AppSync WebSockets With Apollo (iOS) v1+

Introduction

This is a sample implementation for Apollo iOS and AWS AppSync that works for real-time GraphQL endpoints.

The Apollo iOS Documentation is a good starting point when integrating AWS AppSync Graphql endpoints, but it falls a bit short when it comes to integrating a real-time endpoint.

Compatibility

• Apollo iOS v1+

Implementation

Specific customisations need to be made for the real-time / WebSocket implementation to work.

• Server Protocol
  • AppSync's server protocol adheres to graphql-ws
• Custom URL Format
  • For API key or Lambda authorization a custom header / payload format is required
  • See more on required header parameter formats based on AWS AppSync API authorization mode
• Request Body Format
  • The request body format needs to be converted to what is expected by AppSync
    • AppSync expects:

      {
          "id": "subscriptionId",
          "type": "start",
          "payload":
          {
              "data":
              {
                  "query": "query string",
                  "variables": "variables"
              },
              "extensions":
              {
                  "authorization":
                  {
                      "host": "host",
                      "x-api-key": "apikey"
                  }
              }
          }
      }
      

    • Apollo iOS, by default, provides:

      {
          "id": "subscriptionId",
          "type": "start",
          "payload":
          {
              "variables": "variables",
              "extensions": "extensions",
              "operationName": "subscriptionName",
              "query": "query string"
          }
      }