I am working on uploading an image to the media library and then attaching it to the featured image. I put the code below in my functions.php file and submitted a JSON file through postman, but for some reason it uploaded thousands of times until i had to kill the process and remove the code to get it to stop. It is uploading to the media library but keeps creating images. I have no loop in my code. I was just testing the code below to see if i could get it to run once. I am still learning how Wordpress works. Sorry if these are dumb questions.

  1. Does functions.php continuously execute while Wordpress is running?
  2. Should this be in functions.php file and how do i get it to execute only once?
    $url = 'http://localhost/download.png';
    $request = wp_remote_post(
            'headers' => array(
                'Authorization' => 'Basic ' . base64_encode( 'api-user:xxxx xxxx xxxx xxxx xxxx xxxx' ),
                'Content-Disposition' => 'attachment; filename="' . basename( $url ) . '"',
                'Content-Type: ' . wp_get_image_mime( $url ),
            'body' => file_get_contents( $url )
    if( 'Created' === wp_remote_retrieve_response_message( $request ) ) {
        $body = json_decode( wp_remote_retrieve_body( $request ) );
        $featured_image_id = $body->id;
  • "I put the code below in my functions.php file" - did you put it just like that? Because you should instead put it in a function and call the function only when necessary (when you need to upload the image). And what do you mean by "submitted a JSON file through postman" - what JSON file is that? What does it contain and maybe you should add a screenshot of your Postman request.
    – Sally CJ
    Commented Mar 10, 2023 at 10:24
  • Thanks Sally, yes i put it in exactly like how it is laid out. I think i don't fully understand how functions.php works. After your comment, i am assuming that functions.php executes and putting the code in a function and using an add_action() will solve the problem. thanks for clearing that up. I will try it. i am still trying to understand hooks and how they work. its all trial and error at this point for me :)
    – user230659
    Commented Mar 10, 2023 at 15:59
  • I've posted a proper answer, and hopefully it helps you. :)
    – Sally CJ
    Commented Mar 11, 2023 at 5:30

2 Answers 2

  1. Does functions.php continuously execute while Wordpress is running?

Yes, it's run on each page load. You can learn more about the (theme) functions file at https://developer.wordpress.org/themes/basics/theme-functions/.

  1. Should this be in functions.php file and how do i get it to execute only once?

It can be put in that file, however, it should be run conditionally, e.g. put it in a function and then call the function from within your template file, or from within a hook. That's how you can get it to execute only once. (but whether it's actually going to be executed only once, depends on your code)


  • Code in the active theme's functions.php file:

     * Your Theme functions and definitions
     * @link https://developer.wordpress.org/themes/basics/theme-functions/
    function my_upload_image_function() {
        // your code here which uploads the image
  • Then in your template file, just call the function when necessary: my_upload_image_function().

  • Or you can hook the function on a specific action:

    add_action( 'hook_name', 'my_upload_image_function' );

So that's a brief info about the theme functions file, and now, this is about what your code is trying to do.

  • Thank you so much Sally. That is very helpful. I did add it to a function and i am calling it from add_action('rest_api_init', 'add_image_to_library'); I use rest_api_init hook because i am submitting this from Postman. My goal is to submit a JSON file from another server with C#. to the rest api and attaché the image to a custom post time. I added some debugging and even with the add_action() it is still looping through until i stop it and remove the code. i will check out rest_do_request and media_sideload_image . I will continue to dig :)
    – user230659
    Commented Mar 12, 2023 at 0:46
  • Oh noo, that's not how you should do it! 😁 (you should not hook the function on rest_api_init) Can you show a sample of that JSON file? And actually, can't you just upload the image directly via C#? (I.e. Make a remote/HTTP request from that another server to the /wp/v2/media endpoint on your WordPress site.) Why must you "submit a JSON"?
    – Sally CJ
    Commented Mar 12, 2023 at 3:22

Trying to get use to working on this site too. Lost the post for a few days, and didn't register properly i guess. I can't seem to get back to your last response.

The json file is for a custom post type. The custom post works fine. I can create a new custom post with updating custom fields using rest api. In addition i am looking to upload the image for that post, attach the image to the featured image at time of creation of the new custom post. Honestly, i am still learning the rest api and wordpress. In looking at /wp/v2/media and researching code. i only see samples for curl or wp_remote_post(). i pulled everything out of my functions php and it seems to be doing the same thing with wp_remote_post(). it will upload thousands of the image and won't stop. It seems to be getting stuck on wp_remote_post() and never getting past that. I put in debugging and it never gets out of the remote function. If i shouldn't call it on rest_api_init. I will look at the end point again to see if i can make it work directly. Just havn't been successful.

  • Hey there, sorry, only today I remembered this question and then saw your "answer" - you should instead edit your original post and not posting this answer.. 😅 anyway, have you now already solved the issue in question? If so, how? Could you please edit your answer and let us know your solution? ( And accept your answer later on :) )
    – Sally CJ
    Commented Mar 29, 2023 at 14:24

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