dashboard.go

/**
 * OpenBmclAPI (Golang Edition)
 * Copyright (C) 2023 Kevin Z <zyxkad@gmail.com>
 * All rights reserved
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published
 *  by the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package main

import (
	"bytes"
	"compress/gzip"
	"embed"
	"encoding/json"
	"io"
	"io/fs"
	"mime"
	"net/http"
	"path"
	"strings"

	"github.com/LiterMC/go-openbmclapi/utils"
)

//go:generate npm -C dashboard ci
//go:generate npm -C dashboard run build

//go:embed dashboard/dist
var _dsbDist embed.FS
var dsbDist = func() fs.FS {
	s, e := fs.Sub(_dsbDist, "dashboard/dist")
	if e != nil {
		panic(e)
	}
	return s
}()

//go:embed dashboard/dist/index.html
var dsbIndexHtml string

//go:embed dashboard/dist/manifest.webmanifest
var _dsbManifest []byte
var dsbManifest = func() (dsbManifest map[string]any) {
	err := json.Unmarshal(_dsbManifest, &dsbManifest)
	if err != nil {
		panic(err)
	}
	return
}()

func (cr *Cluster) serveDashboard(rw http.ResponseWriter, req *http.Request, pth string) {
	if req.Method != http.MethodGet && req.Method != http.MethodHead {
		rw.Header().Set("Allow", http.MethodGet+", "+http.MethodHead)
		http.Error(rw, "405 Method Not Allowed", http.StatusMethodNotAllowed)
		return
	}
	acceptEncoding := utils.SplitCSV(req.Header.Get("Accept-Encoding"))
	switch pth {
	case "":
		break
	case "manifest.webmanifest":
		buf, err := json.Marshal(dsbManifest)
		if err != nil {
			rw.WriteHeader(http.StatusInternalServerError)
			io.WriteString(rw, err.Error())
			return
		}
		rw.Header().Set("Content-Type", "application/manifest+json")
		http.ServeContent(rw, req, "manifest.webmanifest", startTime, bytes.NewReader(buf))
		return
	case "sw.js":
		// Must not cache service worker
		rw.Header().Set("Cache-Control", "no-store")
		fallthrough
	default:
		fd, err := dsbDist.Open(pth)
		if err == nil {
			defer fd.Close()
			stat, err := fd.Stat()
			if err != nil || stat.IsDir() {
				http.NotFound(rw, req)
				return
			}
			name := path.Base(pth)
			size := stat.Size()
			typ := mime.TypeByExtension(path.Ext(name))
			if typ == "" {
				typ = "application/octet-stream"
			}
			rw.Header().Set("Content-Type", typ)
			if rw.Header().Get("Cache-Control") == "" {
				if strings.HasPrefix(pth, "assets/") {
					rw.Header().Set("Cache-Control", "public, max-age=2592000")
				}
			}
			if acceptEncoding["gzip"] != 0 && size > 1024 {
				buf := bytes.NewBuffer(nil)
				gw := gzip.NewWriter(buf)
				if _, err := io.Copy(gw, fd); err == nil {
					if err = gw.Close(); err == nil {
						rw.Header().Set("Content-Encoding", "gzip")
						http.ServeContent(rw, req, name, startTime, bytes.NewReader(buf.Bytes()))
						return
					}
				}
			}
			http.ServeContent(rw, req, name, startTime, fd.(io.ReadSeeker))
			return
		}
	}
	rw.Header().Set("Content-Type", "text/html; charset=utf-8")
	http.ServeContent(rw, req, "index.html", startTime, strings.NewReader(dsbIndexHtml))
}