VCRURLConnection

An introduction to VCRURLConnection, an iOS and OSX API to record and replay HTTP interactions, inspired by VCR for ruby. Presented at Cocoa Kucha in New York City.

Transcript

1. VCRURLConnection http://github.com/dstnbrkr/VCRURLConnection Dustin Barker http://twitter.com/dstnbrkr November 20th, 2013 Cocoa Kucha NYC
2. VCRURLConnection records and replays HTTP interactions (inspired by VCR for ruby) HTTP GET HTTP GET HTTP 200 OK HTTP 200 OK
3. API VCRURLConnection intercepts HTTP interactions and writes them to disk
4. then it replays those HTTP interactions from disk, without the network
5. record a session when you’re online replay the session when you need to work offline
6. so recording is built into debug builds of Artsy at Artsy, we debug offline often
7. apps connect to many services must degrade gracefully when any are unavailable Payments Transactions Messages x
8. VCRURLConnection lets you test failure cases by simulating failing services Payments Transactions x
9. harden apps further with service roulette by simulating failing services at random ? ? ?
10. non-repeatable interactions are tedious to test HTTP DELETE HTTP 200 HTTP DELETE HTTP 404 API
11. a recording can make these interactions repeatable (and easier to test) HTTP DELETE HTTP 200 HTTP DELETE HTTP 200
12. to begin recording HTTP interactions with VCRURLConnection: [VCR start]; Before requests are made: (ex: application:didFinishLaunchingWithOptions:)
13. to save a recording with VCRURLConnection: [VCR save:path]; After requests are made: (ex: applicationWillTerminate:)
14. [ { "method": "GET", "uri" : "http://foo.com/test.json", "headers" : { "Content-Type": "application/json", ... }, "body": { ... } } ... ] VCRURLConnection records request and response pairs to disk in JSON format
15. to play a recording with VCRURLConnection: NSURL *url = [NSURL fileURLWithPath:path]; [VCR loadCassetteWithContentsOfURL:url]; [VCR start]; Before requests are made: (ex: application:didFinishLaunchingWithOptions:)
16. VCRURLConnection swizzles NSURLConnection message runtime NSURLConnection VCRURLConnection (VCR is off) (VCR is on) to intercept messages to NSURLConnection
17. VCRURLConnection forwards to NSURLConnection message runtime NSURLConnection VCRURLConnection and writes responses to disk
18. What’s Next for VCRURLConnection NSURLConnection NSURLSession Better Support for iOS 7
19. Try VCRURLConnection platform :ios, '7.0' pod 'VCRURLConnection', '~> 0.1.1' git clone https://github.com/dstnbrkr/VCRURLConnection.git Download VCRURLConnection from Github Add VCRURLConnection to your Podfile
20. VCRURLConnection http://github.com/dstnbrkr/VCRURLConnection http://twitter.com/dstnbrkr http://github.com/dstnbrkr Dustin Barker