AFNetWorking源碼之AFURLRequestSerialization
1 概述
AFURLRequestSerialization主要實現了根據不一樣狀況和參數初始化NSURLRequest對象的功能。只有AFHTTPSessionManager有requestSerialization，默認是AFHTTPRequestSerializer對象。尤爲是咱們使用MultipartForm請求的時候，可使用它幫咱們完成繁雜的請求頭拼接過程，這個是最值得推薦的。html
在閱讀源碼以前，必定要對multipart/form-data很是熟悉，否則會有不少地方看不懂。具體能夠看AFNetWorking源碼之AFHTTPSessionManager關於它的那部分。git
2 AFURLRequestSerialization的api分析
AFURLRequestSerialization包含了四個部分：github
全局方法:
AFPercentEscapedStringFromString和AFQueryStringFromParameters。json協議
AFURLRequestSerialization提供了一個序列化parameters參數的方法。咱們能夠把參數轉換爲查詢字符串、HTTP請求體、設置恰當的請求頭等。apiAFHTTPRequestSerializer繼承自AFURLRequestSerialization協議。提供了查詢字符串/URL格式的參數序列化、默認請求頭處理。同時以提供HTTP狀態碼和返回數據的驗證等工做。
_AFMultipartFormData協議。主要用於添加multipart/form-data請求的Content-Disposition: file; filename=#{generated filename}; name=#{name}"和Content-Type: #{generated mimeType}的請求體域。數組類型
AFJSONRequestSerializer和AFPropertyListRequestSerializer。主要針對JSON和Plist類型的序列化優化。緩存
AFPercentEscapedStringFromString返回一個字符串的百分號編碼格式的字符串。由於url只有普通英文字符和數字，特殊字符$-_.+!*'()還有保留字符。因此不少字符都須要編碼,非ASCII編碼的字符串先轉換爲ASCII編碼，而後再轉換爲百分號編碼。cookie
/**
AFPercentEscapedStringFromString方法的做用就是把一個普通字符串轉換爲百分號編碼的字符串
http://blog.csdn.net/qq_32010299/article/details/51790407
@param string 一個字符串
@return 百分號編碼的字符串
*/
NSString * AFPercentEscapedStringFromString(NSString *string) {
//可能須要作百分號編碼處理的字符串
static NSString * const kAFCharactersGeneralDelimitersToEncode = @":#[]@";
static NSString * const kAFCharactersSubDelimitersToEncode = @"!$&'()*+,;=";
//不須要作百分號編碼的字符串集合
NSMutableCharacterSet * allowedCharacterSet = [[NSCharacterSet URLQueryAllowedCharacterSet] mutableCopy];
//獲取目前系統中最終須要作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;
//迭代字符串作百分號編碼
while (index < string.length) {
NSUInteger length = MIN(string.length - index, batchSize);
NSRange range = NSMakeRange(index, length);
//移除字符串中的一些非法字符。好比????
range = [string rangeOfComposedCharacterSequencesForRange:range];
NSString *substring = [string substringWithRange:range];
//指定範圍內的字符作百分號編碼
NSString *encoded = [substring stringByAddingPercentEncodingWithAllowedCharacters:allowedCharacterSet];
[escaped appendString:encoded];
index += range.length;
}
//返回處理之後的字符串
return escaped;
}
私有類AFQueryStringPair的主要功能就是把一個key和vaue的鍵值對轉換爲百分號編碼格式的鍵值對而且用=連接起來網絡
@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鍵值對轉換爲百分號編碼，而且連接起來
@return 轉換後的字符串
*/
- (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，而後再拼接
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鍵值對轉換爲url的query參數。session
/**
把一個字典轉換爲百分號編碼的query參數
@param parameters 要轉換的字典
@return query參數
*/
NSString * AFQueryStringFromParameters(NSDictionary *parameters) {
NSMutableArray *mutablePairs = [NSMutableArray array];
for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {
//調用`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、數組、集合轉換爲一個AFQueryStringPair對象的的數組。
@param key key
@param value value
@return AFQueryStringPair類型數組
*/
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) {
//若是是字典，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) {
//若是是數組，則取出元素，添加一個額外的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 ]]) {
//若是是集合，就是用默認key和集合元素處理
[mutableQueryStringComponents addObjectsFromArray:AFQueryStringPairsFromKeyAndValue(key, obj)];
}
} else {
//添加處理後的key和value
[mutableQueryStringComponents addObject:[[AFQueryStringPair alloc] initWithField:key value:value]];
}
//返回`AFQueryStringPair`對象數組
return mutableQueryStringComponents;
}
AFHTTPRequestSerializerObservedKeyPaths全局方法指定了request請求序列化要觀察的屬性列表、是一個數組，裏面有對蜂窩數據、緩存策略、cookie、管道、網絡狀態、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。好比通用請求頭的添加如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對象的初始化等。
1 AFHTTPRequestSerializer的屬性和初始化
//屬性列表
@interface AFHTTPRequestSerializer ()
//某個request須要觀察的屬性集合
@property (readwrite, nonatomic, strong) NSMutableSet *mutableObservedChangedKeyPaths;
//存儲request的請求頭域
@property (readwrite, nonatomic, strong) NSMutableDictionary *mutableHTTPRequestHeaders;
//用於修改或者設置請求體域的dispatch_queue_t。
@property (readwrite, nonatomic, strong) dispatch_queue_t requestHeaderModificationQueue;
@property (readwrite, nonatomic, assign) AFHTTPRequestQueryStringSerializationStyle queryStringSerializationStyle;
//手動指定parameters參數序列化的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;
//請求頭保存在一個字典中，方便後面構建request的時候拼裝。
self.mutableHTTPRequestHeaders = [NSMutableDictionary dictionary];
//初始化一個操做request的header域的dispatch_queue_t
self.requestHeaderModificationQueue = dispatch_queue_create("requestHeaderModificationQueue", DISPATCH_QUEUE_CONCURRENT);
NSMutableArray *acceptLanguagesComponents = [NSMutableArray array];
/*
*枚舉系統的language列表。而後設置`Accept-Language`請求頭域。優先級逐級下降，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;
}];
//數組元素使用`, `分割
[self setValue:[acceptLanguagesComponents componentsJoinedByString:@", "] forHTTPHeaderField:@"Accept-Language"];
/*
*設置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) {
/*
*若是userAgent裏面包含非ASCII碼的字符，好比中文，則須要轉換。這裏是轉換爲對應的拉丁字母。
AFNetWorking3.X源碼閱讀/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];
//轉換爲拉丁字母
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
//須要把parameters轉換爲query參數的方法集合。
self.HTTPMethodsEncodingParametersInURI = [NSSet setWithObjects:@"GET", @"HEAD", @"DELETE", nil];
self.mutableObservedChangedKeyPaths = [NSMutableSet set];
/*
添加對蜂窩數據、緩存策略、cookie、管道、網絡狀態、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的各類setter方法
首先經過automaticallyNotifiesObserversForKey方法來阻止一些屬性的KVO機制的觸發，而後咱們經過重寫蜂窩數據、緩存策略、cookie、管道、網絡狀態、超時的觀察。能夠用於測試這些屬性變化是否崩潰等。
/**
若是kvo的觸發機制是默認出發。則返回true，不然返回false。在這裏，只要是`AFHTTPRequestSerializerObservedKeyPaths`裏面的屬性，咱們都取消自動出發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
{
//是不是選擇要觀察的屬性
if (context == AFHTTPRequestSerializerObserverContext) {
//若是屬性值爲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 {
//添加到要觀察的屬性的集合
[self.mutableObservedChangedKeyPaths addObject:keyPath];
}
}
}
經過重寫屬性的setter方法來手動觸發kvo
#pragma mark - 手動觸發蜂窩數據、緩存策略、cookie、管道、網絡狀態、超時的觀察。能夠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的各類請求頭域處理方法
/**
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;
}
/**
設置一個請求頭域
@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;
}
/**
設置Basic Authorization的用戶名和密碼。記住須要是base64編碼格式的。
@param username 用戶
@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的各類建立NSMutableURLRequest的方法
經過下面這三種方法處理不一樣類型的request對象的初始化和參數序列化。
/**
根據給定的url、方法名、參數構建一個request。
@param method 方法名
@param URLString url地址
@param parameters 參數，根據不一樣的請求方法構建出不一樣的模式
@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集合裏面的屬性都經過`setValue: forKey`手動設置一下。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。而且經過`AFMultipartFormData`類型的formData來構建請求體
@param method 方法名，通常都是POST
@param URLString 請求地址
@param parameters 請求頭參數
@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對象，而後在構建出multipartFrom的request
* 在這一步將會把parameters加入請求頭或者請求體。而後把`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`對象。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`對象。而後根據取出的key和value處理。
*/
for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {
NSData *data = nil;
//把value處理爲NSData類型
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具體序列化操做
return [formData requestByFinalizingMultipartFormData];
}
/**
經過一個Multipart-Form的request建立一個request。新request的httpBody是`fileURL`指定的文件。
而且是經過`HTTPBodyStream`這個屬性添加，`HTTPBodyStream`屬性的數據會自動添加爲httpBody。
@param request 原request
@param fileURL 文件的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;
//獲取文件的數據流
NSOutputStream *outputStream = [[NSOutputStream alloc] initWithURL:fileURL append:NO];
__block NSError *error = nil;
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//把讀和寫的操做加入當前線程的runloop
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
//打開讀和寫數據流
[inputStream open];
[outputStream open];
//循環作讀和寫操做
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。關閉讀和寫數據流
[outputStream close];
[inputStream close];
//若是有handler，調用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已經經過`HTTPBodyStream`轉換成功
NSMutableURLRequest *mutableRequest = [request mutableCopy];
mutableRequest.HTTPBodyStream = nil;
//返回一個request對象
return mutableRequest;
}
3 AFStreamingMultipartFormData私有類的解析
首先，咱們看幾個全局方法。下面幾個方法用於拼接multipart/form-data的分隔符和文件的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 = @"\r\n";
//生成一個request的請求體中的參數的開始符號，第一個
static inline NSString * AFMultipartFormInitialBoundary(NSString *boundary) {
return [NSString stringWithFormat:@"--%@%@", boundary, kAFMultipartFormCRLF];
}
//生成一個request的請求體中的參數的開始符號，菲第一個。
static inline NSString * AFMultipartFormEncapsulationBoundary(NSString *boundary) {
return [NSString stringWithFormat:@"%@--%@%@", kAFMultipartFormCRLF, boundary, kAFMultipartFormCRLF];
}
//生成一個request的請求體中的參數的結束符號
static inline NSString * AFMultipartFormFinalBoundary(NSString *boundary) {
return [NSString stringWithFormat:@"%@--%@--%@", kAFMultipartFormCRLF, boundary, kAFMultipartFormCRLF];
}
/*
根據文件的擴展名獲取文件的`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。好比boundary的指定、請求體數據的拼接等。
- (instancetype)initWithURLRequest:(NSMutableURLRequest *)urlRequest
stringEncoding:(NSStringEncoding)encoding
{
self = [super init];
if (!self) {
return nil;
}
//須要添加httpbody的request
self.request = urlRequest;
//字符編碼
self.stringEncoding = encoding;
//指定boundary
self.boundary = AFCreateMultipartFormBoundary();
//這個屬性用於存儲httpbody數據
self.bodyStream = [[AFMultipartBodyStream alloc] initWithStringEncoding:encoding];
return self;
}
/*
根據文件的url添加一個`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);
//文件擴展名
NSString *fileName = [fileURL lastPathComponent];
//獲取文件的mimetype的類型
NSString *mimeType = AFContentTypeForPathExtension([fileURL pathExtension]);
return [self appendPartWithFileURL:fileURL name:name fileName:fileName mimeType:mimeType error:error];
}
/**
根據指定類型的fileurl，把數據添加進入bodyStream中。以提供給後面構建request的body。
@param fileURL 文件的url
@param name 參數名稱
@param fileName 文件名稱
@param mimeType 文件類型
@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);
/*
各類錯誤狀況判斷
*/
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;
}
//獲取指定路徑文件的屬性
NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:[fileURL path] error:error];
if (!fileAttributes) {
return NO;
}
//添加`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`對象中。
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;
}
/**
根據指定類型的數據流，把數據添加進入bodyStream中。以提供給後面構建request的body。
@param inputStream 輸入的數據流
@param name 參數名稱
@param fileName 文件名稱
@param mimeType 文件類型
*/
- (void)appendPartWithInputStream:(NSInputStream *)inputStream
name:(NSString *)name
fileName:(NSString *)fileName
length:(int64_t)length
mimeType:(NSString *)mimeType
{
NSParameterAssert(name);
NSParameterAssert(fileName);
NSParameterAssert(mimeType);
//添加`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`對象中
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添加到請求體域中
@param data 數據
@param name 名稱
@param fileName 文件名稱
@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 參數值
@param name 參數名
*/
- (void)appendPartWithFormData:(NSData *)data
name:(NSString *)name
{
NSParameterAssert(name);
NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
[mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"", name] forKey:@"Content-Disposition"];
//把處理好的數據加入對應的request的請求體中`Content-Disposition`部分
[self appendPartWithHeaders:mutableHeaders body:data];
}
/**
給一個multipartForm的`Content-Disposition`添加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`對象獲取封裝好的request對象
@return multipart/form的request對象
*/
- (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添加進入request中
[self.request setHTTPBodyStream:self.bodyStream];
//給requst的請求頭添加Content-Type屬性指定爲`multipart/form-data`類型的request。同時設置請求體的長度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。可是也根據自身不一樣狀況，作了處理。
對於AFJSONRequestSerializer。須要把Content-Type指定爲"application/json。同時HTTPBody
須要使用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`中的值添加進入請求頭中。
[self.HTTPRequestHeaders enumerateKeysAndObjectsUsingBlock:^(id field, id value, BOOL * __unused stop) {
if (![request valueForHTTPHeaderField:field]) {
[mutableRequest setValue:value forHTTPHeaderField:field];
}
}];
if (parameters) {
//設置請求頭的`Content-Type`類型
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轉換爲JSON序列化的data
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:parameters options:self.writingOptions error:error];
if (!jsonData) {
return nil;
}
//JSON序列化的數據設置爲httpbody
[mutableRequest setHTTPBody:jsonData];
}
return mutableRequest;
}
對於AFPropertyListRequestSerializer也是一樣的道理：
- (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`中的值添加進入請求頭中。
[self.HTTPRequestHeaders enumerateKeysAndObjectsUsingBlock:^(id field, id value, BOOL * __unused stop) {
if (![request valueForHTTPHeaderField:field]) {
[mutableRequest setValue:value forHTTPHeaderField:field];
}
}];
if (parameters) {
//設置請求頭的`Content-Type`類型
if (![mutableRequest valueForHTTPHeaderField:@"Content-Type"]) {
[mutableRequest setValue:@"application/x-plist" forHTTPHeaderField:@"Content-Type"];
}
//把parameters轉換爲Plist序列化的data
NSData *plistData = [NSPropertyListSerialization dataWithPropertyList:parameters format:self.format options:self.writeOptions error:error];
if (!plistData) {
return nil;
}
//Plist序列化的數據設置爲httpbody
[mutableRequest setHTTPBody:plistData];
}
return mutableRequest;
}
5 總結
這個類主要實現了對於不一樣狀況的請求的request對象的封裝。尤爲是對於multipart/form-data類型的request的封裝，簡化了咱們本身封裝過程的痛苦。若是咱們要使用multipart/form-data類型的請求。強烈推薦使用AFHTTPSessionManager對象的AFHTTPRequestSerialization來處理參數的序列化過程。下面就是使用AFHTTPRequestSerailization序列化和本身拼裝的不一樣：
- (IBAction)updatePic:(id)sender {
//請求頭參數
NSDictionary *dic = @{
@"businessType":@"CC_USER_CENTER",
@"fileType":@"image",
@"file":@"img.jpeg"
};
//請求體圖片數據
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) {
//請求體裏面的參數
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 {
//參數
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:@"--%@\r\n",boundaryString];
[str appendFormat:@"%@name=\"%@\"\r\n\r\n",@"Content-Disposition: form-data;",key];
[str appendFormat:@"%@\r\n",obj];
}];
NSMutableData *requestMutableData=[NSMutableData data];
[str appendFormat:@"--%@\r\n",boundaryString];
[str appendFormat:@"%@:%@",@"Content-Disposition",@"form-data;"];
[str appendFormat:@"%@=\"%@\";",@"name",@"file"];
[str appendFormat:@"%@=\"%@\"\r\n",@"filename",@"img1.jpeg"];
[str appendFormat:@"%@:%@\r\n\r\n",@"Content-Type",@"image/png"];
//轉換成爲二進制數據
[requestMutableData appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];
NSData *imageData = UIImagePNGRepresentation([UIImage imageNamed:@"1.png"]);
//文件數據部分
[requestMutableData appendData:imageData];
//添加結尾boundary
[requestMutableData appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundaryString] dataUsingEncoding:NSUTF8StringEncoding]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]];
//post方法
[request setHTTPMethod:@"POST"];
// 設置請求頭格式爲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];
}
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相關文章
- 1. 源碼閱讀：AFNetworking（二）——AFURLRequestSerialization
- 2. AFNetworking 3.0 源碼解讀（三）之 AFURLRequestSerialization
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