WordPress: How to create a rewrite rule for a file in a custom plugin

Question

I've been looking for hours trying to find a straightforward answer to this but I just can't seem to find anything out there which tackles this issue. There are numerous examples for rewriting standard URLs, but nothing in-terms of rewriting pages from within a custom plugin.

I've created a custom plugin with a special directory in it called test. The test directory has several pages which are blah.php and shmeh.php. Is it possible to create rewrite rules to these pages i.e. http://example.com/blah, http://example.com/shmeh

Thank you very much for all the help.

Answer 1

So essentially what you are looking for, is to have Wordpress load a specific page template (blah.php) when the user visits http://example.com/blah/. Also, you need it to to be completely generated in your plug-in without actually creating any pages or posts. You are on the right track. What you want to do here is create a rewrite rule that utilizes a specific query var to load the page. Here it is step by step:

Step 1: Rewrite rules

http://codex.wordpress.org/Function_Reference/add_action

http://codex.wordpress.org/Plugin_API/Action_Reference/init

http://codex.wordpress.org/Rewrite_API/add_rewrite_rule

/* Rewrite Rules */
add_action('init', 'yourpluginname_rewrite_rules');
function yourpluginname_rewrite_rules() {
    add_rewrite_rule( 'blah/?$', 'index.php?blah=true', 'top' );
}

So in the above code, your just telling Wordpress that example.com/blah/ should be treated as if the user were visiting example.com/index.php?blah=true. Now "blah" is a query var that you will set up in the next function below. Query vars are just what Wordpress calls $_GET variables. However they must be registered with Wordpress so it can properly store the value (which is "true" in this case). We will do that below in the next function. It's also worth noting the third setting in the function "top", which gives this rewrite rule priority over other rewrite rules. Alternatively, setting it to "bottom" would check that no other rewrite rules match first before using this one.

Step 2: Query Vars

http://codex.wordpress.org/Function_Reference/add_filter

http://codex.wordpress.org/Plugin_API/Filter_Reference/query_vars

/* Query Vars */
add_filter( 'query_vars', 'yourpluginname_register_query_var' );
function yourpluginname_register_query_var( $vars ) {
    $vars[] = 'blah';
    return $vars;
}

In the code above, your just registering the query var "blah" with Wordpress. That way, when someone visits example.com/blah/, which your rewrite rule tells Wordpress to treat it like they are visiting example.com/index.php?blah=true, Wordpress actually bothers to save it's value (which is set to true). This is so you can use it in the next function, which loads the template you want when users visit your url.

Step 3: Template Include

http://codex.wordpress.org/Function_Reference/add_filter

http://codex.wordpress.org/Plugin_API/Filter_Reference/template_include

http://codex.wordpress.org/Class_Reference/WP_Query#Interacting_with_WP_Query

http://codex.wordpress.org/Function_Reference/plugin_dir_path

/* Template Include */
add_filter('template_include', 'yourpluginname_blah_template_include', 1, 1); 
function yourpluginname_blah_template_include($template)
{
    global $wp_query; //Load $wp_query object
    $page_value = $wp_query->query_vars['blah']; //Check for query var "blah"

    if ($page_value && $page_value == "true") { //Verify "blah" exists and value is "true".
        return plugin_dir_path(__FILE__).'test/blah.php'; //Load your template or file
    }

    return $template; //Load normal template when $page_value != "true" as a fallback
}

In the code above, you are simply telling Wordpress to use your blah.php template any time the query var "blah" is present and set to true. In this case it is present because a user is visiting a url with a rewrite rule that utilizes the "blah" query var. The function checks if the "blah" query var is present, then checks if "blah" is set to true, and if so loads the template. Also note that the template path is test/blah.php. You are using plugin_dir_path(__FILE__) to relatively include the template based on the location of your plugin. That way it's relative as a plug-in should be.

Step 4: The Actual Template (blah.php)

http://codex.wordpress.org/Function_Reference/get_header

http://codex.wordpress.org/Function_Reference/get_footer

http://codex.wordpress.org/Function_Reference/get_sidebar

Your template file will need to load the header, footer, and sidebar itself. When using template_include, Wordpress will not automatically load the header and footer as if you were using a page template. Be sure your template file calls get_header(), get_footer(), and get_sidebar() so that you get your complete layout.

Notes

Hope this helps, I was searching for something similar the other day and had to figure it out the hard way. It's also worth noting that I have prefixed all of the functions as "yourpluginname_". You can change this to whatever you want your prefix to be, but be sure to update the function names to match as well.