Retrieving parameters in a query string

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    NSString *scheme = [[[request URL] scheme] lowercaseString];
    
    if([scheme isEqualToString:@"optimizelygoal"]) {
        // Pull the encoded JSON string out of the querystring
        // Decode the string, convert JSON string into usable object
        // Handle the message
        // Return NO to prevent the webview from navigating
        NSDictionary *userInfo = [self userInfoFromQuery:request.URL.absoluteString];
        if (userInfo[@"name"] != nil){
            //Perform tracking
            //[Optimizely trackEvent:(NSString *)userInfo[@"name"]];
        }
        if (userInfo[@"revenue"] != nil){
            //Perform tracking
            //NSNumber *price = [self numberValue:(NSString *)userInfo[@"revenue"]];
            //[Optimizely trackRevenue:price*100];
        }
        return NO;
    }
    
    // Allow normal webview navigation
    return YES;
}


/// Obtains Key value pair from a given url string
///
/// :param: queryString The url query in NSString format
/// :returns: userInfo An instance of NSDictionay containing key-value pair obtained from the url query
- (NSDictionary *)userInfoFromQuery:(NSString *)queryString{
    NSString* urlScheme = @"optimizelygoal://goal?";//Configurable
    NSString* trimmedQueryString = [queryString stringByReplacingOccurrencesOfString:urlScheme withString:@""];
    NSMutableDictionary* userInfo = [NSMutableDictionary new];
    NSArray* components = [trimmedQueryString componentsSeparatedByString:@"&"];
    for (int i = 0; i < components.count; i++) {
        NSString *component = (NSString *)components[i];
        NSArray* pair = [component componentsSeparatedByString:@"="];
        if (pair.count != 2) continue;
        
        NSString* key = pair[0];
        NSString* value = pair[1];
        userInfo[key] = value;
    }
    return userInfo;
}

/// Converts a valid string to NSNumber
///
/// :param: numString The string to be converted to NSNumber. This must contain only numbers and decimals.
/// :returns: The string in NSNumber
- (NSNumber *)numberValue:(NSString*)numString{
    NSNumberFormatter *nf = [NSNumberFormatter new];
    nf.numberStyle = NSNumberFormatterDecimalStyle;
    return [nf numberFromString:numString];
}