How to Automatically Download and Localize External Images in WordPress Posts: functions files

How to Automatically Download and Localize External Images in WordPress Posts: functions files

   December 30, 2024       Ari SEO

---

Write a WordPress image localization function. This function will automatically download external images to the media library when publishing or updating articles.

 <? php
//functions.php

/**
Download external images to your local media library
*/
Function download_external_images ($post_id) {
//Get the content of the article
$Post = get_post ($post_id);
$Content = $post- > post_content;

If the content is empty, return
If (empty ($content)) {
Return;
}

Match all image tags
$Pattern = '/< img [^ >] + src =[\'"]([^\'"]+)[\'"][^>]*>/ i';
preg_match_all ($pattern, $content, $matches);

If (empty ($matches [1])) {
Return;
}

//Get the site URL
$site_url = get_site_url ();
$updated = false;

Foreach ($matches [1] as $image_url) {
//Skip the pictures on this site
If (strpos ($image_url, $site_url)! == false) {
Continue;
}

//download the picture
$Tmp = download_url ($image_url);
If (is_wp_error ($tmp)) {
Continue;
}

//Get file information
$file_array = array (
'Name '= > basename ($image_url),
'tmp_name '= > $tmp
);

//Check the file type
$file_type = wp_check_filetype ($file_array ['name']);
If (! $file_type ['type']) {
Unlink ($tmp);
Continue;
}

//Add the image to the media library
$attachment_id = media_handle_sideload ($file_array, $post_id);

If (is_wp_error ($attachment_id)) {
Unlink ($tmp);
Continue;
}

//Get a new image URL
$new_url = wp_get_attachment_url ($attachment_id);

//Replace the image URL in the content
$Content = str_replace ($image_url, $new_url, $content);
$updated = true;
}

//If there is an update, save the article content
IF ($updated) {
wp_update_post (array (
'ID '= > $post_id,
'post_content '= > $content
));
}
}

//Add a hook to trigger when saving the article
add_action ('save_post', 'download_external_images', 10,1);

/**
* Add image failed to download error handling
*/
Function handle_download_error ($error_msg, $error_code, $error_data, $file) {
error_log ("Image download failed : " . $ error_msg);
Return new WP_Error ($error_code, $error_msg, $error_data);
}
add_filter ('wp_handle_upload_error', 'handle_download_error', 10,4);

Main function description:

Auto-trigger: automatically runs when an article is saved or updated

Image detection: Use regex (regular expression) to match all images in the content of the article

Localization:

Skip the pictures on this site

Download external images

Add to Media Library

Update the image URL in the article content

Error handling:

Check file type

Handling failed to download

Log errors

How to use:

Add the code to the theme's functions.php file

When you publish or edit an article, the function runs automatically

External images are automatically downloaded and replaced with local URLs.

Performance optimization:

Only process external pictures.

Working with files with WordPress build-in function

Update article content only when there are changes

Add error handling to avoid interruptions

Notes:

Make sure WordPress has write permissions

Check that the media library has sufficient storage space

You may need to adjust the PHP execution time limit

It is recommended to test in the testing environment first