IIS team has recently released an update for IIS 7.0 FastCGI module that fixes compatibility problems with several popular PHP applications. In particular, the update changes the behavior of FastCGI module in the following ways:
- REQUEST_URI server variable set by FastCGI module now includes query string and path info. Previously, lack of the query string in this server variable caused the popular CMS application Drupal to not work with FastCGI on IIS 7.0
- REQUEST_URI server variable now contains the originally requested URL path before any URL rewriting was performed. Prior to this fix, the server variable used to contain a final rewritten URL, which caused problems when using URL rewriting to enable “pretty permalinks” for popular blog engine WordPress.
Note that above mentioned problems do not exist in IIS 6.0 FastCGI Extension, which always has been setting the REQUEST_URI server variable correctly.
The update is available for download from the following locations:
- Update for Windows Server 2008
- Update for Windows Server 2008 x64 Edition
- Update for Windows Server 2008 for Itanium-based Systems
- Update for Windows Vista SP1
- Update for Windows Vista SP1 for x64 based Systems
Warning: if your PHP application was coded in a way so that it relied on the REQUEST_URI server variable to contain the requested URL without a query string or to contain the final rewritten URL, then installing this update may break your application. Before applying the update, please make sure that your application does not rely on incorrect behavior of FastCGI module.
Acknowledgements: I want to thank IIS team members (Anil Ruia, Won Yoo, Yamini Jagadeesan) for providing this update and Zend Technologies team (Stanislav Malyshev) for validating the changes in FastCGI module.