This boilerplate gives an example of writing a GraphQL service to wrap some pre-existing REST API. You can add this REST wrapper as a Remote Schema in Hasura.
Node 8.10
Apollo Server (GraphQL framework)
The REST API is implemented in my-rest-api folder. It has the following APIs:
GET /users
GET /users/:userId
POST /users
The GET /users endpoint also takes an optional query param i.e. GET /users?name=abc and the POST /users endpoint expects a valid JSON payload in the body.
We will convert the above REST API into the following GraphQL API:
type User {
id: String!
name: String!
balance: Int!
}
type Query {
getUser(id: String!): User
users(name: String): [User]
}
type Mutation {
addUser(name: String!, balance: Int!): User
}
In our GraphQL service, we have defined a new API for each REST endpoint. This is what our mapping looks like:
| REST | GraphQL |
|---|---|
| GET /users | users (name: String) : [User] |
| GET /users/:userId | getUser(id: String!): User |
| POST /users | addUser(name: String!, balance: Int!): User |
We would have to write a resolver for each API. This is what a typical resolver looks like, for e.g getUser :
getUser: async (_, { id }) => {
return await getData(restAPIEndpoint + '/users/' + id);
}
You need a Heroku account and heroku-cli installed. Execute the following commands in a terminal:
heroku login
# in my-rest-api directory (community/boilerplates/remote-schemas/rest-wrapper/my-rest-api)
heroku create
git push heroku master
The above step will return an endpoint for your REST API. Update the constant restAPIEndpoint in index.js with this endpoint.
Create GRAPHQL API app
# in current directory (community/boilerplates/remote-schemas/rest-wrapper)
heroku create
git push heroku master
The final step will also return a HTTPS URL in the output. Now, you can go to Hasura console and add this URL as a Remote Schema to allow querying it via Hasura.