graphqlclientgen

README

graphqlclientgen

Here Be Dragons 🐉

This is an experiment of generating GraphQL clients in Golang. It's heavily inspired by gqlgen.

• Goals
  • Structure config and generated clients in a future proof way to enable redesign of codegen
  • Single client generated for entire schema
  • ProtoClient interface to support multiple protocols and custom clients
  • Use static types in client interface to check api compability during build time
  • Enable field selection in client to partially fetch objects
• Limitations
  • No support for arguments on fields (yet)

Get started

1. Add graphqlclientgen to tools.go

   //go:build tools
   
   package tools
   
   import (
     _ "github.com/loa/graphqlclientgen/cmd"
   )
   

2. Run go tidy to add graphqlclientgen as dependency

   go mod tidy
   

3. Create a new directory and run graphqlclientgen init

   mkdir exampleclient
   cd exampleclient
   
   go run github.com/loa/graphqlclientgen/cmd init --schema-path='../graph/*.graphqls'
   

4. Run generate (init creates exampleclient.go with go gen comment)

   go generate .
   

Examples

func Example() {
  // create client, supports custom protocols through ProtoClient interface
  c := client.New(graphqlclientgen.NewHttpClient("http://localhost:8080/query"))

  todo, err := c.CreateTodo(context.TODO(),
    // static typed inputs
    client.NewTodo{
      Text:   "bar",
      UserId: "5",
    },
    // explicit requested fields, easy to use with auto-complete
    client.TodoFields{
      client.TodoFieldID,
      client.TodoFieldText,
      // supports requesting specific fields of related objects
      client.TodoFieldUser{
        client.UserFieldID,
        client.UserFieldName,
      },
    })
  }

Documentation

Index

• type Body
• type Error
• type HttpClient
  • func NewHttpClient(url string, opts ...HttpClientOpts) HttpClient
  • func (httpClient HttpClient) Do(ctx context.Context, in Body, out any) error
• type HttpClientOpts
  • func WithHttpClient(c *http.Client) HttpClientOpts
• type ProtoClient
• type Response

Types

type Body

type Body struct {
	Query     string         `json:"query"`
	Variables map[string]any `json:"variables"`
}

type Error

type Error struct {
	Message    string            `json:"message"`
	Extensions map[string]string `json:"extensions"`
}

type HttpClient

type HttpClient struct {
	// contains filtered or unexported fields
}

func NewHttpClient

func NewHttpClient(url string, opts ...HttpClientOpts) HttpClient

NewHttpClient creates a new HttpClient for graphqlclientgen clients

func (HttpClient) Do

func (httpClient HttpClient) Do(ctx context.Context, in Body, out any) error

Do performs http post request towards a GraphQL api

type HttpClientOpts

type HttpClientOpts func(*HttpClient)

func WithHttpClient

func WithHttpClient(c *http.Client) HttpClientOpts

WithHttpClient sets a custom http.Client for HttpClient

type ProtoClient

type ProtoClient interface {
	Do(ctx context.Context, in Body, out any) error
}

type Response

type Response struct {
	Data   json.RawMessage `json:"data"`
	Errors []Error         `json:"errors"`
}