Provide a proxy service for apps to use for fetching resources

[davidbau]

Some resources on the internet are only available if requested by a server, not a browser, so we should provide a simple proxy URL for pencilcode apps to fetch resources by bouncing off the pencilcode server.

Two use cases:

(1) PencilCode/jquery-turtle#25 - smart hit-testing. When using an offdomain image for a turtle, we want to inspect bits so that we can hit-test correctly (i.e., don't collide on transparent corners). But CORS rules prevent us from knowing the bits unless we safely bounce off a server we own. (The security rules are what keeps corp secrets safe from public browser pages javascript.)

(2) PencilCode/jquery-turtle#6 - text-to-speech. When using google translate tts, it only accepts requests without a referrer header. So people who use it bounce their requests off a proxy.

[davidbau]

Design sketch:

http://proxy.pencilcode.net/get?url=(the underlying URL)

This should proxy a get directly, but with CORS-friendly headers.

The jQuery-turtle library should get a "prox" function so that prox 'the url' will create the URL form above. So you can just switch code from "wear URL" to "wear prox URL" to get the proxying.

[davidbau]

This works now, via

http://pencilcode.net/proxy/http://upload.wikimedia.org/wikipedia/commons/b/b2/WhiteCat.jpg