Handle Webhooks with GraphQL Subscriptions

Handle Webhooks with GraphQL Subscriptions in your unified schema using GraphQL Mesh. Use PubSub implementation to bind webhook paths to specific topics and consume them as subscription root fields. You can also generate GraphQL type definitions from sample JSON responses using the JSON Schema Handler.

GraphQL Mesh can consume Webhooks as GraphQL Subscriptions in the unified schema by using the built-in PubSub implementation

Add a new Subscription field

You can use additionalTypeDefs and resolveTo directive to add subscription root fields to your unified schema.

If you subscribe a pubSub topic with webhook:EXPECTED_METHOD:EXPECTED_PATH, the server will automatically bind that path to that topic.

mesh.config.ts

import { defineConfig as defineComposeConfig } from '@graphql-mesh/compose-cli'

export const composeConfig = defineComposeConfig({
  additionalTypeDefs: /* GraphQL */ `
    # If you don't have Subscription type defined anywhere
    # You have to extend subscription definition
    extend schema {
      subscription: Subscription
    }
    type Subscription {
      todoAdded: Todo @resolveTo(
        pubsubTopic: "webhook:post:/webhooks/todo_added"
      # result: "data.someProp.someOtherProp", # You can get nested fields
      # filterBy: "root.userId === args.userId" # You can filter the payload by `userId` for example
      )
    }
  `
})

We can use existing types from our unified schema, and this root field is subscribed to our specific topic in our PubSub service.

But you have to enable webhooks flag in Hive Gateway in this case;

mesh.config.ts

import { defineConfig as defineGatewayConfig } from '@graphql-hive/gateway'

export const gatewayConfig = defineGatewayConfig({
  webhooks: true
})

Use JSON Schema Handler instead

You can also use the JSON Schema handler if you don’t want to write an extra GraphQL type definition. You can generate GraphQL type definitions from sample JSON response;

Just add the following to your existing JSON schema handler configuration in .meshrc.yml file;

mesh.config.ts

import { defineConfig as defineComposeConfig } from '@graphql-mesh/compose-cli'
import { loadJSONSchemaSubgraph } from '@omnigraph/json-schema'

export const composeConfig = defineComposeConfig({
  subgraphs: [
    {
      sourceHandler: loadJSONSchemaSubgraph('API', {
        /* Other configuration options */
        operations: [
          /** Other operations */
          {
            type: OperationTypeNode.SUBSCRIPTION,
            field: 'todoAdded',
            pubsubTopic: 'webhook:post:/webhooks/todo_added',
            responseSample: './todo.json',
            responseTypeName: 'Todo'
          }
        ]
      })
    }
  ]
})