{"id":451,"date":"2026-01-06T10:00:00","date_gmt":"2026-01-06T09:00:00","guid":{"rendered":"https:\/\/plugins.thomaszwirner.de\/?p=451"},"modified":"2026-03-05T17:01:27","modified_gmt":"2026-03-05T16:01:27","slug":"the-plugin-concept","status":"publish","type":"post","link":"https:\/\/plugins.thomaszwirner.de\/en\/external-files-in-the-media-library\/the-plugin-concept\/","title":{"rendered":"The plugin concept"},"content":{"rendered":"

The \u201eExternal files for media library\u201c 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.<\/p>\n\n\n

The origin<\/h2>\n\n\n

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<\/a> entwickelt. Dieses erm\u00f6glicht die Ausgabe von Dateien in einer komfortablen Liste im Block Editor. Man ordnet Dateien aus der Mediathek dem Block zu und zeigt diese dann an.<\/p>\n\n\n\n

Die Anwender dieses Plugins sind interessanterweise vielfach im wissenschaftlichen Bereich t\u00e4tig. Hier geht es z.B. um PDF-basierte Dokumentationen von Ver\u00f6ffentlichungen. Alles kein Problem mit dem Plugin. Aber wissenschaftliche Institutionen speichern solche Dokumente gerne zentral an einer Stelle um sie ggfs. auch aktualisieren und gleichzeitig auf dem Weg verteilen zu k\u00f6nnen. Daraus ergab sich eine f\u00fcr mich v\u00f6llig neue Anforderung:<\/p>\n\n\n\n

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Users of my plugin needed a way to add URLs to the download list block \ud83d\ude12<\/p>\n<\/blockquote>\n\n\n\n

I first tried with ReactReact<\/span> JavaScript program library for the creation of web-based user interfaces<\/span><\/span><\/span> 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.<\/p>\n\n\n

The basic concept<\/h2>\n\n\n

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 Interestingly, I found a few small ones, but they were extremely outdated.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<\/span> File Transfer Protocol<\/span><\/span><\/span> 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.<\/p>\n\n\n\n

So a new plugin was created: External files in the media library<\/em>. Ich erweiterte mit diesem die Mediathek um die M\u00f6glichkeit URLs f\u00fcr Dateien anzugeben, die dann im Projekt wie normale Medien-Dateien verwendet werden konnten.<\/p>\n\n\n\n

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:<\/p>\n\n\n\n

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Store the URL of external files in the media library, not the file itself.<\/p>\n<\/blockquote>\n\n\n\n

Why URL-based?<\/summary>\n

Dateien im Internet sind alle mit einer URL referenziert. Diese kann direkt erreichbar oder mit irgendeinem Zugriffsschutz versehen sein. Aber sie haben alle URLs.<\/p>\n<\/details>\n\n\n\n

Warum nicht den „Einbetten“ Block verwenden?<\/summary>\n

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.<\/p>\n<\/details>\n\n\n

The evolution of the plugin<\/h2>\n\n\n

So I had the actual goal of adding external URLs to the plugin Download list with icons<\/em> verwenden zu k\u00f6nnen, durchaus erreicht. Klar, ein weiteres Plugin was man installieren m\u00fcsste – aber wer es braucht wird es nutzen. Und so begann ich damit es St\u00fcck f\u00fcr St\u00fcck zu erweitern, meist aus eigenem Wunsch heraus, da ich es f\u00fcr mich als technische Herausforderung ansehe. Inzwischen \u00fcbersteigt es weit das urspr\u00fcngliche Ansinnen, eine Unterst\u00fctzung f\u00fcr mein anderes Plugin zu sein – beide sind jedoch weiterhin miteinander kompatibel.<\/p>\n\n\n

Protocols<\/h3>\n\n\n

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

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

And so support for many different protocols was quickly added to the URLs.<\/p>\n\n\n

File types<\/h3>\n\n\n

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<\/a>. 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.<\/p>\n\n\n

Services<\/h3>\n\n\n

Up to this point, the plugin has worked extremely satisfactorily, I began to think bigger<\/em>. Was verwenden WordPress-Anwender zum Verwalten ihrer Dateien abseits von WordPress, die sie dann aber in ihr Projekt integrieren m\u00f6chten? Wie k\u00f6nnte ich denen die Arbeit erleichtern? Ich kam auf verschiedenste Dienstleister, die es erm\u00f6glichen Dateien zu verwalten. Und wie greift man von extern auf diese zu? Ja, per API.<\/p>\n\n\n\n

So I started, piece by piece, to find service providers like DropboxDropbox<\/span> Online data storage<\/span><\/span><\/span>, 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 \u201eExternal files for the media library\u201c. The main effort in the implementation consisted of getting to know the respective API and connecting it.<\/p>\n\n\n\n

Da ich selbst diese Plattformen selten bis gar nicht nutze, betrat ich f\u00fcr mich selbst Neuland – aber genau das fasziniert mich an der IT: die M\u00f6glichkeiten, die man hat ohne von ihnen zu wissen, und sie dann kennenzulernen.<\/p>\n\n\n

Convenient file views with React<\/h3>\n\n\n

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.<\/p>\n\n\n\n

This resulted in a React-based tool called \u201eEasy Directory Listing for WordPress<\/a>\u201c what with GitHubGitHub<\/span> Software development platform<\/span><\/span><\/span> as composercomposer<\/span> application-oriented package manager for PHP<\/span><\/span><\/span> 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.<\/p>\n\n\n\n

\"\"\n\t\t\t\n\t\t\t\t\n\t\t\t<\/svg>\n\t\t<\/button>
Directory view of an external source in the \u201eExternal files in the media library\u201c plugin\u201c<\/figcaption><\/figure>\n\n\n

Compatibility with other plugins<\/h3>\n\n\n

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:<\/p>\n\n\n\n