Using Ruby Libraries from SketchUp

I found this short plugin - it's an RSS reader plugin for SketchUp. Why, you ask? I have no idea, but the author uses some interesting techniques worth noting.


$LOAD_PATH << 'C:\ruby\lib\ruby\1.8'

This line appends the ruby library path to SketchUp Ruby's global $LOAD_PATH variable. Now, SU will look in the appended folder for required files; as demonstrated by the next 2 lines:

require 'rss/1.0'
require 'rss/2.0'

...
The other interesting thing the author does is use open-uri to open and read a document from the Internet into a string:

source = `ruby -r 'open-uri' -e 'puts open("#{uri}").read'`

This code calls the external ruby to do the work. The -r option is equivalent to "require 'open-uri'". The -e means execute the following stuff. So, SketchUp's built-in Ruby is executing the external ruby, which prints the web page to standard out. The ` (backtick?) command in Ruby captures the output, which is then assigned to the "source" variable inside SketchUp. Clever.

Note that instead of the backticks, the author could have used:

%x{ ... }

which is synonymous with the ` ... ` syntax. I would recommend using this syntax as it will help avoid too-many-quotes syndrome.

Here's another example:

page=%x{ruby -r 'uri' -r 'net/http' -e 'Net::HTTP.get_print URI.parse("http://www.google.com/")'}

which you can probably guess what it does.

Although this technique does work, I don't think it's an optimal solution. First off, you will need to have the full Ruby installed on your computer, and there's no guarantee that your plugin's users will have it.