Add Feature image of post/product by using URL programmatically

add-feature-image-programmatically.php

        /****
         ****   Add Feature Image       
         ****/

         $url = "apple.jpg"; 
         $image_url = $url;
         $url_array = explode('/', $url );
         $image_name = $url_array[count($url_array)-1];

         $ch = curl_init();

         curl_setopt ($ch, CURLOPT_URL, $image_url);

         // Getting binary data
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
         curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);

         $image_data = curl_exec($ch);
         curl_close($ch);

        $upload_dir = wp_upload_dir(); // Set upload folder
        $unique_file_name = wp_unique_filename( $upload_dir['path'], $image_name ); //    Generate unique name
        $filename = basename( $unique_file_name ); // Create image file name

        // Check folder permission and define file location
        if( wp_mkdir_p( $upload_dir['path'] ) ) {
            $file = $upload_dir['path'] . '/' . $filename;
        } else {
            $file = $upload_dir['basedir'] . '/' . $filename;
        }

        // Create the image file on the server
        file_put_contents( $file, $image_data );

        // Check image file type
        $wp_filetype = wp_check_filetype( $filename, null );

        // Set attachment data
        $attachment = array(
            'post_mime_type' => $wp_filetype['type'],
            'post_title' => sanitize_file_name( $filename ),
            'post_content' => '',
            'post_status' => 'inherit'
        );

        // Create the attachment
        $attach_id = wp_insert_attachment( $attachment, $file, $post_id );

        // Include image.php
        require_once(ABSPATH . 'wp-admin/includes/image.php');

        // Define attachment metadata
        $attach_data = wp_generate_attachment_metadata( $attach_id, $file );

        // Assign metadata to attachment

        wp_update_attachment_metadata( $attach_id, $attach_data );

        // asign to feature image

        // And finally assign featured image to post
        set_post_thumbnail( $post_id, $attach_id );