让cURL充当PHP的Android / iOS应用程序？

I wants to scrap & post data to website using cURL in PHP but cURL should act like, the request coming from the website own application.

The website have their own iOS/Android app. I wants to send request to website & the website should think the request coming from their own iOS/Android application. Is it possible?

I tried,

curl_setopt($curl, CURLOPT_USERAGENT, $agent);

But didn't worked, I used many user agent. What am I missing?