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May 23rd, 2006
Views: 24,124
This is a PHP script that allows javascript clients to request content they otherwise would not be able to. With the popularity of AJAX (using the XmlHttpRequest object in the browser), many developers are becoming aware of the cross-domain scripting limitation. This is a security feature that prevents client-side scripts from accessing content on domains other than the current website domain.

My PHP Proxy is the solution. Simply place this PHP script on your PHP-enabled webserver. Then have your javascript make cross-domain requests through the proxy. Simple, fast, elegant--a perfect solution.

PHP Proxy makes use of my class_http object. Details and code available at http://www.troywolf.com/articles. Full source for PHP Proxy is below.
php Syntax | 4 stars
  1. <?php
  2. // FILE: proxy.php
  3. //
  4. // LAST MODIFIED: 2006-03-23
  5. //
  6. // AUTHOR: Troy Wolf <troy@troywolf.com>
  7. //
  8. // DESCRIPTION: Allow scripts to request content they otherwise may not be
  9. // able to. For example, AJAX (XmlHttpRequest) requests from a
  10. // client script are only allowed to make requests to the same
  11. // host that the script is served from. This is to prevent
  12. // "cross-domain" scripting. With proxy.php, the javascript
  13. // client can pass the requested URL in and get back the
  14. // response from the external server.
  15. //
  16. // USAGE: "proxy_url" required parameter. For example:
  17. // http://www.mydomain.com/proxy.php?proxy_url=http://www.yahoo.com
  18. //
  19.  
  20. // proxy.php requires Troy's class_http. http://www.troywolf.com/articles
  21. // Alter the path according to your environment.
  22. require_once("class_http.php");
  23.  
  24. $proxy_url = isset($_GET['proxy_url'])?$_GET['proxy_url']:false;
  25. if (!$proxy_url) {
  26. header("HTTP/1.0 400 Bad Request");
  27. echo "proxy.php failed because proxy_url parameter is missing";
  28. exit();
  29. }
  30.  
  31. // Instantiate the http object used to make the web requests.
  32. // More info about this object at www.troywolf.com/articles
  33. if (!$h = new http()) {
  34. header("HTTP/1.0 501 Script Error");
  35. echo "proxy.php failed trying to initialize the http object";
  36. exit();
  37. }
  38.  
  39. $h->url = $proxy_url;
  40. $h->postvars = $_POST;
  41. if (!$h->fetch($h->url)) {
  42. header("HTTP/1.0 501 Script Error");
  43. echo "proxy.php had an error attempting to query the url";
  44. exit();
  45. }
  46.  
  47. // Forward the headers to the client.
  48. $ary_headers = split("\n", $h->header);
  49. foreach($ary_headers as $hdr) { header($hdr); }
  50.  
  51. // Send the response body to the client.
  52. echo $h->body;
  53. ?>
Comments (Newest First)
falstaff | Newbie Poster | 2 Days Ago
Thanks, helped me... is there any easy solution to restrict this proxy for some urls only?
girish13 | Newbie Poster | May 3rd, 2008
As a rule of thumb you cannot directly access the javascript from one domain to the other. However you can pass messages and data across which can then accordingly trigger events in the javascript.

One way is to the use a proxy in between the two domains and relay an AJAX request to the other domain through the proxy. A detailed article on it is on http://www.mabaloo.com/Web-Developme...-tutorial.html

Another way which does not involve a proxy but uses Iframes is by using the URL hash.
http://www.mabaloo.com/Web-Developme...ng-Iframe.html
tedqn | Newbie Poster | Sep 19th, 2007
The instruction wasn't clear but I was able to figure it out. Make sure there're no extra lines below the end line.
?>

What you should do is:
1) create a file called proxy.php. Copy the code content above into that page.
2) create a file called class_http.php. Copy the code content for that file in this page.

modify the client side xmlhttp code, replace the direct url such as

xmlhttp.open("GET", "http://www.xyz.com/somexml.xml", true);

to

xmlhttp.open("GET", "http://www.yourdomain.com/proxy.php?proxy_url=www.xyz.com/somexml.xml", true);
method007 | Newbie Poster | Feb 16th, 2007
Thanks for this code. i keep getting this error :


Cannot modify header information - headers already sent by


Warning: Cannot modify header information - headers already sent by (output started at /proxy/class_http.php:409) in /proxy/proxy.php on line 49

could u help me fix it.Thanks
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