ios AFNetworking3.0 请求网络数据

要求：用AFNetworking 下载一张图片展示出来，或者请求json数据

pod一个最新的AFNetworking，然后想去download一张图片

然后发现下载不下来

错误一：

xcode控制台打印如下错误:

 NSErrorFailingURLKey = "https://raw.githubusercontent.com/robinson911/robinson911.github.io/master/img/contact-bg.jpg";

    NSLocalizedDescription = "Request failed: unacceptable content-type: image/jpeg";

错误分析：

content-type：是请求（request）/或者返回（response）数据的格式类型

从上边的提示可以看出需要设置的是请求content-type类型。

解决：设置一下数据格式类型

[manager.responseSerializersetAcceptableContentTypes:[NSSetsetWithObjects:@"image/png",@"image/jpeg",nil]];

重新rebuild，发现图片还是加载不出来

xcode控制台打印如下错误:

NSDebugDescription = "JSON text did not start with array or object and option to allow fragments not set.";

}----Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}

然后看源码发现：

在默认情况下，afnetworking网络请求都是以json的数据格式返回数据，因此，客户端也会以json为默认格式，如果返回的数据为非json标准格式，则会出现上述错误。

只需要在发送请求前加入:manager.responseSerializer = [AFHTTPResponseSerializer serializer]

便可以解决这个问题了。

然后重新rebuild，发现图片加载正常了

编译通过请求到图片的源码如下：

- (void)requestNetData:(NSString*)url{    NSSet *ljSet = [NSSet setWithObjects:@"application/json", @"text/json", @"text/javascript",@"text/html", @"text/plain",@"application/xml",@"text/xml",@"image/png",@"image/jpeg",nil];    AFHTTPSessionManager *manager =[AFHTTPSessionManager manager];    manager.requestSerializer = [AFHTTPRequestSerializer serializer];    //manager.requestSerializer = [AFJSONRequestSerializer serializer];        //manager.responseSerializer = [AFJSONResponseSerializer serializer];    manager.responseSerializer = [AFHTTPResponseSerializer serializer];    [manager.responseSerializer setAcceptableContentTypes:ljSet];        [manager GET:url parameters:nil progress:^(NSProgress * _Nonnull downloadProgress) {        CHDebugLog(@"totalUnitCount:%lld---completedUnitCount:%lld",downloadProgress.totalUnitCount,downloadProgress.completedUnitCount);    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {        //CHDebugLog(@"%@",responseObject);                if ([url rangeOfString:@"png"].location != NSNotFound || [url rangeOfString:@"jpeg"].location != NSNotFound || [url rangeOfString:@"jpg"].location != NSNotFound) {            dispatchToMain(^{                UIImage *image = [UIImage imageWithData:responseObject];                self.LJImageView.image = image;            });        }        else if ([url rangeOfString:@"json"].location != NSNotFound)        {            /*NSError *error = nil;              1.需要将data转化为json            NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableLeaves error:&error];            CHDebugLog(@"print json data----%@",dict);            */            //2.初始化为 manager.responseSerializer = [AFJSONResponseSerializer serializer]; 来帮助你接收json数据            CHDebugLog(@"print json data----%@",responseObject);        }    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {        CHDebugLog(@"%@----%@",error.userInfo,error);    }];}