Ruby mysql2 gem，无法在Windows 7上构建

Question

I come from OSX where Ruby runs super flawlessly 90% of the time. I haven't touched it in awhile though and happen to be working on a Windows 7 machine right now. I'm trying to run a simple Ruby on Rails project but I can't seem to get past any of my database setup.
I want to run on mysql but when I try to install the mysql2 gem (via bundle install or gem install mysql2 ) I get these errors:

Installing mysql2 (0.2.9) with native extensions C:/Ruby192/lib/ruby/site_ruby/1 .9.1/rubygems/installer.rb:533:in `rescue in block in build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

  C:/Ruby192/bin/ruby.exe extconf.rb checking for 

rb_thread_blocking_region()... * 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.

I'm pretty much a complete newb when it comes to this kind of thing so if anyone has any advice, please help!

Answer 1

To install and compile extensions sometimes you need libraries and headers of the dependencies. In this case, you need MySQL headers and libraries to properly compile.

Assuming you downloaded Ruby from RubyInstaller and also installed the Development Kit and followed it's installation instructions , to successfuly install mysql2 gem I recommend you read this answer in our Troubleshooting page :

1. Download MySQL Connector/C
2. Extract into a path without spaces
3. When installing mysql2 gem, provide the additional options ( gem install mysql2 -v 0.2.10 -- --with-mysql-include=... --with-mysql-lib... )

Provide for --with-mysql-include option the path to the include directory of MySQL Connector/C. The same for --with-mysql-lib but this time point to lib directory.

Don't forget to copy libmysql.dll to your Ruby bin directory.

Hope this helps.

Answer 2

The problem with native extensions on Windows is that there are two different compiler infrastructures: one based on MS VC and its Visual Studio and one based on MinGW (Minimalist GCC for Windows).

There are Ruby native extensions that can be compiled with any of them and other, that only support one. And since most of them come from some kind of Unix, chances are that mingw works better that MSVC.

So you may try to install mingw and use it to compile mysql gem - there is a special package called devkit , which contains a minimal necessary mingw installation which you just put inside your ruby installation.

I had a success compiling several native extensions using devkit: eventmachine, linecache, bson-ext to name a few. And within devkit you will feel much more are home :-) (coming from OSX)

Answer 3

If you have the devkit setup correct as @Tomasz mentions, please make sure you check the compatibility of mysql2 gem version with windows, I have experienced in the past for it to cause issues and had to go and install a previous version to get it working. Last I remember v0.2.6 was the version that supported windows.