AFNetworking request header missing after being set - ios

Question

I'm attempting to set custom headers on a per-request basis using AFNetworking, but occasionally the headers will seemingly disappear after being set. Below is the code used to make a request...
+ (void) getWithURI: (NSString*) uri header: (NSDictionary*) header success: (NSString*) successCallback failure: (NSString*)errorCallback dispatch: (NSString*)dispatchedId
{
createManagerInstance();
AFHTTPRequestOperation* operation = [manager GET:uri
parameters:nil
success:^(AFHTTPRequestOperation *operation, id responseObject) {
[RestWrapper succeededWithJson:operation.responseString dispatchedId:dispatchedId successCallback:successCallback];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
[RestWrapper failedWithJson:operation.responseString dispatchedId:dispatchedId errorCallback:errorCallback];
}];
NSMutableURLRequest* request = (NSMutableURLRequest*)operation.request;
for (NSString* key in header)
{
if([request valueForHTTPHeaderField:key] != nil)
{
[request setValue:header[key] forHTTPHeaderField:key];
}
else
{
[request addValue:header[key] forHTTPHeaderField:key];
}
}
NSLog(#"Headers: %#", request.allHTTPHeaderFields);
[operation start];
}
For 95% of my requests, they go through as anticipated. Sporadically, however, some will fail and indicate a header is missing. This has been confirmed by capturing the requests in question using Fiddler and seeing that the headers are actually missing. Despite this, the console log of request.allHTTPHeaderFields always shows the headers in place.
The only other thing I noticed is that in general Fiddler reports the caching policy as "max-age=0, private, must-revalidate" for each request. However, whenever a request loses the custom headers, it's caching policy is "no-cache".

Answer 1

This is because you're adding HTTP Header fields in wrong way.
You should add it before request. You may try something like this :
+ (void) getWithURI: (NSString*) uri header: (NSDictionary*) header success: (NSString*) successCallback failure: (NSString*)errorCallback dispatch: (NSString*)dispatchedId{
createManagerInstance();
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setValue:header[key] forHTTPHeaderField:key];
AFHTTPRequestOperation* operation = [manager GET:uri
parameters:nil
success:^(AFHTTPRequestOperation *operation, id responseObject) {
[RestWrapper succeededWithJson:operation.responseString dispatchedId:dispatchedId successCallback:successCallback];
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
[RestWrapper failedWithJson:operation.responseString dispatchedId:dispatchedId errorCallback:errorCallback];
}];
[operation start];
}