How to Detect the Front (Home) Page of a WordPress Blog

I recently wanted to add a WordPress widget that would be conditionally visible in the sidebar of the front (home) blog page only. A reasonable search on this topic turns up a large collection of information and discussion — most of which turns out not to work. The following is a brief overview I what I tried and what I ultimately did.

Most of the information on this topic points to either the is_home() or is_front_page() WordPress PHP functions. In theory, you can use either of these functions in a conditional expression and detect if you are in the front (home) page. In practice, however, it is a little more complicated. These functions are not based on the URI of the page that is being loading; instead they are based on several global boolean variables that are set based on what queries have occurred in a page. I imagine there is probably a good reason for this in WordPress-land (and I am not a WordPress expert), but it seems to me that if I call is_front_page() within the front page of a WordPress blog then it should reliably return true, and conversely if I call is_front_page() from any other page in the blog then it should reliably return false. In my case, I was trying to create a conditionally visible widget in the sidebar by modifying wp-include/widgets.php to contain a conditional expression within wp_widgets_init(). What I found was that is_front_page() always returned true when called from within widgets.php for any page on my blog. I traced this to the fact that the values of the global variables upon which is_front_page() is based are changed by some of the standard activities performed within wp_widgets_init() — specifically any query to get posts or categories to populate standard widgets that show archives and categories. The is_home() function seems to suffer from the same issue, as it appears to be based on the same global variables. Several posts described interesting ways to combine is_front_page() or is_home() with other functions to get the correct conditional behavior, but none of these worked in my case, and all of them seemed to be specific to their context, rather than general purpose solutions to the problem.

After banging my head against this for a while, I decided to try a different approach. The is_front_page() and is_home() functions are based on global variables rather than the URI of the blog page. So forget those functions…and find an expression that checks the URI directly. It seems simple enough, and it is:

if ( $_SERVER["REQUEST_URI"] == '/' )
/* do something */

And that’s it. This block of code works reliably throughout the pages of my blog. I am willing to bet that there might be some peculiar WordPress configurations (e.g. using a custom page as the front page, etc.) for which this does not work, but like I said, I am not a WordPress expert, so your mileage may vary.

Hope this helps.