Graphql For Headless Drupal

Introduction

GraphQL is a powerful API query language that allows developers to request only the data they need, making it efficient for client-server communication. Headless Drupal refers to using Drupal as a content management system (CMS) without the traditional front-end, enabling developers to use modern frameworks and libraries for the user interface while leveraging Drupal's capabilities for content storage and management.

Setting Up Your Environment

Before diving into GraphQL, you must set up a Drupal instance. You can do this locally using tools like Acquia, Lando, or DDEV. Once your Drupal setup is ready, you'll need to install the GraphQL module.

Installing the GraphQL Module

You can install the GraphQL module via Composer. Run the following command in your Drupal root directory:

composer require drupal/graphql

After installation, enable the module using Drush or the Drupal admin interface:

drush en graphql

Understanding GraphQL Basics

GraphQL allows you to define types and queries. A query is a request for data, while a type defines the structure of that data. In Drupal, you can expose your content types as GraphQL types.

Defining a Query

Here’s an example of a simple GraphQL query to fetch nodes of a specific content type:

Query Example:

{
  nodeQuery(
    filter: {
      conditions: [{
        field: "type",
        value: "article"
      }]
    }
  ) {
    entities {
      title
      body {
        value
      }
    }
  }
}

Using GraphiQL

After setting up the GraphQL module, you can access the GraphiQL interface by going to /graphql in your browser. This graphical interface allows you to write queries and see the results in real time.

Executing a Query

You can copy the query example from the previous section and paste it in the GraphiQL interface. Upon executing the query, you will receive a structured response containing the requested data.

Expected Output:

{
  "data": {
    "nodeQuery": {
      "entities": [{
        "title": "My Article",
        "body": {
          "value": "This is the body of the article."
        }
      }]
    }
  }
}

Creating Custom GraphQL Endpoints

You can create custom GraphQL endpoints to expose specific data. This involves defining a new GraphQL schema in your custom module.

Example of Custom Resolver

In your custom module, create a file called MyModule.graphqls and define your schema:

Sample Schema:

type Query {
  myCustomData: MyCustomType
}
type MyCustomType {
  field1: String
  field2: Int
}

You would also need to implement the resolver in your module’s PHP code to return the data for myCustomData.

Conclusion

GraphQL provides a flexible and efficient way to interact with your Drupal content in a headless architecture. By leveraging the power of GraphQL with Drupal, you can create highly dynamic and responsive applications that can scale with your content needs.