DCHTTPRequestSerializer.m

////////////////////////////////////////////////////////////////////////////////////////////////////
//
//  DCHTTPRequestSerializer.m
//
//  Created by Dalton Cherry on 5/7/14.
//
////////////////////////////////////////////////////////////////////////////////////////////////////

#import "DCHTTPRequestSerializer.h"
#import "DCHTTPUpload.h"

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//local class used to encode parameters
@interface QueryStringPair : 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

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@interface DCHTTPRequestSerializer ()

@property(nonatomic,strong)NSSet *HTTPMethodsEncodingParametersInURI;
@property(nonatomic,strong)NSSet *HTTPMethodsUploadVerb;
@property(nonatomic,copy)NSString *contentTypeKey;
@property(nonatomic,strong)NSMutableDictionary *headers;

@end

@implementation DCHTTPRequestSerializer

static NSString * const kDCCharactersToBeEscapedInQueryString = @":/?&=;+!@#$()',*";

static NSString * DCPercentEscapedQueryStringKeyFromStringWithEncoding(NSString *string, NSStringEncoding encoding) {
    static NSString * const kAFCharactersToLeaveUnescapedInQueryStringPairKey = @"[].";
    
	return (__bridge_transfer  NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (__bridge CFStringRef)string,
                                                                                  (__bridge CFStringRef)kAFCharactersToLeaveUnescapedInQueryStringPairKey, (__bridge CFStringRef)kDCCharactersToBeEscapedInQueryString, CFStringConvertNSStringEncodingToEncoding(encoding));
}

static NSString * DCPercentEscapedQueryStringValueFromStringWithEncoding(NSString *string, NSStringEncoding encoding) {
	return (__bridge_transfer  NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (__bridge CFStringRef)string, NULL,
                                                                                  (__bridge CFStringRef)kDCCharactersToBeEscapedInQueryString,
                                                                                  CFStringConvertNSStringEncodingToEncoding(encoding));
}
////////////////////////////////////////////////////////////////////////////////////////////////////
- (instancetype)init
{
    self = [super init];
    if(self)
    {
        self.stringEncoding = NSUTF8StringEncoding;
        self.allowsCellularAccess = YES;
        self.cachePolicy = NSURLRequestUseProtocolCachePolicy;
        self.HTTPShouldHandleCookies = YES;
        self.HTTPShouldUsePipelining = NO;
        self.networkServiceType = NSURLNetworkServiceTypeDefault;
        self.timeoutInterval = 60;
        self.HTTPMethodsEncodingParametersInURI = [NSSet setWithObjects:@"GET", @"HEAD", @"DELETE", nil];
        self.HTTPMethodsUploadVerb = [NSSet setWithObjects:@"PUT", @"POST", nil];
        self.contentTypeKey = @"Content-Type";
    }
    return self;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
-(NSURLRequest*)requestBySerializingUrl:(NSURL*)url
                                 method:(NSString*)HTTPMethod
                             parameters:(id)parameters
                                  error:(NSError * __autoreleasing *)error
{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:self.cachePolicy
                                                       timeoutInterval:self.timeoutInterval];
    request.HTTPMethod = HTTPMethod;
    request.allowsCellularAccess = self.allowsCellularAccess;
    request.cachePolicy = self.cachePolicy;
    request.HTTPShouldHandleCookies = self.HTTPShouldHandleCookies;
    request.HTTPShouldUsePipelining = self.HTTPShouldUsePipelining;
    request.timeoutInterval = self.timeoutInterval;
    request.networkServiceType = self.networkServiceType;
    for(id key in self.headers)
        [request setValue:self.headers[key] forHTTPHeaderField:key];
    BOOL isUpload = NO;
    for(id key in parameters)
    {
        if([parameters[key] isKindOfClass:[DCHTTPUpload class]])
        {
            isUpload = YES;
            break;
        }
    }
    if(isUpload)
    {
        if(![self.HTTPMethodsUploadVerb containsObject:request.HTTPMethod])
        {
            *error = [self errorWithDetail:NSLocalizedString(@"File uploads must be preformed with a POST or PUT HTTPMethod.", nil)
                                      code:DCHTTPRequestSerializerErrorCodeInvalidParameter];
            return nil;
        }
        NSString *boundary = [NSString stringWithFormat:@"Boundary+%08X%08X", arc4random(), arc4random()];
        if(![request valueForHTTPHeaderField:self.contentTypeKey]) {
            [request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary] forHTTPHeaderField:self.contentTypeKey];
        }
        NSMutableDictionary *notFileParams = [NSMutableDictionary dictionary];
        NSMutableDictionary *fileParams = [NSMutableDictionary dictionary];
        for(id key in parameters)
        {
            id value = parameters[key];
            if([value isKindOfClass:[DCHTTPUpload class]]) {
                [fileParams setObject:value forKey:key];
            } else {
                [notFileParams setObject:value forKey:key];
            }
        }
        NSMutableData *data = [NSMutableData data];
        NSString *initial = [[self class] multiFormInitialBoundary:boundary];
        [data appendData:[initial dataUsingEncoding:self.stringEncoding]];
        
        NSData *paraData = [[self class] multiFormStringFromParameters:notFileParams boundary:boundary encoding:self.stringEncoding];
        [data appendData:paraData];
        if(notFileParams.count > 0) {
            [data appendData:[[[self class] multiFormBoundary:boundary] dataUsingEncoding:self.stringEncoding]];
        }
        
        NSData *fileData = [[self class] multiFormStringFromFiles:fileParams boundary:boundary encoding:self.stringEncoding];
        [data appendData:fileData];
        
        NSString *final = [[self class] multiFormFinalBoundary:boundary];
        [data appendData:[final dataUsingEncoding:self.stringEncoding]];
        [request setHTTPBody:data];
        [request setValue:[NSString stringWithFormat:@"%lu",(unsigned long)[data length]] forHTTPHeaderField:@"Content-Length"];
        return request;
    }
    
    NSString *query = [[self class] queryStringFromParametersWithEncoding:parameters encoding:self.stringEncoding];
    if(![self.HTTPMethodsEncodingParametersInURI containsObject:request.HTTPMethod]) {
        if(query) {
            request.URL = [NSURL URLWithString:[[request.URL absoluteString] stringByAppendingFormat:request.URL.query ? @"&%@" : @"?%@", query]];
        }
    } else {
        NSString *charset = (__bridge NSString *)CFStringConvertEncodingToIANACharSetName(CFStringConvertNSStringEncodingToEncoding(self.stringEncoding));
        if(![request valueForHTTPHeaderField:self.contentTypeKey]) {
            [request setValue:[NSString stringWithFormat:@"application/x-www-form-urlencoded; charset=%@", charset] forHTTPHeaderField:self.contentTypeKey];
        }
        if(query) {
            [request setHTTPBody:[query dataUsingEncoding:self.stringEncoding]];
        }
    }
    return request;
}
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-(NSError*)errorWithDetail:(NSString*)detail code:(DCHTTPRequestSerializerErrorCode)code
{
    NSMutableDictionary* details = [NSMutableDictionary dictionary];
    [details setValue:detail forKey:NSLocalizedDescriptionKey];
    return [[NSError alloc] initWithDomain:NSLocalizedString(@"DCHTTPRequestSerializer", nil) code:code userInfo:details];
}
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-(void)setValue:(id)value forHTTPHeaderField:(NSString*)key
{
    if(!self.headers)
        self.headers = [NSMutableDictionary new];
    [self.headers setObject:value forKey:key];
}
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+(NSString*)queryStringFromParametersWithEncoding:(NSDictionary *)parameters encoding:(NSStringEncoding)stringEncoding
{
    if(!parameters)
        return nil;
    NSMutableArray *mutablePairs = [NSMutableArray array];
    for(QueryStringPair *pair in [[self class] queryStringPairsFromDictionary:parameters]) {
        [mutablePairs addObject:[pair URLEncodedStringValueWithEncoding:stringEncoding]];
    }
    return [mutablePairs componentsJoinedByString:@"&"];
}
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+(NSArray*)queryStringPairsFromDictionary:(NSDictionary*)dictionary
{
    return [[self class] queryStringPairsFromKey:nil andValue:dictionary];
}
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+(NSArray*)queryStringPairsFromKey:(NSString*)key andValue:(id)value
{
    NSMutableArray *mutableQueryStringComponents = [NSMutableArray array];
    
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"description" ascending:YES selector:@selector(compare:)];
    
    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
        for (id nestedKey in [dictionary.allKeys sortedArrayUsingDescriptors:@[sortDescriptor]]) {
            id nestedValue = [dictionary objectForKey:nestedKey];
            if (nestedValue) {
                [mutableQueryStringComponents addObjectsFromArray:[[self class] queryStringPairsFromKey:(key ? [NSString stringWithFormat:@"%@[%@]", key, nestedKey] : nestedKey)
                                                                                               andValue:nestedValue]];
            }
        }
    } else if ([value isKindOfClass:[NSArray class]]) {
        NSArray *array = value;
        for (id nestedValue in array) {
            [mutableQueryStringComponents addObjectsFromArray:[[self class] queryStringPairsFromKey:[NSString stringWithFormat:@"%@[]", key] andValue:nestedValue]];
        }
    } else if ([value isKindOfClass:[NSSet class]]) {
        NSSet *set = value;
        for (id obj in [set sortedArrayUsingDescriptors:@[ sortDescriptor ]]) {
            [mutableQueryStringComponents addObjectsFromArray:[[self class] queryStringPairsFromKey:key andValue:obj]];
        }
    } else {
        [mutableQueryStringComponents addObject:[[QueryStringPair alloc] initWithField:key value:value]];
    }
    
    return mutableQueryStringComponents;
}
static NSString * const kDCMultipartFormCRLF = @"\r\n";
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+(NSString*)multiFormInitialBoundary:(NSString*)boundary
{
    return [NSString stringWithFormat:@"--%@%@", boundary, kDCMultipartFormCRLF];
}
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+(NSString*)multiFormBoundary:(NSString*)boundary
{
    return [NSString stringWithFormat:@"%@--%@%@", kDCMultipartFormCRLF, boundary, kDCMultipartFormCRLF];
}
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+(NSString*)multiFormFinalBoundary:(NSString*)boundary
{
    return [NSString stringWithFormat:@"%@--%@--%@", kDCMultipartFormCRLF, boundary, kDCMultipartFormCRLF];
}
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+(NSData*)multiFormStringFromParameters:(NSDictionary *)parameters boundary:(NSString*)boundary encoding:(NSStringEncoding)stringEncoding
{
    BOOL addBoundary = NO;
    NSMutableData *data = [NSMutableData data];
    for(QueryStringPair *pair in [[self class] queryStringPairsFromDictionary:parameters]) {
        if(addBoundary)
            [data appendData:[[[self class] multiFormBoundary:boundary] dataUsingEncoding:stringEncoding]];
        [data appendData:[[self class] multiFormHeaders:[pair.field description] fileName:nil type:nil encoding:stringEncoding]];
        [data appendData:[[pair.value description] dataUsingEncoding:stringEncoding]];
        addBoundary = YES;
    }
    return data;
}
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+(NSData*)multiFormStringFromFiles:(NSDictionary *)parameters boundary:(NSString*)boundary encoding:(NSStringEncoding)stringEncoding
{
    BOOL addBoundary = NO;
    NSMutableData *data = [NSMutableData data];
    for(NSString *key in parameters)
    {
        DCHTTPUpload *upload = parameters[key];
        if(addBoundary)
            [data appendData:[[[self class] multiFormBoundary:boundary] dataUsingEncoding:stringEncoding]];
        [data appendData:[[self class] multiFormHeaders:key fileName:upload.fileName type:upload.mimeType encoding:stringEncoding]];
        [data appendData:[upload getData]];
        addBoundary = YES;
    }
    return data;
}
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+(NSData*)multiFormHeaders:(NSString*)name fileName:(NSString*)fileName type:(NSString*)mimeType encoding:(NSStringEncoding)stringEncoding
{
    NSString *content = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"",DCPercentEscapedQueryStringKeyFromStringWithEncoding(name, stringEncoding)];
    if(fileName)
    {
        content = [content stringByAppendingFormat:@"; filename=\"%@\"",fileName];
    }
    content = [content stringByAppendingString:kDCMultipartFormCRLF];
    if(mimeType)
        content = [content stringByAppendingFormat:@"Content-Type: \"%@\"%@",mimeType,kDCMultipartFormCRLF];
    content = [content stringByAppendingString:kDCMultipartFormCRLF];
    return [content dataUsingEncoding:stringEncoding];
}
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@end

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////////////////////////////////////////////////////////////////////////////////////////////////////
@implementation QueryStringPair

////////////////////////////////////////////////////////////////////////////////////////////////////
- (id)initWithField:(id)field value:(id)value
{
    self = [super init];
    if (self)
    {
        self.field = field;
        self.value = value;
    }
    return self;
}
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- (NSString *)URLEncodedStringValueWithEncoding:(NSStringEncoding)stringEncoding
{
    if (!self.value || [self.value isEqual:[NSNull null]]) {
        return DCPercentEscapedQueryStringKeyFromStringWithEncoding([self.field description], stringEncoding);
    } else {
        return [NSString stringWithFormat:@"%@=%@", DCPercentEscapedQueryStringKeyFromStringWithEncoding([self.field description], stringEncoding),
                DCPercentEscapedQueryStringValueFromStringWithEncoding([self.value description], stringEncoding)];
    }
}
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@end

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@implementation DCJSONRequestSerializer

-(NSURLRequest*)requestBySerializingUrl:(NSURL*)url
                                 method:(NSString*)HTTPMethod
                             parameters:(id)parameters
                                  error:(NSError * __autoreleasing *)error
{
    if ([self.HTTPMethodsEncodingParametersInURI containsObject:HTTPMethod]) {
        return [super requestBySerializingUrl:url method:HTTPMethod parameters:parameters error:error];
    }
    
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:self.cachePolicy
                                                       timeoutInterval:self.timeoutInterval];
    
    for(id key in self.headers)
        [request setValue:self.headers[key] forHTTPHeaderField:key];
    
    if (!parameters) {
        return request;
    }
    
    NSString *charset = (__bridge NSString *)CFStringConvertEncodingToIANACharSetName(CFStringConvertNSStringEncodingToEncoding(NSUTF8StringEncoding));
    [request setValue:[NSString stringWithFormat:@"application/json; charset=%@", charset] forHTTPHeaderField:self.contentTypeKey];
    [request setHTTPBody:[NSJSONSerialization dataWithJSONObject:parameters options:0 error:error]];
    
    return request;
}

@end