'require': cannot load such file -- 'nokogiri\nokogiri' (LoadError) when running `rails server`

I'm running a clean install of Ruby 2.2.1 on Windows 8.1 with DevKit. After the installation I run:

gem install rails
rails new testapp
cd testapp
rails server

leaving everything else at default.

The process fails at the last line when, instead of running the server, I get the error message

in 'require': cannot load such file -- 'nokogiri\nokogiri' (LoadError)

It happens every time and I've looked around and tried everything I found to fix it, but nothing so far has worked.

What is the problem here and how do I get a simple test Rails app to work?

Nokogiri doesn't support Ruby 2.2 on Windows yet. The next release will. See https://github.com/sparklemotion/nokogiri/issues/1256

Nokogiri doesn't support native builds (e.g. with devkit) on Windows. Instead it provides gems containing prebuilt DLLs.

There's a discussion which you may want to join or watch on the topic of devkit build support here: https://github.com/sparklemotion/nokogiri/issues/1190

1. First, uninstall the version of Nokogiri you currently have with:

    gem uninstall nokogiri
   

2. Download Nokogiri 1.6.6.2 (x64) or Nokogiri 1.6.6.2 (x86)

3. Install this version locally using:

    gem install --local C:\Users\$user$\Downloads\nokogiri-1.6.6.2-x64-mingw32.gem
   

or if you're running 32bit Ruby:

    gem install --local C:\Users\$user$\Downloads\nokogiri-1.6.6.2-x86-mingw32.gem

The path may differ depending on where you downloaded the file to.

Try to start the server again using ruby bin\rails server, and it should work.

I got Nokogiri running with Ruby 2.2 on Windows 10 with a mix of Mike Dalessios and Julios answer:

1. Look for the latest version of Nokogiri in Nokogiri's github repo.
2. Run gem uninstall nokogiri.
3. Add gem "nokogiri", ">= 1.6.7.rc" to your Gemfile.
4. Run bundle install.
5. Run bundle update nokogiri if bundle has locked Nokogiri at some version.

#Fix

1. Bundle install (gets Nokogiri files)
2. Browse to ruby_dir\lib\ruby\gems\2.2.0\gems\nokogiri-1.6.6.2\ext\nokogiri
3. Open extconf.rb
4. Add dir_config('iconv').any? or pkg_config('libiconv') to #376
5. Download MinGW64 & MSYS folders from Mega
6. Add them to PATH in Windows (remove Devkit path refs - it doesn't work)
7. Download libxml2,libxslt, iconv libraries (or here)
8. Run ruby extconf.rb --platform=ruby --n --use-system-libraries referencing downloaded libraries
9. Run make
10. Run make install

---

#Steps

Bundle Install

First step is to bundle.

This will put the nokogiri gem on your machine without running the pre-packaged compiler (which mostly doesn't work in Windows).

This will show Nokogiri as installed:

Browse

Browse to the nokogiri folder, to find ext/nokogiri/extconf.rb:

Open extconf.rb

... and add dir_config('iconv').any? or pkg_config('libiconv') to #376

Standard Nokogiri installs "rely" on the libxml2 inclusion of iconv - we need to explicitly define it, otherwise iconv.h is missing errors will occur.

Add Toolchain

Don't use devkit for this - it doesn't work.

You need MinGW:

I have zipped my exact MinGW64 and MSYS64 folders on Mega (key: !FJtcq25l-QMsNltCxllMhc1IGqORvap8xv8gWxSUbDA):

Add to PATH

This gives access to gcc & make (both required):

Remove the devkit ref from your path, and add the following:

> - MINGW64_PATH/bin > - MSYS64_PATH/bin

Download Libs

I have added the libs to Mega:

You will unzip them here:

All the libs are from this source.

Run extconf.rb

Once libs are on your system, you can run ruby extconf.rb to configure the build:

> 32bit > > ruby extconf.rb --platform=ruby -N -- --use-system-libraries --with-xml2-dir=C:/Dev/Dependencies/Ruby/lib/nokogiri/32bit/libxml2-2.9.2-win32-x86 --with-xml2-include=C:/Dev/Dependencies/Ruby/lib/nokogiri/32bit/libxml2-2.9.2-win32-x86/include/libxml2 --with-iconv-dir=C:/Dev/Dependencies/Ruby/lib/nokogiri/32bit/iconv-1.14-win32-x86 --with-xslt-dir=C:/Dev/Dependencies/Ruby/lib/nokogiri/32bit/libxslt-1.1.28-win32-x86

> 64bit > > #64 ruby extconf.rb --platform=ruby -N -- --use-system-libraries --with-xml2-dir=C:/Dev/Dependencies/Ruby/lib/nokogiri/64bit/libxml2-2.9.2-win32-x86_64 --with-xml2-include=C:/Dev/Dependencies/Ruby/lib/nokogiri/64bit/libxml2-2.9.2-win32-x86_64/include/libxml2 --with-iconv-dir=C:/Dev/Dependencies/Ruby/lib/nokogiri/64bit/iconv-1.14-win32-x86_64 --with-xslt-dir=C:/Dev/Dependencies/Ruby/lib/nokogiri/64bit/libxslt-1.1.28-win32-x86_64

make

This may create errors / warnings, as long as it says "Error 1 (ignored)", it should be okay.

Following that, use make install:

Then browse to your Rails installation and run rails s:

---

#Explanation

To give context:

Ruby 2.2+ on Windows doesn't compile the extensions Nokogiri requires.

The extensions of a gem are the extra dependencies (libraries) it uses.

They are built when you install the gem:

---

Extensions

Lack of extensions is preventing Nokogiri from running.

Extensions exist in the ext folder of a gem (you can read about them here):

Mysql2,RMagick,PGSQL, Nokogiri etc all use extensions/libraries.

This is why - on Windows - you have to use custom switches (--with-opt-dir) when installing the gem. This gives Ruby / the shell / (cmd) the required lib / include directories required to build the gem's files (it's the equivalent of how PATH works).

On Linux/Mac, these directories are managed with the respective package managers (brew/apt-get). Windows does not have this, so you have to install the extensions manually.

Because Windows does not have a standard set of libraries, you have to download them yourself. You also have to build them yourself (which is tricky).

The fix for Nokogiri install is to use the right libraries and build tools to get the gem installed.

---

Build

The difference with Ruby 2.2+ is the gem will "install" without showing any exceptions. You think it has installed, only to find Rails does not load (hence the nokogiri/nokogiri.so error).

This means you have to make sure you have the files on your system, and run the compiler to install them.

The above documentation should show you how to do that.