Assign category to new post via URL

Question

There are two post categories in my WordPress site, Blog category and News category. I want to create two links in admin dashboard, each of the links will open post-new.php but a different category will be already selected for each of them, so that the user does not need to select them manually.

Suppose, there are two links -

1. Add Blog
2. Add News

Each link will open the Add New Post page, but for Add Blog link the category Blog should be selected by default, and for Add News link, the category News should be selected.

How can I achieve that? Can I set the default post category in URL?

Answer 1

I realize this is an old question, but I wanted to achieve the same thing and I managed to do this by creating a simple plugin and thought I'd share the solution.

1. Create a new plugin file in your WordPress plugins folder, e.g., wp-content/plugins/auto-category-select/auto-category-select.php.

2. Add the following PHP code to the new plugin file:

<?php
/**
 * Plugin Name: Auto Category Select
 * Description: Automatically select a category in the new post page based on a URL parameter.
 */

function auto_category_select_enqueue($hook) {
    if ('post-new.php' != $hook) {
        // Only applies to post creation page
        return;
    }

    wp_enqueue_script('auto_category_select_script', plugins_url('auto-category-select.js', __FILE__));
}

add_action('admin_enqueue_scripts', 'auto_category_select_enqueue');

This code creates a new WordPress plugin that enqueues a JavaScript file named auto-category-select.js when the new post page is loaded.

3. Create a new JavaScript file named auto-category-select.js in the same folder as the plugin file.

4. Add the following JavaScript code to the new JavaScript file:

function checkCategoryCheckbox() {
    const urlParams = new URLSearchParams(window.location.search);
    const category = urlParams.get('category');
    console.log('Category from URL: ' + category);

    if (category) {
        const labels = document.querySelectorAll('.editor-post-taxonomies__hierarchical-terms-choice');
        
        if (labels.length > 0) {
            labels.forEach(function(label) {
                console.log('Label text: ' + label.textContent.trim());
                if (label.textContent.trim() === category) {
                    const checkbox = label.querySelector('input');
                    // Create a new click event
                    var clickEvent = new MouseEvent('click', {
                        'bubbles': true,
                        'cancelable': true,
                    });
                    // Dispatch the click event on the checkbox
                    checkbox.dispatchEvent(clickEvent);
                    console.log('Checkbox should be checked now');
                }
            });
            // If we've found the labels, we can stop checking
            clearInterval(checkInterval);
        }
    }
}

// Start checking for the checkboxes every 500 milliseconds
var checkInterval = setInterval(checkCategoryCheckbox, 500);

You can then add this snippet of code to your functions.php file or by using something like the Code Snippets plugin:

function add_custom_links_to_admin_sidebar() {
    add_menu_page(
        'Add Blog',               // Page title
        'Add Blog',               // Menu title
        'publish_posts',          // Capability
        'post-new.php?category=Blog', // Menu slug
        '',                       // Function
        'dashicons-welcome-write-blog', // Icon URL
        6                         // Position
    );

    add_menu_page(
        'Add News', 
        'Add News', 
        'publish_posts', 
        'post-new.php?category=News', 
        '', 
        'dashicons-welcome-write-blog', 
        7
    );
}

add_action('admin_menu', 'add_custom_links_to_admin_sidebar');

Hope that helps someone out!