Getting Started

What are you going to build?

In this tutorial we are going to create a Hackernews clone with Go and gqlgen, So our API will be able to handle registration, authentication, submitting links and getting list of links.

Project Setup

Here is a description from gqlgen about the generated files:

• gqlgen.yml — The gqlgen config file, knobs for controlling the generated code.
• graph/generated/generated.go — The GraphQL execution runtime, the bulk of the generated code.
• graph/model/models_gen.go — Generated models required to build the graph. Often you will override these with your own models. Still very useful for input types.
• graph/schema.graphqls — This is the file where you will add GraphQL schemas.
• graph/schema.resolvers.go — This is where your application code lives. generated.go will call into this to get the data the user has requested.
• server.go — This is a minimal entry point that sets up an http.Handler to the generated GraphQL server. start the server with go run server.go and open your browser and you should see the graphql playground, So setup is right!

Defining Our Schema

Now let’s start with defining schema we need for our API. We have two types Link and User each of them for representing Link and User to client, a links Query to return list of Links. an input for creating new links and mutation for creating link. we also need mutations to for auth system which includes Login, createUser, refreshToken(I’ll explain them later) then run the command below to regenerate graphql models.

file: graph/schema.graphqls

type Link {
  id: ID!
  title: String!
  address: String!
  user: User!
}

type User {
  id: ID!
  name: String!
}

type Query {
  links: [Link!]!
}

input NewLink {
  title: String!
  address: String!
}

input RefreshTokenInput{
  token: String!
}

input NewUser {
  username: String!
  password: String!
}

input Login {
  username: String!
  password: String!
}

type Mutation {
  createLink(input: NewLink!): Link!
  createUser(input: NewUser!): String!
  login(input: Login!): String!
  # we'll talk about this in authentication section
  refreshToken(input: RefreshTokenInput!): String!
}

Note: If you are getting validation failed: packages.Load error. It may occur, because gqlgen uses todo project as starter template. To get rid of this error, edit graph/schema.resolvers.go file and delete functions CreateTodo and Todos. Now run the command again.

After gqlgen generated code for us, we’ll have to implement our schema, we do that in ‍‍‍‍schema.resolvers.go, as you see there is functions for Queries and Mutations we defined in our schema.