graphql-mesh-headers-not-interpolated

GraphQL Mesh: Issue reproduction for the operation headers not being interpolated when req.headers is a Map

Getting started

• Install dependencies with yarn install
• Start the services then the gateway with yarn start
• Open the Apollo Sandbox at http://localhost:4000 and execute a query:

# Taken from https://rickandmortyapi.com/documentation/

query {
  characters(page: 2, filter: { name: "rick" }) {
    info {
      count
    }
    results {
      name
    }
  }
}

Issue reproduction

Instructions

• Open the Apollo Sandbox at http://localhost:4000 and enter a query depending on headers:

query {
  me {
    id
    name
    email
  }
}

• Click on the "Headers" tab to add the access-token header which is also passed in the operationHeaders mesh config:

Key	Value
access-token	456

• Run the query in the Apollo Sandbox
• ⚠️ data.me is null in the response while it should return the user object because we passed the correct access-token header

Using a debugger

• Open the Node.js DevTools
  • Visit chrome://inspect on Chrome
  • Click on the hyperlink "Open dedicated DevTools for Node"
  • In Node.js DevTools, go to the "Connection" tab and add one for localhost:8123
• Add a debugger statement right before return headers; at the end of this file: node_modules/@graphql-mesh/string-interpolation/dist/cjs/resolver-data-factory.js
• Start the server with node --inspect=8123 server (change the start script of the gateway)
• Run the query in the Apollo Sandbox
• You should see the headers being returned and used as operationHeaders: the access-token should be empty

How to fix

🚀 Run it by checking out the fixed branch

We can simply allow the operationHeaders mesh config to be a function to use as a hook. This way, we trust Javascript to interprete the code instead of adding extra string interpolation based on regular expressions.

operationHeaders: ({ context }) => ({
  'access-token': context.req.headers.get('access-token'),
}),