Set the User Agent With PHP cURL

By  on  

A few months back, I shared with you how to download the contents of a URL and execute a HTTP POST transmission using PHP cURL. For security purposes, some hosts require that a common user agent be present in the POST. If an unacceptable user agent is given, the POST is ignored. Luckily, cURL allows us to "spoof" the server using any user agent we choose:

curl_setopt($ch,CURLOPT_USERAGENT,'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13');

A little sneaky but it could get you out of a jam at some point!

Recent Features

  • By
    Welcome to My New Office

    My first professional web development was at a small print shop where I sat in a windowless cubical all day. I suffered that boxed in environment for almost five years before I was able to find a remote job where I worked from home. The first...

  • By
    Being a Dev Dad

    I get asked loads of questions every day but I'm always surprised that they're rarely questions about code or even tech -- many of the questions I get are more about non-dev stuff like what my office is like, what software I use, and oftentimes...

Incredible Demos

  • By
    Display Images as Grayscale with CSS Filters

    CSS filters aren't yet widely supported but they are indeed impressive and a modern need for web imagery.  CSS filters allow you to modify the display of images in a variety of ways, one of those ways being displaying images as grayscale. Doing so requires the...

  • By
    JavaScript Speech Recognition

    Speech recognition software is becoming more and more important; it started (for me) with Siri on iOS, then Amazon's Echo, then my new Apple TV, and so on.  Speech recognition is so useful for not just us tech superstars but for people who either want to work "hands...

Discussion

  1. Thanks for this tip. Was working on a project and found your tip very handy.

  2. Thanks for this! Was needed for a wikipedia curl request.

  3. Thanks for this, it for me too.

  4. hi..
    How to check whether a user agent string is supported by all the urls or not ? I have tried many urls with different user agent strings but I couldn’t find any user agent which is supported by all urls. When a user agent string is not supported, I get 0 (zero) as http response code and null as mime type. Please help.

  5. Thanks, without setting user agent I was getting this error:

    at nl.bitwalker.useragentutils.Browser.isInUserAgentString(Browser.java:154)

  6. Brilliand

    “for security purposes”… that’s incredibly weak security. I think it’s more common for the website to be doing useragent sniffing (to tailor the response to the browser), and simply not bothering to support uncommon useragents.

  7. perfect – thank for the tip!

  8. MJ

    Thank, that helped!

  9. i get error code like this. curl_setopt() expects parameter 1 to be resource, null given in /home/xxxx/xxxxx

  10. Try this…

    function scrap($url)	{
    	$curl = curl_init($url);
    
    	curl_setopt($curl, CURLOPT_USERAGENT, "My User Agent Name");
    	curl_setopt($curl, CURLOPT_FAILONERROR, true);
    	curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
    	curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    
    	$html = curl_exec($curl);
    	curl_close($curl);
    
    	return $html;
    }
    

    You are getting the error as curl_setopt() required first parameter as a resource returned by the curl_init($url);

  11. This, in fact, just got me out of a jam.

  12. Jim

    Almost a full 10 years later and this post just really helped me out! Thanks!

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!