发送带cookie的请求

建立请求，设置HTTPHeaderField各参数，通过NSURLSessionTask发送请求。
我们封装的AFNetworking组件只能传递参数，不能设置HTTPHeaderField参数，必定发送带HTTPHeaderField参数的请求在少数，不想再修改组件库了。就想到下面间断发送带cookie等HTTPHeaderField参数的请求。我们使用的ReactiveCocoa组件，所以对block的处理采用的是它自带的@weakify(self);和@strongify(self);。若自己ReactiveCocoa，自己找block弱引用的方法，这里就不多说了。

//判断字符串是否为空
#define isEmptyString(str) ([str isKindOfClass:[NSNull class]] || str == nil || ![str isKindOfClass:[NSString class]] || [str length] < 1)

- (void)sendCookieRequestWithUrlString:(NSString *)urlString imageBlock:(void(^)(NSError *error))block {
    if(isEmptyString(urlString))
    {
        if (block) {
            block([NSError errorWithDomain:@"请求地址为空" code:-1 userInfo:nil]);
        }
        return;
    }
    @weakify(self);
    //若想发送同步消息只需要注释下面一行代码和});就可以
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        @strongify(self);
        NSURL * url = [NSURL URLWithString:urlString];
        NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:url];
        NSURLSession * session = [NSURLSession sharedSession];
        NSString *cookie = [self readCurrentCookieWithDomain:urlString];
        [request addValue:cookie forHTTPHeaderField:@"Cookie"];
        // 发送请求
        NSURLSessionTask * sessionTask = [session dataTaskWithRequest:request
                                                    completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                                        if (error) {
                                                            if (block) {
                                                                block(error);
                                                            }
                                                            return;
                                                        }
                                                        NSString *mmmmmmm = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
                                                        NSLog(@"mmmmmmm: %@, response:%@, error:%@, request.allHTTPHeaderFields：%@", mmmmmmm, response, error, request.allHTTPHeaderFields);
                                                        if (block) {
                                                            block(nil);
                                                        }
                                                    }];
        [sessionTask resume];
    });
}

//WKWebView的cookie文件中cookie是针对app所有的网址，传递过来请求的地址也没有用
- (NSString *)readCurrentCookieWithDomain:(NSString *)domainStr{
    NSHTTPCookieStorage*cookieJar = [NSHTTPCookieStorage sharedHTTPCookieStorage];
    NSMutableString * cookieString = [[NSMutableString alloc]init];
    for (NSHTTPCookie*cookie in [cookieJar cookies]) {
        [cookieString appendFormat:@"%@=%@;",cookie.name,cookie.value];
    }

    //删除最后一个“；”
    [cookieString deleteCharactersInRange:NSMakeRange(cookieString.length - 1, 1)];
    return