AFNetworking fails to resume downloads when “Content-Encoding: gzip” is set

问题

I'm using AFNetworking2 to download files from my AWS S3 bucket Everything works fine except when I set the Content-Encoding: gzip for the files. AFNetworking fails to download the partial content response coming back from the server and it gives me the following error:

Error Domain=NSURLErrorDomain Code=-1015 "cannot decode raw data" UserInfo=0x10d2d8ce0 {NSUnderlyingError=0x10d1ace80 "cannot decode raw data", NSErrorFailingURLStringKey=http://s3.amazonaws.com/awdtest/fullzip.pdf, NSErrorFailingURLKey=http://s3.amazonaws.com/awdtest/fullzip.pdf, NSLocalizedDescription=cannot decode raw data}

however, when I remove the "Content-Encoding: gzip" metadata from my file, it works fine. I know that my server supports range request and I have tested it using other methods and it worked fine.

here is the HTTP response from my server:

HTTP/1.1 200 OK

x-amz-id-2: k5b65TtAgrD5Cn3N2aixCCdi6qAmg4j9iuOSNaO0uMRKLHPTQ+DMaA20u9j1CNzA

x-amz-request-id: 7AE5A7DD81ED2B88

Date: Fri, 16 May 2014 04:45:17 GMT

Content-Encoding: gzip

Last-Modified: Fri, 16 May 2014 04:44:51 GMT

ETag: "88bbe0b318bf11dd56a31176d3384e78"

Accept-Ranges: bytes

Content-Type: application/pdf

Content-Length: 1243325

Server: AmazonS3

Here are the sample files that I'm using:

https://s3.amazonaws.com/awdtest/full.pdf

https://s3.amazonaws.com/awdtest/fullzip.pdf (gzipped and have the Content-Encoding set to gip)

I would appreciate it if someone could help me with this issue.

PS: I have already tried the followings and it still does not work

[request setValue:@"gzip" forHTTPHeaderField:@"Accept-Encoding"];


[request setValue:@"deflate" forHTTPHeaderField:@"Accept-Encoding"];


[request setValue:@"gzip, deflate" forHTTPHeaderField:@"Accept-Encoding"];

回答1:

Use Wireshark to see the recevied http body.

It could be the responseSerializer which you used can't parse the raw data .

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html

回答2:

Ok, not sure how you're going about downloading this, or what your purpose is. So, I'm assuming you're using the iOS 7 APIs, specifically an AFHTTPSessionManager, and you're after the raw data of the file. Given that, I wrote a Data serializer to use, and then the actual code is very short:

Serializer (kinda weird):

@interface FFDataResponseSerializer : AFHTTPResponseSerializer

@end

@implementation FFDataResponseSerializer

- (instancetype)init
{
    self = [super init];
    if (!self)
    {
        return nil;
    }

    self.acceptableContentTypes = [[NSSet alloc] initWithObjects:@"application/pdf", nil];

    return self;
}

- (id)responseObjectForResponse:(NSURLResponse *)response
                           data:(NSData *)data
                          error:(NSError *__autoreleasing *)error
{
    if (![self validateResponse:(NSHTTPURLResponse *)response data:data error:error])
    {
        return nil;
    }

    return data;
}

@end

And then, in my code:

NSURLSessionConfiguration *aURLSessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
aURLSessionConfiguration.HTTPAdditionalHeaders = @{@"Accept-Encoding": @"gzip, deflate",
                                                   @"Accept": @"application/pdf"};
AFHTTPSessionManager *urlManager = [[AFHTTPSessionManager alloc] initWithSessionConfiguration:aURLSessionConfiguration];

urlManager.responseSerializer = [FFDataResponseSerializer serializer];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://s3.amazonaws.com/awdtest/fullzip.pdf"]];

NSURLSessionDataTask *dataTask = [urlManager dataTaskWithRequest:request completionHandler:^(NSURLResponse *response, id responseObject, NSError *error) {
    if (error)
    {
        NSLog(@"error: %@", error);
    }
    else
    {
     NSLog(@"response: %@, responseObject: %@", response, responseObject);
     // responseObject is your NSData Object with the PDF data inside of it.
    }
}];

[dataTask resume];

You'll obviously want to handle errors, keep ahold of the variables you'll want to reuse, etc, etc...

来源：https://stackoverflow.com/questions/23692906/afnetworking-fails-to-resume-downloads-when-content-encoding-gzip-is-set

标签

ios

objective-c

http-headers

gzip

afnetworking-2