title: How to use Bundler with offline .gem file?
body: <p>For my application, I need to handle encrypted ZIP files.  Despite their horrific looking site, it seems that Chilkat's <a href="http://www.chilkatsoft.com/ruby-zip.asp" rel="noreferrer">commercial Zip gem</a> is probably the best way to go to implement this.</p>
  
  <p>Because this is a commercial gem, they don't have it in any of the typical gem sources that Bundler looks at.  I was able to install the Linux 64-bit version of the gem under Mac OS X (though I haven't tried to run it yet, so no word yet on if that will actually work).  However, I'm first trying to get Bundler to recognize and load the gem from the .gem file that I downloaded.</p>
  
  <p>Bundler has a <a href="http://gembundler.com/gemfile.html" rel="noreferrer">path attribute</a> which I've tried to utilize in several ways, but I haven't gotten it to work yet:</p>
  
  <ol>
  <li>I tried using path to point to the .gem file itself, but path expects a directory.</li>
  <li>I tried adding .gz to the end of the .gem file and extracting it - I got a directory with a data.tar.gz and metadata.gz inside.  path pointed to the extracted directory with these two files didn't work.</li>
  <li>I tried extracting the data.tar.gz and metadata.gz and placing the extracted versions inside the directory that I pointed path to.  This failed.</li>
  <li>I noticed that the gem didn't have a gemspec file - I created one and placed it inside the directory.  No luck.</li>
  </ol>
  
  <p>This is the error that I get:</p>
  
  <pre><code>$ bundle install
  Fetching source index for http://rubygems.org/
  Fetching source index for http://gems.github.com/
  Could not find gem 'chilkat (&gt;= 0, runtime)' in source at /Users/username/appname/vendor/cache/chilkat-9.1.0-x86_64-linux.
  Source does not contain any versions of 'chilkat (&gt;= 0, runtime)'
  </code></pre>
  
  <p>Any ideas on how I can get Bundler to see that the gem is indeed in this directory?  Any other options other than the path attribute which doesn't seem to be working?</p>
  
  <p>Many thanks!</p>