Adding a query string to an NSURL

gistfile1.m

#import "NSURL+MUAdditions.h"

@implementation NSURL (MUAdditions)

-(NSURL*) URLByAppendingQueryString:(NSString*)queryString
{
    NSString *absoluteString = [self absoluteString];
    NSInteger startOfQueryString = [absoluteString rangeOfString:@"?"].location;
    NSInteger startOfFragment = [absoluteString rangeOfString:@"#"].location;
    
    NSString *absoluteStringWithAdditionalQueryString;
    
    //fragment  & query present
    if (startOfFragment != NSNotFound && startOfQueryString != NSNotFound) {
        NSRange rangeOfQueryString = NSMakeRange(startOfQueryString, startOfFragment-startOfQueryString);
        absoluteStringWithAdditionalQueryString =
            [self URLStringByReplacingQueryStringInURLString:absoluteString queryStringRange:rangeOfQueryString additionalQueryString:queryString];

    }
    //no fragment / with query
    else if (startOfQueryString != NSNotFound) {
        NSRange rangeOfQueryString = NSMakeRange(startOfQueryString, [absoluteString length]-startOfQueryString);
        absoluteStringWithAdditionalQueryString =
            [self URLStringByReplacingQueryStringInURLString:absoluteString queryStringRange:rangeOfQueryString additionalQueryString:queryString];        
    }
    //fragment / no query
    else if (startOfFragment != NSNotFound) {
        NSRange rangeOfQueryString = NSMakeRange(startOfFragment, 0);
        NSString *stringWithQuestionMark = [NSString stringWithFormat:@"?%@",queryString];
        absoluteStringWithAdditionalQueryString = [absoluteString stringByReplacingCharactersInRange:rangeOfQueryString withString:stringWithQuestionMark];
    } else {
        absoluteStringWithAdditionalQueryString = [absoluteString stringByAppendingFormat:@"?%@",queryString];
    }
    
    
    NSURL *newURL = [NSURL URLWithString:absoluteStringWithAdditionalQueryString];
    NSAssert(newURL, @"Expeced URL created non-nil, original: %@ new: %@",absoluteString,absoluteStringWithAdditionalQueryString);
    return newURL;
}

-(NSString*) URLStringByReplacingQueryStringInURLString:(NSString*)absoluteURLString
                                       queryStringRange:(NSRange)queryStringRange
                                  additionalQueryString:(NSString*)additionalQueryString
{
    NSString *stringWithAppendedParams = [NSString stringWithFormat:@"%@&%@",[absoluteURLString substringWithRange:queryStringRange],additionalQueryString];
    NSString *absoluteStringWithAdditionalQueryString = [absoluteURLString stringByReplacingCharactersInRange:queryStringRange withString:stringWithAppendedParams];
    return absoluteStringWithAdditionalQueryString;
}

@end