What I Learned From AFNetworking's GitHub Issues

Transcript

1. What I Learned From AFNetworking's GitHub Issues Mattt Thompson Mobile

   Lead, Heroku
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5. Lessons Learned

6. Lesson 1: Designing Great Software Means Saying No... A Lot

7. Every Line of Code Needs to Justify its Own Existence

8. Every Feature Adds Complexity

9. • Ordered Query String Parameters • Customizable Query String Format

   • Property for DELETE Parameters to be in either Query String or Message Body • Retry Parameter for Operations • Option to Parse Top-Level JSON Fragments

10. ARC w/Macros

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12. Lesson 2: If You Can’t Give Them What They Want,

    Give Them Something Better
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14. Feature Requests are Data Points to Understand What Should Be

    Improved

15. Custom Mime Types

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17. • application/json • application/javascript

18. • application/json • application/javascript • text/javascript

19. • application/json • application/javascript • text/javascript • text/x-javascript • text/x-json

    • application/x-javascript
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21. application/vnd.github+json

22. AFHTTPRequestOperation +addAcceptableContentTypes:

23. JSON Libraries

24. • JSONKit • yajl_json • SBJSON • TouchJSON • NextiveJSON

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26. AFJSONUtilities.h AFJSONEncode() / AFJSONDecode()

27. NSData * AFJSONEncode(id object, NSError **error) { NSData *data =

    nil; SEL _JSONKitSelector = NSSelectorFromString(@"JSONDataWithOptions:error:"); SEL _YAJLSelector = NSSelectorFromString(@"yajl_JSONString"); id _SBJsonWriterClass = NSClassFromString(@"SBJsonWriter"); SEL _SBJsonWriterSelector = NSSelectorFromString(@"dataWithObject:"); id _NXJsonSerializerClass = NSClassFromString(@"NXJsonSerializer"); SEL _NXJsonSerializerSelector = NSSelectorFromString(@"serialize:"); id _NSJSONSerializationClass = NSClassFromString(@"NSJSONSerialization"); SEL _NSJSONSerializationSelector = NSSelectorFromString(@"dataWithJSONObject:options:error:"); #ifdef _AFNETWORKING_PREFER_NSJSONSERIALIZATION_ if (_NSJSONSerializationClass && [_NSJSONSerializationClass respondsToSelector:_NSJSONSerializationSelector]) { goto _af_nsjson_encode; } #endif if (_JSONKitSelector && [object respondsToSelector:_JSONKitSelector]) { NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[object methodSignatureForSelector:_JSONKitSelector]]; invocation.target = object; invocation.selector = _JSONKitSelector; NSUInteger serializeOptionFlags = 0; [invocation setArgument:&serializeOptionFlags atIndex:2]; // arguments 0 and 1 are self and _cmd respectively, automatically set by NSInvocation if (error != NULL) { [invocation setArgument:error atIndex:3]; } [invocation invoke]; [invocation getReturnValue:&data]; } else if (_SBJsonWriterClass && [_SBJsonWriterClass instancesRespondToSelector:_SBJsonWriterSelector]) { id writer = [[_SBJsonWriterClass alloc] init]; NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[writer methodSignatureForSelector:_SBJsonWriterSelector]]; invocation.target = writer; invocation.selector = _SBJsonWriterSelector; [invocation setArgument:&object atIndex:2]; // arguments 0 and 1 are self and _cmd respectively, automatically set by NSInvocation [invocation invoke]; [invocation getReturnValue:&data]; [writer release];

28. NSJSONSerialization

29. ASINetworkQueue

30. ASIHTTPRequest

31. ASINetworkQueue

32. AFHTTPClient -enqueueBatchOfHTTPRequestOperations: progressBlock: completionBlock:

33. Lesson 3: Never Merge In Code That You Don’t Understand

34. Lesson 3: Never Merge In Code That You Don’t Understand

35. dispatch_group

36. AFHTTPClient -enqueueBatchOfHTTPRequestOperations: progressBlock: completionBlock:

37. 1 2 3 4 5 Batch

38. 1 2 3 4 5 Batch

39. 1 2 3 4 5 Batch 1 2 3 4

    5 1 2 3 4 5

40. Thread Safety

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43. Lesson 4: Don’t Settle For Not Understanding Something

44. Thread Safety

45. MVC Networking

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51. • dispatch_async pattern • Dedicated Network Thread • Custom Dispatch

    Queues for Background Processing

52. “The Deallocation Problem”

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54. When you start a secondary thread, it's common for that

    thread to retain the target object. If you don’t ensure that the thread releases that reference before the main thread releases its last reference to the object, bad things happen.

55. - (void)setCompletionBlock:(void (^)(void))block { if (!block) { [super setCompletionBlock:nil]; }

    __block id _blockSelf = self; [super setCompletionBlock:^ { block(); [_blockSelf setCompletionBlock:nil]; }]; }

56. API Consistency

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58. AFHTTPClient -HTTPRequestOperationWithRequest: success: failure: AFHTTPRequestOperation -setCompletionBlockWithSuccess: failure:

59. Lesson 5: The More You Put In, The More You

    Get Out

60. •Be Present •Be Nice •Be Socratic 3 Rules for Project

    Ownership
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62. Thanks!