Expose Data in a Collection

1. Configure Roles for the Collection

App Services enforces collection rules for all incoming GraphQL requests, so you need to define at least one collection role with the permissions that your application requires.

All GraphQL requests include an authentication token that identifies the logged in App Services user that sent the request. App Services evaluates a role for every document included in a GraphQL operation and only returns fields and documents that the user has permission to see. If App Services omits a field, the field has a null value in the returned document.

2. Define a Schema for Documents in the Collection

GraphQL requires that all data conforms to a well-defined type, so you must define a schema for documents in the collection. App Services automatically generates GraphQL types and resolvers for documents in the collection based on the collection schema and regenerates new types whenever the schema changes.

3. Define Relationships to Other Collections

You can define relationships that connect each document in the collection to one or more documents in a foreign collection. To learn how to define a relationship, see Define a Relationship.

Relationships allow you to fluently reference and query related documents in GraphQL read and write operations. For example, you can query for a person and include the full document for each of their children from the same people collection:

query {
  person(query: { name: "Molly Weasley" }) {
    _id
    name
    age
    picture
    children {
      _id
      name
      age
      picture
    }
  }
}

4. Name the Data Type

App Services names the GraphQL types that it generates based on the data type that documents in the collection conform to. You can configure the name of the GraphQL types by setting the title field in a schema to the name of the data type that the schema defines.

There are three situations where you can set the title field:

• You can define the type name for each document in a collection by setting title at the root level of the schema. If you don't specify a title, App Services uses the name of the collection instead.

• You can define the type name for an embedded object by setting title in the embedded object schema.

• You can define the type name for a field that has a defined relationship by setting title in the field schema. App Services uses the title instead of the defined field name when it resolves relationships in GraphQL.

{
  "title": "movie",
  "properties": {
    "_id": { "bsonType": "objectId" },
    "title": { "bsonType": "string" },
    "year": { "bsonType": "int" },
    "director": { "bsonType": "int" }
  }
}

{
  "title": "Mouse",
  "bsonType": "object",
  "properties": {
    "_id": { "bsonType": "objectId" },
    "name": { "bsonType": "string" },
    "age": { "bsonType": "int" }
  }
}

query Mice {
  mouse(query: { _id: "5ebe6819197003ddb1f74475" }) {
    name
    age
  }
  mice {
    name
    age
  }
}