By default, the Views module can display data contained in any field attached to an entity that is exposed in Views, and the content of any database column exposed to Views via an implementation of hook_views_data(). It's also possible to create pseudo fields. These appear in the Views UI like any other field, but don't map directly to the data stored in a database column and instead allow the data to be preprocessed. This could be performing a calculation, combining multiple fields into one, and much more.

A common example in core is the fields that allow you to perform edit or delete operations on a node. These don't correspond to a specific database column. And they can't be hard-coded because they require dynamic content specific to the node in question. Instead, they are the result of taking the entity ID and combining it with knowledge about the appropriate route for someone to edit the entity and outputting that as a link.

Another example: Imagine a cooking website where you collect cook time and preparation time (prep time) for recipes and want to also display the full time to prepare. In this case cook time and prep time could be fields on the recipe content type and total time could be handled as a calculated output of both fields, added together and converted into hours and minutes. To achieve this, you can create a custom Views pseudo field and specify the calculation and processing logic in the render function.

In this tutorial we'll:

• Learn how to define a custom Views field plugin for a pseudo field
• Attach the created field to node entities, and expose it to display in a view

By the end of this tutorial you should know how to define a Views pseudo field plugin, attach it to the node entity type via hook_views_data_alter(), and display it in a view.

Style plugins are responsible for determining how to output a set of rows. Individual rows are rendered by row plugins. Drupal core provides style plugins that include grid, HTML list, table, and unordered list styles. If you need to render the results in a different way, for example as tabs or accordions, or have special markup based on your project requirements, you may want to write a custom style plugin for Views. The advantage of this approach versus overriding the templates in a theme is that you may reuse this plugin in different views throughout the site, or even on different sites.

In this tutorial we'll:

• Learn how to create a custom Views style plugin and render output in the form of an accordion using the HTML5 <details> element.
• Demonstrate how to use a custom style plugin when building a view.

By the end of this tutorial you should know how to declare custom Views style plugins.

Identifing the fields in your data model that contain presentation data is an important part of documenting and planning your API. Examining your existing data model will help put you in the correct mindset when creating or changing it. It is important to reflect on the implications of each field for each hypothetical consumer (even consumers your API is not serving). This process will improve your content model and your API.

In this tutorial we will:

• Go through the article content type's data model
• Locate any fields that contain presentation data

The article model is created out of the box by Drupal when using the standard installation profile.

By the end of this tutorial you'll know how to do these checks, and identify presentation data in your content model, on any content type in your project.

In a monolithic architecture (non-decoupled) there is an implicit proof that the user in the front-end is the same one in the back-end. This empowers the front-end to offload all the authentication and authorization to the back-end, typically using a session cookie. In a decoupled architecture there will be multiple consumers, and some of them will not support using cookies. There are several alternatives to session cookies to authenticate our requests in a decoupled project.

In this tutorial we will:

• Learn about authorization versus authentication
• The impact on a decoupled project of having logged in users
• Learn about the available options for authentication when using a Drupal back-end.

By the end of this tutorial you should be able to explain the difference between authentication and authorization and know how to get started implementing both in a Drupal-backed web services API.

It is important to have good up-to-date documentation about your web services. Doing so will boost developer productivity in a decoupled project. Drupal offers several tools that help maintain your API documentation with minimal effort.

In this tutorial we'll:

• Learn about the JSON schema format for describing data structures
• Generate schemas for our fake articles REST resource
• Visualize those schemas in a human-readable format

By the end of this tutorial you should be able to generate documentation for your REST resources that is kept up-to-date automatically by Drupal.

Traditional Drupal development using the render pipeline allows you to ignore the pitfalls of mixing content and presentation logic in your data model. In a scenario with multiple distribution channels, this separation becomes of critical importance.

In this tutorial we will learn how to:

• Understand the importance of presentation and content separation (delivering clean content, not caring about how to show that content)
• Develop strategies to avoid these presentational problems with minimal damage to the content API

By the end of this tutorial you'll have a better understanding of why keeping presentation data out of your content model is important, and some tips for doing so.

JavaScript applications are the most common type of consumers. They are commonly used to create a website that runs in a web browser. Running decoupled applications in the browser will involve Cross-Origin Resource Sharing (CORS), which requires some setup on the Drupal side in order to work.

In this tutorial we'll:

• Learn about what CORS is and when/why we need to care about it
• Configure Drupal to return an appropriate CORS header, enabling browser-based consumers access to our API

By the end of this tutorial you will have a better understanding of CORS, and how to configure Drupal to serve an API that works with CORS.

When you are implementing an HTTP API for a decoupled project, one of the critical, but often overlooked, aspects is the API documentation. Documenting your API will allow front-end developers (and you six months from now) to learn how to use that particular API.

In Drupal, there are several modules that can read your site configuration and generate documentation for you automatically.

In this tutorial we're going to:

• Learn about the importance of good documentation.
• Decide whether or not to use an existing specification for our API such as JSON:API or GraphQL.
• Review options for automatically generating documentation.

By the end of this tutorial you'll be able to decide whether or not using an existing documentation specification is a good fit for your project, and choose an option based on those available for use with Drupal.

JSON:API includes a way to request a list of entities of a given resource from the server. Collections are the best way to find content based on filters, and to build listings into the consumers. Moreover, collections can be combined with all the options you can apply to a single resource, like sparse fieldsets and includes.

In this tutorial we'll:

• Learn about what collections are in JSON:API
• Learn how to request, sort, and paginate lists of content

By the end of this tutorial you should know how to retrieve a list of resources from the JSON:API server, and how to optionally sort and paginate the items in the list.

Often, web services require the user to create content. Votes on content, ratings, comments, and user-submitted stories are good examples of this. The JSON:API module supports the creation of entities by sending data in POST requests.

In this tutorial we will:

• Add an appropriate set of HTTP headers to a request that generates a new entity
• Construct a JSON object for the entity we want to create
• Issue a POST request that creates a new article node in Drupal

By the end of this tutorial you should be able to create a POST request that creates a new entity of any type via the JSON:API.

Sometimes unexpected things happen and Drupal needs to generate an error. The JSON:API specification describes how the server should return those errors. Understanding what to expect allows consumers to plan for errors and react gracefully.

In this tutorial we will:

• Discuss how HTTP errors are used in conjunction with JSON:API
• Learn about how JSON:API embeds information about the error encountered into the response object

By the end of this tutorial, you should have a basic understanding of the types of errors you can expect to receive when making JSON:API requests and what you can do to handle them.

Collections are a very powerful feature because they allow us to access multiple items at the same time. However, in many situations we do not want to access all the entities of a given type, but only the ones that meet some specific criteria. In order to reduce the set of entities in the collection to the ones we care about, we use filters.

In this tutorial we will:

• Look at the filter query string parameter and how it can be used with JSON:API collections
• Learn how to use filters in combination with the JSON:API module for Drupal to reduce the list of entities in a collection

By the end of this tutorial you should be able to request a list of entities in the form of a JSON:API collection and filter that list to include only the entities that match a specific set of requirements.

Embedding resources at the consumer's demand is one of the crucial features of a modern API. We mentioned in Modern Web Services with JSON:API and GraphQL that multiple round trips to the server is harmful for performance. This issue can be overcome by making a request that embeds any required related resources into the response for the resource we're retrieving.

In this tutorial, we'll learn how to use JSON:API's include parameter to embed resources in a response.

By the end of this tutorial, you should be able to make a single request that retrieves multiple embeded resources in order to improve the performance of your application when interacting with a JSON:API server.

The JSON:API module is our recommended starting point for creating REST APIs with Drupal. JSON:API module is now part of Drupal core as of 8.7, so installing the module no longer requires a separate download step.

In this tutorial we'll:

• Walk through installing the JSON:API module for Drupal
• Look at what you get out of the box with the JSON:API module

By the end of this tutorial you should be able to install the JSON:API module, and know what tools it provides you with.

Includes and filters are really powerful features. When combined together you can achieve almost any query your consumer application needs. Fancy filters we mentioned in a previous tutorial allow us to filter a collection based on fields of related entities, in addition to the fields directly under that entity.

In this tutorial we will:

• Learn about filtering based on data in related resources
• Filter based on multiple conditions and multi-value fields
• Demonstrate how to filter a collection of articles based on author or tags

By the end of this tutorial you should be able to use nested filters in conjunction with relationships to further refine the list of content returned in a JSON:API collection.

Drupal allows for a rich data model where entity reference fields can be used to relate any number of different items together in different ways. The data models that you can build with Drupal are often prolific in relationships, which means we need a way to handle these in our API. While Drupal treats a field with a string, and a field with an entity reference the same, JSON:API distinguishes between attributes and relationships.

In this tutorial we'll:

• Look at how JSON:API represents relationships between two or more resources
• How to distinguish between an attribute and a relationship in a response object
• Learn about what information is available for each relationship and how we can use it

By the end of this tutorial, you should have a better understanding of how the JSON:API specification represents relationships modeled using Drupal entity reference fields.

Occasionally we need to remove entities from the backend using the API. REST APIs, and in particular JSON:API, use the HTTP DELETE method to accomplish this.

In this tutorial we'll create a request for deleting a single entity. By the end of this tutorial you should be able to issue requests that can delete any entity via JSON:API.

Being able to retrieve resources from an API is a fundamental first step.

In this tutorial we will learn how to:

• Issue an HTTP request to extract information about a node from the JSON:API server
• Examine the response from the server

By the end of this tutorial you should know how to use an HTTP Get request to return a resource from the JSON:API server, and know what the default response for the resource will contain.

When you enable the JSON:API module you're significantly increasing the attack surface of your application. So it's a good idea to make sure that you understand the implications of doing so, and how to mitigate potential security issues. In most cases it doesn't require much work to do, but it's worth taking the time to make sure you've done it right.

In this tutorial we'll learn:

• What JSON:API already does to keep you secure
• How to protect against common attacks
• How to limit access to resources exposed by JSON:API

By the end of this tutorial you should know what to look for when auditing your JSON:API configuration to help prevent against common attacks.

By default, the JSON:API returns all the available data for an object in its response. Using JSON:API sparse fieldsets you can increase the performance of your consumer application by reducing the fields in the returned response object to just those that you need.

In this tutorial, we will learn how to reduce the output to get exactly the information that we need from the API.

This is one of the most important features of modern APIs like JSON:API.

By the end of this tutorial, you'll know what sparse fieldsets are, the role they fulfill, and how to use them when requesting data from a JSON:API server.