debian-mirror-gitlab/doc/api/graphql/getting_started.md

Getting started with GitLab GraphQL API

This guide demonstrates basic usage of GitLab's GraphQL API.

See the GraphQL API style guide for implementation details aimed at developers who wish to work on developing the API itself.

Running examples

The examples documented here can be run using:

• The command line.
• GraphiQL.

Command line

You can run GraphQL queries in a curl request on the command line on your local machine. A GraphQL request can be made as a POST request to /api/graphql with the query as the payload. You can authorize your request by generating a personal access token to use as a bearer token.

Example:

GRAPHQL_TOKEN=<your-token>
curl 'https://gitlab.com/api/graphql' --header "Authorization: Bearer $GRAPHQL_TOKEN" --header "Content-Type: application/json" --request POST --data "{\"query\": \"query {currentUser {name}}\"}"

GraphiQL

GraphiQL (pronounced “graphical”) allows you to run queries directly against the server endpoint with syntax highlighting and autocomplete. It also allows you to explore the schema and types.

The examples below:

• Can be run directly against GitLab 11.0 or later, though some of the types and fields may not be supported in older versions.
• Will work against GitLab.com without any further setup. Make sure you are signed in and navigate to the GraphiQL Explorer.

If you want to run the queries locally, or on a self-managed instance, you will need to either:

• Create the gitlab-org group with a project called graphql-sandbox under it. Create several issues within the project.
• Edit the queries to replace gitlab-org/graphql-sandbox with your own group and project.

Please refer to running GraphiQL for more information.

NOTE: Note: If you are running GitLab 11.0 to 12.0, enable the graphql feature flag.

Queries and mutations

The GitLab GraphQL API can be used to perform:

• Queries for data retrieval.
• Mutations for creating, updating, and deleting data.

NOTE: Note: In the GitLab GraphQL API, id generally refers to a global ID, which is an object identifier in the format of gid://gitlab/Issue/123.

GitLab's GraphQL Schema outlines which objects and fields are available for clients to query and their corresponding data types.

Example: Get only the names of all the projects the currently logged in user can access (up to a limit, more on that later) in the group gitlab-org.

query {
  group(fullPath: "gitlab-org") {
    id
    name
    projects {
      nodes {
        name
      }
    }
  }
}

Example: Get a specific project and the title of Issue #2.

query {
  project(fullPath: "gitlab-org/graphql-sandbox") {
    name
    issue(iid: "2") {
      title
    }
  }
}

Graph traversal

When retrieving child nodes use:

• the edges { node { } } syntax.
• the short form nodes { } syntax.

Underneath it all is a graph we are traversing, hence the name GraphQL.

Example: Get a project (only its name) and the titles of all its issues.

query {
  project(fullPath: "gitlab-org/graphql-sandbox") {
    name
    issues {
      nodes {
        title
        description
      }
    }
  }
}

More about queries: GraphQL docs

Authorization

Authorization uses the same engine as the GitLab application (and GitLab.com). So if you've signed in to GitLab and use GraphiQL, all queries will be performed as you, the signed in user. For more information, see the GitLab API documentation.

Mutations

Mutations make changes to data. We can update, delete, or create new records. Mutations generally use InputTypes and variables, neither of which appear here.

Mutations have:

• Inputs. For example, arguments, such as which emoji you'd like to award, and to which object.
• Return statements. That is, what you'd like to get back when it's successful.
• Errors. Always ask for what went wrong, just in case.

Creation mutations

Example: Let's have some tea - add a :tea: reaction emoji to an issue.

mutation {
  addAwardEmoji(input: { awardableId: "gid://gitlab/Issue/27039960",
      name: "tea"
    }) {
    awardEmoji {
      name
      description
      unicode
      emoji
      unicodeVersion
      user {
        name
      }
    }
    errors
  }
}

Example: Add a comment to the issue (we're using the ID of the GitLab.com issue - but if you're using a local instance, you'll need to get the ID of an issue you can write to).

mutation {
  createNote(input: { noteableId: "gid://gitlab/Issue/27039960",
      body: "*sips tea*"
    }) {
    note {
      id
      body
      discussion {
        id
      }
    }
    errors
  }
}

Update mutations

When you see the result id of the note you created - take a note of it. Now let's edit it to sip faster!

mutation {
  updateNote(input: { id: "gid://gitlab/Note/<note id>",
      body: "*SIPS TEA*"
    }) {
    note {
      id
      body
    }
    errors
  }
}

Deletion mutations

Let's delete the comment, since our tea is all gone.

mutation {
  destroyNote(input: { id: "gid://gitlab/Note/<note id>" }) {
    note {
      id
      body
    }
    errors
  }
}

You should get something like the following output:

{
  "data": {
    "destroyNote": {
      "errors": [],
      "note": null
    }
  }
}

We've asked for the note details, but it doesn't exist anymore, so we get null.

More about mutations: GraphQL Docs.

Introspective queries

Clients can query the GraphQL endpoint for information about its own schema. by making an introspective query.

It is through an introspection query that the GraphiQL Query Explorer gets all of its knowledge about our GraphQL schema to do autocompletion and provide its interactive Docs tab.

Example: Get all the type names in the schema.

{
  __schema {
    types {
      name
    }
  }
}

Example: Get all the fields associated with Issue. kind tells us the enum value for the type, like OBJECT, SCALAR or INTERFACE.

query IssueTypes {
  __type(name: "Issue") {
    kind
    name
    fields {
      name
      description
      type {
        name
      }
    }
  }
}

More about introspection: GraphQL docs

Sorting

Some of GitLab's GraphQL endpoints allow you to specify how you'd like a collection of objects to be sorted. You can only sort by what the schema allows you to.

Example: Issues can be sorted by creation date:

query {
  project(fullPath: "gitlab-org/graphql-sandbox") {
   name
    issues(sort: created_asc) {
      nodes {
        title
        createdAt
      }
    }
  }
}

Pagination

Pagination is a way of only asking for a subset of the records (say, the first 10). If we want more of them, we can make another request for the next 10 from the server (in the form of something like "please give me the next 10 records").

By default, GitLab's GraphQL API will return only the first 100 records of any collection. This can be changed by using first or last arguments. Both arguments take a value, so first: 10 will return the first 10 records, and last: 10 the last 10 records.

Example: Retrieve only the first 2 issues (slicing). The cursor field gives us a position from which we can retrieve further records relative to that one.

query {
  project(fullPath: "gitlab-org/graphql-sandbox") {
    name
    issues(first: 2) {
      edges {
        node {
          title
        }
      }
      pageInfo {
        endCursor
        hasNextPage
      }
    }
  }
}

Example: Retrieve the next 3. (The cursor value eyJpZCI6IjI3MDM4OTMzIiwiY3JlYXRlZF9hdCI6IjIwMTktMTEtMTQgMDU6NTY6NDQgVVRDIn0 could be different, but it's the cursor value returned for the second issue returned above.)

query {
  project(fullPath: "gitlab-org/graphql-sandbox") {
    name
    issues(first: 3, after: "eyJpZCI6IjI3MDM4OTMzIiwiY3JlYXRlZF9hdCI6IjIwMTktMTEtMTQgMDU6NTY6NDQgVVRDIn0") {
      edges {
        node {
          title
        }
        cursor
      }
      pageInfo {
        endCursor
        hasNextPage
      }
    }
  }
}

More on pagination and cursors: GraphQL docs