Using a custom URL scheme with UIWebView

Question

I have a black box container. I love black boxes, they obfuscate things so well.

This black box is an encrypted zip (sort of) and has inside some html files (this is the short, not so painful to explain, version).

Those files need to be displayed in an UIWebView. Now, the easy way to do it, decrypt, unzip to filesystem, load file from filesystem. That's good, except, the black box contains secret stuff, and can't just lay around on the filesystem, not even a sec, so, I made a C library that actually streams the contents of the box (directly out of the box).

Now, I have this streaming capability and have to somehow make it work with UIWebView. First thing that comes in my mind would be to use a mini local HTTP server where the UIWebView can sent its requests. I would then manage the requests myself and return the contents the UIWebView requires using the streaming lib I've done. That would work I suppose well, but I think a mini HTTP server would somehow, maybe, be a little bit of a overkill.

So, I was wondering, is there another way to interfere between UIWebView and the filesystem? Maybe using a custom schema? Like myschema://? And every time the UIWebView makes a request to myschema://myfile.html I would somehow interfere and return the data it needs?

Is such a idea viable? Where should I look to start from? Maybe NSURLRequest?

EDIT: I found this: iPhone SDK: Loading resources from custom URL scheme. It sounds good, however, how will the browser know the size of the request, the type (xml/binary/xhtml) and all the info HTTP puts in its header?

Answer 1

Create a custom NSURLProtocol subclass and register it so it will handle the HTTP requests. This will allow you to handle the requests that come from the UIWebView however you see fit, including supplying the data from your library. You can examine an implementation of one that performs disk caching of requests to allow offline browsing by looking at RNCachingURLProtocol. I personally use a custom NSURLProtocol subclass that I wrote to handle injecting some javascript code into pages that are loaded in the UIWebView, and it works very well.