AFHTTPClient.m

// AFHTTPClient.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 <Foundation/Foundation.h>

#import "AFHTTPClient.h"
#import "AFHTTPRequestOperation.h"

#import <Availability.h>

#ifdef _SYSTEMCONFIGURATION_H
#import <netinet/in.h>
#import <netinet6/in6.h>
#import <arpa/inet.h>
#import <ifaddrs.h>
#import <netdb.h>
#endif

#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
#import <UIKit/UIKit.h>
#endif

#ifdef _SYSTEMCONFIGURATION_H
NSString * const AFNetworkingReachabilityDidChangeNotification = @"com.alamofire.networking.reachability.change";
NSString * const AFNetworkingReachabilityNotificationStatusItem = @"AFNetworkingReachabilityNotificationStatusItem";

typedef SCNetworkReachabilityRef AFNetworkReachabilityRef;
typedef void (^AFNetworkReachabilityStatusBlock)(AFNetworkReachabilityStatus status);
#else
typedef id AFNetworkReachabilityRef;
#endif

typedef void (^AFCompletionBlock)(void);

static NSString * AFBase64EncodedStringFromString(NSString *string) {
    NSData *data = [NSData dataWithBytes:[string UTF8String] length:[string lengthOfBytesUsingEncoding:NSUTF8StringEncoding]];
    NSUInteger length = [data length];
    NSMutableData *mutableData = [NSMutableData dataWithLength:((length + 2) / 3) * 4];

    uint8_t *input = (uint8_t *)[data bytes];
    uint8_t *output = (uint8_t *)[mutableData mutableBytes];

    for (NSUInteger i = 0; i < length; i += 3) {
        NSUInteger value = 0;
        for (NSUInteger j = i; j < (i + 3); j++) {
            value <<= 8;
            if (j < length) {
                value |= (0xFF & input[j]);
            }
        }

        static uint8_t const kAFBase64EncodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

        NSUInteger idx = (i / 3) * 4;
        output[idx + 0] = kAFBase64EncodingTable[(value >> 18) & 0x3F];
        output[idx + 1] = kAFBase64EncodingTable[(value >> 12) & 0x3F];
        output[idx + 2] = (i + 1) < length ? kAFBase64EncodingTable[(value >> 6)  & 0x3F] : '=';
        output[idx + 3] = (i + 2) < length ? kAFBase64EncodingTable[(value >> 0)  & 0x3F] : '=';
    }

    return [[NSString alloc] initWithData:mutableData encoding:NSASCIIStringEncoding];
}

static NSString * AFPercentEscapedQueryStringPairMemberFromStringWithEncoding(NSString *string, NSStringEncoding encoding) {
    static NSString * const kAFCharactersToBeEscaped = @":/?&=;+!@#$()~',*";
    static NSString * const kAFCharactersToLeaveUnescaped = @"[].";

	return (__bridge_transfer  NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (__bridge CFStringRef)string, (__bridge CFStringRef)kAFCharactersToLeaveUnescaped, (__bridge CFStringRef)kAFCharactersToBeEscaped, CFStringConvertNSStringEncodingToEncoding(encoding));
}

#pragma mark -

@interface AFQueryStringPair : NSObject
@property (readwrite, nonatomic, strong) id field;
@property (readwrite, nonatomic, strong) id value;

- (id)initWithField:(id)field value:(id)value;

- (NSString *)URLEncodedStringValueWithEncoding:(NSStringEncoding)stringEncoding;
@end

@implementation AFQueryStringPair
@synthesize field = _field;
@synthesize value = _value;

- (id)initWithField:(id)field value:(id)value {
    self = [super init];
    if (!self) {
        return nil;
    }

    self.field = field;
    self.value = value;

    return self;
}

- (NSString *)URLEncodedStringValueWithEncoding:(NSStringEncoding)stringEncoding {
    if (!self.value || [self.value isEqual:[NSNull null]]) {
        return AFPercentEscapedQueryStringPairMemberFromStringWithEncoding([self.field description], stringEncoding);
    } else {
        return [NSString stringWithFormat:@"%@=%@", AFPercentEscapedQueryStringPairMemberFromStringWithEncoding([self.field description], stringEncoding), AFPercentEscapedQueryStringPairMemberFromStringWithEncoding([self.value description], stringEncoding)];
    }
}

@end

#pragma mark -

extern NSArray * AFQueryStringPairsFromDictionary(NSDictionary *dictionary);
extern NSArray * AFQueryStringPairsFromKeyAndValue(NSString *key, id value);

NSString * AFQueryStringFromParametersWithEncoding(NSDictionary *parameters, NSStringEncoding stringEncoding) {
    NSMutableArray *mutablePairs = [NSMutableArray array];
    for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {
        [mutablePairs addObject:[pair URLEncodedStringValueWithEncoding:stringEncoding]];
    }

    return [mutablePairs componentsJoinedByString:@"&"];
}

NSArray * AFQueryStringPairsFromDictionary(NSDictionary *dictionary) {
    return AFQueryStringPairsFromKeyAndValue(nil, dictionary);
}

NSArray * AFQueryStringPairsFromKeyAndValue(NSString *key, id value) {
    NSMutableArray *mutableQueryStringComponents = [NSMutableArray array];

    if ([value isKindOfClass:[NSDictionary class]]) {
        NSDictionary *dictionary = value;
        // Sort dictionary keys to ensure consistent ordering in query string, which is important when deserializing potentially ambiguous sequences, such as an array of dictionaries
        NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"description" ascending:YES selector:@selector(caseInsensitiveCompare:)];
        for (id nestedKey in [dictionary.allKeys sortedArrayUsingDescriptors:@[ sortDescriptor ]]) {
            id nestedValue = dictionary[nestedKey];
            if (nestedValue) {
                [mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue((key ? [NSString stringWithFormat:@"%@[%@]", key, nestedKey] : nestedKey), nestedValue)];
            }
        }
    } else if ([value isKindOfClass:[NSArray class]]) {
        NSArray *array = value;
        for (id nestedValue in array) {
            [mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue([NSString stringWithFormat:@"%@[]", key], nestedValue)];
        }
    } else if ([value isKindOfClass:[NSSet class]]) {
        NSSet *set = value;
        for (id obj in set) {
            [mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue(key, obj)];
        }
    } else {
        [mutableQueryStringComponents addObject:[[AFQueryStringPair alloc] initWithField:key value:value]];
    }

    return mutableQueryStringComponents;
}

@interface AFStreamingMultipartFormData : NSObject <AFMultipartFormData>
- (id)initWithURLRequest:(NSMutableURLRequest *)urlRequest
          stringEncoding:(NSStringEncoding)encoding;

- (NSMutableURLRequest *)requestByFinalizingMultipartFormData;
@end

#pragma mark -

@interface AFHTTPClient ()
@property (readwrite, nonatomic, strong) NSURL *baseURL;
@property (readwrite, nonatomic, strong) NSMutableArray *registeredHTTPOperationClassNames;
@property (readwrite, nonatomic, strong) NSMutableDictionary *defaultHeaders;
@property (readwrite, nonatomic, strong) NSURLCredential *defaultCredential;
@property (readwrite, nonatomic, strong) NSOperationQueue *operationQueue;
#ifdef _SYSTEMCONFIGURATION_H
@property (readwrite, nonatomic, assign) AFNetworkReachabilityRef networkReachability;
@property (readwrite, nonatomic, assign) AFNetworkReachabilityStatus networkReachabilityStatus;
@property (readwrite, nonatomic, copy) AFNetworkReachabilityStatusBlock networkReachabilityStatusBlock;
#endif

#ifdef _SYSTEMCONFIGURATION_H
- (void)startMonitoringNetworkReachability;
- (void)stopMonitoringNetworkReachability;
#endif
@end

@implementation AFHTTPClient
@synthesize baseURL = _baseURL;
@synthesize stringEncoding = _stringEncoding;
@synthesize parameterEncoding = _parameterEncoding;
@synthesize registeredHTTPOperationClassNames = _registeredHTTPOperationClassNames;
@synthesize defaultHeaders = _defaultHeaders;
@synthesize defaultCredential = _defaultCredential;
@synthesize operationQueue = _operationQueue;
#ifdef _SYSTEMCONFIGURATION_H
@synthesize networkReachability = _networkReachability;
@synthesize networkReachabilityStatus = _networkReachabilityStatus;
@synthesize networkReachabilityStatusBlock = _networkReachabilityStatusBlock;
#endif

+ (instancetype)clientWithBaseURL:(NSURL *)url {
    return [[self alloc] initWithBaseURL:url];
}

- (id)initWithBaseURL:(NSURL *)url {
    NSParameterAssert(url);

    self = [super init];
    if (!self) {
        return nil;
    }

    // Ensure terminal slash for baseURL path, so that NSURL +URLWithString:relativeToURL: works as expected
    if ([[url path] length] > 0 && ![[url absoluteString] hasSuffix:@"/"]) {
        url = [url URLByAppendingPathComponent:@""];
    }

    self.baseURL = url;

    self.stringEncoding = NSUTF8StringEncoding;
    self.parameterEncoding = AFFormURLParameterEncoding;

    self.registeredHTTPOperationClassNames = [NSMutableArray array];

	self.defaultHeaders = [NSMutableDictionary dictionary];

    // Accept-Language HTTP Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4
    NSMutableArray *acceptLanguagesComponents = [NSMutableArray array];
    [[NSLocale preferredLanguages] enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        float q = 1.0f - (idx * 0.1f);
        [acceptLanguagesComponents addObject:[NSString stringWithFormat:@"%@;q=%0.1g", obj, q]];
        *stop = q <= 0.5f;
    }];
    [self setDefaultHeader:@"Accept-Language" value:[acceptLanguagesComponents componentsJoinedByString:@", "]];
    
#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
    // User-Agent Header; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.43
    [self setDefaultHeader:@"User-Agent" value:[NSString stringWithFormat:@"%@/%@ (%@; iOS %@; Scale/%0.2f)", [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleExecutableKey] ?: [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleIdentifierKey], (__bridge id)CFBundleGetValueForInfoDictionaryKey(CFBundleGetMainBundle(), kCFBundleVersionKey) ?: [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleVersionKey], [[UIDevice currentDevice] model], [[UIDevice currentDevice] systemVersion], ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] ? [[UIScreen mainScreen] scale] : 1.0f)]];
#elif defined(__MAC_OS_X_VERSION_MIN_REQUIRED)
    [self setDefaultHeader:@"User-Agent" value:[NSString stringWithFormat:@"%@/%@ (Mac OS X %@)", [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleExecutableKey] ?: [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleIdentifierKey], [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"] ?: [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString *)kCFBundleVersionKey], [[NSProcessInfo processInfo] operatingSystemVersionString]]];
#endif

#ifdef _SYSTEMCONFIGURATION_H
    self.networkReachabilityStatus = AFNetworkReachabilityStatusUnknown;
    [self startMonitoringNetworkReachability];
#endif

    self.operationQueue = [[NSOperationQueue alloc] init];
	[self.operationQueue setMaxConcurrentOperationCount:NSOperationQueueDefaultMaxConcurrentOperationCount];

    // #ifdef included for backwards-compatibility
#ifdef _AFNETWORKING_ALLOW_INVALID_SSL_CERTIFICATES_
    self.allowsInvalidSSLCertificate = YES;
#endif
    
    return self;
}

- (void)dealloc {
#ifdef _SYSTEMCONFIGURATION_H
    [self stopMonitoringNetworkReachability];
#endif
}

- (NSString *)description {
    return [NSString stringWithFormat:@"<%@: %p, baseURL: %@, defaultHeaders: %@, registeredOperationClasses: %@, operationQueue: %@>", NSStringFromClass([self class]), self, [self.baseURL absoluteString], self.defaultHeaders, self.registeredHTTPOperationClassNames, self.operationQueue];
}

#pragma mark -

#ifdef _SYSTEMCONFIGURATION_H
static BOOL AFURLHostIsIPAddress(NSURL *url) {
    struct sockaddr_in sa_in;
    struct sockaddr_in6 sa_in6;

    return [url host] && (inet_pton(AF_INET, [[url host] UTF8String], &sa_in) == 1 || inet_pton(AF_INET6, [[url host] UTF8String], &sa_in6) == 1);
}

static AFNetworkReachabilityStatus AFNetworkReachabilityStatusForFlags(SCNetworkReachabilityFlags flags) {
    BOOL isReachable = ((flags & kSCNetworkReachabilityFlagsReachable) != 0);
    BOOL needsConnection = ((flags & kSCNetworkReachabilityFlagsConnectionRequired) != 0);
    BOOL isNetworkReachable = (isReachable && !needsConnection);

    AFNetworkReachabilityStatus status = AFNetworkReachabilityStatusUnknown;
    if (isNetworkReachable == NO) {
        status = AFNetworkReachabilityStatusNotReachable;
    }
#if	TARGET_OS_IPHONE
    else if ((flags & kSCNetworkReachabilityFlagsIsWWAN) != 0) {
        status = AFNetworkReachabilityStatusReachableViaWWAN;
    }
#endif
    else {
        status = AFNetworkReachabilityStatusReachableViaWiFi;
    }

    return status;
}

static void AFNetworkReachabilityCallback(SCNetworkReachabilityRef __unused target, SCNetworkReachabilityFlags flags, void *info) {
    AFNetworkReachabilityStatus status = AFNetworkReachabilityStatusForFlags(flags);
    AFNetworkReachabilityStatusBlock block = (__bridge AFNetworkReachabilityStatusBlock)info;
    if (block) {
        block(status);
    }

    dispatch_async(dispatch_get_main_queue(), ^{
        NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
        [notificationCenter postNotificationName:AFNetworkingReachabilityDidChangeNotification object:nil userInfo:[NSDictionary dictionaryWithObject:[NSNumber numberWithInteger:status] forKey:AFNetworkingReachabilityNotificationStatusItem]];
    });
}

static const void * AFNetworkReachabilityRetainCallback(const void *info) {
    return (__bridge_retained const void *)([(__bridge AFNetworkReachabilityStatusBlock)info copy]);
}

static void AFNetworkReachabilityReleaseCallback(const void *info) {
    if (info) {
        CFRelease(info);
    }
}

- (void)startMonitoringNetworkReachability {
    [self stopMonitoringNetworkReachability];

    if (!self.baseURL) {
        return;
    }

    self.networkReachability = SCNetworkReachabilityCreateWithName(kCFAllocatorDefault, [[self.baseURL host] UTF8String]);

    if (!self.networkReachability) {
        return;
    }

    __weak __typeof(&*self)weakSelf = self;
    AFNetworkReachabilityStatusBlock callback = ^(AFNetworkReachabilityStatus status) {
        __strong __typeof(&*weakSelf)strongSelf = weakSelf;
        if (!strongSelf) {
            return;
        }

        strongSelf.networkReachabilityStatus = status;
        if (strongSelf.networkReachabilityStatusBlock) {
            strongSelf.networkReachabilityStatusBlock(status);
        }
    };

    SCNetworkReachabilityContext context = {0, (__bridge void *)callback, AFNetworkReachabilityRetainCallback, AFNetworkReachabilityReleaseCallback, NULL};
    SCNetworkReachabilitySetCallback(self.networkReachability, AFNetworkReachabilityCallback, &context);
    SCNetworkReachabilityScheduleWithRunLoop(self.networkReachability, CFRunLoopGetMain(), (CFStringRef)NSRunLoopCommonModes);

    /* Network reachability monitoring does not establish a baseline for IP addresses as it does for hostnames, so if the base URL host is an IP address, the initial reachability callback is manually triggered.
     */
    if (AFURLHostIsIPAddress(self.baseURL)) {
        SCNetworkReachabilityFlags flags;
        SCNetworkReachabilityGetFlags(self.networkReachability, &flags);
        dispatch_async(dispatch_get_main_queue(), ^{
            AFNetworkReachabilityStatus status = AFNetworkReachabilityStatusForFlags(flags);
            callback(status);
        });
    }
}

- (void)stopMonitoringNetworkReachability {
    if (_networkReachability) {
        SCNetworkReachabilityUnscheduleFromRunLoop(_networkReachability, CFRunLoopGetMain(), (CFStringRef)NSRunLoopCommonModes);
        CFRelease(_networkReachability);
        _networkReachability = NULL;
    }
}

- (void)setReachabilityStatusChangeBlock:(void (^)(AFNetworkReachabilityStatus status))block {
    self.networkReachabilityStatusBlock = block;
}
#endif

#pragma mark -

- (BOOL)registerHTTPOperationClass:(Class)operationClass {
    if (![operationClass isSubclassOfClass:[AFHTTPRequestOperation class]]) {
        return NO;
    }

    NSString *className = NSStringFromClass(operationClass);
    [self.registeredHTTPOperationClassNames removeObject:className];
    [self.registeredHTTPOperationClassNames insertObject:className atIndex:0];

    return YES;
}

- (void)unregisterHTTPOperationClass:(Class)operationClass {
    NSString *className = NSStringFromClass(operationClass);
    [self.registeredHTTPOperationClassNames removeObject:className];
}

#pragma mark -

- (NSString *)defaultValueForHeader:(NSString *)header {
	return [self.defaultHeaders valueForKey:header];
}

- (void)setDefaultHeader:(NSString *)header value:(NSString *)value {
	[self.defaultHeaders setValue:value forKey:header];
}

- (void)setAuthorizationHeaderWithUsername:(NSString *)username password:(NSString *)password {
	NSString *basicAuthCredentials = [NSString stringWithFormat:@"%@:%@", username, password];
    [self setDefaultHeader:@"Authorization" value:[NSString stringWithFormat:@"Basic %@", AFBase64EncodedStringFromString(basicAuthCredentials)]];
}

- (void)setAuthorizationHeaderWithToken:(NSString *)token {
    [self setDefaultHeader:@"Authorization" value:[NSString stringWithFormat:@"Token token=\"%@\"", token]];
}

- (void)clearAuthorizationHeader {
	[self.defaultHeaders removeObjectForKey:@"Authorization"];
}

#pragma mark -

- (NSMutableURLRequest *)requestWithMethod:(NSString *)method
                                      path:(NSString *)path
                                parameters:(NSDictionary *)parameters
{
    NSParameterAssert(method);

    if (!path) {
        path = @"";
    }

    NSURL *url = [NSURL URLWithString:path relativeToURL:self.baseURL];
	NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
    [request setHTTPMethod:method];
    [request setAllHTTPHeaderFields:self.defaultHeaders];

    if (parameters) {
        if ([method isEqualToString:@"GET"] || [method isEqualToString:@"HEAD"] || [method isEqualToString:@"DELETE"]) {
            url = [NSURL URLWithString:[[url absoluteString] stringByAppendingFormat:[path rangeOfString:@"?"].location == NSNotFound ? @"?%@" : @"&%@", AFQueryStringFromParametersWithEncoding(parameters, self.stringEncoding)]];
            [request setURL:url];
        } else {
            NSString *charset = (__bridge NSString *)CFStringConvertEncodingToIANACharSetName(CFStringConvertNSStringEncodingToEncoding(self.stringEncoding));
            NSError *error = nil;

            switch (self.parameterEncoding) {
                case AFFormURLParameterEncoding:;
                    [request setValue:[NSString stringWithFormat:@"application/x-www-form-urlencoded; charset=%@", charset] forHTTPHeaderField:@"Content-Type"];
                    [request setHTTPBody:[AFQueryStringFromParametersWithEncoding(parameters, self.stringEncoding) dataUsingEncoding:self.stringEncoding]];
                    break;
                case AFJSONParameterEncoding:;
                    [request setValue:[NSString stringWithFormat:@"application/json; charset=%@", charset] forHTTPHeaderField:@"Content-Type"];
                    [request setHTTPBody:[NSJSONSerialization dataWithJSONObject:parameters options:0 error:&error]];
                    break;
                case AFPropertyListParameterEncoding:;
                    [request setValue:[NSString stringWithFormat:@"application/x-plist; charset=%@", charset] forHTTPHeaderField:@"Content-Type"];
                    [request setHTTPBody:[NSPropertyListSerialization dataWithPropertyList:parameters format:NSPropertyListXMLFormat_v1_0 options:0 error:&error]];
                    break;
            }

            if (error) {
                NSLog(@"%@ %@: %@", [self class], NSStringFromSelector(_cmd), error);
            }
        }
    }

	return request;
}

- (NSMutableURLRequest *)multipartFormRequestWithMethod:(NSString *)method
                                                   path:(NSString *)path
                                             parameters:(NSDictionary *)parameters
                              constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block
{
    NSParameterAssert(method);
    NSParameterAssert(![method isEqualToString:@"GET"] && ![method isEqualToString:@"HEAD"]);

    NSMutableURLRequest *request = [self requestWithMethod:method path:path parameters:nil];

    __block AFStreamingMultipartFormData *formData = [[AFStreamingMultipartFormData alloc] initWithURLRequest:request stringEncoding:self.stringEncoding];

    if (parameters) {
        for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {
            NSData *data = nil;
            if ([pair.value isKindOfClass:[NSData class]]) {
                data = pair.value;
            } else if ([pair.value isEqual:[NSNull null]]) {
                data = [NSData data];
            } else {
                data = [[pair.value description] dataUsingEncoding:self.stringEncoding];
            }

            if (data) {
                [formData appendPartWithFormData:data name:[pair.field description]];
            }
        }
    }

    if (block) {
        block(formData);
    }

    return [formData requestByFinalizingMultipartFormData];
}

- (AFHTTPRequestOperation *)HTTPRequestOperationWithRequest:(NSURLRequest *)urlRequest
                                                    success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
                                                    failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
    AFHTTPRequestOperation *operation = nil;
    
    for (NSString *className in self.registeredHTTPOperationClassNames) {
        Class operationClass = NSClassFromString(className);
        if (operationClass && [operationClass canProcessRequest:urlRequest]) {
            operation = [(AFHTTPRequestOperation *)[operationClass alloc] initWithRequest:urlRequest];
            break;
        }
    }

    if (!operation) {
        operation = [[AFHTTPRequestOperation alloc] initWithRequest:urlRequest];
    }

    [operation setCompletionBlockWithSuccess:success failure:failure];

    operation.credential = self.defaultCredential;
#ifdef _AFNETWORKING_PIN_SSL_CERTIFICATES_
    operation.SSLPinningMode = self.defaultSSLPinningMode;
#endif
    operation.allowsInvalidSSLCertificate = self.allowsInvalidSSLCertificate;

    return operation;
}

#pragma mark -

- (void)enqueueHTTPRequestOperation:(AFHTTPRequestOperation *)operation {
    [self.operationQueue addOperation:operation];
}

- (void)cancelAllHTTPOperationsWithMethod:(NSString *)method
                                     path:(NSString *)path
{
    NSString *pathToBeMatched = [[[self requestWithMethod:(method ?: @"GET") path:path parameters:nil] URL] path];

    for (NSOperation *operation in [self.operationQueue operations]) {
        if (![operation isKindOfClass:[AFHTTPRequestOperation class]]) {
            continue;
        }

        BOOL hasMatchingMethod = !method || [method isEqualToString:[[(AFHTTPRequestOperation *)operation request] HTTPMethod]];
        BOOL hasMatchingPath = [[[[(AFHTTPRequestOperation *)operation request] URL] path] isEqual:pathToBeMatched];

        if (hasMatchingMethod && hasMatchingPath) {
            [operation cancel];
        }
    }
}

- (void)enqueueBatchOfHTTPRequestOperationsWithRequests:(NSArray *)urlRequests
                                          progressBlock:(void (^)(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations))progressBlock
                                        completionBlock:(void (^)(NSArray *operations))completionBlock
{
    NSMutableArray *mutableOperations = [NSMutableArray array];
    for (NSURLRequest *request in urlRequests) {
        AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithRequest:request success:nil failure:nil];
        [mutableOperations addObject:operation];
    }

    [self enqueueBatchOfHTTPRequestOperations:mutableOperations progressBlock:progressBlock completionBlock:completionBlock];
}

- (void)enqueueBatchOfHTTPRequestOperations:(NSArray *)operations
                              progressBlock:(void (^)(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations))progressBlock
                            completionBlock:(void (^)(NSArray *operations))completionBlock
{
    __block dispatch_group_t dispatchGroup = dispatch_group_create();
    NSBlockOperation *batchedOperation = [NSBlockOperation blockOperationWithBlock:^{
        dispatch_group_notify(dispatchGroup, dispatch_get_main_queue(), ^{
            if (completionBlock) {
                completionBlock(operations);
            }
        });
#if !OS_OBJECT_USE_OBJC
        dispatch_release(dispatchGroup);
#endif
    }];

    for (AFHTTPRequestOperation *operation in operations) {
        AFCompletionBlock originalCompletionBlock = [operation.completionBlock copy];
        __weak __typeof(&*operation)weakOperation = operation;
        operation.completionBlock = ^{
            __strong __typeof(&*weakOperation)strongOperation = weakOperation;
            dispatch_queue_t queue = strongOperation.successCallbackQueue ?: dispatch_get_main_queue();
            dispatch_group_async(dispatchGroup, queue, ^{
                if (originalCompletionBlock) {
                    originalCompletionBlock();
                }

                NSInteger numberOfFinishedOperations = [[operations indexesOfObjectsPassingTest:^BOOL(id op, NSUInteger __unused idx,  BOOL __unused *stop) {
                    return [op isFinished];
                }] count];

                if (progressBlock) {
                    progressBlock(numberOfFinishedOperations, [operations count]);
                }

                dispatch_group_leave(dispatchGroup);
            });
        };

        dispatch_group_enter(dispatchGroup);
        [batchedOperation addDependency:operation];
    }
    [self.operationQueue addOperations:operations waitUntilFinished:NO];
    [self.operationQueue addOperation:batchedOperation];
}

#pragma mark -

- (void)getPath:(NSString *)path
     parameters:(NSDictionary *)parameters
        success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
        failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
	NSURLRequest *request = [self requestWithMethod:@"GET" path:path parameters:parameters];
    AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithRequest:request success:success failure:failure];
    [self enqueueHTTPRequestOperation:operation];
}

- (void)postPath:(NSString *)path
      parameters:(NSDictionary *)parameters
         success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
         failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
	NSURLRequest *request = [self requestWithMethod:@"POST" path:path parameters:parameters];
	AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithRequest:request success:success failure:failure];
    [self enqueueHTTPRequestOperation:operation];
}

- (void)putPath:(NSString *)path
     parameters:(NSDictionary *)parameters
        success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
        failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
	NSURLRequest *request = [self requestWithMethod:@"PUT" path:path parameters:parameters];
	AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithRequest:request success:success failure:failure];
    [self enqueueHTTPRequestOperation:operation];
}

- (void)deletePath:(NSString *)path
        parameters:(NSDictionary *)parameters
           success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
           failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
	NSURLRequest *request = [self requestWithMethod:@"DELETE" path:path parameters:parameters];
	AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithRequest:request success:success failure:failure];
    [self enqueueHTTPRequestOperation:operation];
}

- (void)patchPath:(NSString *)path
       parameters:(NSDictionary *)parameters
          success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
          failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure
{
    NSURLRequest *request = [self requestWithMethod:@"PATCH" path:path parameters:parameters];
	AFHTTPRequestOperation *operation = [self HTTPRequestOperationWithRequest:request success:success failure:failure];
    [self enqueueHTTPRequestOperation:operation];
}

#pragma mark - NSCoding

- (id)initWithCoder:(NSCoder *)aDecoder {
    NSURL *baseURL = [aDecoder decodeObjectForKey:@"baseURL"];

    self = [self initWithBaseURL:baseURL];
    if (!self) {
        return nil;
    }

    self.stringEncoding = [aDecoder decodeIntegerForKey:@"stringEncoding"];
    self.parameterEncoding = (AFHTTPClientParameterEncoding) [aDecoder decodeIntegerForKey:@"parameterEncoding"];
    self.registeredHTTPOperationClassNames = [aDecoder decodeObjectForKey:@"registeredHTTPOperationClassNames"];
    self.defaultHeaders = [aDecoder decodeObjectForKey:@"defaultHeaders"];

    return self;
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:self.baseURL forKey:@"baseURL"];
    [aCoder encodeInteger:(NSInteger)self.stringEncoding forKey:@"stringEncoding"];
    [aCoder encodeInteger:self.parameterEncoding forKey:@"parameterEncoding"];
    [aCoder encodeObject:self.registeredHTTPOperationClassNames forKey:@"registeredHTTPOperationClassNames"];
    [aCoder encodeObject:self.defaultHeaders forKey:@"defaultHeaders"];
}

#pragma mark - NSCopying

- (id)copyWithZone:(NSZone *)zone {
    AFHTTPClient *HTTPClient = [[[self class] allocWithZone:zone] initWithBaseURL:self.baseURL];

    HTTPClient.stringEncoding = self.stringEncoding;
    HTTPClient.parameterEncoding = self.parameterEncoding;
    HTTPClient.registeredHTTPOperationClassNames = [self.registeredHTTPOperationClassNames copyWithZone:zone];
    HTTPClient.defaultHeaders = [self.defaultHeaders copyWithZone:zone];
#ifdef _SYSTEMCONFIGURATION_H
    HTTPClient.networkReachabilityStatusBlock = self.networkReachabilityStatusBlock;
#endif
    return HTTPClient;
}

@end

#pragma mark -

static NSString * const kAFMultipartFormBoundary = @"Boundary+0xAbCdEfGbOuNdArY";

static NSString * const kAFMultipartFormCRLF = @"\r\n";

static NSInteger const kAFStreamToStreamBufferSize = 1024 * 1024; //1 meg default

static inline NSString * AFMultipartFormInitialBoundary() {
    return [NSString stringWithFormat:@"--%@%@", kAFMultipartFormBoundary, kAFMultipartFormCRLF];
}

static inline NSString * AFMultipartFormEncapsulationBoundary() {
    return [NSString stringWithFormat:@"%@--%@%@", kAFMultipartFormCRLF, kAFMultipartFormBoundary, kAFMultipartFormCRLF];
}

static inline NSString * AFMultipartFormFinalBoundary() {
    return [NSString stringWithFormat:@"%@--%@--%@", kAFMultipartFormCRLF, kAFMultipartFormBoundary, kAFMultipartFormCRLF];
}

static inline NSString * AFContentTypeForPathExtension(NSString *extension) {
#ifdef __UTTYPE__
    NSString *UTI = (__bridge_transfer NSString *)UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (__bridge CFStringRef)extension, NULL);
    NSString *contentType = (__bridge_transfer NSString *)UTTypeCopyPreferredTagWithClass((__bridge CFStringRef)UTI, kUTTagClassMIMEType);
    if (!contentType) {
        return @"application/octet-stream";
    } else {
        return contentType;
    }
#else
    return @"application/octet-stream";
#endif
}

NSUInteger const kAFUploadStream3GSuggestedPacketSize = 1024 * 16;
NSTimeInterval const kAFUploadStream3GSuggestedDelay = 0.2;

@interface AFHTTPBodyPart : NSObject
@property (nonatomic, assign) NSStringEncoding stringEncoding;
@property (nonatomic, strong) NSDictionary *headers;
@property (nonatomic, strong) id body;
@property (nonatomic, assign) unsigned long long bodyContentLength;
@property (nonatomic, strong) NSInputStream *inputStream;

@property (nonatomic, assign) BOOL hasInitialBoundary;
@property (nonatomic, assign) BOOL hasFinalBoundary;

@property (nonatomic, readonly, getter = hasBytesAvailable) BOOL bytesAvailable;
@property (nonatomic, readonly) unsigned long long contentLength;

- (NSInteger)read:(uint8_t *)buffer
        maxLength:(NSUInteger)length;
@end

@interface AFMultipartBodyStreamProvider : NSObject
@property (nonatomic, assign) NSUInteger bufferLength;
@property (nonatomic, assign) NSTimeInterval delay;
@property (nonatomic, strong) NSInputStream *inputStream;
@property (nonatomic, readonly) unsigned long long contentLength;
@property (nonatomic, readonly, getter = isEmpty) BOOL empty;

- (id)initWithStringEncoding:(NSStringEncoding)encoding;
- (void)setInitialAndFinalBoundaries;
- (void)appendHTTPBodyPart:(AFHTTPBodyPart *)bodyPart;
@end

#pragma mark -

@interface AFStreamingMultipartFormData ()
@property (readwrite, nonatomic, copy) NSMutableURLRequest *request;
@property (readwrite, nonatomic, strong) AFMultipartBodyStreamProvider *bodyStream;
@property (readwrite, nonatomic, assign) NSStringEncoding stringEncoding;
@end

@implementation AFStreamingMultipartFormData
@synthesize request = _request;
@synthesize bodyStream = _bodyStream;
@synthesize stringEncoding = _stringEncoding;

- (id)initWithURLRequest:(NSMutableURLRequest *)urlRequest
          stringEncoding:(NSStringEncoding)encoding
{
    self = [super init];
    if (!self) {
        return nil;
    }

    self.request = urlRequest;
    self.stringEncoding = encoding;
    self.bodyStream = [[AFMultipartBodyStreamProvider alloc] initWithStringEncoding:encoding];

    return self;
}

- (BOOL)appendPartWithFileURL:(NSURL *)fileURL
                         name:(NSString *)name
                        error:(NSError * __autoreleasing *)error
{
    NSParameterAssert(fileURL);
    NSParameterAssert(name);

    NSString *fileName = [fileURL lastPathComponent];
    NSString *mimeType = AFContentTypeForPathExtension([fileURL pathExtension]);
    
    return [self appendPartWithFileURL:fileURL name:name fileName:fileName mimeType:mimeType error:error];
}

- (BOOL)appendPartWithFileURL:(NSURL *)fileURL
                         name:(NSString *)name
                     fileName:(NSString *)fileName
                     mimeType:(NSString *)mimeType
                        error:(NSError * __autoreleasing *)error
{
    NSParameterAssert(fileURL);
    NSParameterAssert(name);
    NSParameterAssert(fileName);
    NSParameterAssert(mimeType);

    if (![fileURL isFileURL]) {
        NSDictionary *userInfo = [NSDictionary dictionaryWithObject:NSLocalizedStringFromTable(@"Expected URL to be a file URL", @"AFNetworking", nil) forKey:NSLocalizedFailureReasonErrorKey];
        if (error != NULL) {
            *error = [[NSError alloc] initWithDomain:AFNetworkingErrorDomain code:NSURLErrorBadURL userInfo:userInfo];
        }

        return NO;
    } else if ([fileURL checkResourceIsReachableAndReturnError:error] == NO) {
        NSDictionary *userInfo = [NSDictionary dictionaryWithObject:NSLocalizedStringFromTable(@"File URL not reachable.", @"AFNetworking", nil) forKey:NSLocalizedFailureReasonErrorKey];
        if (error != NULL) {
            *error = [[NSError alloc] initWithDomain:AFNetworkingErrorDomain code:NSURLErrorBadURL userInfo:userInfo];
        }

        return NO;
    }

    NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
    [mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"; filename=\"%@\"", name, fileName] forKey:@"Content-Disposition"];
    [mutableHeaders setValue:mimeType forKey:@"Content-Type"];

    AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
    bodyPart.stringEncoding = self.stringEncoding;
    bodyPart.headers = mutableHeaders;
    bodyPart.body = fileURL;

    NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:[fileURL path] error:nil];
    bodyPart.bodyContentLength = [[fileAttributes objectForKey:NSFileSize] unsignedLongLongValue];

    [self.bodyStream appendHTTPBodyPart:bodyPart];

    return YES;
}


- (void)appendPartWithInputStream:(NSInputStream *)inputStream
                             name:(NSString *)name
                         fileName:(NSString *)fileName
                           length:(unsigned long long)length
                         mimeType:(NSString *)mimeType
{
    NSParameterAssert(name);
    NSParameterAssert(fileName);
    NSParameterAssert(mimeType);

    NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
    [mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"; filename=\"%@\"", name, fileName] forKey:@"Content-Disposition"];
    [mutableHeaders setValue:mimeType forKey:@"Content-Type"];


    AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
    bodyPart.stringEncoding = self.stringEncoding;
    bodyPart.headers = mutableHeaders;
    bodyPart.body = inputStream;

    bodyPart.bodyContentLength = length;

    [self.bodyStream appendHTTPBodyPart:bodyPart];
}

- (void)appendPartWithFileData:(NSData *)data
                          name:(NSString *)name
                      fileName:(NSString *)fileName
                      mimeType:(NSString *)mimeType
{
    NSParameterAssert(name);
    NSParameterAssert(fileName);
    NSParameterAssert(mimeType);

    NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
    [mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"; filename=\"%@\"", name, fileName] forKey:@"Content-Disposition"];
    [mutableHeaders setValue:mimeType forKey:@"Content-Type"];

    [self appendPartWithHeaders:mutableHeaders body:data];
}

- (void)appendPartWithFormData:(NSData *)data
                          name:(NSString *)name
{
    NSParameterAssert(name);

    NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
    [mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"", name] forKey:@"Content-Disposition"];

    [self appendPartWithHeaders:mutableHeaders body:data];
}

- (void)appendPartWithHeaders:(NSDictionary *)headers
                         body:(NSData *)body
{
    NSParameterAssert(body);

    AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
    bodyPart.stringEncoding = self.stringEncoding;
    bodyPart.headers = headers;
    bodyPart.bodyContentLength = [body length];
    bodyPart.body = body;

    [self.bodyStream appendHTTPBodyPart:bodyPart];
}

- (void)throttleBandwidthWithPacketSize:(NSUInteger)numberOfBytes
                                  delay:(NSTimeInterval)delay
{
    self.bodyStream.bufferLength = numberOfBytes;
    self.bodyStream.delay = delay;
}

- (NSMutableURLRequest *)requestByFinalizingMultipartFormData {
    if ([self.bodyStream isEmpty]) {
        return self.request;
    }

    // Reset the initial and final boundaries to ensure correct Content-Length
    [self.bodyStream setInitialAndFinalBoundaries];

    [self.request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", kAFMultipartFormBoundary] forHTTPHeaderField:@"Content-Type"];
    [self.request setValue:[NSString stringWithFormat:@"%llu", [self.bodyStream contentLength]] forHTTPHeaderField:@"Content-Length"];
    [self.request setHTTPBodyStream:self.bodyStream.inputStream];

    return self.request;
}

@end

#pragma mark -

@interface AFMultipartBodyStreamProvider () <NSCopying, NSStreamDelegate>
@property (nonatomic, assign) NSStringEncoding stringEncoding;
@property (nonatomic, strong) NSMutableArray *HTTPBodyParts;
@property (nonatomic, strong) NSEnumerator *HTTPBodyPartEnumerator;
@property (nonatomic, strong) AFHTTPBodyPart *currentHTTPBodyPart;
@property (nonatomic, strong) NSOutputStream *outputStream;
@property (nonatomic, strong) NSMutableData *buffer;
@end

static const NSUInteger AFMultipartBodyStreamProviderDefaultBufferLength = 4096;

@implementation AFMultipartBodyStreamProvider {
@private
    // Workaround for stream delegates being weakly referenced, but otherwise unowned
    __strong id _self;
}
@synthesize stringEncoding = _stringEncoding;
@synthesize HTTPBodyParts = _HTTPBodyParts;
@synthesize HTTPBodyPartEnumerator = _HTTPBodyPartEnumerator;
@synthesize currentHTTPBodyPart = _currentHTTPBodyPart;
@synthesize inputStream = _inputStream;
@synthesize outputStream = _outputStream;
@synthesize buffer = _buffer;
@synthesize bufferLength = _numberOfBytesInPacket;
@synthesize delay = _delay;

- (id)initWithStringEncoding:(NSStringEncoding)encoding {
    self = [super init];
    if (!self) {
        return nil;
    }

    self.stringEncoding = encoding;
    self.HTTPBodyParts = [NSMutableArray array];
    self.bufferLength = NSIntegerMax;
    
    self.buffer = [[NSMutableData alloc] init];
    self.bufferLength = AFMultipartBodyStreamProviderDefaultBufferLength;
    
    return self;
}

- (void)dealloc {
    _outputStream.delegate = nil;
}

- (void)setInitialAndFinalBoundaries {
    if ([self.HTTPBodyParts count] > 0) {
        for (AFHTTPBodyPart *bodyPart in self.HTTPBodyParts) {
            bodyPart.hasInitialBoundary = NO;
            bodyPart.hasFinalBoundary = NO;
        }

        [[self.HTTPBodyParts objectAtIndex:0] setHasInitialBoundary:YES];
        [[self.HTTPBodyParts lastObject] setHasFinalBoundary:YES];
    }
}

- (void)appendHTTPBodyPart:(AFHTTPBodyPart *)bodyPart {
    [self.HTTPBodyParts addObject:bodyPart];
}

- (NSInputStream *)inputStream {
    if (_inputStream == nil) {
        CFReadStreamRef readStream;
        CFWriteStreamRef writeStream;
        CFStreamCreateBoundPair(NULL, &readStream, &writeStream, self.bufferLength);
        _inputStream = CFBridgingRelease(readStream);
        _outputStream = CFBridgingRelease(writeStream);
        
        _outputStream.delegate = self;
        if ([NSThread isMainThread]) {
            [_outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        } else {
            dispatch_sync(dispatch_get_main_queue(), ^{
                [_outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
            });
        }
        [_outputStream open];

        _self = self;
    }
    
    return _inputStream;
}

- (BOOL)isEmpty {
    return [self.HTTPBodyParts count] == 0;
}

#pragma mark - NSStreamDelegate

- (void)stream:(NSStream *)stream
   handleEvent:(NSStreamEvent)eventCode
{
    if (eventCode & NSStreamEventHasSpaceAvailable) {
        [self handleOutputStreamSpaceAvailable];
    }
}

- (void)handleOutputStreamSpaceAvailable {
    while ([_outputStream hasSpaceAvailable]) {
        if ([_buffer length] > 0) {
            NSInteger numberOfBytesWritten = [_outputStream write:(uint8_t const *)[_buffer bytes] maxLength:[_buffer length]];
            if (numberOfBytesWritten < 0) {
                [self close];
                return;
            }

            [_buffer replaceBytesInRange:NSMakeRange(0, numberOfBytesWritten) withBytes:NULL length:0];
        } else {
            if (!self.currentHTTPBodyPart) {
                if (!self.HTTPBodyPartEnumerator) {
                    self.HTTPBodyPartEnumerator = [self.HTTPBodyParts objectEnumerator];
                }
                self.currentHTTPBodyPart = [self.HTTPBodyPartEnumerator nextObject];
            }
            
            if (!self.currentHTTPBodyPart) {
                [self close];
                return;
            }
            
            [_buffer setLength:self.bufferLength];
            
            NSInteger numberOfBytesRead = [self.currentHTTPBodyPart read:(uint8_t *)[_buffer mutableBytes] maxLength:[_buffer length]];
            if (numberOfBytesRead < 0) {
                [self close];
                return;
            }
            
            [_buffer setLength:numberOfBytesRead];

            if (numberOfBytesRead == 0) {
                self.currentHTTPBodyPart = nil;
            }

            if (self.delay > 0.0f) {
                [NSThread sleepForTimeInterval:self.delay];
            }
        }
    }
}

- (void)close {
    NSOutputStream *outputStream = self.outputStream;
    
    [outputStream close];
    outputStream.delegate = nil;
    
    /*
     Workaround for a race condition in CFStream _CFStreamCopyRunLoopsAndModes. This outputstream needs to be retained just a little longer.
     
     See: https://github.com/AFNetworking/AFNetworking/issues/907
     */
    double delayInSeconds = 2.0;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
    dispatch_after(popTime, dispatch_get_main_queue(), ^{
        outputStream.delegate = nil;
    });
    
    _self = nil;
}

- (unsigned long long)contentLength {
    unsigned long long length = 0;
    for (AFHTTPBodyPart *bodyPart in self.HTTPBodyParts) {
        length += [bodyPart contentLength];
    }

    return length;
}

#pragma mark - NSCopying

- (id)copyWithZone:(NSZone *)zone {
    AFMultipartBodyStreamProvider *bodyStreamCopy = [[[self class] allocWithZone:zone] initWithStringEncoding:self.stringEncoding];

    for (AFHTTPBodyPart *bodyPart in self.HTTPBodyParts) {
        [bodyStreamCopy appendHTTPBodyPart:[bodyPart copy]];
    }

    [bodyStreamCopy setInitialAndFinalBoundaries];

    return bodyStreamCopy;
}

@end

#pragma mark -

typedef enum {
    AFInitialPhase               = 0,
    AFEncapsulationBoundaryPhase = 1,
    AFHeaderPhase                = 2,
    AFBodyPhase                  = 3,
    AFFinalBoundaryPhase         = 4,
    AFCompletedPhase             = 5,
} AFHTTPBodyPartReadPhase;

@interface AFHTTPBodyPart () <NSCopying> {
    AFHTTPBodyPartReadPhase _phase;
    NSInputStream *_inputStream;
    unsigned long long _phaseReadOffset;
}

- (BOOL)transitionToNextPhase;
- (NSInteger)readData:(NSData *)data
           intoBuffer:(uint8_t *)buffer
            maxLength:(NSUInteger)length;
@end

@implementation AFHTTPBodyPart
@synthesize stringEncoding = _stringEncoding;
@synthesize headers = _headers;
@synthesize body = _body;
@synthesize bodyContentLength = _bodyContentLength;
@synthesize hasInitialBoundary = _hasInitialBoundary;
@synthesize hasFinalBoundary = _hasFinalBoundary;

- (id)init {
    self = [super init];
    if (!self) {
        return nil;
    }

    [self transitionToNextPhase];

    return self;
}

- (void)dealloc {
    if (_inputStream) {
        [_inputStream close];
        _inputStream = nil;
    }
}

- (NSInputStream *)inputStream {
    if (!_inputStream) {
        if ([self.body isKindOfClass:[NSData class]]) {
            _inputStream = [NSInputStream inputStreamWithData:self.body];
        } else if ([self.body isKindOfClass:[NSURL class]]) {
            _inputStream = [NSInputStream inputStreamWithURL:self.body];
        } else if ([self.body isKindOfClass:[NSInputStream class]]) {
            _inputStream = self.body;
        }
    }

    return _inputStream;
}

- (NSString *)stringForHeaders {
    NSMutableString *headerString = [NSMutableString string];
    for (NSString *field in [self.headers allKeys]) {
        [headerString appendString:[NSString stringWithFormat:@"%@: %@%@", field, [self.headers valueForKey:field], kAFMultipartFormCRLF]];
    }
    [headerString appendString:kAFMultipartFormCRLF];

    return [NSString stringWithString:headerString];
}

- (unsigned long long)contentLength {
    unsigned long long length = 0;

    NSData *encapsulationBoundaryData = [([self hasInitialBoundary] ? AFMultipartFormInitialBoundary() : AFMultipartFormEncapsulationBoundary()) dataUsingEncoding:self.stringEncoding];
    length += [encapsulationBoundaryData length];

    NSData *headersData = [[self stringForHeaders] dataUsingEncoding:self.stringEncoding];
    length += [headersData length];

    length += _bodyContentLength;

    NSData *closingBoundaryData = ([self hasFinalBoundary] ? [AFMultipartFormFinalBoundary() dataUsingEncoding:self.stringEncoding] : [NSData data]);
    length += [closingBoundaryData length];

    return length;
}

- (BOOL)hasBytesAvailable {
    // Allows `read:maxLength:` to be called again if `AFMultipartFormFinalBoundary` doesn't fit into the available buffer
    if (_phase == AFFinalBoundaryPhase) {
        return YES;
    }

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcovered-switch-default"
    switch (self.inputStream.streamStatus) {
        case NSStreamStatusNotOpen:
        case NSStreamStatusOpening:
        case NSStreamStatusOpen:
        case NSStreamStatusReading:
        case NSStreamStatusWriting:
            return YES;
        case NSStreamStatusAtEnd:
        case NSStreamStatusClosed:
        case NSStreamStatusError:
        default:
            return NO;
    }
#pragma clang diagnostic pop

}

- (NSInteger)read:(uint8_t *)buffer
        maxLength:(NSUInteger)length
{
    NSInteger bytesRead = 0;

    if (_phase == AFEncapsulationBoundaryPhase) {
        NSData *encapsulationBoundaryData = [([self hasInitialBoundary] ? AFMultipartFormInitialBoundary() : AFMultipartFormEncapsulationBoundary()) dataUsingEncoding:self.stringEncoding];
        bytesRead += [self readData:encapsulationBoundaryData intoBuffer:&buffer[bytesRead] maxLength:(length - (NSUInteger)bytesRead)];
    }

    if (_phase == AFHeaderPhase) {
        NSData *headersData = [[self stringForHeaders] dataUsingEncoding:self.stringEncoding];
        bytesRead += [self readData:headersData intoBuffer:&buffer[bytesRead] maxLength:(length - (NSUInteger)bytesRead)];
    }

    if (_phase == AFBodyPhase) {
        if ([self.inputStream hasBytesAvailable]) {
            bytesRead += [self.inputStream read:&buffer[bytesRead] maxLength:(length - (NSUInteger)bytesRead)];
        }

        if (![self.inputStream hasBytesAvailable]) {
            [self transitionToNextPhase];
        }
    }

    if (_phase == AFFinalBoundaryPhase) {
        NSData *closingBoundaryData = ([self hasFinalBoundary] ? [AFMultipartFormFinalBoundary() dataUsingEncoding:self.stringEncoding] : [NSData data]);
        bytesRead += [self readData:closingBoundaryData intoBuffer:&buffer[bytesRead] maxLength:(length - (NSUInteger)bytesRead)];
    }

    return bytesRead;
}

- (NSInteger)readData:(NSData *)data
           intoBuffer:(uint8_t *)buffer
            maxLength:(NSUInteger)length
{
    NSRange range = NSMakeRange((NSUInteger)_phaseReadOffset, MIN([data length] - ((NSUInteger)_phaseReadOffset), length));
    [data getBytes:buffer range:range];

    _phaseReadOffset += range.length;

    if (((NSUInteger)_phaseReadOffset) >= [data length]) {
        [self transitionToNextPhase];
    }

    return (NSInteger)range.length;
}

- (BOOL)transitionToNextPhase {
    if (![[NSThread currentThread] isMainThread]) {
        [self performSelectorOnMainThread:@selector(transitionToNextPhase) withObject:nil waitUntilDone:YES];
        return YES;
    }

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcovered-switch-default"
    switch (_phase) {
        case AFInitialPhase:
            _phase = AFEncapsulationBoundaryPhase;
            break;
        case AFEncapsulationBoundaryPhase:
            _phase = AFHeaderPhase;
            break;
        case AFHeaderPhase:
            [self.inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
            [self.inputStream open];
            _phase = AFBodyPhase;
            break;
        case AFBodyPhase:
            [self.inputStream close];
            _phase = AFFinalBoundaryPhase;
            break;
        case AFFinalBoundaryPhase:
        case AFCompletedPhase:
        default:
            _phase = AFCompletedPhase;
            break;
    }
    _phaseReadOffset = 0;
#pragma clang diagnostic pop

    return YES;
}

#pragma mark - NSCopying

- (id)copyWithZone:(NSZone *)zone {
    AFHTTPBodyPart *bodyPart = [[[self class] allocWithZone:zone] init];

    bodyPart.stringEncoding = self.stringEncoding;
    bodyPart.headers = self.headers;
    bodyPart.bodyContentLength = self.bodyContentLength;
    bodyPart.body = self.body;

    return bodyPart;
}

@end