Extract Completions Handler Block into method using typdef - objective-c

Question

I would like to clean up my code some and extract a completion block to its own method. It's my understanding that I have to define a typdef with the same signature.
In the below example, I want to move the NSURLSessionUploadTask's on completion handler to its own method. I've looked at the Apple documentation and other SO questions, but I don't know if I am searching for the right thing.
typedef void (^PostCompletionHandler)(NSData *data,NSURLResponse *response,NSError *error);
#interface MyDemoClass() {
#property (copy, nonatomic) PostCompletionHandler completePostHandler;
#end
#implementation MyDemoClass
- (void) post {
NSData *postData = //data to pos;
NSMutableURLRequest * req = //create request;
NSURLSession * session = // create session;
NSURLSessionUploadTask *queryTask = [session uploadTaskWithRequest:req
fromData:postData
completionHandler:^(NSData *data,NSURLResponse *response,NSError *error) {
if (error) {
NSLog(#"Error: %#",error.localizedDescription);
} else {
NSDictionary * response = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
NSLog(#"Post Response: %#",response.description);
}
}];
[queryTask resume];
}
- (void)someMethodThatTakesABlock:(PostCompletionHandler)blockName {
}
#end
This is what I would like to do is something like this:
NSURLSessionUploadTask *queryTask = [session uploadTaskWithRequest:req
fromData:postData
completionHandler:^(NSData *data,NSURLResponse *response,NSError *error) {
// What do I do here?
}];
- (void)someMethodThatTakesABlock:(PostCompletionHandler)blockName {
//how do I access the data, response and error parameters?
if (error) {
NSLog(#"Error: %#",error.localizedDescription);
} else {
NSDictionary * response = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
NSLog(#"Post Response: %#",response.description);
}
}

Answer 1

The someMethodThatTakesABlock: has a single parameter, which is the block. The block is a reference to code that can be executed. It does not contain data.
If you want to separate out your completion handling to a separate method, then write a method
- (void)processCompletionWithData:(NSData*)data response:(NSURLResponse*)response error:(NSError*)error {
// Process it...
}
Then in the completion handler
NSURLSessionUploadTask *queryTask =
[session uploadTaskWithRequest:req
fromData:postData
completionHandler:^(NSData* data, NSURLResponse* response, NSError* error) {
[self processCompletionWithData:data response:response error:error];
}];