Question

I have a custom UILabel. I want to upper-case and bold any URL’s that I detect. URL’s aren’t being upper-cased and bolded. I have a feeling my detection is wrong.

Here is my regex:

static NSRegularExpression *websiteRegularExpression;
static inline NSRegularExpression * WebsiteRegularExpression() {
    if (!websiteRegularExpression) {
        websiteRegularExpression = [[NSRegularExpression alloc] initWithPattern:@"\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|!:,.;]*[A-Z0-9+&@#/%=~_|]" 
                                                                        options:NSRegularExpressionCaseInsensitive 
                                                                          error:nil];
    }

    return websiteRegularExpression;
}

Here is the where I do the parsing:

-(void)setBodyText
{
    __block NSRegularExpression *regexp = nil;   
    NSString* labelText = @"http://www.google.com is a cool website";
    [self.bodyLabel setText:labelText afterInheritingLabelAttributesAndConfiguringWithBlock:^NSAttributedString *(NSMutableAttributedString *mutableAttributedString) {

        NSRange stringRange = NSMakeRange(0, [mutableAttributedString length]);

        regexp = WebsiteRegularExpression ();
        NSRange nameRange = [regexp rangeOfFirstMatchInString:[mutableAttributedString string] options:0 range:stringRange];
        UIFont *boldSystemFont = [UIFont boldSystemFontOfSize:18.0]; 
        CTFontRef boldFont = CTFontCreateWithName((CFStringRef)boldSystemFont.fontName, boldSystemFont.pointSize, NULL);
        if (boldFont) {
            [mutableAttributedString addAttribute:(NSString *)kCTFontAttributeName value:(id)boldFont range:nameRange];
            CFRelease(boldFont);
        }

        if (nameRange.location != NSNotFound)
            [mutableAttributedString replaceCharactersInRange:nameRange withString:[[[mutableAttributedString string] substringWithRange:nameRange] uppercaseString]];
        return mutableAttributedString;
    }];

    regexp = WebsiteRegularExpression();
    NSRange linkRange = [regexp rangeOfFirstMatchInString:labelText options:0 range:NSMakeRange(0, [labelText length])];
    NSURL *url = [NSURL URLWithString:@"http://www.google.com"];
    [self.bodyLabel addLinkToURL:url withRange:linkRange];
}

Answer 1

Don’t use regular expressions for detecting URLs. Use an NSDataDetector, and then use the -range of the NSTextCheckingResult to bold the range.