Filter to add parameters to each request (to assist with versioning)

ExampleFilter.m

- (void)handleRequest:(NSURLRequest *)request
               next:(MSFilterNextBlock)next
           response:(MSFilterResponseBlock)response
{
    // A wrapped response block that decrements the busy counter
    MSFilterResponseBlock wrappedResponse = ^(NSHTTPURLResponse *innerResponse, NSData *data, NSError *error) {
        response(innerResponse, data, error);
    };
    
    // add additional versioning information to the querystring for versioning purposes
    NSString *append = [NSString stringWithFormat:@"build=%@&version=%@", self.build, self.version];
    NSURL *url = nil;
    NSRange range = [request.URL.absoluteString rangeOfString:@"?"];
    if (range.length > 0) {
        url = [NSURL URLWithString:[NSString stringWithFormat:@"%@&%@&p=iOS", request.URL.absoluteString, append]];
    }
    else {
        url = [NSURL URLWithString:[NSString stringWithFormat:@"%@?%@&p=iOS", request.URL.absoluteString, append]];
    }
    
    NSMutableURLRequest *newRequest = [request mutableCopy];
    newRequest.URL = url;
    
    next(newRequest, wrappedResponse);
}

// elsewhere in the file
self.version = [self urlEncoded:[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"]];
self.build = [self urlEncoded:[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"]];

-(NSString *)urlEncoded:(NSString *) input
{
    CFStringRef urlString = CFURLCreateStringByAddingPercentEscapes(
                                                                    NULL,
                                                                    (CFStringRef)input,
                                                                    NULL,
                                                                    (CFStringRef)@"!*'\"();:@&=+$,/?%#[]%. ",
                                                                    kCFStringEncodingUTF8 );
    return (__bridge NSString *)urlString;
}