Getting to know the GraphQL API

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In this chapter you will get a quick introduction to Enonic’s GraphQL API - aka Guillotine. It is the point of integration between Next.js and Enonic.

Intro

Enonic provides a ridiculously flexible GraphQL API that dynamically reflects changes in your applications and content. Like Content Studio, the Guillotine app (and its API) was automatically downloaded and installed when you created your sandbox.

New to GraphQL as well? Check out the GraphQL documentation

Task: GraphQL Playground

For every content project in your sandbox, you will automatically get an API. By clicking the GraphQL Playground icon in your Content Studio menu, you should see the following

+ content studio guillotine

The API can be accessed directly following URL: http://localhost:8080/site/intro.

hmdb is the name of your Content Studio project.

Task: Run a simple query

Query playground lets us browse and use the API directly. Use the left hand field to type/paste in queries, press the "play" button to run the query, and the result will be presented in the right hand field.

  1. Query movies:

    One of the objectives in this tutorial is listing and presenting movie details. Run this simple query that retrieves the ID and displayName of some movies:

    Query to fetch movies from the Headless API:
    {
        guillotine {
            queryDsl(
              query: {
                boolean: {
                  must:[
                    {term: {field: "valid", value: {boolean:true}}}
                    {term: {field: "type", value: {string: "com.example.myproject:movie"}}}
                  ]
                }
              }
              sort: {
              	field:"displayName"
              	direction:ASC
            	}
            ) {
                id: _id
                displayName
            }
        }
    }
    com.example.myproject refers to the name of the application you created in the previous chapter. movie is a specific content type within the app.
  2. View the Result

    After executing the query, you should get a result in the right hand response panel. content studio basic query

Task: Query variables

In addition to the query itself, GraphQL also supports optional query variables. Query variables enable you to re-use the same query, but for instance fetch different content each time.

  1. Add query to the GraphQL playground:

    query($path:ID!){               (1)
      guillotine {
        get(key:$path) {            (2)
          type
          _id
          displayName
        }
      }
    }
    1 path is declared (with a $ marking it as a variable in the query). The declaration includes its type (ID), and a ! marking it as a required parameter).
    2 The path variable here used as the value of the key parameter, passed to the get field.
  2. Add query Variables. In the bottom left of Query Playground, you will find a the `Query variables`tab. Add the following JSON to the field.

    Tthe path field in the JSON corresponds to the $path in the query string above:
    {
        "path": "/movies/se7en"
    }
  3. Run the query to validate that the parameter working as expected.

Task: Type introspection

The queries above only specify fields like _id and displayName for each content found. These are general fields in the CMS, available across all content types.

Content types may also define their own custom fields. These are stored under the data field. In the headless API, deeper data and functionality belonging to a content type is accessed through introspection.

For example, you may introspect the fields that are exclusive to the com.example.myproject:movie content type like this:

Content type introspection:
... on com_example_myproject_Movie
The fully-qualified content type name is used, dots are replaced with underscores, and the name is capitalized Movie.
  1. Fetch a complex data set

    Lets get content for a movie, the referenced image items media:image and person items com.example.myproject:person in a single query:

    Paste this query into the GraphQL Playground:

    A query with nested introspections
    query($path:ID!){
      guillotine {
        get(key:$path) {
          type
          displayName
          ... on com_example_myproject_Movie {
            data {
              subtitle
              abstract
              trailer
              release
              photos {
                ... on media_Image {
                    imageUrl: imageUrl(type: absolute, scale: "width(500)")
                }
              }
              cast {
                character
                actor {
                  displayName
                  ... on com_example_myproject_Person {
                    _path
                    data {
                      photos {
                        ... on media_Image {
                          imageUrl: imageUrl(type: absolute, scale: "block(100,100)")
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
    1 Notice how imageUrl is requested with parameters of its own? Type introspections can expose certain functions for processing data before returning it.
  2. Keep the query variables from the previous step:

    {
        "path": "/movies/se7en"
    }

    Run the query in the Playground. It should produce a complete set of data - which will come in handy later in this tutorial.

    All in all, this allows for fetching deep and rich content data in a single API request.

In the next chapter you’ll get introduced to the concept of sites.


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