AFNetworking 网络请求使用
AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc]initWithBaseURL:[NSURL URLWithString:@"http://www.sojson.com"]];
[manager GET:@"/open/api/weather/json.shtml" parameters:@{@"city":@"北京"} progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
NSLog(@"%@", responseObject);
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
NSLog(@"%@", error);
}];
从初始化AFHTTPSessionManager方法得到以下调用栈
- [AFHTTPSessionManager initWithBaseURL:]
- [AFHTTPSessionManager initWithBaseURL:sessionConfiguration:]
- [AFURLSessionManager initWithSessionConfiguration:]
- [NSURLSession sessionWithConfiguration:delegate:delegateQueue:]
- [AFJSONResponseSerializer serializer] // 负责序列化响应
- [AFSecurityPolicy defaultPolicy] // 负责身份认证
- [AFNetworkReachabilityManager sharedManager] // 查看网络连接情况
- [AFHTTPRequestSerializer serializer] // 负责序列化请求
- [AFJSONResponseSerializer serializer] // 负责序列化响应
可以看出AFHTTPSessionManager继承AFURLSessionManager
针对于HTTP快速创建请求GET、POST等
AFNetworking 整体框架
af2.png
查看 -GET:parameter:process:success:failure:调用栈
- [AFHTTPSessionManager GET:parameters:process:success:failure:]
- [AFHTTPSessionManager dataTaskWithHTTPMethod:parameters:uploadProgress:downloadProgress:success:failure:] // 返回 NSURLSessionDataTask #1
- [AFHTTPRequestSerializer requestWithMethod:URLString:parameters:error:] // 返回 NSMutableURLRequest
- [AFURLSessionManager dataTaskWithRequest:uploadProgress:downloadProgress:completionHandler:] // 返回 NSURLSessionDataTask #2
- [NSURLSession dataTaskWithRequest:] // 返回 NSURLSessionDataTask #3
- [AFURLSessionManager addDelegateForDataTask:uploadProgress:downloadProgress:completionHandler:]
- [AFURLSessionManagerTaskDelegate init]
- [AFURLSessionManager setDelegate:forTask:]
- [NSURLSessionDataTask resume]
AFURLSessionManager 介绍
`AFURLSessionManager` creates and manages an `NSURLSession` object based on a specified `NSURLSessionConfiguration` object, which conforms to `<NSURLSessionTaskDelegate>`, `<NSURLSessionDataDelegate>`, `<NSURLSessionDownloadDelegate>`, and `<NSURLSessionDelegate>`.
1.负责创建和管理NSURLSession
2.管理NSURLSessionTask
3.实现NSURLSession中各种代理协议
4.引入AFSecurityPolicy保证请求的安全
5.引入AFNetworkingReachabilityManager监控网络状态
AFURLSessionManager 初始化方法
- (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];
#if !TARGET_OS_WATCH
self.reachabilityManager = [AFNetworkReachabilityManager sharedManager];
#endif
self.mutableTaskDelegatesKeyedByTaskIdentifier = [[NSMutableDictionary alloc] init];
self.lock = [[NSLock alloc] init];
self.lock.name = AFURLSessionManagerLockName;
[self.session getTasksWithCompletionHandler:^(NSArray *dataTasks, NSArray *uploadTasks, NSArray *downloadTasks) {
for (NSURLSessionDataTask *task in dataTasks) {
[self addDelegateForDataTask:task uploadProgress:nil downloadProgress:nil completionHandler:nil];
}
for (NSURLSessionUploadTask *uploadTask in uploadTasks) {
[self addDelegateForUploadTask:uploadTask progress:nil completionHandler:nil];
}
for (NSURLSessionDownloadTask *downloadTask in downloadTasks) {
[self addDelegateForDownloadTask:downloadTask progress:nil destination:nil completionHandler:nil];
}
}];
return self;
}
AFURLSessionManager实例化后，创建NSURLSessionData实例，方法包括
/**
Creates an `NSURLSessionDataTask` with the specified request.
@param request The HTTP request for the request.
@param completionHandler A block object to be executed when the task finishes. This block has no return value and takes three arguments: the server response, the response object created by that serializer, and the error that occurred, if any.
*/
- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request
completionHandler:(nullable void (^)(NSURLResponse *response, id _Nullable responseObject, NSError * _Nullable error))completionHandler;
/**
Creates an `NSURLSessionDataTask` with the specified request.
@param request The HTTP request for the request.
@param uploadProgressBlock A block object to be executed when the upload progress is updated. Note this block is called on the session queue, not the main queue.
@param downloadProgressBlock A block object to be executed when the download progress is updated. Note this block is called on the session queue, not the main queue.
@param completionHandler A block object to be executed when the task finishes. This block has no return value and takes three arguments: the server response, the response object created by that serializer, and the error that occurred, if any.
*/
- (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;
具体的调用如下
- (NSURLSessionDataTask *)dataTaskWithRequest:(NSURLRequest *)request
completionHandler:(void (^)(NSURLResponse *response, id responseObject, NSError *error))completionHandler
{
return [self dataTaskWithRequest:request uploadProgress:nil downloadProgress:nil completionHandler:completionHandler];
}
- (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;
}
该方法中，AFURLSessionManager调用
[AFURLSessionManager addDelegateForDataTask:uploadProgress:downloadProgress:completionHandler:] 该方法，将completionHandler uploadProgressBlock和downloadProgressBlock传入创建的AFURLSessionManagerTaskDelegate对象中并在相应事件发生时进行回调。
该方法具体实现，处于AFURLSessionManager.M文件中
- (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;
}
通过调用 - [AFURLSessionManager setDelegate:forTask:]来设置代理：
- (void)setDelegate:(AFURLSessionManagerTaskDelegate *)delegate
forTask:(NSURLSessionTask *)task
{
NSParameterAssert(task);
NSParameterAssert(delegate);
[self.lock lock];
self.mutableTaskDelegatesKeyedByTaskIdentifier[@(task.taskIdentifier)] = delegate;
[delegate setupProgressForTask:task];
[self addNotificationObserverForTask:task];
[self.lock unlock];
}
可以看出，AFURLSessionManager通过字典mutableTaskDelegatesKeyedByTaskIdentifier 来存储和管理每个NSURLSessionTask，以taskIdentifier为key值。
查看AFURLSessionManager中实现的各种代理包括：
NSURLSessionDelegate
NSURLSessionTaskDelegate
NSURLSessionDataDelegate
NSURLSessionDownDelegate
将NSURLSession的代理指向AFURLSessionManager的代码
self.session = [NSURLSession sessionWithConfiguration:self.sessionConfiguration delegate:self delegateQueue:self.operationQueue];
NSURLSessionDelegate 对应的方法
/*
* Messages related to the URL session as a whole
*/
@protocol NSURLSessionDelegate <NSObject>
@optional
/* The last message a session receives. A session will only become
* invalid because of a systemic error or when it has been
* explicitly invalidated, in which case the error parameter will be nil.
*/
- (void)URLSession:(NSURLSession *)session didBecomeInvalidWithError:(nullable NSError *)error;
/* If implemented, when a connection level authentication challenge
* has occurred, this delegate will be given the opportunity to
* provide authentication credentials to the underlying
* connection. Some types of authentication will apply to more than
* one request on a given connection to a server (SSL Server Trust
* challenges). If this delegate message is not implemented, the
* behavior will be to use the default handling, which may involve user
* interaction.
*/
- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential * _Nullable credential))completionHandler;
/* If an application has received an
* -application:handleEventsForBackgroundURLSession:completionHandler:
* message, the session delegate will receive this message to indicate
* that all messages previously enqueued for this session have been
* delivered. At this time it is safe to invoke the previously stored
* completion handler, or to begin any internal updates that will
* result in invoking the completion handler.
*/
- (void)URLSessionDidFinishEventsForBackgroundURLSession:(NSURLSession *)session API_AVAILABLE(ios(7.0), watchos(2.0), tvos(9.0)) API_UNAVAILABLE(macos);
通过实现该代理，再执行AFURLSessionManager实现的Block。
例如AFURLSessionManager 暴露的方法
/**
Sets a block to be executed when the managed session becomes invalid, as handled by the `NSURLSessionDelegate` method `URLSession:didBecomeInvalidWithError:`.
@param block A block object to be executed when the managed session becomes invalid. The block has no return value, and takes two arguments: the session, and the error related to the cause of invalidation.
*/
- (void)setSessionDidBecomeInvalidBlock:(nullable void (^)(NSURLSession *session, NSError *error))block;
/**
Sets a block to be executed when a connection level authentication challenge has occurred, as handled by the `NSURLSessionDelegate` method `URLSession:didReceiveChallenge:completionHandler:`.
@param block A block object to be executed when a connection level authentication challenge has occurred. The block returns the disposition of the authentication challenge, and takes three arguments: the session, the authentication challenge, and a pointer to the credential that should be used to resolve the challenge.
*/
- (void)setSessionDidReceiveAuthenticationChallengeBlock:(nullable NSURLSessionAuthChallengeDisposition (^)(NSURLSession *session, NSURLAuthenticationChallenge *challenge, NSURLCredential * _Nullable __autoreleasing * _Nullable credential))block;
AFURLSession中NSURLSessionDelegate的实现
#pragma mark - NSURLSessionDelegate
- (void)URLSession:(NSURLSession *)session
didBecomeInvalidWithError:(NSError *)error
{
if (self.sessionDidBecomeInvalid) {
self.sessionDidBecomeInvalid(session, error);
}
[[NSNotificationCenter defaultCenter] postNotificationName:AFURLSessionDidInvalidateNotification object:session];
}
AFURLSessionManager 中AFURLSessionManagerTaskDelegate代理管理task进度并在结束时进行回调。
主要方法
- (void)setupProgressForTask:(NSURLSessionTask *)task
该方法的主要作用
1.设置uploadProgress，downloadProgress回调代码
2.添加KVO 对task中NSProgress中属性进行键值观测
AFURLSessionManagerTaskDelegate 中实现的 NSURLSessionTaskDelegate代理方法
- (void)URLSession:(__unused NSURLSession *)session
task:(NSURLSessionTask *)task
didCompleteWithError:(NSError *)error
具体实现可参照该框架
- (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`
}
}
AFNetWorking 总结
AFURLSessionManager是对NSURLSession的封装
它通过- [AFURLSessionManager dataTaskWithRequest:completionHandler:]等接口创建NSURLSessionDataTask的实例
持有一个字典mutableTaskDelegatesKeyedByTaskIdentifier管理这些data task 实例
引入AFURLSessionManagerTaskDelegate来对传入的uploadProgressBlock downloadProgressBlock completionHandler 在合适的时间进行调用
实现了全部的代理方法来提供block接口
通过方法调用在data task 状态改变时，发出通知
