Best way to parse URL string to get values for keys?

Question

I need to parse a URL string like this one:

&ad_eurl=http://www.youtube.com/video/4bL4FI1Gz6s&hl=it_IT&iv_logging_level=3&ad_flags=0&ends         


        

Answer 1

edit (June 2018): this answer is better. Apple added NSURLComponents in iOS 7.

I would create a dictionary, get an array of the key/value pairs with

NSMutableDictionary *queryStringDictionary = [[NSMutableDictionary alloc] init];
NSArray *urlComponents = [urlString componentsSeparatedByString:@"&"];

Then populate the dictionary :

for (NSString *keyValuePair in urlComponents)
{
    NSArray *pairComponents = [keyValuePair componentsSeparatedByString:@"="];
    NSString *key = [[pairComponents firstObject] stringByRemovingPercentEncoding];
    NSString *value = [[pairComponents lastObject] stringByRemovingPercentEncoding];

    [queryStringDictionary setObject:value forKey:key];
}

You can then query with

[queryStringDictionary objectForKey:@"ad_eurl"];

This is untested, and you should probably do some more error tests.