Return NSRegularexpression results in an array - ios

Question

I am attempting to retrieve image url strings from some text, and then create an array containing all of these image url strings. I think I know how to get the image urls using NSRegularExpression, but I just don't know how to grab each individual result. I'm done find and replace before, but that just involves manipulating one giant string. Here is my code:
-(NSArray*)parseImages:(NSString*)contents {
NSArray* imageArray = [[NSArray alloc] init];
NSError* error = nil;
NSString* imageHandler = #"\(\?:\\<a\\shref=\"\)https\?:\/\/[\^\/\\s]\+\/\\S\+\\\.\(jpg|png|gif\)";
NSRegularExpression *imageGrabber = [NSRegularExpression regularExpressionWithPattern:imageHandler options:NSRegularExpressionCaseInsensitive error:&error];
if (error)
{
NSLog(#"Couldn't create regex with given string and options");
return nil;
} else {
//Code to add each individual match to imageArray
return imageArray;
}

Answer 1

Here's what I use for multiple matches in a regular expression:
NSArray *matchesArray = [self rangesOfString:#"{regex}" inString:aString];
for (NSValue *rangeVal in matchesArray)
{
NSRange range = [rangeVal rangeValue];
if (range.location != NSNotFound) {
// do stuff with the found range - like add to an NSMutableArray!
}
}
And the rangesOfString method:
- (NSArray *)rangesOfString:(NSString *)searchString inString:(NSString *)str {
NSMutableArray *results = [NSMutableArray array];
NSRange searchRange = NSMakeRange(0, [str length]);
NSRange range;
while ((range = [str rangeOfString:searchString options:NSRegularExpressionSearch|NSCaseInsensitiveSearch range:searchRange]).location != NSNotFound) {
[results addObject:[NSValue valueWithRange:range]];
searchRange = NSMakeRange(NSMaxRange(range), [str length] - NSMaxRange(range));
}
return results;
}

Answer 2

Let Apple do the heavy-lifting with NSDataDetector
NSString *text = #"jibberish http://link1.com jibberish http://link2.com jibberish";
NSError *error;
NSDataDetector *dd = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];
NSArray *matches = [dd matchesInString:text options:0 range:NSMakeRange(0, text.length)];
NSMutableArray *links = [NSMutableArray new];
for (NSTextCheckingResult *result in matches) {
[links addObject:[result URL]];
}
NSLog(#"links: %#", links);
NSLog output:
links: (
"http://link1.com",
"http://link2.com"
)
If there is a need to restrict to extension types:
Add the extensions to a set:
NSSet *extensions = [NSSet setWithArray: #[#"jpg", #"png", #"gif"]];
Add only to the array only if the extension is in the set:
NSString *ext = [[url resourceSpecifier] pathExtension];
if ([extensions containsObject:ext]) {
[links addObject:url];
}