CODEWITHSUNDEEP
rubyrubygems
sawa
sawa

Reputation: 168259

Checking if a library is installed on the computer

Is there a way to check without raising (and rescuing) an error if a library/gem "foo" is installed on the computer and is available?

Probably, ruby-gems or bundler should have some relevant code in the source, but I cannot spot it.

Upvotes: 1

Views: 292

Answers (2)

sawa
sawa

Reputation: 168259

I spotted the relevant source. I can do:

  • Checking the entire load path:

     Gem.find_files("foo").any?

  • Checking for only gems:

     Gem.find_files("foo", false).any?

Upvotes: 1

Arup Rakshit
Arup Rakshit

Reputation: 118299

If you have installed the pry,then you can do as below using the method Pry::Rubygem.installed?:

kirti@kirti-Aspire-5733Z:~$ irb
2.0.0p0 :001 > require 'pry'
 => true 
2.0.0p0 :002 > pry
[1] pry(main)> Pry::Rubygem.installed?('nokogiri')
=> true
[2] pry(main)> Pry::Rubygem.installed?('foo')
=> false
[3] pry(main)>

Or you can do as below:

require 'rubygems'

def installed?(name)
  if Gem::Specification.respond_to?(:find_all_by_name)
    Gem::Specification.find_all_by_name(name).any?
  else
    Gem.source_index.find_name(name).first
  end
end

installed?('nokogiri') # => true
installed?('foo') # => false

Upvotes: 0

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