Extracting a URL from within a string

Question

My app receives numerous text strings which may or may not contain a URL anywhere within the string. What would be the best method to extract a URL from within a string? Thank you.

Answer 1

If you are working on a Mac application, Mac OS X 10.6 offers a new API to let you detect URLs with the spell checker. You may do it this way.

NSString *s = @"http://example.com"
NSInteger wordCount = 0;
NSOrthography *orthography = nil;
NSArray *checkResults = [[NSSpellChecker sharedSpellChecker] checkString:s range:NSMakeRange(0, [s length]) types:NSTextCheckingTypeLink options:nil inSpellDocumentWithTag:0 orthography:&orthography wordCount:&wordCount];
for (NSTextCheckingResult *result in checkResults) {
    NSRange range = result.range;
    NSURL *URL = result.URL;
}