Hooks allow you to define a URL to send a POST request to when mutation on some type is performed. This lets you react to user actions and integrate third-party services without much hassle.

Hooks are stored in type ReindexHook. It has the following fields:

• type - type, from operation on which hook triggers. If null, hook will trigger to any type operation.
• trigger - event that triggers the hook. Can be afterCreate, afterUpdate or afterDelete.
• url - full URL to send the request to
• fragment - fragment body on the corresponding type payload. Must be surrounded by {} and not have a name. Can include typed inline fragments.
• logLevel - all, error or none. Defines which results of the hook fragment execution to save in ReindexHookLog. all - all results are saved, error - only failed hooks are saved.

For example, let’s assume we have a service listening at http://www.example.com/testservice and we want to POST to it when new todo is created.

First, we need to find the ID of Todo ReindexType.

{
  reindexTypeByName(name: "Todo") {
    id,
  }
}

After that we can create a hook. Fragment is used on the same type as the mutation result (payload). Let’s say we want to get todo’s text and the user id that it belongs to.

mutation {
  createReindexHook(input: {
    type: "YOUR-TODO-TYPE-ID",
    trigger: afterCreate,
    url: "http://www.example.com/testservice",
    fragment: "{ changedTodo { text, user { id } } }",
    logLevel: error
  }) {
    id
  }
}

Now every time new Todo will be created, the service should receive a POST request.

Operations on many-to-many relationships trigger hooks for both of the affected nodes.

Hook log #

Often it’s useful to check if your hook is actually doing something. It’s easy to make mistake in a fragment or URL. Hook logs provide a way to log executed hooks and then check if there was a problem.

Depending on your hook logLevel, hook log will contain a list of hook log results. You can access it directly by reading the corresponding hook:

{
  reindexHookById(id: "YOUR-HOOK-ID") {
    log(orderBy: CREATED_AT_DESC) {
      nodes {
        createdAt,
        type,
        errors
      }
    }
  }
}

Hookbook #

Sending emails with Mailgun through Zapier #

Zapier provides out of the box integrations with many services. This guide shows how to send emails through Mailgun by using Zapier Post-hook app.