NSURLConnectionVCR /

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NSURLConnectionVCR provides an easy way to record and re-play NSURLConnection requests/responses. By removing the dependency on external web servers, your tests will run fast and deterministic. Don't worry, no need to change your existing NSURLConnection-based code. NSURLConnectionVCR hooks into NSURLConnection by 'swizzling' implementations at run-time.

This project is inspired on Myron Marston's VCR for Ruby on Rails.

Getting Started

First, start the VCR and give it a storage path:

[NSURLConnectionVCR startVCRWithPath:@"fixtures/vcr_cassettes" error:nil];

Then perform a request using NSURLConnection:

NSURL* url = [NSURL URLWithString:@"http://api.example.com/fancy.json"];
NSURLRequest* request = [NSURLRequest requestWithURL:url];
NSHTTPURLResponse* response = nil;
NSData* data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];

The first time this code is run, it will run the request and store the response in a file at the specified path. Run it again, and VCR will 'play back' the recorded response from disk, without making a call to the web server.

Optionally, stop the VCR once you're done:

[NSURLConnection stopVCRWithError:nil];

Adding NSURLConnectionVCR to your project


  • Mac OS X 10.7 SDK or later
  • iOS 5.0 SDK or later
  • ARC (Automatic Reference Counting)

Just add NSURLConnectionVCR.m and NSURLConnectionVCR.h to your project. There are no external dependencies, except of course Foundation.framework and the Objective C runtime.

Quicklook plug-in

NSURLConnectionVCR creates one file per unique request and stores it at the specified path. The provided Quicklook plug-in makes basic inspection of these cache files convenient. A cache file is basically an archive containing the NSURLResponse and NSData that were returned when the request was done. The name of the cache file is the MD5 digest of the original NSURLRequest. The Quicklook preview displays the response data and puts the original URL and HTTP status code as title of the preview window.