WordPress – output categories, posts and images to JSON - php

Question

I'm trying to recreate a JSON file with a specific structure and only getting so far as I'm not that familiar with PHP.
I'd like to list all used/non-empty categories, then all posts within each category and then all images/other details used in each post.
I'm not sure how the code should look in the loop. I'd need the JSON to be exactly like below (brackets) as I'm feeding it to a D3 script:
{
"project": "Farm", // website name
"about": "What we have on the farm.",
"categories": [ //post categories
{
"slug": "fruits",
"title": "Fruits",
"description": "All about fruits.",
"posts": [ // all posts within a category
{
"slug": "apples",
"title": "Apples",
"excerpt": "Apple trees and fruits.",
"tags": "tree, apple",
"post_images": [
{
"id": 25,
"title": "Apple trees.",
"filename": "apple-trees.jpg",
"desc": "Rows of apple trees.",
"tags": ""
},
(...)
The PHP script so far (in functions.php):
function export_to_json() {
global $post;
$post_args = array(
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => -1,
);
$cat_args = array(
'orderby' => 'name',
'order' => 'ASC'
);
$posts = array();
$cats = get_categories( $cat_args );
foreach( $cats as $cat ) {
$query = new WP_Query( $post_args );
while ( $query->have_posts() ): $query->the_post();
$posts[] = array(
'categories' => [
'title' => $cat->cat_name,
'description' => $cat->description,
'posts' => [
'title' => get_the_title(),
'excerpt' => get_the_excerpt(),
'images' => get_attached_media( 'image' ),
'tags' => get_tags()
]
]
);
endwhile;
wp_reset_query();
}
$data = json_encode($posts, JSON_PRETTY_PRINT);
$upload_dir = wp_get_upload_dir();
$file_name = date('Y-m-d') . '.json';
$save_path = $upload_dir['basedir'] . '/' . $file_name;
$f = fopen($save_path, "w");
fwrite($f, $data);
fclose($f);
}
add_action('save_post', 'export_to_json');
The script is wrong because categories get repeated for each post and I'd like all posts within a category to be properly nested.
Any help with this would be much appreciated. Thanks.

Answer 1

Here you go:
function export_to_json() {
global $post;
$categories = array();
$cat_args = array(
'orderby' => 'name',
'order' => 'ASC'
);
$cats = get_categories( $cat_args );
foreach( $cats as $cat ) {
$post_args = array(
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => -1,
'category__in' => $cat->term_id
);
$get_posts = array();
$posts = get_posts( $post_args );
foreach($posts as $post){
$tags = get_the_tags($post->ID);
$i = 0;
$tag_names = '';
$post_images = array();
if( $tags) {
foreach( $tags as $tag ) { $i++;
$comma = $i == count($tags) ? '' : ', ';
$tag_names .= $tag->name . $comma;
}
}
$images = get_post_gallery($post->ID, false);
if($images){
$image_ids = explode(",", $images['ids']);
foreach ($image_ids as $image ){
$img = wp_prepare_attachment_for_js($image);
$post_images[] = array(
"id" => $img['id'],
"title" => $img['name'],
"filename" => $img['filename'],
"desc" => $img['description'], //Pulls the image description
'tags' => $tag_names
);
}
}
$get_posts[] = array(
'slug' => $post->post_name,
'title' => get_the_title(),
'excerpt' => get_the_excerpt(),
'tags' => $tag_names,
'post_images' => $post_images
);
}
$categories[] = array(
'slug' => $cat->slug,
'title' => $cat->cat_name,
'description' => $cat->description,
'posts' => $get_posts
);
}
$output = array(
'project' => get_bloginfo('name'),
'about' => get_bloginfo('description'),
'categories' => $categories
);
$data = json_encode($output, JSON_PRETTY_PRINT);
}