This is How to Query Category Posts with Twig and WordPress
As a WordPress developer, you'll often find yourself needing to query posts based on specific categories. This can be a crucial requirement for many websites, where you need to display content in a certain way or exclude certain categories from being shown.
In this blog post, we'll delve into the process of querying category posts using Twig, a powerful templating engine, and WordPress, the content management system (CMS) that powers millions of websites worldwide.
Understanding the Code
Let's start by examining the code snippet you provided:
if (!empty($params['category_exclude'])) { // Exclude categories
$args['tax_query'] = array(
array(
'taxonomy' => 'category',
'terms' => explode(',', $params['category_exclude']), // "cat1,cat2" would become ["cat1","cat2"] here
'field' => 'slug',
'operator' => 'NOT IN',
),
);
}
In this code, the $params['category_exclude']
variable is used to determine if any categories should be excluded from the query. If the variable is not empty, the code sets up a tax_query
array within the $args
variable.
The tax_query
array is used to filter the posts based on the specified categories. The 'taxonomy' => 'category'
line tells WordPress that we're working with the "category" taxonomy, and the 'terms' => explode(',', $params['category_exclude'])
line splits the $params['category_exclude']
string by commas to create an array of category slugs.
Finally, the 'field' => 'slug'
line specifies that we're using the category slug to identify the categories, and the 'operator' => 'NOT IN'
line tells WordPress to exclude the specified categories from the query.
The Problem and the Solution
The issue that you've identified in the code is the way the category_exclude
parameter is used. According to the description, the line [blog_list category_exclude="in-the-news videos"]
should be changed to [blog_list category_exclude="in-the-news,videos"]
.
The reason for this is that the code uses the explode()
function to split the $params['category_exclude']
string into an array. By default, the explode()
function uses whitespace (spaces, tabs, newlines, etc.) as the delimiter. However, in your case, you want to use commas as the delimiter.
To fix this, you should separate the category slugs with commas, as shown in the updated line: [blog_list category_exclude="in-the-news,videos"]
. This will ensure that the explode()
function correctly creates an array of the category slugs to be excluded from the query.
Querying Category Posts with Twig and WordPress
Now that we understand the problem and the solution, let's dive deeper into how you can use Twig and WordPress to query category posts.
Twig is a popular templating engine for PHP, and it can be seamlessly integrated with WordPress. By using Twig, you can create more organized and maintainable WordPress templates, making it easier to manage your website's structure and design.
Here's an example of how you can use Twig and WordPress to query category posts:
{# templates/blog-list.twig #}
{% extends 'base.twig' %}
{% block content %}
<h1>Blog Posts</h1>
{% set args = {
'post_type': 'post',
'posts_per_page': 10,
'orderby': 'date',
'order': 'DESC',
} %}
{% if category_exclude is not empty %}
{% set args = args|merge({
'tax_query': [{
'taxonomy': 'category',
'terms': category_exclude.split(','),
'field': 'slug',
'operator': 'NOT IN',
}]
}) %}
{% endif %}
{% set posts = fn('get_posts', args) %}
{% if posts %}
<ul>
{% for post in posts %}
<li>
<a href="{{ post.link }}">{{ post.title }}</a>
<p>{{ post.excerpt }}</p>
</li>
{% endfor %}
</ul>
{% else %}
<p>No posts found.</p>
{% endif %}
{% endblock %}
In this example, we're using Twig to create a blog list template (blog-list.twig
). The template extends a base template (base.twig
) and includes a content block.
Inside the content block, we first set up the $args
array with the default query parameters, such as post_type
, posts_per_page
, orderby
, and order
.
Next, we check if the category_exclude
variable is not empty. If it is not empty, we merge the tax_query
parameter into the $args
array. This tax_query
parameter is created using the category_exclude
variable, which is split by commas to create an array of category slugs.
Finally, we use the WordPress get_posts()
function to fetch the posts based on the $args
array, and we loop through the results to display the post titles and excerpts.
This example demonstrates how you can use Twig and WordPress to query category posts and exclude specific categories from the results. By using Twig, you can create more organized and maintainable WordPress templates, making it easier to manage your website's structure and design.
Conclusion
In this blog post, we've explored how to query category posts with Twig and WordPress. We've identified the problem with the original code snippet and provided a solution by properly separating the category slugs with commas.
Furthermore, we've shown an example of how you can use Twig and WordPress to create a blog list template that allows you to exclude specific categories from the query. By leveraging the power of Twig and the flexibility of WordPress, you can build more efficient and scalable WordPress websites that meet the needs of your users.
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