Upload PowerPoint via AFNetworking gets corrupt - objective-c

Question

I receive a successfully response when uploading a PowerPoint via the below code. It does get upload but the file is corrupt. When opening the corrupt file on the server via PowerPoint I get this message:
"PowerPoint found a problem with content in filename.pptx. PowerPoint can attempt to repair the presentation."
- (void)updateDocument:(NSString *) path parameters:(FileUploadParameters*)para success:(void (^)(void))success failure:(void (^)(NSError *error))failure
{
_postData = nil;
AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:[ConfigurationUtil objectForKey:#"baseURL"]]];
_postData = [NSMutableData dataWithContentsOfFile:[path stringByStandardizingPath]];
_postData = [NSMutableData dataWithContentsOfFile:[path stringByStandardizingPath] options:NSDataReadingMapped error:nil];
NSMutableURLRequest *request = [httpClient multipartFormRequestWithMethod:HTTP_METHOD_POST
path:[self getQueryString:path parameter:para]
parameters:nil
constructingBodyWithBlock: ^(id <AFMultipartFormData>formData)
{
[formData appendPartWithFileData:_postData
name:[[path lastPathComponent] stringByDeletingPathExtension]
fileName:[[path lastPathComponent] stringByDeletingPathExtension] mimeType:#"application/powerpoint"];
}];
[request addValue:[NSString stringWithFormat:#"WRAP access_token=%#",[Tenant loadSharedTenantInstance].authToken] forHTTPHeaderField:#"Authorization"];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject)
{
if (success)
success();
}
failure:^(AFHTTPRequestOperation* operation, NSError* error)
{
if (failure)
failure(error);
}
];
[operation start];
}

Answer 1

Your AFNetworking code looks fine. I don't think that's the culprit.
You can use the cmp command line tool to compare the two files (the original and the upload) byte-for-byte and see if there's a difference. I think there won't be.
More likely: it's a misleading error message, and it's actually a permissions issue on the computer with Powerpoint installed, as outlined in this Microsoft Knowledge Base article.

Answer 2

The below code corrects the problem. It appears that appendPartWithFileData was causing the issue. It changes the filesize and that seemed to register the file as corrupt.
_postData = nil;
_postData = [NSMutableData dataWithContentsOfFile:[path stringByStandardizingPath]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]init];
NSString *queryString =[self getQueryString:path parameter:nil];
[request setURL:[NSURL URLWithString:queryString]];
[request setHTTPMethod:#"POST"];
[request setHTTPBody:_postData];
[request addValue:[NSString stringWithFormat:#"WRAP access_token=%#",[Tenant loadSharedTenantInstance].authToken] forHTTPHeaderField:#"Authorization"];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject)
{
if (success)
success();
}
failure:^(AFHTTPRequestOperation* operation, NSError* error)
{
if (failure)
failure(error);
}
];
[operation start];