AEM GraphQL API for use with Content Fragments

Learn how to use Content Fragments in Adobe Experience Manager (AEM) with the AEM GraphQL API for headless content delivery.

AEM GraphQL API used with Content Fragments is heavily based on the standard, open source GraphQL API.

Using the GraphQL API in AEM enables the efficient delivery of Content Fragments to JavaScript clients in headless CMS implementations:

• Avoiding iterative API requests as with REST,
• Ensuring that delivery is limited to the specific requirements,
• Allowing for bulk delivery of exactly what is needed for rendering as the response to a single API query.

The GraphQL API

GraphQL is:

• “…a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.”.

  See GraphQL.org

• “…an open spec for a flexible API layer. Put GraphQL over your existing backends to build products faster than ever before…”.

  See Explore GraphQL.

• “…a data query language and specification developed internally by Facebook in 2012 before being publicly open sourced in 2015. It provides an alternative to REST-based architectures with the purpose of increasing developer productivity and minimizing amounts of data transferred. GraphQL is used in production by hundreds of organizations of all sizes…”

  See GraphQL Foundation.

For further information about the GraphQL API, see the following sections (amongst many other resources):

• At graphql.org:

  • Introduction to GraphQL

  • The GraphQL Specification

• At graphql.com:

  • Guides

  • Tutorials

  • Case Studies

The GraphQL for AEM implementation is based on the standard GraphQL Java Library. See:

• graphQL.org - Java

• GraphQL Java at GitHub

GraphQL Terminology

GraphQL uses the following:

• Queries

• Schemas and Types:

  • Schemas are generated by AEM based on the Content Fragment Models.
  • Using your schemas, GraphQL presents the types and operations allowed for the GraphQL for AEM implementation.

• Fields

• GraphQL Endpoint

  • The path in AEM that responds to GraphQL queries, and provides access to the GraphQL schemas.

  • See Enabling your GraphQL Endpoint for further details.

See the (GraphQL.org) Introduction to GraphQL for comprehensive details, including the Best Practices.

GraphQL Query Types

With GraphQL you can perform queries to return either:

• A single entry

• A list of entries

You can also perform:

• Persisted Queries, that are cached

The GraphQL for AEM Endpoint

The endpoint is the path used to access GraphQL for AEM. Using this path you (or your app) can:

• access the GraphQL schema,
• send your GraphQL queries,
• receive the responses (to your GraphQL queries).

There are two types of endpoints in AEM:

• Global
  • Available for use by all sites.
  • This endpoint can use all Content Fragment Models from all Sites configurations (defined in the Configuration Browser).
  • If there are any Content Fragment Models that should be shared among Sites configurations, then these should be created under the global Sites configurations.
• Sites configurations:
  • Corresponds to a Sites configuration, as defined in the Configuration Browser.
  • Specific to a specified site/project.
  • A Sites configuration specific endpoint will use the Content Fragment Models from that specific Sites configuration together with those from the global Sites configuration.

The repository path of the GraphQL for AEM global endpoint is:

/content/cq:graphql/global/endpoint

For which your app can use the following path in the request URL:

/content/_cq_graphql/global/endpoint.json

To enable an endpoint for GraphQL for AEM you need to:

• Enable your GraphQL Endpoint
• Publish your GraphQL Endpoint

Enabling your GraphQL Endpoint

To enable a GraphQL Endpoint you first need to have an appropriate configuration. See Content Fragments - Configuration Browser.

To enable the corresponding endpoint:

1. Navigate to Tools, Assets, then select GraphQL.

2. Select Create.

3. The Create new GraphQL Endpoint dialog will open. Here you can specify:

   • Name: name of the endpoint; you can enter any text.
   • Use GraphQL schema provided by: use the dropdown to select the required site/project.
   NOTE

   The following warning is shown in the dialog:

   • GraphQL endpoints may introduce data security and performance issues if not managed carefully. Please ensure to set appropriate permissions after creating an endpoint.

4. Confirm with Create.

5. The Next steps dialog will provide a direct link to the Security console so that you can ensure that newly created endpoint has suitable permissions.

   CAUTION

   The endpoint is accessible to everyone. This can - especially on publish instances - pose a security concern, as GraphQL queries can impose a heavy load on the server.

   You can set up ACLs, appropriate to your use case, on the endpoint.

Publishing your GraphQL Endpoint

Select the new endpoint and Publish to make it fully available in all environments.

GraphiQL Interface

An implementation of the standard GraphiQL interface is available for use with AEM GraphQL. This can be installed with AEM.

This interface allows you to directly input, and test, queries.

For example:

• http://localhost:4502/content/graphiql.html

This provides features such as syntax-highlighting, auto-complete, auto-suggest, together with a history and online documentation:

Installing the AEM GraphiQL interface

The GraphiQL user interface can be installed on AEM with a dedicated package: the GraphiQL Content Package v0.0.6 (2021.3) package.

Use Cases for Author and Publish Environments

The use cases can depend on the type of AEM environment:

• Publish environment; used to:

  • Query data for JS application (standard use-case)

• Author environment; used to:

  • Query data for “content management purposes”:
    • GraphQL in AEM is currently a read-only API.
    • The REST API can be used for CR(u)D operations.

Permissions

The permissions are those required for accessing Assets.

Schema Generation

GraphQL is a strongly typed API, which means that data must be clearly structured and organized by type.

The GraphQL specification provides a series of guidelines on how to create a robust API for interrogating data on a certain instance. To do this, a client needs to fetch the Schema, which contains all the types necessary for a query.

For Content Fragments, the GraphQL schemas (structure and types) are based on Enabled Content Fragment Models and their data types.

For example, if a user created a Content Fragment Model called Article, then AEM generates the object article that is of a type ArticleModel. The fields within this type correspond to the fields and data types defined in the model.

1. A Content Fragment Model:

   

2. The corresponding GraphQL schema (output from GraphiQL automatic documentation):
   

   This shows that the generated type ArticleModel contains several fields.

   • Three of them have been controlled by the user: author, main and referencearticle.

   • The other fields were added automatically by AEM, and represent helpful methods to provide information about a certain Content Fragment; in this example, _path, _metadata, _variations. These helper fields are marked with a preceding _ to distinguish between what has been defined by the user and what has been auto-generated.

3. After a user creates a Content Fragment based on the Article model, it can then be interrogated through GraphQL. For examples, see the Sample Queries (based on a sample Content Fragment structure for use with GraphQL).

In GraphQL for AEM, the schema is flexible. This means that it is auto-generated each and every time a Content Fragment Model is created, updated or deleted. The data schema caches are also refreshed when you update a Content Fragment Model.

The Sites GraphQL service listens (in the background) for any modifications made to a Content Fragment Model. When updates are detected, only that part of the schema is regenerated. This optimization saves time and provides stability.

So for example, if you:

1. Install a package containing Content-Fragment-Model-1 and Content-Fragment-Model-2:

   1. GraphQL types for Model-1 and Model-2 will be generated.

2. Then modify Content-Fragment-Model-2:

   1. Only the Model-2 GraphQL type will get updated.

   2. Whereas Model-1 will remain the same.

The schema is served through the same endpoint as the GraphQL queries, with the client handling the fact that the schema is called with the extension GQLschema. For example, performing a simple GET request on /content/cq:graphql/global/endpoint.GQLschema will result in the output of the schema with the Content-type: text/x-graphql-schema;charset=iso-8859-1.

Schema Generation - Unpublished Models

When Content Fragments are nested it can happen that a parent Content Fragment Model is published, but a referenced model is not.

When this happens, AEM generates an incomplete Schema for the parent Content Fragment Model. This means that the Fragment Reference, which is dependent on the unpublished model, is removed from the schema.

Fields

Within the schema there are individual fields, of two basic categories:

• Fields that you generate.

  A selection of Field Types are used to create fields based on how you configure your Content Fragment Model. The field names are taken from the Property Name field of the Data Type.

  • There is also the Render As property to take into consideration, because users can configure certain data types; for example, as either a single line text or a multifield.

• GraphQL for AEM also generates a number of helper fields.

  These are used to identify a Content Fragment, or to get more information about a content fragment.

Field Types

GraphQL for AEM supports a list of types. All the supported Content Fragment Model Data Types and the corresponding GraphQL types are represented:

Helper Fields

In addition to the data types for user generated fields, GraphQL for AEM also generates a number of helper fields in order to help identify a Content Fragment, or to provide additional information about a Content Fragment.

Path

The path field is used as an identifier in GraphQL. It represents the path of the Content Fragment asset inside the AEM repository. We have chosen this as the identifier of a content fragment, because it:

• is unique within AEM,
• can be easily fetched.

The following code will display the paths of all Content Fragments that were created based on the Content Fragment Model Person.

{
  personList {
    items {
      _path
    }
  }
}

To retrieve a single Content Fragment of a specific type, you also need to determine its path first. for example:

{
  personByPath(_path: "/content/dam/path/to/fragment/john-doe") {
    item {
      _path
      firstName
      name
    }
  }
}

See Sample Query - A Single Specific City Fragment.

Metadata

Through GraphQL, AEM also exposes the metadata of a Content Fragment. Metadata is the information that describes a content fragment, such as the title of a content fragment, the thumbnail path, the description of a Content Fragment, the date it was created, amongst others.

Because Metadata is generated through the Schema Editor and as such does not have a specific structure, the TypedMetaData GraphQL type was implemented to expose the metadata of a Content Fragment. TypedMetaData exposes the information grouped by the following scalar types:

Each scalar type represents either a single name-value pair or an array of name-value pairs, where the value of that pair is of the type it was grouped in.

For example, if you want to retrieve the title of a Content Fragment, we know that this property is a String property, so we would query for all the String Metadata:

To query for metadata:

{
  personByPath(_path: "/content/dam/path/to/fragment/john-doe") {
    item {
      _path
      _metadata {
        stringMetadata {
          name
          value
        }
      }
    }
  }
}

You can view all the metadata GraphQL types if you view the Generated GraphQL schema. All model types have the same TypedMetaData.

See Sample Query for Metadata - List the Metadata for Awards titled GB.

Variations

The _variations field has been implemented to simplify querying the variations that a Content Fragment has. For example:

{
  personByPath(_path: "/content/dam/path/to/fragment/john-doe") {
    item {
      _variations
    }
  }
}

See Sample Query - All Cities with a Named Variation.

GraphQL Variables

GraphQL permits variables to be placed in the query. For more information you can see the GraphQL documentation for Variables.

For example, to get all Content Fragments of type Article that have a specific variation, you can specify the variable variation in GraphiQL.

### query
query GetArticlesByVariation($variation: String!) {
    articleList(variation: $variation) {
        items {
            _path
            author
        }
    }
}

### in query variables
{
    "variation": "uk"
}

GraphQL Directives

In GraphQL there is a possibility to change the query based on variables, called GraphQL Directives.

For example there you can include the adventurePrice field in a query for all the AdventureModels, based on a variable includePrice.

### query
query GetAdventureByType($includePrice: Boolean!) {
  adventureList {
    items {
      adventureTitle
      adventurePrice @include(if: $includePrice)
    }
  }
}

### in query variables
{
    "includePrice": true
}

Filtering

You can also use filtering in your GraphQL queries to return specific data.

Filtering uses a syntax based on logical operators and expressions.

For example, the following (basic) query filters all persons that have a name of Jobs or Smith:

query {
  personList(filter: {
    name: {
      _logOp: OR
      _expressions: [
        {
          value: "Jobs"
        },
        {
          value: "Smith"
        }
      ]
    }
  }) {
    items {
      name
      firstName
    }
  }
}

For further examples, see:

• details of the GraphQL for AEM extensions

• Sample Queries using this Sample Content and Structure

  • And the Sample Content and Structure prepared for use in sample queries

• Sample Queries based on the WKND Project

GraphQL for AEM - Summary of Extensions

The basic operation of queries with GraphQL for AEM adhere to the standard GraphQL specification. For GraphQL queries with AEM there are a few extensions:

• If you require a single result:

  • use the model name; eg city

• If you expect a list of results:

  • add List to the model name; for example, cityList
  • See Sample Query - All Information about All Cities

• The filter includeVariations is included in the List query type. To retrieve Content Fragment Variations in the query results, then the includeVariations filter must be set to true.

  CAUTION

  The filter includeVariations cannot be used together with the system-generated field _variation.

• If you want to use a logical OR:

  • use _logOp: OR
  • See Sample Query - All Persons that have a name of “Jobs” or “Smith”

• Logical AND also exists, but is (often) implicit

• You can query on field names that correspond to the fields within the Content Fragment Model

  • See Sample Query - Full Details of a Company’s CEO and Employees

• In addition to the fields from your model, there are some system-generated fields (preceded by underscore):

  • For content:

    • _locale : to reveal the language; based on Language Manager

      • See Sample Query for multiple Content Fragments of a given locale

    • _metadata : to reveal metadata for your fragment

      • See Sample Query for Metadata - List the Metadata for Awards titled GB

    • _model : allow querying for a Content Fragment Model (path and title)

      • See Sample Query for a Content Fragment Model from a Model

    • _path : the path to your Content Fragment within the repository

      • See Sample Query - A Single Specific City Fragment

    • _reference : to reveal references; including inline references in the Rich Text Editor

      • See Sample Query for multiple Content Fragments with Prefetched References

    • _variation : to reveal specific Variations within your Content Fragment

      NOTE

      If the given variation does not exist for a Content Fragment, then the master variation will be returned as a (fallback) default.

      CAUTION

      The system-generated field _variation cannot be used together with the filter includeVariations.

      • See Sample Query - All Cities with a Named Variation

    • _tags : to reveal the IDs of Content Fragments or Variations that contain tags; this is an array of cq:tags identifiers.

      • See Sample Query - Names of All Cities Tagged as City Breaks
      • See Sample Query for Content Fragment Variations of a given Model that have a specific tag attached
      NOTE

      Tags can also be queried by listing the Metadata of a Content Fragment.

  • And operations:

    • _operator : apply specific operators; EQUALS, EQUALS_NOT, GREATER_EQUAL, LOWER, CONTAINS, STARTS_WITH

      • See Sample Query - All Persons that do not have a name of “Jobs”
      • See Sample Query - All Adventures where the _path starts with a specific prefix

    • _apply : to apply specific conditions; for example, AT_LEAST_ONCE

      • See Sample Query - Filter on an array with an item that must occur at least once

    • _ignoreCase : to ignore the case when querying

      • See Sample Query - All cities with SAN in the name, irrespective of case

• GraphQL union types are supported:

  • use ... on
    • See Sample Query for a Content Fragment of a specific Model with a Content Reference

• Fallback when querying nested fragments:

  • If the requested variation does not exist in a nested fragment, then the Master variation will be returned.

Persisted Queries (Caching)

After preparing a query with a POST request, it can be executed with a GET request that can be cached by HTTP caches or a CDN.

This is required as POST queries are usually not cached, and if using GET with the query as a parameter there is a significant risk of the parameter becoming too large for HTTP services and intermediates.

Persisted queries must always use the endpoint related to the appropriate Sites configuration; so they can use either, or both:

• The Global configuration and endpoint
  The query has access to all Content Fragment Models.
• Specific Sites configuration(s) and endpoint(s)
  Creating a persisted query for a specific Sites configuration requires a corresponding Sites-configuration-specific endpoint (to provide access to the related Content Fragment Models).
  For example, to create a persisted query specifically for the WKND Sites configuration, a corresponding WKND-specific Sites configuration, and a WKND-specific endpoint must be created in advance.

For example, if there is a particular query called my-query, which uses a model my-model from the Sites configuration my-conf:

• You can create a query using the my-conf specific endpoint, and then the query will be saved as following:
  /conf/my-conf/settings/graphql/persistentQueries/my-query
• You can create the same query using global endpoint, but then the query will be saved as following:
  /conf/global/settings/graphql/persistentQueries/my-query

Here are the steps required to persist a given query:

1. Prepare the query by PUTing it to the new endpoint URL /graphql/persist.json/<config>/<persisted-label>.

   For example, create a persisted query:

   $ curl -X PUT \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -H "Content-Type: application/json" \
       "http://localhost:4502/graphql/persist.json/wknd/plain-article-query" \
       -d \
   '{
     articleList {
       items{
           _path
           author
           main {
               json
           }
       }
     }
   }'
   

2. At this point, check the response.

   For example, check for success:

   {
     "action": "create",
     "configurationName": "wknd",
     "name": "plain-article-query",
     "shortPath": "/wknd/plain-article-query",
     "path": "/conf/wknd/settings/graphql/persistentQueries/plain-article-query"
   }
   

3. You can then replay the persisted query by GETing the URL /graphql/execute.json/<shortPath>.

   For example, use the persisted query:

   $ curl -X GET \
       http://localhost:4502/graphql/execute.json/wknd/plain-article-query
   

4. Update a persisted query by POSTing to an already existing query path.

   For example, use the persisted query:

   $ curl -X POST \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -H "Content-Type: application/json" \
       "http://localhost:4502/graphql/persist.json/wknd/plain-article-query" \
       -d \
   '{
     articleList {
       items{
           _path
           author
           main {
               json
           }
         referencearticle {
           _path
         }
       }
     }
   }'
   

5. Create a wrapped plain query.

   For example:

   $ curl -X PUT \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -H "Content-Type: application/json" \
       "http://localhost:4502/graphql/persist.json/wknd/plain-article-query-wrapped" \
       -d \
   '{ "query": "{articleList { items { _path author main { json } referencearticle { _path } } } }"}'
   

6. Create a wrapped plain query with cache control.

   For example:

   $ curl -X PUT \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -H "Content-Type: application/json" \
       "http://localhost:4502/graphql/persist.json/wknd/plain-article-query-max-age" \
       -d \
   '{ "query": "{articleList { items { _path author main { json } referencearticle { _path } } } }", "cache-control": { "max-age": 300 }}'
   

7. Create a persisted query with parameters:

   For example:

   $ curl -X PUT \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -H "Content-Type: application/json" \
       "http://localhost:4502/graphql/persist.json/wknd/plain-article-query-parameters" \
       -d \
   'query GetAsGraphqlModelTestByPath($apath: String!, $withReference: Boolean = true) {
     articleByPath(_path: $apath) {
       item {
         _path
           author
           main {
           plaintext
           }
           referencearticle @include(if: $withReference) {
           _path
           }
         }
       }
     }'
   

8. Executing a query with parameters.

   For example:

   $ curl -X POST \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -H "Content-Type: application/json" \
       "http://localhost:4502/graphql/execute.json/wknd/plain-article-query-parameters;apath=%2fcontent2fdam2fwknd2fen2fmagazine2falaska-adventure2falaskan-adventures;withReference=false"
   
   $ curl -X GET \
       "http://localhost:4502/graphql/execute.json/wknd/plain-article-query-parameters;apath=%2fcontent2fdam2fwknd2fen2fmagazine2falaska-adventure2falaskan-adventures;withReference=false"
   

9. To execute the query on publish, the related persist tree need to replicated

   • Using a POST for replication:

     $curl -X POST   http://localhost:4502/bin/replicate.json \
       -H 'authorization: Basic YWRtaW46YWRtaW4=' \
       -F path=/conf/wknd/settings/graphql/persistentQueries/plain-article-query \
       -F cmd=activate
     

   • Using a package:

     1. Create a new package definition.
     2. Include the configuration (for example, /conf/wknd/settings/graphql/persistentQueries).
     3. Build the package.
     4. Replicate the package.

   • Using replication/distribution tool.

     1. Go to the Distribution tool.
     2. Select tree activation for the configuration (for example, /conf/wknd/settings/graphql/persistentQueries).

   • Using a workflow (via workflow launcher configuration):

     1. Define a workflow launcher rule for executing a workflow model that would replicate the configuration on different events (for example, create, modify, amongst others).

10. Once the query configuration is on publish, the same principles apply, just using the publish endpoint.

    NOTE

    For anonymous access the system assumes that the ACL allows “everyone” to have access to the query configuration.

    If that is not the case it will not be able to execute.

    NOTE

    Any semicolons (“;”) in the URLs need to be encoded.

    For example, as in the request to Execute a persisted query:

    curl -X GET \ "http://localhost:4502/graphql/execute.json/wknd/plain-article-query-parameters%3bapath=%2fcontent2fdam2fwknd2fen2fmagazine2falaska-adventure2falaskan-adventures;withReference=false"
    

Querying the GraphQL endpoint from an External Website

To access the GraphQL endpoint from an external website you need to configure the:

• CORS Filter
• Referrer Filter

CORS Filter

To access the GraphQL endpoint, a CORS policy must be configured in the customer Git repository. This is done by adding an appropriate OSGi CORS configuration file for the desired endpoint(s).

This configuration must specify a trusted website origin alloworigin or alloworiginregexp for which access must be granted.

For example, to grant access to the GraphQL endpoint and persisted queries endpoint for https://my.domain you can use:

{
  "supportscredentials":true,
  "supportedmethods":[
    "GET",
    "HEAD",
    "POST"
  ],
  "exposedheaders":[
    ""
  ],
  "alloworigin":[
    "https://my.domain"
  ],
  "maxage:Integer":1800,
  "alloworiginregexp":[
    ""
  ],
  "supportedheaders":[
    "Origin",
    "Accept",
    "X-Requested-With",
    "Content-Type",
    "Access-Control-Request-Method",
    "Access-Control-Request-Headers"
  ],
  "allowedpaths":[
    "/content/_cq_graphql/global/endpoint.json",
    "/graphql/execute.json/.*"
  ]
}

If you have configured a vanity path for the endpoint, you can also use it in allowedpaths.

Referrer Filter

In addition to CORS configuration, a Referrer filter must be configured to allow access from third party hosts.

This is done by adding an appropriate OSGi Referrer Filter configuration file that:

• specifies a trusted website host name; either allow.hosts or allow.hosts.regexp,
• grants access for this host name.

For example, to grant access for requests with the Referrer my.domain you can:

{
    "allow.empty":false,
    "allow.hosts":[
      "my.domain"
    ],
    "allow.hosts.regexp":[
      ""
    ],
    "filter.methods":[
      "POST",
      "PUT",
      "DELETE",
      "COPY",
      "MOVE"
    ],
    "exclude.agents.regexp":[
      ""
    ]
}

Authentication

See Authentication for Remote AEM GraphQL Queries on Content Fragments.

FAQs

Questions that have arisen:

1. Q: “How is the GraphQL API for AEM different from Query Builder API?”

   • A:
     “The AEM GraphQL API offers total control on the JSON output, and is an industry standard for querying content.
     Moving forward, AEM is planning to invest in the AEM GraphQL API.”

Tutorial - Getting Started with AEM Headless and GraphQL

Looking for a hands-on tutorial? Check out Getting Started with AEM Headless and GraphQL end-to-end tutorial illustrating how to build-out and expose content using AEM’s GraphQL APIs and consumed by an external app, in a headless CMS scenario.

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