Invalid URI file:// with custom CDN specified

[veeg]

I have the following specified in my .npmrc.

phantomjs_cdnurl=file:///net/ymir/volume1/share/internet-mirror/javascript/phantomjs/

And this fails with

error /home/user/project/src/node_modules/phantomjs-prebuilt: Command failed.
Exit code: 1
Command: node install.js
Arguments: 
Directory: /home/user/project/src/node_modules/phantomjs-prebuilt
Output:
PhantomJS not found on PATH
Downloading file:///net/ymir/volume1/share/internet-mirror/javascript/phantomjs//phantomjs-2.1.1-linux-x86_64.tar.bz2
Saving to /tmp/phantomjs/phantomjs-2.1.1-linux-x86_64.tar.bz2
Receiving...

Error making request.
Error: Invalid URI "file:///net/ymir/volume1/share/internet-mirror/javascript/phantomjs//phantomjs-2.1.1-linux-x86_64.tar.bz2"

My issue isnt really that this protocol is not supported, but rather that the error message states 'Invalid URI', when it fact, it is a perfectly valid URI, it just so happens that you do not support this protocol.

Suggestions (any or all):

• Detect valid protocols and change error message to reflect invalid protocol instead of invalid URI.
• Document valid protocols in the CDN section of the documentation.
• Implement the file:// protocol.