为什么 AFNetworking 总是进入失败块？

Question

我在我的项目中集成了 here 的 AFNetworking。但是当我确实使用 AFNetworking 收到请求时，它总是进入失败块。下面是我的代码。请让我知道，我在这里做错了什么？

NSString *baseUrl = @"http://www.nactem.ac.uk/software/acromine/dictionary.py?sf=ETA";
    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    [manager GET:baseUrl parameters:nil progress:^(NSProgress * _Nonnull downloadProgress) {
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        NSLog(@"%@",responseObject);

   //Always it invoke the Failure block
    }failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        NSHTTPURLResponse *response = error.userInfo[AFNetworkingOperationFailingURLResponseErrorKey];
        NSInteger statusCode = response.statusCode;
        NSLog(@"Error Code=%ld",statusCode);
        NSLog(@"Desc=%@",response.description);
    }];

注意：- 这是有效的 URL。 http://www.nactem.ac.uk/software/acromine/dictionary.py?sf=ETA

下面还有错误代码和描述：-

Error Code 200
Error Description <NSHTTPURLResponse: 0x7fbab8509860> { URL: http://www.nactem.ac.uk/software/acromine/dictionary.py?sb=hmm } { status code: 200, headers {
    Connection = close;
    "Content-Type" = "text/plain; charset=UTF-8";
    Date = "Wed, 20 Apr 2016 00:17:27 GMT";
    Server = "Apache/2.2.15 (Scientific Linux)";
    "Transfer-Encoding" = Identity;
} }

Answer 1

查看错误描述，您会看到有用的解释

Domain=com.alamofire.error.serialization.response Code=-1016 "Request failed: unacceptable content-type: text/plain"

正确的解决方法是使内容类型 application/json，因为它看起来确实是 JSON。

Answer 2

我找到了答案:-

NSString *url = @"http://www.nactem.ac.uk/software/acromine/dictionary.py?sf=hmm";
AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];

//Missing this line (Any request or response serializer dealing with HTTP is encouraged to subclass)
manager.responseSerializer = [AFHTTPResponseSerializer serializer];
[manager GET:url parameters:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseObject
                                                             options:kNilOptions
                                                               error:&error];
        NSLog(@"Success= %@",json);

    }failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        NSHTTPURLResponse *response = error.userInfo[AFNetworkingOperationFailingURLResponseErrorKey];
        NSInteger statusCode = response.statusCode;
        NSLog(@"Fail=%ld",statusCode);
    }];

Answer 3

问题在于 AFNetworking 正在寻找的响应类型。如果您明确告诉它期望 text/plain 响应，那么您应该执行成功回调。以下代码行直接跟在您初始化 manager 对象的位置之后：

manager.responseSerializer.acceptableContentTypes = [NSSet setWithObject:@"text/plain"];

为什么 AFNetworking 总是进入失败块？

Why AFNetworking always go into Failure block?

objective-c

ios

afnetworking-3