A function for temporarily changing the WordPress post context

Last updated • October 4th, 2019

If you’ve ever found yourself in a situation where you need to render something from some other post whilst in the context of another, you may have ended up just overriding the global $post variable. It works fine but can be problematic where you mess it up or just forget to clean up after yourself.

Being as picky as I am, I usually find myself cringing at the resulting template code. It always ends up feeling like a bit of a mess and it’s always a little bit of a speed hump to have to think about how to tackle the situation whenever I’m in it.

So, to help things along, I threw together a function that allows me to specify an alternative post – either by ID or with the WP_Post object itself – and pass it an anonymous function where I run whatever code I need.

Here’s a look at the function:

 <?php
 /**
  * Easy overriding of current post object for using template tags dynamically.
  * This is particularly useful if we need to use a template function that produces
  * side effects but doesn't have a complete 'get_xxx' equivalent; e.g; the_content();
  *
  * @param int|WP_Post $alternative_post The post ID or object for the new context.
  * @param Closure $callback A callback function that handles the calls to the
  * required template tags and returns output.
  *
  * @return mixed
  */
 function override_post_context( $alternative_post, $callback ) {
  global $post;
  $post = get_post( $alternative_post );
  setup_postdata( $post );
  $return = call_user_func( $callback, $alternative_post );
  wp_reset_postdata();
  return $return;
 }

view raw override-wp-post-context-function.php hosted with ❤ by GitHub

To use it, you just need to pass the post you want to work on along with your callback which needs to return something. This can be markup or data for you to working with.

Here’s an example of how to use it:

 <?php
 /*
  * This is a rather simple and contrived example but it illustrates how this
  * function can be used to temporarily change the post context.
  */
 $alt_post_content = override_post_context( 1234, function ( $post ) {
  ob_start();
  // Do whatever you need here. The $post variable, in this scope, is the
  // $post object we are currently working with.
  get_template_part('some/template');
  return ob_get_clean();
 } );

view raw override-wp-post-context-function-usage-example.php hosted with ❤ by GitHub

The function has helped me a number of times now and hopefully, it helps you too.

A function for temporarily changing the WordPress post context

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