add graphql httpdelivery

internal/graphql/delivery/http/http_handler.go

@@ -0,0 +1,77 @@
+package httpdelivery
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/99designs/gqlgen/graphql/handler"
+	"github.com/99designs/gqlgen/graphql/handler/extension"
+	"github.com/99designs/gqlgen/graphql/handler/lru"
+	"github.com/99designs/gqlgen/graphql/handler/transport"
+	"github.com/99designs/gqlgen/graphql/playground"
+	"github.com/gin-gonic/gin"
+	"github.com/zdam-egzamin-zawodowy/backend/internal/graphql/directive"
+	"github.com/zdam-egzamin-zawodowy/backend/internal/graphql/generated"
+	"github.com/zdam-egzamin-zawodowy/backend/internal/graphql/resolvers"
+	"github.com/zdam-egzamin-zawodowy/backend/pkg/mode"
+)
+
+const (
+	playgroundTTL      = time.Hour / time.Second
+	graphqlEndpoint    = "/graphql"
+	playgroundEndpoint = "/"
+)
+
+type Config struct {
+	Resolver  *resolvers.Resolver
+	Directive *directive.Directive
+}
+
+func Attach(group *gin.RouterGroup, cfg Config) error {
+	if cfg.Resolver == nil {
+		return fmt.Errorf("Graphql resolver cannot be nil")
+	}
+	gqlHandler := graphqlHandler(cfg.Resolver, cfg.Directive)
+	group.GET(graphqlEndpoint, gqlHandler)
+	group.POST(graphqlEndpoint, gqlHandler)
+	if mode.Get() == mode.DevelopmentMode {
+		group.GET(playgroundEndpoint, playgroundHandler())
+	}
+	return nil
+}
+
+// Defining the GraphQL handler
+func graphqlHandler(r *resolvers.Resolver, d *directive.Directive) gin.HandlerFunc {
+	cfg := generated.Config{Resolvers: r}
+	cfg.Directives.Authenticated = d.Authenticated
+	cfg.Directives.HasRole = d.HasRole
+	srv := handler.New(generated.NewExecutableSchema(cfg))
+
+	srv.AddTransport(transport.GET{})
+	srv.AddTransport(transport.POST{})
+	srv.AddTransport(transport.MultipartForm{
+		MaxUploadSize: 32 << 18,
+		MaxMemory:     32 << 18,
+	})
+	srv.Use(extension.AutomaticPersistedQuery{
+		Cache: lru.New(100),
+	})
+	if mode.Get() == mode.DevelopmentMode {
+		srv.Use(extension.Introspection{})
+	}
+
+	return func(c *gin.Context) {
+		c.Header("Cache-Control", "no-store, must-revalidate")
+		srv.ServeHTTP(c.Writer, c.Request)
+	}
+}
+
+// Defining the Playground handler
+func playgroundHandler() gin.HandlerFunc {
+	h := playground.Handler("Playground", graphqlEndpoint)
+
+	return func(c *gin.Context) {
+		c.Header("Cache-Control", fmt.Sprintf(`public, max-age=%d`, playgroundTTL))
+		h.ServeHTTP(c.Writer, c.Request)
+	}
+}