1 概述
AFURLRequestSerialization主要實現了根據不同情況和引數初始化NSURLRequest物件的功能。只有AFHTTPSessionManager有requestSerialization，預設是AFHTTPRequestSerializer物件。尤其是我們使用MultipartForm請求的時候，可以使用它幫我們完成繁雜的請求頭拼接過程，這個是最值得推薦的。
在閱讀原始碼之前，一定要對multipart/form-data非常熟悉，不然會有很多地方看不懂。具體可以看AFNetWorking原始碼之AFHTTPSessionManager關於它的那部分。
2 AFURLRequestSerialization的api分析
AFURLRequestSerialization包含了四個部分：
-
全域性方法:
AFPercentEscapedStringFromString和AFQueryStringFromParameters。 -
協議
AFURLRequestSerialization提供了一個序列化parameters引數的方法。我們可以把引數轉換為查詢字串、HTTP請求體、設定恰當的請求頭等。 -
AFHTTPRequestSerializer繼承自AFURLRequestSerialization協議。提供了查詢字串/URL格式的引數序列化、預設請求頭處理。同時以提供HTTP狀態碼和返回資料的驗證等工作。
_AFMultipartFormData協議。主要用於新增multipart/form-data請求的Content-Disposition: file; filename=#{generated filename}; name=#{name}"和Content-Type: #{generated mimeType}的請求體域。 -
型別
AFJSONRequestSerializer和AFPropertyListRequestSerializer。主要針對JSON和Plist型別的序列化優化。
AFPercentEscapedStringFromString返回一個字串的百分號編碼格式的字串。因為url只有普通英文字元和數字，特殊字元$-_.+!*`()還有保留字元。所以很多字元都需要編碼,非ASCII編碼的字串先轉換為ASCII編碼，然後再轉換為百分號編碼。
/**
AFPercentEscapedStringFromString方法的作用就是把一個普通字串轉換為百分號編碼的字串
http://blog.csdn.net/qq_32010299/article/details/51790407
@param string 一個字串
@return 百分號編碼的字串
*/
NSString * AFPercentEscapedStringFromString(NSString *string) {
//可能需要做百分號編碼處理的字串
static NSString * const kAFCharactersGeneralDelimitersToEncode = @":#[]@";
static NSString * const kAFCharactersSubDelimitersToEncode = @"!$&`()*+,;=";
//不需要做百分號編碼的字串集合
NSMutableCharacterSet * allowedCharacterSet = [[NSCharacterSet URLQueryAllowedCharacterSet] mutableCopy];
//獲取目前系統中最終需要做百分號編碼轉換的字符集合
[allowedCharacterSet removeCharactersInString:[kAFCharactersGeneralDelimitersToEncode stringByAppendingString:kAFCharactersSubDelimitersToEncode]];
static NSUInteger const batchSize = 50;
NSUInteger index = 0;
NSMutableString *escaped = @"".mutableCopy;
//迭代字串做百分號編碼
while (index < string.length) {
NSUInteger length = MIN(string.length - index, batchSize);
NSRange range = NSMakeRange(index, length);
//移除字串中的一些非法字元。比如????
range = [string rangeOfComposedCharacterSequencesForRange:range];
NSString *substring = [string substringWithRange:range];
//指定範圍內的字元做百分號編碼
NSString *encoded = [substring stringByAddingPercentEncodingWithAllowedCharacters:allowedCharacterSet];
[escaped appendString:encoded];
index += range.length;
}
//返回處理以後的字串
return escaped;
}私有類AFQueryStringPair的主要功能就是把一個key和vaue的鍵值對轉換為百分號編碼格式的鍵值對並且用=連結起來
@interface AFQueryStringPair : NSObject
@property (readwrite, nonatomic, strong) id field;
@property (readwrite, nonatomic, strong) id value;
- (instancetype)initWithField:(id)field value:(id)value;
- (NSString *)URLEncodedStringValue;
@end
@implementation AFQueryStringPair
- (instancetype)initWithField:(id)field value:(id)value {
self = [super init];
if (!self) {
return nil;
}
self.field = field;
self.value = value;
return self;
}
/**
把key、value鍵值對轉換為百分號編碼，並且連結起來
@return 轉換後的字串
*/
- (NSString *)URLEncodedStringValue {
if (!self.value || [self.value isEqual:[NSNull null]]) {
return AFPercentEscapedStringFromString([self.field description]);
} else {
//先用百分號編碼處理，然後再拼接
return [NSString stringWithFormat:@"%@=%@", AFPercentEscapedStringFromString([self.field description]), AFPercentEscapedStringFromString([self.value description])];
}
}
@end方法AFQueryStringPairsFromDictionary和AFQueryStringPairsFromKeyAndValue分別把一個字典或者key、value鍵值對轉換為url的query引數。
/**
把一個字典轉換為百分號編碼的query引數
@param parameters 要轉換的字典
@return query引數
*/
NSString * AFQueryStringFromParameters(NSDictionary *parameters) {
NSMutableArray *mutablePairs = [NSMutableArray array];
for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {
//呼叫`AFQueryStringPair`序列化
[mutablePairs addObject:[pair URLEncodedStringValue]];
}
return [mutablePairs componentsJoinedByString:@"&"];
}
NSArray * AFQueryStringPairsFromDictionary(NSDictionary *dictionary) {
return AFQueryStringPairsFromKeyAndValue(nil, dictionary);
}
/**
分別把一個字典、陣列、集合轉換為一個AFQueryStringPair物件的的陣列。
@param key key
@param value value
@return AFQueryStringPair型別陣列
*/
NSArray * AFQueryStringPairsFromKeyAndValue(NSString *key, id value) {
NSMutableArray *mutableQueryStringComponents = [NSMutableArray array];
//使用`description`排序
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"description" ascending:YES selector:@selector(compare:)];
if ([value isKindOfClass:[NSDictionary class]]) {
NSDictionary *dictionary = value;
for (id nestedKey in [dictionary.allKeys sortedArrayUsingDescriptors:@[ sortDescriptor ]]) {
id nestedValue = dictionary[nestedKey];
if (nestedValue) {
//如果是字典，就取出每一對key、value處理
[mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue((key ? [NSString stringWithFormat:@"%@[%@]", key, nestedKey] : nestedKey), nestedValue)];
}
}
} else if ([value isKindOfClass:[NSArray class]]) {
NSArray *array = value;
for (id nestedValue in array) {
//如果是陣列，則取出元素，新增一個額外的key處理
[mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue([NSString stringWithFormat:@"%@[]", key], nestedValue)];
}
} else if ([value isKindOfClass:[NSSet class]]) {
NSSet *set = value;
for (id obj in [set sortedArrayUsingDescriptors:@[ sortDescriptor ]]) {
//如果是集合，就是用預設key和集合元素處理
[mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue(key, obj)];
}
} else {
//新增處理後的key和value
[mutableQueryStringComponents addObject:[[AFQueryStringPair alloc] initWithField:key value:value]];
}
//返回`AFQueryStringPair`物件陣列
return mutableQueryStringComponents;
}AFHTTPRequestSerializerObservedKeyPaths全域性方法指定了request請求序列化要觀察的屬性列表、是一個陣列，裡面有對蜂窩資料、快取策略、cookie、管道、網路狀態、超時這幾個元素。
static NSArray * AFHTTPRequestSerializerObservedKeyPaths() {
static NSArray *_AFHTTPRequestSerializerObservedKeyPaths = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_AFHTTPRequestSerializerObservedKeyPaths = @[NSStringFromSelector(@selector(allowsCellularAccess)), NSStringFromSelector(@selector(cachePolicy)), NSStringFromSelector(@selector(HTTPShouldHandleCookies)), NSStringFromSelector(@selector(HTTPShouldUsePipelining)), NSStringFromSelector(@selector(networkServiceType)), NSStringFromSelector(@selector(timeoutInterval))];
});
return _AFHTTPRequestSerializerObservedKeyPaths;
}
2.1 AFHTTPRequestSerializer的解析
AFHTTPRequestSerializer主要實現了大部分request拼接轉化功能。比如通用請求頭的新增如userAgent、request屬性的KVO觀察、手動指定請求頭序列化的Block、負責具體的request物件的初始化等。
1 AFHTTPRequestSerializer的屬性和初始化
//屬性列表
@interface AFHTTPRequestSerializer ()
//某個request需要觀察的屬性集合
@property (readwrite, nonatomic, strong) NSMutableSet *mutableObservedChangedKeyPaths;
//儲存request的請求頭域
@property (readwrite, nonatomic, strong) NSMutableDictionary *mutableHTTPRequestHeaders;
//用於修改或者設定請求體域的dispatch_queue_t。
@property (readwrite, nonatomic, strong) dispatch_queue_t requestHeaderModificationQueue;
@property (readwrite, nonatomic, assign) AFHTTPRequestQueryStringSerializationStyle queryStringSerializationStyle;
//手動指定parameters引數序列化的Block
@property (readwrite, nonatomic, copy) AFQueryStringSerializationBlock queryStringSerialization;
@end
//初始化方法
- (instancetype)init {
self = [super init];
if (!self) {
return nil;
}
//指定序列化編碼格式
self.stringEncoding = NSUTF8StringEncoding;
//請求頭儲存在一個字典中，方便後面構建request的時候拼裝。
self.mutableHTTPRequestHeaders = [NSMutableDictionary dictionary];
//初始化一個操作request的header域的dispatch_queue_t
self.requestHeaderModificationQueue = dispatch_queue_create("requestHeaderModificationQueue", DISPATCH_QUEUE_CONCURRENT);
NSMutableArray *acceptLanguagesComponents = [NSMutableArray array];
/*
*列舉系統的language列表。然後設定`Accept-Language`請求頭域。優先順序逐級降低，最多五個。
*/
[[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;
}];
//陣列元素使用`, `分割
[self setValue:[acceptLanguagesComponents componentsJoinedByString:@", "] forHTTPHeaderField:@"Accept-Language"];
/*
*設定User-Agent請求頭域的值。
*/
NSString *userAgent = nil;
userAgent = [NSString stringWithFormat:@"%@/%@ (%@; iOS %@; Scale/%0.2f)", [[NSBundle mainBundle] infoDictionary][(__bridge NSString *)kCFBundleExecutableKey] ?: [[NSBundle mainBundle] infoDictionary][(__bridge NSString *)kCFBundleIdentifierKey], [[NSBundle mainBundle] infoDictionary][@"CFBundleShortVersionString"] ?: [[NSBundle mainBundle] infoDictionary][(__bridge NSString *)kCFBundleVersionKey], [[UIDevice currentDevice] model], [[UIDevice currentDevice] systemVersion], [[UIScreen mainScreen] scale]];
if (userAgent) {
/*
*如果userAgent裡面包含非ASCII碼的字元，比如中文，則需要轉換。這裡是轉換為對應的拉丁字母。
AFNetWorking3.X原始碼閱讀/1.0 (iPhone; iOS 10.2; Scale/2.00)
AFNetWorking3.X yuan ma yue du/1.0 (iPhone; iOS 10.2; Scale/2.00)
*/
if (![userAgent canBeConvertedToEncoding:NSASCIIStringEncoding]) {
NSMutableString *mutableUserAgent = [userAgent mutableCopy];
//轉換為拉丁字母
if (CFStringTransform((__bridge CFMutableStringRef)(mutableUserAgent), NULL, (__bridge CFStringRef)@"Any-Latin; Latin-ASCII; [:^ASCII:] Remove", false)) {
userAgent = mutableUserAgent;
}
}
[self setValue:userAgent forHTTPHeaderField:@"User-Agent"];
}
// HTTP Method Definitions; see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html
//需要把parameters轉換為query引數的方法集合。
self.HTTPMethodsEncodingParametersInURI = [NSSet setWithObjects:@"GET", @"HEAD", @"DELETE", nil];
self.mutableObservedChangedKeyPaths = [NSMutableSet set];
/*
新增對蜂窩資料、快取策略、cookie、管道、網路狀態、超時這幾個屬性的觀察。
*/
for (NSString *keyPath in AFHTTPRequestSerializerObservedKeyPaths()) {
if ([self respondsToSelector:NSSelectorFromString(keyPath)]) {
[self addObserver:self forKeyPath:keyPath options:NSKeyValueObservingOptionNew context:AFHTTPRequestSerializerObserverContext];
}
}
return self;
}2 AFHTTPRequestSerializer的各種setter方法
首先通過automaticallyNotifiesObserversForKey方法來阻止一些屬性的KVO機制的觸發，然後我們通過重寫蜂窩資料、快取策略、cookie、管道、網路狀態、超時的觀察。可以用於測試這些屬性變化是否崩潰等。
/**
如果kvo的觸發機制是預設出發。則返回true，否則返回false。在這裡，只要是`AFHTTPRequestSerializerObservedKeyPaths`裡面的屬性，我們都取消自動出發kvo機制，使用手動觸發。
@param key kvo的key
@return bool值
*/
+ (BOOL)automaticallyNotifiesObserversForKey:(NSString *)key {
if ([AFHTTPRequestSerializerObservedKeyPaths() containsObject:key]) {
return NO;
}
return [super automaticallyNotifiesObserversForKey:key];
}
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(__unused id)object
change:(NSDictionary *)change
context:(void *)context
{
//是否是選擇要觀察的屬性
if (context == AFHTTPRequestSerializerObserverContext) {
//如果屬性值為null，則表示麼有這個屬性，移除對其的觀察
if ([change[NSKeyValueChangeNewKey] isEqual:[NSNull null]]) {
[self.mutableObservedChangedKeyPaths removeObject:keyPath];
} else {
//新增到要觀察的屬性的集合
[self.mutableObservedChangedKeyPaths addObject:keyPath];
}
}
}通過重寫屬性的setter方法來手動觸發kvo
#pragma mark - 手動觸發蜂窩資料、快取策略、cookie、管道、網路狀態、超時的觀察。可以用於測試這些屬性變化是否崩潰等。
- (void)setAllowsCellularAccess:(BOOL)allowsCellularAccess {
[self willChangeValueForKey:NSStringFromSelector(@selector(allowsCellularAccess))];
_allowsCellularAccess = allowsCellularAccess;
[self didChangeValueForKey:NSStringFromSelector(@selector(allowsCellularAccess))];
}
- (void)setCachePolicy:(NSURLRequestCachePolicy)cachePolicy {
[self willChangeValueForKey:NSStringFromSelector(@selector(cachePolicy))];
_cachePolicy = cachePolicy;
[self didChangeValueForKey:NSStringFromSelector(@selector(cachePolicy))];
}
- (void)setHTTPShouldHandleCookies:(BOOL)HTTPShouldHandleCookies {
[self willChangeValueForKey:NSStringFromSelector(@selector(HTTPShouldHandleCookies))];
_HTTPShouldHandleCookies = HTTPShouldHandleCookies;
[self didChangeValueForKey:NSStringFromSelector(@selector(HTTPShouldHandleCookies))];
}
- (void)setHTTPShouldUsePipelining:(BOOL)HTTPShouldUsePipelining {
[self willChangeValueForKey:NSStringFromSelector(@selector(HTTPShouldUsePipelining))];
_HTTPShouldUsePipelining = HTTPShouldUsePipelining;
[self didChangeValueForKey:NSStringFromSelector(@selector(HTTPShouldUsePipelining))];
}
- (void)setNetworkServiceType:(NSURLRequestNetworkServiceType)networkServiceType {
[self willChangeValueForKey:NSStringFromSelector(@selector(networkServiceType))];
_networkServiceType = networkServiceType;
[self didChangeValueForKey:NSStringFromSelector(@selector(networkServiceType))];
}
- (void)setTimeoutInterval:(NSTimeInterval)timeoutInterval {
[self willChangeValueForKey:NSStringFromSelector(@selector(timeoutInterval))];
_timeoutInterval = timeoutInterval;
[self didChangeValueForKey:NSStringFromSelector(@selector(timeoutInterval))];
}3 AFHTTPRequestSerializer的各種請求頭域處理方法
/**
返回請求頭域key和vaue
@return 字典
*/
- (NSDictionary *)HTTPRequestHeaders {
NSDictionary __block *value;
dispatch_sync(self.requestHeaderModificationQueue, ^{
value = [NSDictionary dictionaryWithDictionary:self.mutableHTTPRequestHeaders];
});
return value;
}
/**
設定一個請求頭域
@param value vaue
@param field 域名
*/
- (void)setValue:(NSString *)value
forHTTPHeaderField:(NSString *)field
{
dispatch_barrier_async(self.requestHeaderModificationQueue, ^{
[self.mutableHTTPRequestHeaders setValue:value forKey:field];
});
}
/**
返回指定請求頭域的值
@param field 域名
@return 值
*/
- (NSString *)valueForHTTPHeaderField:(NSString *)field {
NSString __block *value;
dispatch_sync(self.requestHeaderModificationQueue, ^{
value = [self.mutableHTTPRequestHeaders valueForKey:field];
});
return value;
}
/**
設定Basic Authorization的使用者名稱和密碼。記住需要是base64編碼格式的。
@param username 使用者
@param password 密碼
*/
- (void)setAuthorizationHeaderFieldWithUsername:(NSString *)username
password:(NSString *)password
{
NSData *basicAuthCredentials = [[NSString stringWithFormat:@"%@:%@", username, password] dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64AuthCredentials = [basicAuthCredentials base64EncodedStringWithOptions:(NSDataBase64EncodingOptions)0];
[self setValue:[NSString stringWithFormat:@"Basic %@", base64AuthCredentials] forHTTPHeaderField:@"Authorization"];
}
/**
移除Basic Authorization的請求頭
*/
- (void)clearAuthorizationHeader {
dispatch_barrier_async(self.requestHeaderModificationQueue, ^{
[self.mutableHTTPRequestHeaders removeObjectForKey:@"Authorization"];
});
}4 AFHTTPRequestSerializer的各種建立NSMutableURLRequest的方法
通過下面這三種方法處理不同型別的request物件的初始化和引數序列化。
/**
根據給定的url、方法名、引數構建一個request。
@param method 方法名
@param URLString url地址
@param parameters 引數，根據不同的請求方法構建出不同的模式
@param error 構建出錯
@return 返回一個非multipartForm請求
*/
- (NSMutableURLRequest *)requestWithMethod:(NSString *)method
URLString:(NSString *)URLString
parameters:(id)parameters
error:(NSError *__autoreleasing *)error
{
NSParameterAssert(method);
NSParameterAssert(URLString);
NSURL *url = [NSURL URLWithString:URLString];
NSParameterAssert(url);
NSMutableURLRequest *mutableRequest = [[NSMutableURLRequest alloc] initWithURL:url];
mutableRequest.HTTPMethod = method;
/*
*mutableObservedChangedKeyPaths集合裡面的屬性都通過`setValue: forKey`手動設定一下。估計目的是觸發這幾個屬性的kvo。
*/
for (NSString *keyPath in AFHTTPRequestSerializerObservedKeyPaths()) {
if ([self.mutableObservedChangedKeyPaths containsObject:keyPath]) {
[mutableRequest setValue:[self valueForKeyPath:keyPath] forKey:keyPath];
}
}
/*
根據parameters和HTTPRequestHeaders構建一個request
*/
mutableRequest = [[self requestBySerializingRequest:mutableRequest withParameters:parameters error:error] mutableCopy];
return mutableRequest;
}
/**
構建一個multipartForm的request。並且通過`AFMultipartFormData`型別的formData來構建請求體
@param method 方法名，一般都是POST
@param URLString 請求地址
@param parameters 請求頭引數
@param block 用於構建請求體的Block
@param error 構建請求體出錯
@return 返回一個構建好的request
*/
- (NSMutableURLRequest *)multipartFormRequestWithMethod:(NSString *)method
URLString:(NSString *)URLString
parameters:(NSDictionary *)parameters
constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block
error:(NSError *__autoreleasing *)error
{
NSParameterAssert(method);
NSParameterAssert(![method isEqualToString:@"GET"] && ![method isEqualToString:@"HEAD"]);
/*
先構建一個普通的request物件，然後在構建出multipartFrom的request
* 在這一步將會把parameters加入請求頭或者請求體。然後把`AFURLRequestSerialization`指定的headers加入request的請求頭中。這個request就只差構建multipartFrom部分了
*/
NSMutableURLRequest *mutableRequest = [self requestWithMethod:method URLString:URLString parameters:nil error:error];
/*
*初始化一個`AFStreamingMultipartFormData`物件。用於封裝multipartFrom的body部分
*/
__block AFStreamingMultipartFormData *formData = [[AFStreamingMultipartFormData alloc] initWithURLRequest:mutableRequest stringEncoding:NSUTF8StringEncoding];
if (parameters) {
/*
把parameters拼接成`AFQueryStringPair`物件。然後根據取出的key和value處理。
*/
for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {
NSData *data = nil;
//把value處理為NSData型別
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);
}
//body具體序列化操作
return [formData requestByFinalizingMultipartFormData];
}
/**
通過一個Multipart-Form的request建立一個request。新request的httpBody是`fileURL`指定的檔案。
並且是通過`HTTPBodyStream`這個屬性新增，`HTTPBodyStream`屬性的資料會自動新增為httpBody。
@param request 原request
@param fileURL 檔案的url
@param handler 錯誤處理
@return 處理完成的request
*/
- (NSMutableURLRequest *)requestWithMultipartFormRequest:(NSURLRequest *)request
writingStreamContentsToFile:(NSURL *)fileURL
completionHandler:(void (^)(NSError *error))handler
{
NSParameterAssert(request.HTTPBodyStream);
NSParameterAssert([fileURL isFileURL]);
//獲取`HTTPBodyStream`屬性
NSInputStream *inputStream = request.HTTPBodyStream;
//獲取檔案的資料流
NSOutputStream *outputStream = [[NSOutputStream alloc] initWithURL:fileURL append:NO];
__block NSError *error = nil;
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//把讀和寫的操作加入當前執行緒的runloop
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
//開啟讀和寫資料流
[inputStream open];
[outputStream open];
//迴圈做讀和寫操作
while ([inputStream hasBytesAvailable] && [outputStream hasSpaceAvailable]) {
uint8_t buffer[1024];
NSInteger bytesRead = [inputStream read:buffer maxLength:1024];
if (inputStream.streamError || bytesRead < 0) {
error = inputStream.streamError;
break;
}
NSInteger bytesWritten = [outputStream write:buffer maxLength:(NSUInteger)bytesRead];
if (outputStream.streamError || bytesWritten < 0) {
error = outputStream.streamError;
break;
}
if (bytesRead == 0 && bytesWritten == 0) {
break;
}
}
//讀和寫完成。關閉讀和寫資料流
[outputStream close];
[inputStream close];
//如果有handler，呼叫handler這個Block
if (handler) {
dispatch_async(dispatch_get_main_queue(), ^{
handler(error);
});
}
});
//獲取一個新的request，新的request的httpBody已經通過`HTTPBodyStream`轉換成功
NSMutableURLRequest *mutableRequest = [request mutableCopy];
mutableRequest.HTTPBodyStream = nil;
//返回一個request物件
return mutableRequest;
}3 AFStreamingMultipartFormData私有類的解析
首先，我們看幾個全域性方法。下面幾個方法用於拼接multipart/form-data的分隔符和檔案的MIMEType。
/*
生成multipartForm的request的boundary
*/
static NSString * AFCreateMultipartFormBoundary() {
return [NSString stringWithFormat:@"Boundary+%08X%08X", arc4random(), arc4random()];
}
//回車換行符
static NSString * const kAFMultipartFormCRLF = @"
";
//生成一個request的請求體中的引數的開始符號，第一個
static inline NSString * AFMultipartFormInitialBoundary(NSString *boundary) {
return [NSString stringWithFormat:@"--%@%@", boundary, kAFMultipartFormCRLF];
}
//生成一個request的請求體中的引數的開始符號，菲第一個。
static inline NSString * AFMultipartFormEncapsulationBoundary(NSString *boundary) {
return [NSString stringWithFormat:@"%@--%@%@", kAFMultipartFormCRLF, boundary, kAFMultipartFormCRLF];
}
//生成一個request的請求體中的引數的結束符號
static inline NSString * AFMultipartFormFinalBoundary(NSString *boundary) {
return [NSString stringWithFormat:@"%@--%@--%@", kAFMultipartFormCRLF, boundary, kAFMultipartFormCRLF];
}
/*
根據檔案的副檔名獲取檔案的`MIMEType`
*/
static inline NSString * AFContentTypeForPathExtension(NSString *extension) {
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;
}
}AFStreamingMultipartFormData負責multipart/form-data的Body的具體構建。比如boundary的指定、請求體資料的拼接等。
- (instancetype)initWithURLRequest:(NSMutableURLRequest *)urlRequest
stringEncoding:(NSStringEncoding)encoding
{
self = [super init];
if (!self) {
return nil;
}
//需要新增httpbody的request
self.request = urlRequest;
//字元編碼
self.stringEncoding = encoding;
//指定boundary
self.boundary = AFCreateMultipartFormBoundary();
//這個屬性用於儲存httpbody資料
self.bodyStream = [[AFMultipartBodyStream alloc] initWithStringEncoding:encoding];
return self;
}
/*
根據檔案的url新增一個`multipart/form-data`請求的請求體域
*/
- (BOOL)appendPartWithFileURL:(NSURL *)fileURL
name:(NSString *)name
error:(NSError * __autoreleasing *)error
{
NSParameterAssert(fileURL);
NSParameterAssert(name);
//副檔名
NSString *fileName = [fileURL lastPathComponent];
//獲取檔案的mimetype的型別
NSString *mimeType = AFContentTypeForPathExtension([fileURL pathExtension]);
return [self appendPartWithFileURL:fileURL name:name fileName:fileName mimeType:mimeType error:error];
}
/**
根據指定型別的fileurl，把資料新增進入bodyStream中。以提供給後面構建request的body。
@param fileURL 檔案的url
@param name 引數名稱
@param fileName 檔名稱
@param mimeType 檔案型別
@param error 錯誤
@return 是否成功
*/
- (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);
/*
各種錯誤情況判斷
*/
if (![fileURL isFileURL]) {
NSDictionary *userInfo = @{NSLocalizedFailureReasonErrorKey: NSLocalizedStringFromTable(@"Expected URL to be a file URL", @"AFNetworking", nil)};
if (error) {
*error = [[NSError alloc] initWithDomain:AFURLRequestSerializationErrorDomain code:NSURLErrorBadURL userInfo:userInfo];
}
return NO;
} else if ([fileURL checkResourceIsReachableAndReturnError:error] == NO) {
NSDictionary *userInfo = @{NSLocalizedFailureReasonErrorKey: NSLocalizedStringFromTable(@"File URL not reachable.", @"AFNetworking", nil)};
if (error) {
*error = [[NSError alloc] initWithDomain:AFURLRequestSerializationErrorDomain code:NSURLErrorBadURL userInfo:userInfo];
}
return NO;
}
//獲取指定路徑檔案的屬性
NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:[fileURL path] error:error];
if (!fileAttributes) {
return NO;
}
//新增`Content-Disposition`和`Content-Type`這兩個請求體域
NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
[mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name="%@"; filename="%@"", name, fileName] forKey:@"Content-Disposition"];
[mutableHeaders setValue:mimeType forKey:@"Content-Type"];
//把一個完整的請求體域封裝進一個`AFHTTPBodyPart`物件中。
AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
bodyPart.stringEncoding = self.stringEncoding;
bodyPart.headers = mutableHeaders;
bodyPart.boundary = self.boundary;
bodyPart.body = fileURL;
bodyPart.bodyContentLength = [fileAttributes[NSFileSize] unsignedLongLongValue];
[self.bodyStream appendHTTPBodyPart:bodyPart];
return YES;
}
/**
根據指定型別的資料流，把資料新增進入bodyStream中。以提供給後面構建request的body。
@param inputStream 輸入的資料流
@param name 引數名稱
@param fileName 檔名稱
@param mimeType 檔案型別
*/
- (void)appendPartWithInputStream:(NSInputStream *)inputStream
name:(NSString *)name
fileName:(NSString *)fileName
length:(int64_t)length
mimeType:(NSString *)mimeType
{
NSParameterAssert(name);
NSParameterAssert(fileName);
NSParameterAssert(mimeType);
//新增`Content-Disposition`和`Content-Type`這兩個請求體域
NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
[mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name="%@"; filename="%@"", name, fileName] forKey:@"Content-Disposition"];
[mutableHeaders setValue:mimeType forKey:@"Content-Type"];
//把一個完整的請求體域封裝進一個`AFHTTPBodyPart`物件中
AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
bodyPart.stringEncoding = self.stringEncoding;
bodyPart.headers = mutableHeaders;
bodyPart.boundary = self.boundary;
bodyPart.body = inputStream;
bodyPart.bodyContentLength = (unsigned long long)length;
[self.bodyStream appendHTTPBodyPart:bodyPart];
}
/**
根據指定的data新增到請求體域中
@param data 資料
@param name 名稱
@param fileName 檔名稱
@param mimeType mimeType
*/
- (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];
}
/**
根據指定的key和value拼接到`Content-Disposition`屬性中
@param data 引數值
@param name 引數名
*/
- (void)appendPartWithFormData:(NSData *)data
name:(NSString *)name
{
NSParameterAssert(name);
NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
[mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name="%@"", name] forKey:@"Content-Disposition"];
//把處理好的資料加入對應的request的請求體中`Content-Disposition`部分
[self appendPartWithHeaders:mutableHeaders body:data];
}
/**
給一個multipartForm的`Content-Disposition`新增boundary
@param headers 請求頭域
@param body 值
*/
- (void)appendPartWithHeaders:(NSDictionary *)headers
body:(NSData *)body
{
NSParameterAssert(body);
AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
bodyPart.stringEncoding = self.stringEncoding;
bodyPart.headers = headers;
bodyPart.boundary = self.boundary;
bodyPart.bodyContentLength = [body length];
bodyPart.body = body;
[self.bodyStream appendHTTPBodyPart:bodyPart];
}
- (void)throttleBandwidthWithPacketSize:(NSUInteger)numberOfBytes
delay:(NSTimeInterval)delay
{
self.bodyStream.numberOfBytesInPacket = numberOfBytes;
self.bodyStream.delay = delay;
}
/**
根據一個request對應的`AFStreamingMultipartFormData`物件獲取封裝好的request物件
@return multipart/form的request物件
*/
- (NSMutableURLRequest *)requestByFinalizingMultipartFormData {
if ([self.bodyStream isEmpty]) {
return self.request;
}
// Reset the initial and final boundaries to ensure correct Content-Length
//重置boundary，從而確保`Content-Length`正確
[self.bodyStream setInitialAndFinalBoundaries];
//把拼接好的bodyStream新增進入request中
[self.request setHTTPBodyStream:self.bodyStream];
//給requst的請求頭新增Content-Type屬性指定為`multipart/form-data`型別的request。同時設定請求體的長度Content-Length。
[self.request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", self.boundary] forHTTPHeaderField:@"Content-Type"];
[self.request setValue:[NSString stringWithFormat:@"%llu", [self.bodyStream contentLength]] forHTTPHeaderField:@"Content-Length"];
return self.request;
}4 AFJSONRequestSerializer和AFPropertyListRequestSerializer
這兩個類繼承自AFHTTPRequestSerializer。他們的基本實現都是繼承自父類。但是也根據自身不同情況，做了處理。
對於AFJSONRequestSerializer。需要把Content-Type指定為"application/json。同時HTTPBody
需要使用JSON序列化：
- (NSURLRequest *)requestBySerializingRequest:(NSURLRequest *)request
withParameters:(id)parameters
error:(NSError *__autoreleasing *)error
{
NSParameterAssert(request);
/*
對於`GET`,`HEAD`,`DELETE`等方法中。直接使用父類的處理方式
*/
if ([self.HTTPMethodsEncodingParametersInURI containsObject:[[request HTTPMethod] uppercaseString]]) {
return [super requestBySerializingRequest:request withParameters:parameters error:error];
}
NSMutableURLRequest *mutableRequest = [request mutableCopy];
//把`HTTPRequestHeaders`中的值新增進入請求頭中。
[self.HTTPRequestHeaders enumerateKeysAndObjectsUsingBlock:^(id field, id value, BOOL * __unused stop) {
if (![request valueForHTTPHeaderField:field]) {
[mutableRequest setValue:value forHTTPHeaderField:field];
}
}];
if (parameters) {
//設定請求頭的`Content-Type`型別
if (![mutableRequest valueForHTTPHeaderField:@"Content-Type"]) {
[mutableRequest setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
}
if (![NSJSONSerialization isValidJSONObject:parameters]) {
if (error) {
NSDictionary *userInfo = @{NSLocalizedFailureReasonErrorKey: NSLocalizedStringFromTable(@"The `parameters` argument is not valid JSON.", @"AFNetworking", nil)};
*error = [[NSError alloc] initWithDomain:AFURLRequestSerializationErrorDomain code:NSURLErrorCannotDecodeContentData userInfo:userInfo];
}
return nil;
}
//把parameters轉換為JSON序列化的data
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:parameters options:self.writingOptions error:error];
if (!jsonData) {
return nil;
}
//JSON序列化的資料設定為httpbody
[mutableRequest setHTTPBody:jsonData];
}
return mutableRequest;
}對於AFPropertyListRequestSerializer也是同樣的道理：
- (NSURLRequest *)requestBySerializingRequest:(NSURLRequest *)request
withParameters:(id)parameters
error:(NSError *__autoreleasing *)error
{
NSParameterAssert(request);
/*
對於`GET`,`HEAD`,`DELETE`等方法中。直接使用父類的處理方式
*/
if ([self.HTTPMethodsEncodingParametersInURI containsObject:[[request HTTPMethod] uppercaseString]]) {
return [super requestBySerializingRequest:request withParameters:parameters error:error];
}
NSMutableURLRequest *mutableRequest = [request mutableCopy];
//把`HTTPRequestHeaders`中的值新增進入請求頭中。
[self.HTTPRequestHeaders enumerateKeysAndObjectsUsingBlock:^(id field, id value, BOOL * __unused stop) {
if (![request valueForHTTPHeaderField:field]) {
[mutableRequest setValue:value forHTTPHeaderField:field];
}
}];
if (parameters) {
//設定請求頭的`Content-Type`型別
if (![mutableRequest valueForHTTPHeaderField:@"Content-Type"]) {
[mutableRequest setValue:@"application/x-plist" forHTTPHeaderField:@"Content-Type"];
}
//把parameters轉換為Plist序列化的data
NSData *plistData = [NSPropertyListSerialization dataWithPropertyList:parameters format:self.format options:self.writeOptions error:error];
if (!plistData) {
return nil;
}
//Plist序列化的資料設定為httpbody
[mutableRequest setHTTPBody:plistData];
}
return mutableRequest;
}5 總結
這個類主要實現了對於不同情況的請求的request物件的封裝。尤其是對於multipart/form-data型別的request的封裝，簡化了我們自己封裝過程的痛苦。如果我們要使用multipart/form-data型別的請求。強烈推薦使用AFHTTPSessionManager物件的AFHTTPRequestSerialization來處理引數的序列化過程。下面就是使用AFHTTPRequestSerailization序列化和自己拼裝的不同：
- (IBAction)updatePic:(id)sender {
//請求頭引數
NSDictionary *dic = @{
@"businessType":@"CC_USER_CENTER",
@"fileType":@"image",
@"file":@"img.jpeg"
};
//請求體圖片資料
NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@"1.png"]);
//建立request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]];
//post方法
[request setHTTPMethod:@"POST"];
AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc]initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSURLSessionDataTask *task = [manager POST:url parameters:dic constructingBodyWithBlock:^(id<AFMultipartFormData> _Nonnull formData) {
//請求體裡面的引數
NSDictionary *bodyDic = @{
@"Content-Disposition":@"form-data;name="file";filename="img.jpeg"",
@"Content-Type":@"image/png",
};
[formData appendPartWithHeaders:bodyDic body:imageData];
} progress:^(NSProgress * _Nonnull uploadProgress) {
NSLog(@"下載進度");
} success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
NSLog(@"下載成功:%@",responseObject);
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
NSLog(@"下載失敗%@",error);
}];
[task resume];
}
- (IBAction)multipartformPost3:(id)sender {
//引數
NSDictionary *dic = @{
@"businessType":@"CC_USER_CENTER",
@"fileType":@"image",
@"file":@"img.jpeg"
};
NSString *boundaryString = @"xxxxx";
NSMutableString *str = [NSMutableString string];
[dic enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
[str appendFormat:@"--%@
",boundaryString];
[str appendFormat:@"%@name="%@"
",@"Content-Disposition: form-data;",key];
[str appendFormat:@"%@
",obj];
}];
NSMutableData *requestMutableData=[NSMutableData data];
[str appendFormat:@"--%@
",boundaryString];
[str appendFormat:@"%@:%@",@"Content-Disposition",@"form-data;"];
[str appendFormat:@"%@="%@";",@"name",@"file"];
[str appendFormat:@"%@="%@"
",@"filename",@"img1.jpeg"];
[str appendFormat:@"%@:%@
",@"Content-Type",@"image/png"];
//轉換成為二進位制資料
[requestMutableData appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];
NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@"1.png"]);
//檔案資料部分
[requestMutableData appendData:imageData];
//新增結尾boundary
[requestMutableData appendData:[[NSString stringWithFormat:@"
--%@--
",boundaryString] dataUsingEncoding:NSUTF8StringEncoding]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]];
//post方法
[request setHTTPMethod:@"POST"];
// 設定請求頭格式為Content-Type:multipart/form-data; boundary=xxxxx
[request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundaryString] forHTTPHeaderField:@"Content-Type"];
request.HTTPBody = requestMutableData;
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
NSString *result = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"%@",result);
}];
[task resume];
}