When i generate a 'campaign url', here:
[[UIApplication sharedApplication] get_campaign_url_for_download:^(NSString*) URL
NSLog(@"link I clicked to download this app was %@",URL);
The official reply from Apple is
Thank you for contacting Apple Developer Technical Support (DTS). Our engineers have reviewed your request and have concluded that there is no supported way to achieve the desired functionality given the currently shipping system configurations.
If Apple cannot support this functionality then I am 100% certain there is no external service that can provide this functionality either