem install command to specify build parameters.

If you’ve got the proper config scripts:

1
2
3
4

gem install nokogiri -- \
    --use-system-libraries \
    --with-xml2-config=/path/to/xml2-config \
    --with-xslt-config=/path/to/xslt-config

or, you can specify the installation root directory:

1
2
3
4

gem install nokogiri -- \
    --use-system-libraries \
    --with-xml2-dir=/path/to/dir \
    --with-xslt-dir=/path/to/dir

or, you can specify include and library directories separately:

1
2
3
4
5
6

gem install nokogiri -- \
    --use-system-libraries \
    --with-xml2-lib=/path/to/builds/lib \
    --with-xml2-include=/path/to/builds/include/libxml2 \
    --with-xslt-lib=/path/to/builds/lib \
    --with-xslt-include=/path/to/builds/include

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

It’s likely that you’ll also need to specify the location of your zlib and iconv (and possibly exslt) install directories as well. In that case, you can add the options:

1
2
3
4
5
6
7

gem install nokogiri -- \
    --use-system-libraries \
    # ...
    --with-iconv-dir=/path/to/dir \
    --with-zlib-dir=/path/to/dir \
    [--with-exslt-dir=/path/to/dir]
    [--with-exslt-config=/path/to/exslt-config]

How to tell Bundler to use custom parameters

1
2
3
4
5
6
7
8

bundle config build.nokogiri \
       --use-system-libraries \
       --with-xml2-lib=/usr/local/lib \
       --with-xml2-include=/usr/local/include/libxml2/libxml \
       --with-xslt-lib=/usr/local/lib \
       --with-xslt-include=/usr/local/include/libxslt \
       --with-iconv-lib=/usr/local/lib \
       --with-iconv-include=/usr/local/include

Do not attempt Bundler installation using Bundler versions before v1.8.3. See related issue here. But if you really want to, see earlier git history of this file, which includes a workaround.

SmartOS (Nonstandard)

SmartOS installation requires building and using libxml2/libxslt/libiconv in a nonstandard location. Building on the previous section, here’s how to do it:

(Note: pkgsrc is included in JPC SmartOS instances)

1
2
3
4
5
6
7
8
9
10
11
12

pkgin install ruby gcc49 libxml2 libxslt zlib libiconv ruby22-rake gmake
ln -s /opt/local/gcc49/bin/gcc /opt/local/bin/gcc

gem install nokogiri -- \
    --use-system-libraries \
    --with-xml2-lib=/opt/local/lib \
    --with-xml2-include=/opt/local/include/libxml2 \
    --with-xslt-lib=/opt/local/lib \
    --with-xslt-include=/opt/local/include/libxslt \
    --with-iconv-lib=/opt/local/lib \
    --with-iconv-include=/opt/local/include \
    --with-zlib-dir=/opt/local/lib

See the previous section for guidance on how to instruct Bundler to use these options.

Parsing an HTML/XML document →