I am creating a Wordpress plugin which create pages (with get_header(), get_footer() and get_sidebar()) for searching through an API.

Of course, I have defined some rules for URL rewriting like this:

function init() {
    global $wp_rewrite;
    add_rewrite_rule('my_plugin/(.+)/results?', 'index.php?my_plugin=results&data=$matches[1]', 'top');

This function is called with this line in the constructor of my plugin:

add_action('init', array(&$this, 'init'));

The plugin works perfectly but I need to activate manually URL rewriting in Settings > Permalinks in my Admin Dashboard. I need only to select one option: Day and name, Month and name, Numeric,... (whatever).

The problem is that when I install the plugin on a new Wordpress with Permalinks disable (Default), I am getting always a 404 error. This will only work if I activate manually Permalinks.
(I know this is done by the .htaccess).

Is there is a way to bypass this or to activate automatically Permalinks through my plugin ?
Other good solution is welcome.

I hope my question is clear.
Thank you.

  • $wp_rewrite->flush_rules(); - This is an extremely expensive line of code for every page load. – Brian Fegter May 28 '13 at 7:40
  • I look at this: http://codex.wordpress.org/Rewrite_API/flush_rules.Rules are defined in my init function but I have a function for the activation plugin. Can I move the URL rewriting code ? – Florent Hemmi May 28 '13 at 7:43
  • add_rewrite_rule() can live outside of a callback function. It doesn't have dependencies on any hook or callback. – Brian Fegter May 28 '13 at 8:31

Whenever I create a plugin that needs permalinks enabled i check on the plugin activation and if its not set i display a message for the user:

// Add Check if permalinks are set on plugin activation
register_activation_hook( __FILE__, 'is_permalink_activate' );
function is_permalink_activate() {
    //add notice if user needs to enable permalinks
    if (! get_option('permalink_structure') )
        add_action('admin_notices', 'permalink_structure_admin_notice');

function permalink_structure_admin_notice(){
    echo '<div id="message" class="error"><p>Please Make sure to enable <a href="options-permalink.php">Permalinks</a>.</p></div>';
  • 1
    This is my preferred approach. Plugins should never brute force change blog settings without the user's consent. – Brian Fegter May 28 '13 at 8:30
  • Yes, I think it's a better idea. I try this! – Florent Hemmi May 28 '13 at 8:36
  • Thanks for the get_option('permalink_structure')! – Florent Hemmi May 28 '13 at 10:51

I found the code.

function modify_permalinks($permalink_structure, $category_base, $tag_base){
    global $wp_rewrite;

    require_once(ABSPATH . 'wp-admin/includes/file.php');
    require_once(ABSPATH . 'wp-admin/includes/misc.php');

    # get paths

    $home_path = get_home_path();
    $iis7_permalinks = iis7_supports_permalinks();

    # set the structure

    $permalink_structure = preg_replace('#/+#', '/', '/' . $permalink_structure);

    $category_base = preg_replace('#/+#', '/', '/' . $category_base);

    $tag_base = preg_replace('#/+#', '/', '/' . $tag_base);

    # check if there is a file to rewrite

    if ( $iis7_permalinks ) {
        if ( ( ! file_exists($home_path . 'web.config') && win_is_writable($home_path) ) || win_is_writable($home_path . 'web.config') )
            $writable = true;
            $writable = false;
    } else {
        if ( ( ! file_exists($home_path . '.htaccess') && is_writable($home_path) ) || is_writable($home_path . '.htaccess') )
            $writable = true;
            $writable = false;

    # flush the rules

    update_option('rewrite_rules', FALSE);
  • Can you explain how this solves the issue? – Brian Fegter May 28 '13 at 7:39
  • The problem is that I do not want to change user Permalinks setting if it is already activated. I have an idea: apply this if there is no .htaccess and put a default setting for Permalinks but it not very clean. Any other idea ? – Florent Hemmi May 28 '13 at 7:55

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