MongoMapper and bson_ext problem

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'

Answer 2

This is generally caused by installing a version of bson_ext not equal to the version number required by MongoMapper. Check which version of bson MongoMapper is requiring, and then make sure that you have that version and no other installed.