extract_youtube_id.mm

//
//  extract_youtube_id.m
//  TestRegex
//
//  Created by zdk on 1/8/2013 BE.
//  Copyright (c) 2013 zdk. All rights reserved.
//

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        //test list
        NSArray *youtubeURLs = [NSArray arrayWithObjects:
                                    @"http://youtu.be/NLqAF9hrVbY",
                                    @"http://www.youtube.com/watch?feature=player_embedded&v=DJjDrajmbIQ",
                                    @"http://www.youtube.com/watch?v=dQw4w9WgXcQ",
                                    @"http://www.youtube.com/embed/NLqAF9hrVbY",
                                    @"https://www.youtube.com/embed/NLqAF9hrVbY",
                                    @"http://www.youtube.com/watch?v=NLqAF9hrVbY",
                                    @"http://www.youtube.com/v/dQw4w9WgXcQ",
                                    @"http://youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US",
                                    @"http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US",
                                    @"http://youtube.com/watch?v=NLqAF9hrVbY",
                                    @"http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo",
                                    @"http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I",
                                    @"http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/2/PPS-8DMrAn4",
                                    @"http://gdata.youtube.com/feeds/api/videos/NLqAF9hrVbY",
                                    @"http://www.youtube.com/watch?v=spDj54kf-vY&feature=g-vrec",
                                    nil];
        
        //construct regex pettern
        //NSString *pattern = @"(?:(?:\.be\/|embed\/|v\/|\\?v=|\&v=|\/videos\/)|(?:[\\w+]+#\\w\/\\w(?:\/[\\w]+)?\/\\w\/))([\\w-_]+)";
        NSString *pattern = @"(?:(?:\\.be\\/|embed\\/|v\\/|\\?v=|\\&v=|\\/videos\\/)|(?:[\\w+]+#\\w\\/\\w(?:\\/[\\w]+)?\\/\\w\\/))([\\w-_]+)";
        
        for (NSString *url in youtubeURLs) {
            NSError *error = NULL;
            NSRegularExpression *regex  = [NSRegularExpression regularExpressionWithPattern: pattern
                                                                                    options: NSRegularExpressionCaseInsensitive
                                                                                      error: &error];
            NSTextCheckingResult *match = [regex firstMatchInString: url
                                                            options: 0
                                                              range: NSMakeRange(0, [url length])];
            if ( match ) {
                NSRange videoIDRange             = [match rangeAtIndex:1];
                NSString *substringForFirstMatch = [url substringWithRange:videoIDRange];
                
                NSLog(@"url: %@, Youtube ID: %@", url, substringForFirstMatch);
            } else {
                NSLog(@"No string matched! %@", url);
            }
        }
        
    }
    return 0;
}