BACKGROUND

RNCachingURLProtocol is a simple shim for the HTTP protocol (that’s not
nearly as scary as it sounds). Anytime a URL is downloaded, the response is
cached to disk. Anytime a URL is requested, if we’re online then things
proceed normally. If we’re offline, then we retrieve the cached version.

The point of RNCachingURLProtocol is mostly to demonstrate how this is done.
The current implementation is extremely simple. In particular, it doesn’t
worry about cleaning up the cache. The assumption is that you’re caching just
a few simple things, like your “Latest News” page (which was the problem I
was solving). It caches all HTTP traffic, so without some modifications, it’s
not appropriate for an app that has a lot of HTTP connections (see
MKNetworkKit for that). But if you need to cache some URLs and not others,
that is easy to implement.

You should also look at AFCache for a
more powerful caching engine that is currently integrating the ideas of
RNCachingURLProtocol.

USAGE

1. To build, you will need the Reachability code from Apple (included). That requires that you link with
   SystemConfiguration.framework.

2. At some point early in the program (usually application:didFinishLaunchingWithOptions:),
   call the following:

   [NSURLProtocol registerClass:[RNCachingURLProtocol class]];

3. There is no step 3.

For more details see
Drop-in offline caching for UIWebView (and NSURLProtocol).

EXAMPLE

See the CachedWebView project for example usage.

LICENSE

This code is licensed under the MIT License:

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the “Software”),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.