AFNetworking 3.0 源碼解讀（六）之 AFHTTPSessionManager

本文轉載自查看原文 2016-08-20 16:36 1829 源碼閱讀系列

AFHTTPSessionManager相對來說比較好理解，代碼也比較短。但卻是我們平時可能使用最多的類。

AFNetworking 3.0 源碼解讀（一）之 AFNetworkReachabilityManager

AFNetworking 3.0 源碼解讀（二）之 AFSecurityPolicy

AFNetworking 3.0 源碼解讀（三）之 AFURLRequestSerialization

AFNetworking 3.0 源碼解讀（四）之 AFURLResponseSerialization

AFNetworking 3.0 源碼解讀（五）之 AFURLSessionManager

前言

AFHTTPSessionManager是AFURLSessionManager的子類，是專門為HTTP請求設計的。里邊涉及到了GET,POST,PUT,DELETE 等等HTTPMehtod。因此我們要想正確的使用各種方法，就要理解每個method的含義。
可以通過這篇文章來了解HTTP Method詳細解讀(GET HEAD POST OPTIONS PUT DELETE TRACE CONNECT)

1.相對路徑(relative)

假如有一個基礎路徑NSURL *baseURL = [NSURL URLWithString:@"http://example.com/v1/"];我們暫時命名為baseURL.所謂相對肯定跟這個baseURL有關系。

我們可以通過NSURL +URLWithString:relativeToURL:這個方法來獲取一個路徑，至於怎么使用，我們通過一個例子來說明：

NSURL *baseURL = [NSURL URLWithString:@"http://example.com/v1/"];
[NSURL URLWithString:@"foo" relativeToURL:baseURL];                  // http://example.com/v1/foo
[NSURL URLWithString:@"foo?bar=baz" relativeToURL:baseURL];          // http://example.com/v1/foo?bar=baz
[NSURL URLWithString:@"/foo" relativeToURL:baseURL];                 // http://example.com/foo
[NSURL URLWithString:@"foo/" relativeToURL:baseURL];                 // http://example.com/v1/foo
[NSURL URLWithString:@"/foo/" relativeToURL:baseURL];                // http://example.com/foo/
[NSURL URLWithString:@"http://example2.com/" relativeToURL:baseURL]; // http://example2.com/

至於 絕對路徑 和 相對路徑 的定義，使用方法，優缺點，這里就不提了，大家可以自行了解。說一下為什么使用相對路徑吧。

在真實開發中，一般都會有一個線上的服務器和一下測試服務器，當然也可能多個。在ios開發中切換開發環境有好幾種方法，

通過target
自定義一個字段HTTPURL，用它來控制路徑
通過相對路徑來切換接口

2.GET

// 使用GET 方法獲取數據，不帶進度
- (NSURLSessionDataTask *)GET:(NSString *)URLString
                   parameters:(id)parameters
                      success:(void (^)(NSURLSessionDataTask *task, id responseObject))success
                      failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{

    return [self GET:URLString parameters:parameters progress:nil success:success failure:failure];
}
// 使用GET 方法獲取數據，帶進度
- (NSURLSessionDataTask *)GET:(NSString *)URLString
                   parameters:(id)parameters
                     progress:(void (^)(NSProgress * _Nonnull))downloadProgress
                      success:(void (^)(NSURLSessionDataTask * _Nonnull, id _Nullable))success
                      failure:(void (^)(NSURLSessionDataTask * _Nullable, NSError * _Nonnull))failure
{

    NSURLSessionDataTask *dataTask = [self dataTaskWithHTTPMethod:@"GET"
                                                        URLString:URLString
                                                       parameters:parameters
                                                   uploadProgress:nil
                                                 downloadProgress:downloadProgress
                                                          success:success
                                                          failure:failure];

    [dataTask resume];

    return dataTask;
}

3.HEAD

// 使用HEAD 方法獲取數據，
- (NSURLSessionDataTask *)HEAD:(NSString *)URLString
                    parameters:(id)parameters
                       success:(void (^)(NSURLSessionDataTask *task))success
                       failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{
    NSURLSessionDataTask *dataTask = [self dataTaskWithHTTPMethod:@"HEAD" URLString:URLString parameters:parameters uploadProgress:nil downloadProgress:nil success:^(NSURLSessionDataTask *task, __unused id responseObject) {
        if (success) {
            success(task);
        }
    } failure:failure];

    [dataTask resume];

    return dataTask;
}

4.POST

- (NSURLSessionDataTask *)POST:(NSString *)URLString
                    parameters:(id)parameters
                       success:(void (^)(NSURLSessionDataTask *task, id responseObject))success
                       failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{
    return [self POST:URLString parameters:parameters progress:nil success:success failure:failure];
}

- (NSURLSessionDataTask *)POST:(NSString *)URLString
                    parameters:(id)parameters
                      progress:(void (^)(NSProgress * _Nonnull))uploadProgress
                       success:(void (^)(NSURLSessionDataTask * _Nonnull, id _Nullable))success
                       failure:(void (^)(NSURLSessionDataTask * _Nullable, NSError * _Nonnull))failure
{
    NSURLSessionDataTask *dataTask = [self dataTaskWithHTTPMethod:@"POST" URLString:URLString parameters:parameters uploadProgress:uploadProgress downloadProgress:nil success:success failure:failure];

    [dataTask resume];

    return dataTask;
}

5.上傳數據

- (NSURLSessionDataTask *)POST:(NSString *)URLString
                    parameters:(nullable id)parameters
     constructingBodyWithBlock:(nullable void (^)(id<AFMultipartFormData> _Nonnull))block
                       success:(nullable void (^)(NSURLSessionDataTask * _Nonnull, id _Nullable))success
                       failure:(nullable void (^)(NSURLSessionDataTask * _Nullable, NSError * _Nonnull))failure
{
    return [self POST:URLString parameters:parameters constructingBodyWithBlock:block progress:nil success:success failure:failure];
}

- (NSURLSessionDataTask *)POST:(NSString *)URLString
                    parameters:(id)parameters
     constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block
                      progress:(nullable void (^)(NSProgress * _Nonnull))uploadProgress
                       success:(void (^)(NSURLSessionDataTask *task, id responseObject))success
                       failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{
    NSError *serializationError = nil;
    NSMutableURLRequest *request = [self.requestSerializer multipartFormRequestWithMethod:@"POST" URLString:[[NSURL URLWithString:URLString relativeToURL:self.baseURL] absoluteString] parameters:parameters constructingBodyWithBlock:block error:&serializationError];
    if (serializationError) {
        if (failure) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wgnu"
            dispatch_async(self.completionQueue ?: dispatch_get_main_queue(), ^{
                failure(nil, serializationError);
            });
#pragma clang diagnostic pop
        }

        return nil;
    }

    __block NSURLSessionDataTask *task = [self uploadTaskWithStreamedRequest:request progress:uploadProgress completionHandler:^(NSURLResponse * __unused response, id responseObject, NSError *error) {
        if (error) {
            if (failure) {
                failure(task, error);
            }
        } else {
            if (success) {
                success(task, responseObject);
            }
        }
    }];

    [task resume];

    return task;
}

6.PUT

- (NSURLSessionDataTask *)PUT:(NSString *)URLString
                   parameters:(id)parameters
                      success:(void (^)(NSURLSessionDataTask *task, id responseObject))success
                      failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{
    NSURLSessionDataTask *dataTask = [self dataTaskWithHTTPMethod:@"PUT" URLString:URLString parameters:parameters uploadProgress:nil downloadProgress:nil success:success failure:failure];

    [dataTask resume];

    return dataTask;
}

7.PATCH

- (NSURLSessionDataTask *)PATCH:(NSString *)URLString
                     parameters:(id)parameters
                        success:(void (^)(NSURLSessionDataTask *task, id responseObject))success
                        failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{
    NSURLSessionDataTask *dataTask = [self dataTaskWithHTTPMethod:@"PATCH" URLString:URLString parameters:parameters uploadProgress:nil downloadProgress:nil success:success failure:failure];

    [dataTask resume];

    return dataTask;
}

8.DELETE

- (NSURLSessionDataTask *)DELETE:(NSString *)URLString
                      parameters:(id)parameters
                         success:(void (^)(NSURLSessionDataTask *task, id responseObject))success
                         failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure
{
    NSURLSessionDataTask *dataTask = [self dataTaskWithHTTPMethod:@"DELETE" URLString:URLString parameters:parameters uploadProgress:nil downloadProgress:nil success:success failure:failure];

    [dataTask resume];

    return dataTask;
}

9.私有方法

- (NSURLSessionDataTask *)dataTaskWithHTTPMethod:(NSString *)method
                                       URLString:(NSString *)URLString
                                      parameters:(id)parameters
                                  uploadProgress:(nullable void (^)(NSProgress *uploadProgress)) uploadProgress
                                downloadProgress:(nullable void (^)(NSProgress *downloadProgress)) downloadProgress
                                         success:(void (^)(NSURLSessionDataTask *, id))success
                                         failure:(void (^)(NSURLSessionDataTask *, NSError *))failure
{
    NSError *serializationError = nil;
    NSMutableURLRequest *request = [self.requestSerializer requestWithMethod:method URLString:[[NSURL URLWithString:URLString relativeToURL:self.baseURL] absoluteString] parameters:parameters error:&serializationError];
    if (serializationError) {
        if (failure) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wgnu"
            dispatch_async(self.completionQueue ?: dispatch_get_main_queue(), ^{
                failure(nil, serializationError);
            });
#pragma clang diagnostic pop
        }

        return nil;
    }

    __block NSURLSessionDataTask *dataTask = nil;
    dataTask = [self dataTaskWithRequest:request
                          uploadProgress:uploadProgress
                        downloadProgress:downloadProgress
                       completionHandler:^(NSURLResponse * __unused response, id responseObject, NSError *error) {
        if (error) {
            if (failure) {
                failure(dataTask, error);
            }
        } else {
            if (success) {
                success(dataTask, responseObject);
            }
        }
    }];

    return dataTask;
}

這篇文章確實比較簡單，有了前幾篇文章的鋪墊，到了我們真正使用的時候，一切都變得那么簡單自然啊.我們已經不知不覺中學到了很多知識，但有一點，知識這東西，要反復的記憶才能記住。舉個例子吧，平時可能我們需要在web端查看json數據，當我們把參數拼接到paramter中，該怎么查看呢？

找到AFURLRequestSerialization這個.m
找到requestBySerializingRequest: withParameters: error:這個方法
NSLog(@"URL: %@",mutableRequest.URL.absoluteString);

說明

接下來先把 AFNetworking 的分類再解析完，然后開始搭建網絡框架。

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