Installing Nokogiri Gem Less Painfully

If you don't care about my story and just want that damn easy solutions you should skip to TLDR; section at the end of this post. Leave a comment if that doesn't work for you.

Story-telling

I think I have already faced this pain of installing nokogiri multiple times in my journey as rails developer. This time let me document whatever I do for successful installation so that my future self will have a good place of reference.

While writing this post, latest nokogiri version is 1.6.7

Let's install nokogiri together

So here I begin with installing nokogiri skipping documentations.

gem install nokogiri -q --no-rdoc --no-ri

Yeeaaah! got the error!

Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

    /home/prakash/.rvm/rubies/ruby-2.2.3/bin/ruby -r ./siteconf20151206-24990-5h73vv.rb extconf.rb
checking if the C compiler accepts ... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/prakash/.rvm/rubies/ruby-2.2.3/bin/$(RUBY_BASE_NAME)
    --help
    --clean
/home/prakash/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
    from /home/prakash/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/mkmf.rb:571:in `block in try_compile'
    from /home/prakash/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/mkmf.rb:522:in `with_werror'
    from /home/prakash/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/mkmf.rb:571:in `try_compile'
    from extconf.rb:80:in `nokogiri_try_compile'
    from extconf.rb:87:in `block in add_cflags'
    from /home/prakash/.rvm/rubies/ruby-2.2.3/lib/ruby/2.2.0/mkmf.rb:619:in `with_cflags'
    from extconf.rb:86:in `add_cflags'
    from extconf.rb:336:in `<main>'

extconf failed, exit code 1

Gem files will remain installed in /home/prakash/.rvm/gems/ruby-2.2.3/gems/nokogiri-1.6.7 for inspection.
Results logged to /home/prakash/.rvm/gems/ruby-2.2.3/extensions/x86_64-linux/2.2.0/nokogiri-1.6.7/gem_make.out

I don't actually care about that really long error! I have figured out, it's about missing dependency. So here I try something from suggestions @ stack overflow.

sudo apt-get install libxslt-dev libxml2-dev

But some errors persist. So now I follow nokogiri instructions for ubuntu

# make sure you have all the tooling necessary to compile C extensions
sudo apt-get install build-essential patch

# this is final try to fix dependencies
sudo apt-get install ruby-dev zlib1g-dev

After that I again tried installing nokogiri: gem install nokogiri -q --no-rdoc --no-ri And this time it installs without any problem.

TLDR;

# install all dependencies
sudo apt-get install libxslt-dev libxml2-dev ruby-dev zlib1g-dev

# install the nokogiri
gem install nokogiri -q --no-rdoc --no-ri