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tailscale/client/web/assets.go

132 lines
3.9 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package web
import (
"io"
"io/fs"
"log"
"net/http"
"net/http/httputil"
"net/url"
"os"
"os/exec"
"path/filepath"
"strings"
"time"
prebuilt "github.com/tailscale/web-client-prebuilt"
)
var start = time.Now()
func assetsHandler(devMode bool) (_ http.Handler, cleanup func()) {
if devMode {
// When in dev mode, proxy asset requests to the Vite dev server.
cleanup := startDevServer()
return devServerProxy(), cleanup
}
fsys := prebuilt.FS()
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
path := strings.TrimPrefix(r.URL.Path, "/")
f, err := openPrecompressedFile(w, r, path, fsys)
if err != nil {
// Rewrite request to just fetch index.html and let
// the frontend router handle it.
r = r.Clone(r.Context())
path = "index.html"
f, err = openPrecompressedFile(w, r, path, fsys)
}
if f == nil {
http.Error(w, err.Error(), http.StatusNotFound)
return
}
defer f.Close()
// fs.File does not claim to implement Seeker, but in practice it does.
fSeeker, ok := f.(io.ReadSeeker)
if !ok {
http.Error(w, "Not seekable", http.StatusInternalServerError)
return
}
if strings.HasPrefix(path, "assets/") {
// Aggressively cache static assets, since we cache-bust our assets with
// hashed filenames.
w.Header().Set("Cache-Control", "public, max-age=31535996")
w.Header().Set("Vary", "Accept-Encoding")
}
http.ServeContent(w, r, path, start, fSeeker)
}), nil
}
func openPrecompressedFile(w http.ResponseWriter, r *http.Request, path string, fs fs.FS) (fs.File, error) {
if f, err := fs.Open(path + ".gz"); err == nil {
w.Header().Set("Content-Encoding", "gzip")
return f, nil
}
return fs.Open(path) // fallback
}
// startDevServer starts the JS dev server that does on-demand rebuilding
// and serving of web client JS and CSS resources.
func startDevServer() (cleanup func()) {
root := gitRootDir()
webClientPath := filepath.Join(root, "client", "web")
yarn := filepath.Join(root, "tool", "yarn")
node := filepath.Join(root, "tool", "node")
vite := filepath.Join(webClientPath, "node_modules", ".bin", "vite")
log.Printf("installing JavaScript deps using %s...", yarn)
out, err := exec.Command(yarn, "--non-interactive", "-s", "--cwd", webClientPath, "install").CombinedOutput()
if err != nil {
log.Fatalf("error running tailscale web's yarn install: %v, %s", err, out)
}
log.Printf("starting JavaScript dev server...")
cmd := exec.Command(node, vite)
cmd.Dir = webClientPath
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if err := cmd.Start(); err != nil {
log.Fatalf("Starting JS dev server: %v", err)
}
log.Printf("JavaScript dev server running as pid %d", cmd.Process.Pid)
return func() {
cmd.Process.Signal(os.Interrupt)
err := cmd.Wait()
log.Printf("JavaScript dev server exited: %v", err)
}
}
// devServerProxy returns a reverse proxy to the vite dev server.
func devServerProxy() *httputil.ReverseProxy {
// We use Vite to develop on the web client.
// Vite starts up its own local server for development,
// which we proxy requests to from Server.ServeHTTP.
// Here we set up the proxy to Vite's server.
handleErr := func(w http.ResponseWriter, r *http.Request, err error) {
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusBadGateway)
w.Write([]byte("The web client development server isn't running. " +
"Run `./tool/yarn --cwd client/web start` from " +
"the repo root to start the development server."))
w.Write([]byte("\n\nError: " + err.Error()))
}
viteTarget, _ := url.Parse("http://127.0.0.1:4000")
devProxy := httputil.NewSingleHostReverseProxy(viteTarget)
devProxy.ErrorHandler = handleErr
return devProxy
}
func gitRootDir() string {
top, err := exec.Command("git", "rev-parse", "--show-toplevel").Output()
if err != nil {
log.Fatalf("failed to find git top level (not in corp git?): %v", err)
}
return strings.TrimSpace(string(top))
}