GraphQL batch support for gqlgen

gqlgen-batching is an extension of gqlgen to support GraphQL Batching.

1. Add package import

   import "github.com/davewhit3/gqlgen-batching"

2. Add batching transport

   srv.AddTransport(batching.POST{})

3. Prepare your server

    schema := generated.NewExecutableSchema(graph.NewResolver())
    srv := handler.New(schema)
   
    srv.AddTransport(transport.Websocket{
    	KeepAlivePingInterval: 10 * time.Second,
    })
    srv.AddTransport(transport.Options{})
    srv.AddTransport(transport.GET{})
    srv.AddTransport(batching.POST{})
    srv.AddTransport(transport.MultipartForm{})
   
    srv.SetQueryCache(lru.New(1000))
   
    srv.Use(extension.Introspection{})
    srv.Use(extension.AutomaticPersistedQuery{
    	Cache: lru.New(100),
    })
   
    http.Handle("/", playground.Handler("Starwars", "/query"))
    http.Handle("/query", srv)
   
    log.Fatal(http.ListenAndServe(":8080", nil))

Add header to request X-Batch: true

curl -X POST http://localhost:8080/query \
-H "X-Batch: true" -H "Content-Type: application/json" \
-d '[{"query":"{hero(episode: JEDI) { name }}"},{"query":"{hero(episode: EMPIRE) { name }}"}]'

Result:

[
   {
      "data": {
         "hero": {
            "name": "R2-D2"
         }
      }
   },
   {
      "data": {
         "hero": {
            "name": "Luke Skywalker"
         }
      }
   }
]