title: I need to write a web crawler for specific user agent
body: <p>I need to write a web crawler, and want to be able to crawl using a known user agent.  For example, I want my crawler to act as an iphone to crawl the mobile site of a website, then crawl again using Mozilla PC agent, etc.</p>
  
  <p>That way, Ill be able to crawl every "type" of site (mobile &amp; PC).  However, I also want to be able to set my crawler's user agent, so webmasters also see in their stats that it's a crawler that visited their whole website, not real users.</p>
  
  <p>So my question is, do you guys know how to set a mobile agent + a crawler agent at the same time, in PHP?  Is it even possible?</p>