How to parse JSON response from Rest API - ios

Question

I am working on an app that will parse data from a Rest API. As I haven't done this before, I was wondering if NSScanner or NSRange would work for this. Here is an example using NSScanner for such purposes. It's a small string so it doesn't take much code, so it seemed like a quick and dirty option. Is there an easier and quicker way to do this?
- (void)GetAliasName:(NSString *)cno selector:(NSString*)selectorName completionHandler:(void (^)(NSDictionary *, NSError *))handler
{
NSMutableDictionary *d = [[NSMutableDictionary alloc] init];
[d setValue:interface forKey:#"interface"];
[d setValue:#"GetAlias" forKey:#"method"];
NSMutableDictionary *p = [[NSMutableDictionary alloc] init];
cno = [[NSUserDefaults standardUserDefaults] objectForKey:#"cno"];
[p setValue:cno forKey:#"cno"];
[p setValue:selectorName forKey:#"selector"];
[d setValue:p forKey:#"parameters"];
NSData *data = [NSJSONSerialization dataWithJSONObject:d options:0 error:nil];
[self load:data completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
NSLog(#"done");
NSString *s = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"GetAlias RAW response = %#", s);
if (apiConditions)
{
dispatch_async(dispatch_get_main_queue(),
^{
[hud hide:YES];
[MBProgressHUD hideHUDForView:self.view animated:YES];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error" message:#"No network connection or no data found" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
NSLog(#"data is NIL");
});
}
else
{
NSDictionary *d = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
handler(d, error);
//scans for aliasname
NSString *match = #"AliasName\": \"";
NSString *preTel;
NSString *postTel;
NSScanner *scanner = [NSScanner scannerWithString:s];
[scanner scanUpToString:match intoString:&preTel];
[scanner scanString:match intoString:nil];
postTel = [s substringFromIndex:scanner.scanLocation];
//removes newlines, characters, and whitespaces from aliasname
NSCharacterSet *trim = [NSCharacterSet characterSetWithCharactersInString:#"}]\""];
postTel = [[postTel componentsSeparatedByCharactersInSet: trim] componentsJoinedByString: #""];
postTel = [[postTel componentsSeparatedByCharactersInSet: [NSCharacterSet whitespaceAndNewlineCharacterSet]] componentsJoinedByString: #""];
NSLog(#"postTel: %#", postTel);
NSString *docno = [[NSUserDefaults standardUserDefaults] objectForKey:#"docno"];
//if docno is filled in, look up TR by docno
if ([docno isEqual: #""])
{
[self GetTR:(NSString*)postTel customStatus:customStatus completionhandler:^(NSDictionary *dictionary, NSError *error) {
nil;
}];
}
}];
}

Answer 1

There is NSJSONSerialization which is built for this.
Use it as follows:
NSError *error = nil;
NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
NSString *aliasName = dictionary[#"AliasName"];
Edit
Since you already use this, and have dictionary, the only step you needed was to access dictionary with needed key(last step).