How to test if a module/gem is installed

[snacktime]

Is there a way to test if a particular module/extension/gem is
installed on the system ruby is running on?

Chris

 

[Trans]

I wrote this extension for that. Not sure how robust it is though.

module Gem

def self.active?(gemname)
@loaded_specs ||= Hash.new
@loaded_specs.key? gemname
end

end

T.

 

[Paul Lynch]

Is there a way to test if a particular module/extension/gem is
installed on the system ruby is running on?

If you know the library name for a require statement, use require and
trap the LoadError? Returns true if the require succeeds.

Paul

 

[J2M]

you can find all the installed gems with a version of this;

def find_my_gem(name)
spec_dir = File.join(Gem.dir, "specifications")
gems = Gem::SourceIndex.from_installed_gems(spec_dir)
gems.each {|path, gem| return true if name == gem.name}
return false
end

this is a bit of a hack together, but gives you the basic idea.

 

[J2M]

probably need brackets around trun in the return(true)

 

[snacktime]

Thanks for all the tips guys, was a great help.