Generalize JSON data processing from server - objective-c

Question

I am getting JSON data from a server. Since data returned may be used for different purposes, different processing methods are required.
Below is my expected function:
- (void)getFrom:(NSString *)server method:(SEL)processingMethod {
NSURL *url = [NSURL URLWithString:server];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
[req setHTTPMethod:#"GET"];
[req setValue:#"application/x-www-form-urlencoded charset=utf-8"
forHTTPHeaderField:#"Content-Type"];
[NSURLConnection sendAsynchronousRequest:req
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (error) {
NSLog(#"error requesting: %#", error.localizedDescription);
return;
}
NSLog(#"data: %#", [[NSString alloc] initWithData:data
encoding:NSUTF8StringEncoding]); // print JSON
// How to call appropriate method (passed from parameter) here??
[self passJSON:data toMethod:processingMethod];
}];
}
- (void)passJSON:(NSData *)data toMethod:(SEL)method {
if ([self respondsToSelector:method]) {
[self performSelector:#selector(method) // WARNING: Undeclared selector method
withObject:data];
}
}
- (void)processData1:(NSData *)JSON {
// process data1
}
- (void)processData2:(NSData *)JSON {
// process data2
}
What would I do to call my function - (void)getFrom:(NSString *)server method:(SEL)processingMethod having any processingMethod of my interest passed in, such as:
- (void)somefunction {
[self getFrom:#"http://www.datasite.com/data1" method:#selector(processData1:)]; // after getting data1, processData1 is called having JSON data1 passed in
[self getFrom:#"http://www.datasite.com/data2" method:#selector(processData2:)]; // after getting data2, processData2 is called having JSON data2 passed in
}
Then I found this link (especially wbyoung's reply): performselector may cause a leak
But I could not figure out how to pass a parameter, in this case: JSON data, to someMethod
Any suggestion?
Thanks,

Answer 1

Thank to Scott's reply in the link above perform selector may cause a leak
I put some pragma marks around [self performSelector:method withObject:data] to silent the warning, and all work well.
Below is my complete code:
- (void)getFrom:(NSString *)server method:(SEL)processingMethod {
NSURL *url = [NSURL URLWithString:server];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
[req setHTTPMethod:#"GET"];
[req setValue:#"application/x-www-form-urlencoded charset=utf-8"
forHTTPHeaderField:#"Content-Type"];
[NSURLConnection sendAsynchronousRequest:req
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (error) {
NSLog(#"error requesting: %#", error.localizedDescription);
return;
}
NSLog(#"data: %#", [[NSString alloc] initWithData:data
encoding:NSUTF8StringEncoding]); // print JSON
// How to call appropriate method (passed from parameter) here??
[self passJSON:data toMethod:processingMethod];
}];
}
- (void)passJSON:(NSData *)data toMethod:(SEL)method {
if ([self respondsToSelector:method]) {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
[self performSelector:method
withObject:data];
#pragma clang diagnostic pop
}
}
- (void)processData1:(NSData *)JSON {
// process data1
}
- (void)processData2:(NSData *)JSON {
// process data2
}
Usage:
- (void)somefunction {
[self getFrom:#"http://www.datasite.com/data1" method:#selector(processData1:)]; // after getting data1, processData1 is called having JSON data1 passed in
[self getFrom:#"http://www.datasite.com/data2" method:#selector(processData2:)]; // after getting data2, processData2 is called having JSON data2 passed in
}
However, this approach is just to suppress the warning, not actually/completely solve the problem by coding in a right way. Any more suggestions, ideas are welcome!
Regards,