Wordpress REST API - Write to JSON File? - php

Question

I've been messing around with the Wordpress REST API, and created my custom endpoint, and getting the exact data I want. Basically I created an endpoint to receive all my post/pages/acf - Instead of calling the API on each page load, I just wanted to call the API once during my preloader.
However, when I call the API, all the logic runs, which then causes a loading time of 1 to 2 seconds. Is there a possibility that whenever I make an update on Wordpress, it will call my endpoint, and write a JSON file on the server, so data.json? This way, when I load my site, it can call that data.json, with absolutely no delay at all.
I'm not sure if this is possible but wanted to try asking here.

Answer 1

I found 3 different ways to address the question, all of them here on Stackoverflow, but I'll go with the one that Tanner started, just published in full:
function export_posts_in_json() {
$args = array(
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => -1,
);
$query = new WP_Query($args);
$posts = array();
while ($query->have_posts()): $query->the_post();
$posts[] = array(
'title' => get_the_title(),
'excerpt' => get_the_excerpt(),
'author' => get_the_author(),
// any extra field you might need
);
endwhile;
wp_reset_query();
$data = json_encode($posts);
$upload_dir = wp_get_upload_dir(); // set to save in the /wp-content/uploads folder
$file_name = date('Y-m-d') . '.json';
$save_path = $upload_dir['basedir'] . '/' . $file_name;
$f = fopen($save_path, "w"); //if json file doesn't gets saved, comment this and uncomment the one below
//$f = #fopen( $save_path , "w" ) or die(print_r(error_get_last(),true)); //if json file doesn't gets saved, uncomment this to check for errors
fwrite($f, $data);
fclose($f);
}
add_action('save_post', 'export_posts_in_json');
Original snippet here: https://wordpress.stackexchange.com/questions/232708/export-all-post-from-database-to-json-only-when-the-database-gets-updated
Hope this helps.

Answer 2

This method allow you to write a json from and external or internal API endpoint;
it is less sofisticated than the one above (destination folder wise), but uses the REST API so you can fetch the full posts object without having to specify all the fields:
// Export API Data to JSON, another method
add_action('publish_post', function ($ID, $post) {
$wp_uri = get_site_url();
$customApiEndpoint = '/wp-json/wp/v2/posts'; // or your custom endpoint
$url = $wp_uri . $customApiEndpoint; // outputs https://your-site.com/wp-json/wp/v2/posts
// $url = 'https://your-site.com/wp-json/wp/v2/posts'; // use this full path variable in case you want to use an absolute path
$response = wp_remote_get($url);
$responseData = json_encode($response); // saved under the wp root installation, can be customized to any folder
file_put_contents('your_api_data_backup.json', $responseData);
}, 10, 2);
inspired from https://stackoverflow.com/questions/46082213/wordpress-save-api-json-after-publish-a-post

Answer 3

You should be able to accomplish something along those lines. Check out the code below:
function export_posts_in_json () {
$args = array(
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => -1,
);
$query = new WP_Query( $args );
...
$data = json_encode($posts);
$folder = 'YOUR_EXPORT_PATH_HERE';
$file_name = date('Y-m-d') . '.json';
file_put_contents($folder.$file_name, $data);
}
add_action( 'save_post', 'export_posts_in_json' );
This should save a json file every time a post is made. I'm sure you can modify it to export all the data you need for your site.