s3browser-backend/internal/httpServer.go

package s3browser

import (
	"context"
	"fmt"
	"io"
	"mime"
	"net/http"
	"path/filepath"

	"github.com/graph-gophers/dataloader"
	"github.com/graphql-go/graphql"
	"github.com/graphql-go/handler"
	"github.com/minio/minio-go/v7"
)

// initHttp setup and start the http server. Blocking
func initHttp(resolveContext context.Context, schema graphql.Schema) error {
	h := handler.New(&handler.Config{
		Schema:     &schema,
		Pretty:     true,
		GraphiQL:   false,
		Playground: true,
	})

	http.HandleFunc("/graphql", func(rw http.ResponseWriter, r *http.Request) {
		h.ContextHandler(resolveContext, rw, r)
	})

	http.HandleFunc("/api/file", func(rw http.ResponseWriter, r *http.Request) {
		if r.Method == "GET" {
			httpGetFile(resolveContext, rw, r)
			return
		}

		if r.Method == "POST" {
			httpPostFile(resolveContext, rw, r)
			return
		}
	})

	return http.ListenAndServe(":8080", nil)
}

func httpGetFile(ctx context.Context, rw http.ResponseWriter, r *http.Request) {
	s3Client := ctx.Value("s3Client").(*minio.Client)
	id := r.URL.Query().Get("id")
	objInfo, err := s3Client.StatObject(context.Background(), bucketName, id, minio.GetObjectOptions{})

	if err != nil {
		rw.WriteHeader(http.StatusInternalServerError)
		return
	}

	reqEtag := r.Header.Get("If-None-Match")
	if reqEtag == objInfo.ETag {
		rw.WriteHeader(http.StatusNotModified)
		return
	}

	obj, err := s3Client.GetObject(context.Background(), bucketName, id, minio.GetObjectOptions{})

	if err != nil {
		rw.WriteHeader(http.StatusInternalServerError)
		return
	}

	rw.Header().Set("Cache-Control", "must-revalidate")
	rw.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filepath.Base((objInfo.Key))))
	rw.Header().Set("Content-Type", objInfo.ContentType)
	rw.Header().Set("ETag", objInfo.ETag)

	_, err = io.Copy(rw, obj)

	if err != nil {
		rw.WriteHeader(http.StatusInternalServerError)
		return
	}
}

func httpPostFile(ctx context.Context, rw http.ResponseWriter, r *http.Request) {
	s3Client := ctx.Value("s3Client").(*minio.Client)
	loader := ctx.Value("loader").(map[string]*dataloader.Loader)

	id := r.URL.Query().Get("id")

	contentType := r.Header.Get("Content-Type")
	mimeType, _, _ := mime.ParseMediaType(contentType)

	info, err := s3Client.PutObject(context.Background(), bucketName, id, r.Body, r.ContentLength, minio.PutObjectOptions{
		ContentType: mimeType,
	})

	if err != nil {
		rw.WriteHeader(http.StatusInternalServerError)
		return
	}

	// Invalidate cache
	loader["getFile"].Clear(ctx, dataloader.StringKey(info.Key))
	loader["listObjects"].Clear(ctx, dataloader.StringKey(info.Key))
	loader["getFiles"].Clear(ctx, dataloader.StringKey(filepath.Dir(info.Key)))

	rw.WriteHeader(http.StatusCreated)
}