Question

I can’t get MongoMapper to work with my Rails app. I get this error message:

**Notice: C extension not loaded. This is required for optimum MongoDB Ruby driver performance.
You can install the extension as follows:
gem install bson_ext

If you continue to receive this message after installing, make sure that the
bson_ext gem is in your load path and that the bson_ext and mongo gems are of the same version.

I have installed DevKit and installed the gem: gem install bson_ext –no-rdoc –no-ri (result: bson_ext-1.0.1 installed)

I’m running on Windows 7. The Rails version is 2.3.7. I used the RubyInstaller when installing. Can anyone point me in the right direction?

Answer 1

The problem is: the bson_ext gem version and the mongo gem version need to match, also, mongo_mapper isn’t ready for mongo-1.0.1 yet, so the versions of the mongo and bson_ext gems you should be using are 1.0 for each, respectively.

so, do the following:

gem install mongo -v=1.0 --no-ri --no-rdoc && \
gem install bson_ext -v=1.0 --no-ri --no-rdoc

then for Rails 2.x in your config/environment.rb do:

config.gem 'mongo', :version => '1.0'
config.gem 'bson_ext', :version => '1.0'

or for Rails 3, in your Gemfile:

gem 'mongo', '1.0'
gem 'bson_ext', '1.0'