Drupal comes with many capabilities for handling and manipulating files and images and has been adding to its toolset more and more with recent versions. Of course, this is not to say that media management has not been always a pain point for Drupal developers. In Drupal 7, a complicated suite of contributed modules was needed to achieve a basic level of functionality, something that users of "competitors" like WordPress enjoy out of the box. In Drupal 8, there is more emphasis placed on media management, however much of the work is still in the contributed sphere. But due to the new way Drupal development will work, it's expected that much of this effort will find its way into the core system with future versions.

In this chapter, we will look at how we can work with files and images in Drupal, supported by the core features. We are not going to go into topics such as media management but rather focus on the module developer tools that can be used for working with files. We will see some examples along the way. So, what are we going to discuss?

First, we are going to get an understanding of the Drupal filesystems. Developers from previous versions of Drupal should already be familiar with these in theory, and we will see how these work in Drupal 8. Related to this, we're going to talk about stream wrappers and how Drupal handles native PHP file operations. We will even create our own custom stream wrapper a bit later in the chapter.

Then, we will talk a bit about the different ways to handle files in Drupal, namely managed (tracked) and unmanaged files. In exemplifying the work with managed files, we will add an image field to our Product entity type and have images imported from a fictional remote environment. We will also create a brand new CSV-based importer by which the product data is imported from a CSV file we process. In this process, we will mention the Entity CRUD hooks, a very important extension point in Drupal 8, and see how we can use those in our example context.

We will end the chapter by seeing how we can work with various APIs that deal specifically with images; especially for manipulating them via image toolkits and working with image styles. So let's get to it.