AFNetworking 的核心 AFURLSessionManager(二)
来源:互联网 发布:淘宝大学鹰图学院 编辑:程序博客网 时间:2024/05/16 16:58
Blog: [Draveness](http://draveness.me)
<iframe src="http://ghbtns.com/github-btn.html?user=draveness&type=follow&size=large" height="30" width="240" frameborder="0" scrolling="0" style="width:240px; height: 30px;" allowTransparency="true"></iframe>
`AFURLSessionManager` 绝对可以称得上是 AFNetworking的核心。
1. [负责创建和管理 `NSURLSession`](#NSURLSession)
2. [管理 `NSURLSessionTask`](#NSURLSessionTask)
3. [实现 `NSURLSessionDelegate`等协议中的代理方法](#NSURLSessionDelegate)
4. [使用 `AFURLSessionManagerTaskDelegate`管理进度](#AFURLSessionManagerTaskDelegate)
5. [使用 `_AFURLSessionTaskSwizzling`调剂方法](#_AFURLSessionTaskSwizzling)
6. [引入 `AFSecurityPolicy`保证请求的安全](#AFSecurityPolocy)
7. [引入 `AFNetworkReachabilityManager`监控网络状态](#AFNetworkReachabilityManager)
我们会在这里着重介绍上面七个功能中的前五个,分析它是如何包装`NSURLSession`以及众多代理方法的。
## <a id="NSURLSession"></a>创建和管理 `NSURLSession`
在使用`AFURLSessionManager` 时,第一件要做的事情一定是初始化:
```objectivec
- (instancetype)initWithSessionConfiguration:(NSURLSessionConfiguration *)configuration {
self = [super init];
if (!self) {
return nil;
}
if (!configuration) {
configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
}
self.sessionConfiguration = configuration;
self.operationQueue = [[NSOperationQueue alloc] init];
self.operationQueue.maxConcurrentOperationCount = 1;
self.session = [NSURLSession sessionWithConfiguration:self.sessionConfiguration delegate:self delegateQueue:self.operationQueue];
self.responseSerializer = [AFJSONResponseSerializer serializer];
self.securityPolicy = [AFSecurityPolicy defaultPolicy];
self.reachabilityManager = [AFNetworkReachabilityManager sharedManager];
self.mutableTaskDelegatesKeyedByTaskIdentifier = [[NSMutableDictionary alloc] init];
self.lock = [[NSLock alloc] init];
self.lock.name = AFURLSessionManagerLockName;
#1: 为已有的 task设置代理,略
return self;
}
```
在初始化方法中,需要完成初始化一些自己持有的实例:
1. 初始化**会话配置**(NSURLSessionConfiguration),默认为 `defaultSessionConfiguration`
2. 初始化会话(session),并设置会话的代理以及代理队列
3. 初始化管理**响应序列化**(AFJSONResponseSerializer),**安全认证**(AFSecurityPolicy)以及**监控网络状态**(AFNetworkReachabilityManager)的实例
4. 初始化保存 data task的字典(mutableTaskDelegatesKeyedByTaskIdentifier)
## <a id="NSURLSessionTask"></a>管理 `NSURLSessionTask`
接下来,在获得了 `AFURLSessionManager`的实例之后,我们可以通过以下方法创建 `NSURLSessionDataTask`的实例:
```objectivec
- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request
uploadProgress:(nullable void (^)(NSProgress *uploadProgress)) uploadProgressBlock
downloadProgress:(nullable void (^)(NSProgress *downloadProgress)) downloadProgressBlock
completionHandler:(nullable void (^)(NSURLResponse *response, id _Nullable responseObject, NSError * _Nullable error))completionHandler;
- (NSURLSessionUploadTask *)uploadTaskWithRequest:(NSURLRequest *)request
fromFile:(NSURL *)fileURL
progress:(nullable void (^)(NSProgress *uploadProgress)) uploadProgressBlock
completionHandler:(nullable void (^)(NSURLResponse *response, id _Nullable responseObject, NSError * _Nullable error))completionHandler;
...
- (NSURLSessionDownloadTask *)downloadTaskWithRequest:(NSURLRequest *)request
progress:(nullable void (^)(NSProgress *downloadProgress)) downloadProgressBlock
destination:(nullable NSURL * (^)(NSURL *targetPath, NSURLResponse *response))destination
completionHandler:(nullable void (^)(NSURLResponse *response, NSURL * _Nullable filePath, NSError * _Nullable error))completionHandler;
...
```
这里省略了一些返回 `NSURLSessionTask`的方法,因为这些接口的形式都是差不多的。
<a id="dataTaskWithRequest:uploadProgress:downloadProgress:completionHandler:"></id>我们将以 `-[AFURLSessionManager dataTaskWithRequest:uploadProgress:downloadProgress:completionHandler:]`方法的实现为例,分析它是如何实例化并返回一个 `NSURLSessionTask`的实例的:
```objectivec
- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request
uploadProgress:(nullable void (^)(NSProgress *uploadProgress)) uploadProgressBlock
downloadProgress:(nullable void (^)(NSProgress *downloadProgress)) downloadProgressBlock
completionHandler:(nullable void (^)(NSURLResponse *response, id _Nullable responseObject, NSError * _Nullable error))completionHandler {
__block NSURLSessionDataTask *dataTask = nil;
url_session_manager_create_task_safely(^{
dataTask = [self.session dataTaskWithRequest:request];
});
[self addDelegateForDataTask:dataTask uploadProgress:uploadProgressBlock downloadProgress:downloadProgressBlock completionHandler:completionHandler];
return dataTask;
}
```
> `url_session_manager_create_task_safely`的调用是因为苹果框架中的一个 bug [#2093](https://github.com/AFNetworking/AFNetworking/issues/2093),如果有兴趣可以看一下,在这里就不说明了
1. 调用 `-[NSURLSession dataTaskWithRequest:]` 方法传入 `NSURLRequest`
2. 调用 `-[AFURLSessionManager addDelegateForDataTask:uploadProgress:downloadProgress:completionHandler:]`方法返回一个 `AFURLSessionManagerTaskDelegate`对象
3. 将 `completionHandler` `uploadProgressBlock`和 `downloadProgressBlock`传入该对象并在相应事件发生时进行回调
```objectivec
- (void)addDelegateForDataTask:(NSURLSessionDataTask *)dataTask
uploadProgress:(nullable void (^)(NSProgress *uploadProgress)) uploadProgressBlock
downloadProgress:(nullable void (^)(NSProgress *downloadProgress)) downloadProgressBlock
completionHandler:(void (^)(NSURLResponse *response, id responseObject, NSError *error))completionHandler
{
AFURLSessionManagerTaskDelegate *delegate = [[AFURLSessionManagerTaskDelegate alloc] init];
delegate.manager = self;
delegate.completionHandler = completionHandler;
dataTask.taskDescription = self.taskDescriptionForSessionTasks;
[self setDelegate:delegate forTask:dataTask];
delegate.uploadProgressBlock = uploadProgressBlock;
delegate.downloadProgressBlock = downloadProgressBlock;
}
```
在这个方法中同时调用了另一个方法 `-[AFURLSessionManager setDelegate:forTask:]` 来设置代理:
```objectivec
- (void)setDelegate:(AFURLSessionManagerTaskDelegate *)delegate
forTask:(NSURLSessionTask *)task
{
#1: 检查参数,略
[self.lock lock];
self.mutableTaskDelegatesKeyedByTaskIdentifier[@(task.taskIdentifier)] = delegate;
[delegate setupProgressForTask:task];
[self addNotificationObserverForTask:task];
[self.lock unlock];
}
```
正如上面所提到的,`AFURLSessionManager`就是通过字典 `mutableTaskDelegatesKeyedByTaskIdentifier`来存储并管理每一个 `NSURLSessionTask`,它以 `taskIdentifier` 为键存储 task。
该方法使用 `NSLock`来保证不同线程使用 `mutableTaskDelegatesKeyedByTaskIdentifier`时,不会出现**线程竞争**的问题。
同时调用 [- setupProgressForTask:](#setupProgressForTask),我们会在下面具体介绍这个方法。
## <a id="NSURLSessionDelegate"></a>实现 `NSURLSessionDelegate`等协议中的代理方法
在 `AFURLSessionManager`的头文件中可以看到,它遵循了多个协议,其中包括:
+ `NSURLSessionDelegate`
+ `NSURLSessionTaskDelegate`
+ `NSURLSessionDataDelegate`
+ `NSURLSessionDownloadDelegate`
它在初始化方法 `-[AFURLSessionManager initWithSessionConfiguration:]` 将 `NSURLSession`的代理指向 `self`,然后**实现这些方法**,提供更简洁的 block 的接口:
```objectivec
- (void)setSessionDidBecomeInvalidBlock:(nullable void (^)(NSURLSession *session, NSError *error))block;
- (void)setSessionDidReceiveAuthenticationChallengeBlock:(nullable NSURLSessionAuthChallengeDisposition (^)(NSURLSession *session, NSURLAuthenticationChallenge *challenge, NSURLCredential * _Nullable __autoreleasing * _Nullable credential))block;
...
```
它为所有的代理协议都提供了对应的 block接口,方法实现的思路都是相似的,我们以 `-[AFNRLSessionManager setSessionDidBecomeInvalidBlock:]` 为例。
首先调用 setter方法,将 block存入 `sessionDidBecomeInvalid`属性中:
```objectivec
- (void)setSessionDidBecomeInvalidBlock:(void (^)(NSURLSession *session, NSError *error))block {
self.sessionDidBecomeInvalid = block;
}
```
当代理方法调用时,如果存在对应的 block,会执行对应的 block:
```objectivec
- (void)URLSession:(NSURLSession *)session
didBecomeInvalidWithError:(NSError *)error
{
if (self.sessionDidBecomeInvalid) {
self.sessionDidBecomeInvalid(session, error);
}
[[NSNotificationCenter defaultCenter] postNotificationName:AFURLSessionDidInvalidateNotification object:session];
}
```
其他相似的接口实现也都差不多,这里直接跳过了。
## <a id="AFURLSessionManagerTaskDelegate"></a>使用 `AFURLSessionManagerTaskDelegate`管理进度
在上面我们提到过 `AFURLSessionManagerTaskDelegate`类,它主要为 task提供**进度管理**功能,并在 task 结束时**回调**,也就是调用在 `-[AFURLSessionManager dataTaskWithRequest:uploadProgress:downloadProgress:completionHandler:]`等方法中传入的 `completionHandler`。
<a id="setupProgressForTask"></a>我们首先分析一下 `AFURLSessionManagerTaskDelegate`是如何对进度进行跟踪的:
```objectivec
- (void)setupProgressForTask:(NSURLSessionTask *)task {
#1:设置在上传进度或者下载进度状态改变时的回调
#2:KVO
}
```
该方法的实现有两个部分,一部分是对代理持有的两个属性 `uploadProgress`和 `downloadProgress`设置回调
```objectivec
__weak __typeof__(task) weakTask = task;
self.uploadProgress.totalUnitCount = task.countOfBytesExpectedToSend;
[self.uploadProgress setCancellable:YES];
[self.uploadProgress setCancellationHandler:^{
__typeof__(weakTask) strongTask = weakTask;
[strongTask cancel];
}];
[self.uploadProgress setPausable:YES];
[self.uploadProgress setPausingHandler:^{
__typeof__(weakTask) strongTask = weakTask;
[strongTask suspend];
}];
if ([self.uploadProgress respondsToSelector:@selector(setResumingHandler:)]) {
[self.uploadProgress setResumingHandler:^{
__typeof__(weakTask) strongTask = weakTask;
[strongTask resume];
}];
}
```
这里只有对 `uploadProgress`设置回调的代码,设置 `downloadProgress`与这里完全相同
> 主要目的是在对应 `NSProgress`的状态改变时,调用 `resume` `suspend`等方法改变 task的状态。
第二部分是对 task和 `NSProgress`属性进行键值观测:
```objectivec
[task addObserver:self
forKeyPath:NSStringFromSelector(@selector(countOfBytesReceived))
options:NSKeyValueObservingOptionNew
context:NULL];
[task addObserver:self
forKeyPath:NSStringFromSelector(@selector(countOfBytesExpectedToReceive))
options:NSKeyValueObservingOptionNew
context:NULL];
[task addObserver:self
forKeyPath:NSStringFromSelector(@selector(countOfBytesSent))
options:NSKeyValueObservingOptionNew
context:NULL];
[task addObserver:self
forKeyPath:NSStringFromSelector(@selector(countOfBytesExpectedToSend))
options:NSKeyValueObservingOptionNew
context:NULL];
[self.downloadProgress addObserver:self
forKeyPath:NSStringFromSelector(@selector(fractionCompleted))
options:NSKeyValueObservingOptionNew
context:NULL];
[self.uploadProgress addObserver:self
forKeyPath:NSStringFromSelector(@selector(fractionCompleted))
options:NSKeyValueObservingOptionNew
context:NULL];
```
在 `observeValueForKeypath:ofObject:change:context:`方法中改变进度,并调用 block
```objectivec
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context {
if ([object isKindOfClass:[NSURLSessionTask class]]) {
if ([keyPath isEqualToString:NSStringFromSelector(@selector(countOfBytesReceived))]) {
self.downloadProgress.completedUnitCount = [change[@"new"] longLongValue];
} else if ([keyPath isEqualToString:NSStringFromSelector(@selector(countOfBytesExpectedToReceive))]) {
self.downloadProgress.totalUnitCount = [change[@"new"] longLongValue];
} else if ([keyPath isEqualToString:NSStringFromSelector(@selector(countOfBytesSent))]) {
self.uploadProgress.completedUnitCount = [change[@"new"] longLongValue];
} else if ([keyPath isEqualToString:NSStringFromSelector(@selector(countOfBytesExpectedToSend))]) {
self.uploadProgress.totalUnitCount = [change[@"new"] longLongValue];
}
}
else if ([object isEqual:self.downloadProgress]) {
if (self.downloadProgressBlock) {
self.downloadProgressBlock(object);
}
}
else if ([object isEqual:self.uploadProgress]) {
if (self.uploadProgressBlock) {
self.uploadProgressBlock(object);
}
}
}
```
对象的某些属性改变时更新 `NSProgress`对象或使用 block传递 `NSProgress`对象 `self.uploadProgressBlock(object)`。
### 代理方法 `URLSession:task:didCompleteWithError:`
在每一个 `NSURLSessionTask`结束时,都会在代理方法 `URLSession:task:didCompleteWithError:`中:
1. 调用传入的 `completionHander` block
2. 发出 `AFNetworkingTaskDidCompleteNotification`通知
```objectivec
- (void)URLSession:(__unused NSURLSession *)session
task:(NSURLSessionTask *)task
didCompleteWithError:(NSError *)error
{
#1:获取数据,存储 `responseSerializer`和 `downloadFileURL`
if (error) {
#2:在存在错误时调用 `completionHandler`
} else {
#3:调用 `completionHandler`
}
}
```
这是整个代理方法的骨架,先看一下最简单的第一部分代码:
```objectivec
__block NSMutableDictionary *userInfo = [NSMutableDictionary dictionary];
userInfo[AFNetworkingTaskDidCompleteResponseSerializerKey] = manager.responseSerializer;
//Performance Improvement from #2672
NSData *data = nil;
if (self.mutableData) {
data = [self.mutableData copy];
//We no longer need the reference, so nil it out to gain back some memory.
self.mutableData = nil;
}
if (self.downloadFileURL) {
userInfo[AFNetworkingTaskDidCompleteAssetPathKey] = self.downloadFileURL;
} else if (data) {
userInfo[AFNetworkingTaskDidCompleteResponseDataKey] = data;
}
```
这部分代码从 `mutableData`中取出了数据,设置了 `userInfo`。
```objectivec
userInfo[AFNetworkingTaskDidCompleteErrorKey] = error;
dispatch_group_async(manager.completionGroup ?: url_session_manager_completion_group(), manager.completionQueue ?: dispatch_get_main_queue(), ^{
if (self.completionHandler) {
self.completionHandler(task.response, responseObject, error);
}
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:AFNetworkingTaskDidCompleteNotification object:task userInfo:userInfo];
});
});
```
如果当前 `manager`持有 `completionGroup`或者 `completionQueue`就使用它们。否则会创建一个 `dispatch_group_t`并在主线程中调用 `completionHandler`并发送通知(在主线程中)。
如果在执行当前 task时没有遇到错误,那么先**对数据进行序列化**,然后同样调用 block 并发送通知。
```objectivec
dispatch_async(url_session_manager_processing_queue(), ^{
NSError *serializationError = nil;
responseObject = [manager.responseSerializer responseObjectForResponse:task.response data:data error:&serializationError];
if (self.downloadFileURL) {
responseObject = self.downloadFileURL;
}
if (responseObject) {
userInfo[AFNetworkingTaskDidCompleteSerializedResponseKey] = responseObject;
}
if (serializationError) {
userInfo[AFNetworkingTaskDidCompleteErrorKey] = serializationError;
}
dispatch_group_async(manager.completionGroup ?: url_session_manager_completion_group(), manager.completionQueue ?: dispatch_get_main_queue(), ^{
if (self.completionHandler) {
self.completionHandler(task.response, responseObject, serializationError);
}
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter] postNotificationName:AFNetworkingTaskDidCompleteNotification object:task userInfo:userInfo];
});
});
});
```
### 代理方法 `URLSession:dataTask:didReceiveData:`和 `- URLSession:downloadTask:didFinishDownloadingToURL:`
这两个代理方法分别会在收到数据或者完成下载对应文件时调用,作用分别是为 `mutableData`追加数据和处理下载的文件:
```objectivec
- (void)URLSession:(__unused NSURLSession *)session
dataTask:(__unused NSURLSessionDataTask *)dataTask
didReceiveData:(NSData *)data
{
[self.mutableData appendData:data];
}
- (void)URLSession:(NSURLSession *)session
downloadTask:(NSURLSessionDownloadTask *)downloadTask
didFinishDownloadingToURL:(NSURL *)location
{
NSError *fileManagerError = nil;
self.downloadFileURL = nil;
if (self.downloadTaskDidFinishDownloading) {
self.downloadFileURL = self.downloadTaskDidFinishDownloading(session, downloadTask, location);
if (self.downloadFileURL) {
[[NSFileManager defaultManager] moveItemAtURL:location toURL:self.downloadFileURL error:&fileManagerError];
if (fileManagerError) {
[[NSNotificationCenter defaultCenter] postNotificationName:AFURLSessionDownloadTaskDidFailToMoveFileNotification object:downloadTask userInfo:fileManagerError.userInfo];
}
}
}
}
```
## <a id="_AFURLSessionTaskSwizzling"></a>使用 `_AFURLSessionTaskSwizzling`调剂方法
`_AFURLSessionTaskSwizzling`的唯一功能就是修改 `NSURLSessionTask`的 `resume`和 `suspend`方法,使用下面的方法替换原有的实现
```objectivec
- (void)af_resume {
NSAssert([self respondsToSelector:@selector(state)], @"Does not respond to state");
NSURLSessionTaskState state = [self state];
[self af_resume];
if (state != NSURLSessionTaskStateRunning) {
[[NSNotificationCenter defaultCenter] postNotificationName:AFNSURLSessionTaskDidResumeNotification object:self];
}
}
- (void)af_suspend {
NSAssert([self respondsToSelector:@selector(state)], @"Does not respond to state");
NSURLSessionTaskState state = [self state];
[self af_suspend];
if (state != NSURLSessionTaskStateSuspended) {
[[NSNotificationCenter defaultCenter] postNotificationName:AFNSURLSessionTaskDidSuspendNotification object:self];
}
}
```
这样做的目的是为了在方法 `resume`或者 `suspend`被调用时发出通知。
具体方法调剂的过程是在 `+ load`方法中进行的
> `load`方法只会在整个文件被引入时调用一次
```objectivec
+ (void)load {
if (NSClassFromString(@"NSURLSessionTask")) {
NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration ephemeralSessionConfiguration];
NSURLSession * session = [NSURLSession sessionWithConfiguration:configuration];
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnonnull"
NSURLSessionDataTask *localDataTask = [session dataTaskWithURL:nil];
#pragma clang diagnostic pop
IMP originalAFResumeIMP = method_getImplementation(class_getInstanceMethod([self class], @selector(af_resume)));
Class currentClass = [localDataTask class];
while (class_getInstanceMethod(currentClass, @selector(resume))) {
Class superClass = [currentClass superclass];
IMP classResumeIMP = method_getImplementation(class_getInstanceMethod(currentClass, @selector(resume)));
IMP superclassResumeIMP = method_getImplementation(class_getInstanceMethod(superClass, @selector(resume)));
if (classResumeIMP != superclassResumeIMP &&
originalAFResumeIMP != classResumeIMP) {
[self swizzleResumeAndSuspendMethodForClass:currentClass];
}
currentClass = [currentClass superclass];
}
[localDataTask cancel];
[session finishTasksAndInvalidate];
}
}
```
1. 首先用 `NSClassFromString(@"NSURLSessionTask")`判断当前部署的 iOS版本是否含有类 `NSURLSessionTask`
2. 因为 iOS7和 iOS8上对于 `NSURLSessionTask`的实现不同,所以会通过 `-[NSURLSession dataTaskWithURL:]` 方法返回一个 `NSURLSessionTask`实例
3. 取得当前类 `_AFURLSessionTaskSwizzling`中的实现 `af_resume`
4. 如果当前类 `currentClass`有 `resume`方法
+ 真:5
+ 假:6
5. 使用 `swizzleResumeAndSuspendMethodForClass:`调剂该类的 `resume`和 `suspend`方法
6. `currentClass = [currentClass superclass]`
> 这里复杂的实现是为了解决 bug [#2702](https://github.com/AFNetworking/AFNetworking/pull/2702)
## <a id='AFSecurityPolicy'></a>引入 `AFSecurityPolicy`保证请求的安全
`AFSecurityPolicy`是 `AFNetworking`用来保证 HTTP请求安全的类,它被 `AFURLSessionManager`持有,如果你在 `AFURLSessionManager`的实现文件中搜索 *self.securityPolicy*,你只会得到三条结果:
1. 初始化 `self.securityPolicy =[AFSecurityPolicy defaultPolicy]`
2. 收到连接层的验证请求时
3. 任务接收到验证请求时
在 API调用上,后两者都调用了 `-[AFSecurityPolicy evaluateServerTrust:forDomain:]` 方法来判断**当前服务器是否被信任**,我们会在接下来的文章中具体介绍这个方法的实现的作用。
```objectivec
- (void)URLSession:(NSURLSession *)session
task:(NSURLSessionTask *)task
didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler
{
NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengePerformDefaultHandling;
__block NSURLCredential *credential = nil;
if (self.taskDidReceiveAuthenticationChallenge) {
disposition = self.taskDidReceiveAuthenticationChallenge(session, task, challenge, &credential);
} else {
if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
if ([self.securityPolicy evaluateServerTrust:challenge.protectionSpace.serverTrust forDomain:challenge.protectionSpace.host]) {
disposition = NSURLSessionAuthChallengeUseCredential;
credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
} else {
disposition = NSURLSessionAuthChallengeRejectProtectionSpace;
}
} else {
disposition = NSURLSessionAuthChallengePerformDefaultHandling;
}
}
if (completionHandler) {
completionHandler(disposition, credential);
}
}
```
如果没有传入 `taskDidReceiveAuthenticationChallenge` block,只有在上述方法返回 `YES` 时,才会获得认证凭证 `credential`。
## <a id='AFNetworkReachabilityManager'></a>引入 `AFNetworkReachabilityManager`监控网络状态
与 `AFSecurityPolicy`相同,`AFURLSessionManager`对网络状态的监控是由 `AFNetworkReachabilityManager`来负责的,它仅仅是持有一个 `AFNetworkReachabilityManager`的对象。
> 真正需要判断网络状态时,仍然**需要开发者调用对应的 API获取网络状态**。
## 小结
1. `AFURLSessionManager`是对 `NSURLSession`的封装
2. 它通过 `-[AFURLSessionManager dataTaskWithRequest:completionHandler:]`等接口创建 `NSURLSessionDataTask`的实例
3. 持有一个字典 `mutableTaskDelegatesKeyedByTaskIdentifier`管理这些 data task实例
4. 引入 `AFURLSessionManagerTaskDelegate`来对传入的 `uploadProgressBlock` `downloadProgressBlock` `completionHandler` 在合适的时间进行调用
5. 实现了全部的代理方法来提供 block接口
6. 通过方法调剂在 data task状态改变时,发出通知
## 相关文章
关于其他 AFNetworking源代码分析的其他文章:
+ [AFNetworking 概述(一)](https://github.com/Draveness/iOS-Source-Code-Analyze/blob/master/AFNetworking/AFNetworking%20概述(一).md)
+ [AFNetworking 的核心 AFURLSessionManager(二)](https://github.com/Draveness/iOS-Source-Code-Analyze/blob/master/AFNetworking/AFNetworking%20的核心%20AFURLSessionManager(二).md)
+ [处理请求和响应 AFURLSerialization(三)](https://github.com/Draveness/iOS-Source-Code-Analyze/blob/master/AFNetworking/处理请求和响应%20AFURLSerialization(三).md)
+ [AFNetworkReachabilityManager 监控网络状态(四)](https://github.com/Draveness/iOS-Source-Code-Analyze/blob/master/AFNetworking/AFNetworkReachabilityManager%20监控网络状态(四).md)
<iframe src="http://ghbtns.com/github-btn.html?user=draveness&type=follow&size=large" height="30" width="240" frameborder="0" scrolling="0" style="width:240px; height: 30px;" allowTransparency="true"></iframe>
Follow: [@Draveness](https://github.com/Draveness)
- AFNetworking 的核心 AFURLSessionManager(二)
- AFNetworking 的核心 AFURLSessionManager(二)
- AFNetworking 的核心 AFURLSessionManager(二)
- AFNetWorking(3.0)源码分析(二)——AFURLSessionManager
- AFNetworking汉化之“AFURLSessionManager”
- AFNetworking汉化之“AFURLSessionManager”
- AFNetworking汉化之“AFURLSessionManager”
- AFNetworking知识点之AFURLSessionManager
- AFNetworking 3.0 源码解读(五)之 AFURLSessionManager
- AFNetworking 3.0 源码解读(五)之 AFURLSessionManager
- AFNetworking 源码解析之“AFURLSessionManager”
- 248,AFNetworking 3的使用(二)
- iOS网络——AFNetworking AFURLSessionManager源码解析
- AFNetworking核心类AFURLConnectionOperation的详解
- iOS AFN 封装POST网络请求(AFURLSessionManager) (续二) download下载方法
- AFNetworking 源码解析(二)
- AFNetWorking源码详解(二)
- 简单封装AFNetworking(二)
- 【经验总结】tcp_tw_recycle参数引发的故障
- 栈的演示1.
- Make 命令教程
- vectorLine画线
- android studio 如何打包成jar包
- AFNetworking 的核心 AFURLSessionManager(二)
- poj2488 A Knight's Journey
- sphinx 配置文件全解析
- C#编写的获取天气信息
- 一步一步解析集合框架ArrayList源码(2)
- 程序猿男票为何特别想要那个?
- Hive安装与使用
- 交流直流测试
- Hibernate和Spring整合时,获取Session失败