AFJSONRequestOperation.m

// AFJSONRequestOperation.m
//
// Copyright (c) 2011 Gowalla (http://gowalla.com/)
//
// 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 NONINFRINGEMENT. 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.

#import "AFJSONRequestOperation.h"

static dispatch_queue_t json_request_operation_processing_queue() {
    static dispatch_queue_t af_json_request_operation_processing_queue;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        af_json_request_operation_processing_queue = dispatch_queue_create("com.alamofire.networking.json-request.processing", DISPATCH_QUEUE_CONCURRENT);
    });

    return af_json_request_operation_processing_queue;
}

@interface AFJSONRequestOperation ()
@property (readwrite, nonatomic, strong) id responseJSON;
@property (readwrite, nonatomic, strong) NSError *JSONError;
@property (readwrite, nonatomic, strong) NSRecursiveLock *lock;
@end

@implementation AFJSONRequestOperation
@synthesize responseJSON = _responseJSON;
@synthesize JSONReadingOptions = _JSONReadingOptions;
@synthesize JSONError = _JSONError;
@dynamic lock;

+ (instancetype)JSONRequestOperationWithRequest:(NSURLRequest *)urlRequest
										success:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, id JSON))success
										failure:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON))failure
{
    AFJSONRequestOperation *requestOperation = [(AFJSONRequestOperation *)[self alloc] initWithRequest:urlRequest];
    [requestOperation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        if (success) {
            success(operation.request, operation.response, responseObject);
        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        if (failure) {
            failure(operation.request, operation.response, error, [(AFJSONRequestOperation *)operation responseJSON]);
        }
    }];

    return requestOperation;
}


- (id)responseJSON {
    [self.lock lock];
    if (!_responseJSON && [self.responseData length] > 0 && [self isFinished] && !self.JSONError) {
        NSError *error = nil;

        // Workaround for behavior of Rails to return a single space for `head :ok` (a workaround for a bug in Safari), which is not interpreted as valid input by NSJSONSerialization.
        // See https://github.com/rails/rails/issues/1742
        if ([self.responseData length] == 0 || [self.responseString isEqualToString:@" "]) {
            self.responseJSON = nil;
        } else {
            // Workaround for a bug in NSJSONSerialization when Unicode character escape codes are used instead of the actual character
            // See http://stackoverflow.com/a/12843465/157142
            NSData *JSONData = [self.responseString dataUsingEncoding:self.responseStringEncoding];
            self.responseJSON = [NSJSONSerialization JSONObjectWithData:JSONData options:self.JSONReadingOptions error:&error];
        }

        self.JSONError = error;
    }
    [self.lock unlock];

    return _responseJSON;
}

- (NSError *)error {
    if (_JSONError) {
        return _JSONError;
    } else {
        return [super error];
    }
}

#pragma mark - AFHTTPRequestOperation

+ (NSSet *)acceptableContentTypes {
    return [NSSet setWithObjects:@"application/json", @"text/json", @"text/javascript", nil];
}

+ (BOOL)canProcessRequest:(NSURLRequest *)request {
    return [[[request URL] pathExtension] isEqualToString:@"json"] || [super canProcessRequest:request];
}

- (void)setCompletionBlockWithSuccess:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
                              failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-retain-cycles"
    self.completionBlock = ^ {
        if (self.error) {
            if (failure) {
                dispatch_async(self.failureCallbackQueue ?: dispatch_get_main_queue(), ^{
                    failure(self, self.error);
                });
            }
        } else {
            dispatch_async(json_request_operation_processing_queue(), ^{
                id JSON = self.responseJSON;

                if (self.JSONError) {
                    if (failure) {
                        dispatch_async(self.failureCallbackQueue ?: dispatch_get_main_queue(), ^{
                            failure(self, self.error);
                        });
                    }
                } else {
                    if (success) {
                        dispatch_async(self.successCallbackQueue ?: dispatch_get_main_queue(), ^{
                            success(self, JSON);
                        });
                    }
                }
            });
        }
    };
#pragma clang diagnostic pop
}

@end