One post tagged with "resolvers"

I'm delighted that you've reached this point, and I hope you're finding the journey enjoyable. As we continue with this series, there's still much more ground to cover. Now, let's shift our focus to the modernization of the API. I understand if you've been pondering, "What's considered modern about this server?" especially since it relies on the trusted 'express.' Take a moment to relax because you're about to delve into the contemporary aspects of this series.

we are going to cover the following topcs in this guide:

• Install additional dependencies - GraphQl Tools, Apollo Server 4
• Reconfigure the API to have separate routes, one for Graphql and one for REST
• Implement GraphQL Endpont and resolvers
• Test the API

Alright, no more talking – let's jump right in!

# install all dependencies for graphql to work in our API
pnpm api add graphql @apollo/server @graphql-tools/load @graphql-tools/graphql-file-loader

The graphql package is now installed. we can proceed to configure our API. firstly we need to create a graphql folder in the api folder. this is where our graphql files will be stored. i will create a main.graphql file in that folder.

We are going to have three types initialized in this file:

• Response - custom type for responses
• Query - required root graphql query type
• Mutation - required root mution type

type Response {
    message: String!
    success: Boolean!
    error: String
}

type Query {
    hello: String
}

type Mutation {
    hello: String
}

Up next we need to move some code from main.ts to be isolated to their own module. i am refering to the router which is set inside the main file.

// ... rest of code
const router = express.Router();
// Set initial route
router.get("/", (_req, res) => {
    res.send({ message: "Monorepo API Configured!", success: true});
});
// .. rest of code 

We are moving this part to a separate module called api/src/endpoints/rest/restEndpoints.ts. where we will do some modifications and export the module

// api/src/endpoints/rest/restEndpoints.ts
import express, { Router } from "express";

const restEndpoint: Router = express.Router();
// define routes
restEndpoint.get("/", (_req, res) => {
    res.send({ message: "Rest Endpoint Initialized!" });
})

export { restEndpoint }

Now lets updated api/src/main.ts to use the rest endpoint.

import { restEndpoint } from './endpoints';

// ... rest of code
// Set v1/api endpoint
app.use("/v1/api", restEndpoint);
// .. rest of code 

We can run our server again to be sure that we did not break anything.

# run server
pnpm api dev
# our server should be running properly  as expected. 
# http://localhost:9100 or http://localhost:9000 depending on the PORT set in .env file

Hold on, this isn't GraphQL yet; we're still operating a REST API! yes you are right, its one of the steps toward adding multiple routes tou our API. Up next we are going to create another route for our API inside api/src/endpoints/graphql/graphqlEndpoints.ts module. Additionally we also need to create a resolver module api/src/endpoints/graphql/resolvers.ts which is going to be responsible for implementating all resolvers.

// api/src/endpoints/graphql/graphqlEndpoints.ts
import { ApolloServer } from '@apollo/server';
import { loadSchemaSync } from '@graphql-tools/load';
import { GraphQLFileLoader } from '@graphql-tools/graphql-file-loader';
import { resolvers } from '.';
// load schema from graphql files
const typeDefs=loadSchemaSync('./graphql/*.graphql', {
    loaders: [
        new GraphQLFileLoader()
    ]
});

// create apollo server
const server = new ApolloServer({
    typeDefs,
    resolvers
});

// export server
 export {  server}

please note this is a minimal configuration for now.

// api/src/endpoints/graphql/resolvers.ts

export const resolvers = {
    Query: {
        hello: () => `Hello there welcome to api monorepo`
    },
    Mutation: {
        hello: (_: unknown, args: { name: string }) => `Hello ${args.name} welcome to api monorepo`

    }
}

A sigh of relief we are now ready to test our REST + GraphQL APIs running on the same server.

# run server
pnpm api dev
# our server should be running properly  as expected. 
# http://localhost:9100/v1/rest and http://localhost:9000/v1/graphql