How did the plugin come about? Here I describe the background and the concept.

The plugin concept - WordPress plugins by Thomas Zwirner

The „External files for media library“ plugin has evolved over time from a small application into a comprehensive tool. It can help to solve many different use cases in connection with files in WordPress. Here I explain the concept behind it to show the possibilities it can offer for many WordPress-based projects.

The origin

To understand the concept, you need to understand something of the history of its creation. A few years ago, I had the plugin Download list with icons has been developed. This enables the output of files in a convenient list in the block editor as a block. You assign files from the media library to the block and then display them.

Interestingly, many of the users of this plugin worked in the scientific field. Here, for example, it was about PDF-based documentation of publications. No problem with the plugin. But scientific institutions like to store such documents centrally in one place so that they can be updated and distributed at the same time. This resulted in a completely new requirement for me:

Users of my plugin needed a way to add URLs to the download list block 😒

I first tried with ReactReact JavaScript program library for the creation of web-based user interfaces to create a way of inserting this directly into the block. However, I failed, mainly due to the user interface, which was simply not suitable for this.

The basic concept

First of all, I looked around to see if there was a plugin somewhere in the WordPress plugin repository for this very purpose. Interestingly, I found a few small ones, but they were extremely outdated. For example, they enabled the download of a file via FTPFTP File Transfer Protocol in the media library. It wasn't quite what I was looking for. And the way these plugins were programmed didn't meet my quality standards or those of the WordPress repository, which has changed for the better in recent times.

So a new plugin was created: External files for the media library. I used this to extend the media library with the option of specifying URLs for files that could then be integrated into the project.

Initially, I simply downloaded the files from the URLs provided and saved them in the media library. However, this did not correspond to the goal described above of leaving the files external. So I looked at what I could do to save external files as such in the media library - and it worked surprisingly well. So I came up with my basic concept for the plugin:

Store the URL of external files in the media library, not the file itself.

Why URL-based?

Files on the Internet are all referenced with a URL. This can be directly accessible or provided with some kind of access protection. But they all have URLs.

Why not use the embed block?

This allows you to integrate wonderful external content into your own website. But it does not enable the linking in my block for the download list.

The evolution of the plugin

So I had the actual goal of adding external URLs to the plugin Download list with icons to be able to use the plugin. Sure, it's another plugin that you have to install - but anyone who needs it will use it. And so I started to expand it bit by bit, mostly out of my own desire, as I see it as a technical challenge. In the meantime, it far exceeds the original intention of being a support for my other plugin, but both are still compatible with each other.

Protocols

URLs naturally also use different protocols. HTTPHTTP Hypertext Transfer Protocol is familiar to everyone, and FTP still means something to some. There are also HTTPSHTTPS Hypertext Transfer Protocol Secure, SFTPSFTP Secure File Transfer Protocol, FTPSFTPS Method for encrypting the File Transfer Protocol (FTP), SSH and others (even something like Gopher). Most of them are access-protected, some are only optional. So I started to support these protocols in the plugin.

What is particularly helpful in this development is that WordPress itself already has everything you need. With the WP_Filesystem() based objects, you can easily query a wide variety of protocols. Some of them, of course, set corresponding PHPPHP PHP is a scripting language with a syntax based on C and Perl, which is mainly used to create dynamic websites or web applications. https://de.wikipedia.org/wiki/PHP-modules. But I didn't have to reinvent the wheel.

And so support for many different protocols was quickly added to the URLs.

File types

WordPress itself only allows the upload of certain file types during a fresh installation. PDF, JPG, PNG and others are commonplace for most users. I didn't want to extend these rules with my plugin, as External files for the media library is intended for external files and not for managing file types - that's why there's other very good plugins. So my plugin accesses this list from WordPress (which other plugins can extend) to check whether an external file is permitted. In the plugin settings, you can at least choose which format WordPress supports for external files.

Services

Up to this point, the plugin has worked extremely satisfactorily, I began to think bigger. What do WordPress users use to manage their files outside of WordPress that they want to integrate into their project? How could I make their work easier? I came across various service providers that make it possible to manage files. And how do you access them externally? Yes, via API.

So I started, piece by piece, to find service providers like DropboxDropbox Online data storage, Google Drive, Google Cloud Storage and AWS S3 into the plugin. Again, these are URLs of files that I received via API - so no problem for the basic functions of „External files for the media library“. The main effort in the implementation consisted of getting to know the respective API and connecting it.

As I rarely or never use these platforms myself, I was entering uncharted territory for myself - but that's exactly what fascinates me about IT: the possibilities you have without knowing about them and then getting to know them.

Convenient file views with React

Everything I have described up to this point involves activities in the background. Objects and tasks are created in the plugin that have no visual output for the user in the WordPress backend. But I also had to provide the user with an interface for the services so that they can see what files are there and select from them.

This resulted in a React-based tool called „Easy Directory Listing for WordPress“ what with GitHubGitHub Software development platform as composercomposer application-oriented package manager for PHP package is available. This is used by my plugin to handle all file listings in the backend. It provides a tree on the left and the file list on the right. There are also options for importing and a few other things.

Compatibility with other plugins

Another major shortcoming of the media library in WordPress is that you can't organize files there. They are just there without categorization and classification. This can be solved with various plugins:

... just to name a few, there are more. Since I am aware that users of my plugin may also want to categorize the external files, I created compatibility with many of these third-party plugins. This allows you to specify during import that and where you want to categorize a file if you use a plugin to categorize files in the media library and „External files for the media library“ provides support for this.

In addition, there is also compatibility with WooCommerce with its CSV-based import and various other plugins that handle files in the media library.

Synchronization

After the manual method worked so well for the various sources, I also started to consider an automatic method. The use case could be, for example, that you want to update a gallery automatically - simply because there is a new file in an external source. The plugin can now also do this and offers it for almost all external sources.

Exporting files

And while I'm on the subject of file handling: until now, the plugin could only fetch files into the media library. But what if you also want to save a file from the media library externally? The classic case of offloading files. Since I already had the connection to the sources, it was easy to enable the export.

In conclusion

My concept formulated above has changed due to the many possibilities that the plugin now offers. After more than 3 years of development, I would describe it as follows at the end of 2025:

Optimization of the management of files in the media library with external sources.

The plugin concept