一.思路

整个项目的所有api请求看成一个tableView，那么每一个api请求就相当于一个cell。每一次api请求，就是把parameters和url赋值给cell，然后调用afn的api。

• 在调用afn的api之前，先监听一下当前网络状态，做相应的逻辑处理。
• 退出某个页面之前，api请求还没有结果返回，取消该请求。

二.第一层封装（简单的调用afn）

- (NSURLSessionDataTask *)requestWithConfigure:(HttpRequestConfigure *)configure
                                       Success:(ResponseSuccess)success
                                       Failure:(ResponseFailed)failure
                                      Finished:(ResponseFinished)finished{
    AFHTTPSessionManager *sessionManger = [AFHTTPSessionManager sharedManager];
    // -- 网络超时时间设置 --
    [sessionManger.requestSerializer willChangeValueForKey:@"timeoutInterval"];
    sessionManger.requestSerializer.timeoutInterval = configure.timeoutInterval;
    [sessionManger.requestSerializer didChangeValueForKey:@"timeoutInterval"];
    
    switch (configure.requestType) {
        case RequestTypeGET:{
            return [sessionManger GET:configure.requestUrl
                           parameters:configure.parameters
                             progress:nil
                              success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
                                  success(task,responseObject);
                                  finished(task,responseObject,nil);
                              }
                              failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
                        failure(task,error);
                        finished(task,nil,error);
                   }];
            break;
        }
        case RequestTypePOST:{
            return [sessionManger POST:configure.requestUrl
                            parameters:configure.parameters
                              progress:nil
                               success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
                                   success(task,responseObject);
                                   finished(task,responseObject,nil);
                               }
                               failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
                       failure(task,error);
                       finished(task,nil,error);
                   }];
            break;
        }
        // --如果还需要其他类型的请求，可以在这里继续添加--
    }
}

如果afn更新，相应api变动，只需要在这里修改。

三.第二层封装

- (NSURLSessionDataTask *)sendRequest:(ResponseConfigure)configureBlock
                              Success:(SuccessCallBackData)success
                              Failure:(FailedCallBackReason)failure
                             Finished:(FinishedCallBack)finished{
    HttpRequestConfigure *configure = [HttpRequestConfigure setConfigure];
    if (configureBlock) {
        configureBlock(configure);
    }
    HttpRequestConfigure *requestConfigure = [self resetRequestConfiguration:configure];
    if ([[HttpNetwork sharedNetwork] isReachable]) {
        return [[HttpRequestBasics defaultCenter] requestWithConfigure:requestConfigure Success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
            NSDictionary *data = [self analyzeResponseData:responseObject];
            if (success) {
                success(data);
            }
        } Failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
            NSString *reason = [self returnErrorDescription:error];
            if (failure) {
                failure(reason);
            }
        } Finished:^(NSURLSessionDataTask * _Nullable task, id  _Nullable responseObject, NSError * _Nullable error) {
            NSDictionary *data = [self analyzeResponseData:responseObject];
            NSString *reason = [self returnErrorDescription:error];
            if (finished) {
                finished(data, reason);
            }
        }];
    }
    else{
        failure(kNotHttpNetExpression);
        return nil;
    }
}

• 将外部传进来的parameters和url赋值给请求配置cell （即HttpRequestConfigure对象），把cell传递到第一层。
• 在调用第一层方法之前，判断网络可用性（使用Reachability）：
  [[HttpNetwork sharedNetwork] isReachable]

四. 外部调用

    // 没有回调
    [HttpRequestTool sendRequest:^(HttpRequestConfigure *configure) {
        configure.requestType = RequestTypePOST;
        configure.specialUrl = kHomePage_Ad_URL;
    }];
    // 成功回调
    [HttpRequestTool sendRequest:^(HttpRequestConfigure *configure) {
        configure.requestType = RequestTypePOST;
        configure.specialUrl = kHomePage_Ad_URL;
    } Success:^(NSDictionary *dict) {
        NSLog(@"dict:%@",dict);
    }];
    // 失败回调
    [HttpRequestTool sendRequest:^(HttpRequestConfigure *configure) {
        configure.requestType = RequestTypePOST;
        configure.specialUrl = kHomePage_Ad_URL;
    } Failure:^(NSString *reason) {
        NSLog(@"reason:%@",reason);
    }];
    // 结束回调
    [HttpRequestTool sendRequest:^(HttpRequestConfigure *configure) {
        configure.requestType = RequestTypePOST;
        configure.specialUrl = kHomePage_Ad_URL;
    } Finished:^(NSDictionary * _Nullable dict, NSString *reason) {
        NSLog(@"--");
    }];
    // 成功和失败回调
    [HttpRequestTool sendRequest:^(HttpRequestConfigure *configure) {
        configure.requestType = RequestTypePOST;
        configure.specialUrl = kHomePage_Ad_URL;
    } Success:^(NSDictionary *dict) {
        NSLog(@"dict:%@",dict);
    } Failure:^(NSString *reason) {
        NSLog(@"reason:%@",reason);
    }];
    // 成功，失败和结束回调
    NSURLSessionDataTask *task = [HttpRequestTool sendRequest:^(HttpRequestConfigure *configure) {
        configure.requestType = RequestTypePOST;
        configure.specialUrl = kHomePage_Ad_URL;
    } Success:^(NSDictionary *dict) {
        NSLog(@"dict:%@",dict);
    } Failure:^(NSString *reason) {
        NSLog(@"reason:%@",reason);
    } Finished:^(NSDictionary * _Nullable dict, NSString *reason) {
        NSLog(@"--");
    }];
    // 在需要取消请求的地方取消请求
    [task cancel];

[task cancel];取消该线程，一般会在控制器销毁（dealloc）的时候调用。

五. Demo

HttpRequestTool

六.讨论

该请求工具我亲试，没有发现什么问题，而且也非常方便。如果遇到问题或者有什么建议，欢迎评论探讨。