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// Copyright (C) 2015 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"archive/zip"
"bufio"
"bytes"
"compress/gzip"
"encoding/json"
"errors"
"flag"
"io"
"io/ioutil"
"log"
"net"
"net/http"
"net/url"
"os"
"os/exec"
"path/filepath"
"regexp"
"strings"
"sync"
"time"
"golang.org/x/tools/godoc/vfs/httpfs"
"golang.org/x/tools/godoc/vfs/zipfs"
)
var (
plugins = flag.String("plugins", "", "comma seperated plugin paths to serve")
port = flag.String("port", "localhost:8081", "address to serve HTTP requests on")
host = flag.String("host", "gerrit-review.googlesource.com", "Host to proxy requests to")
scheme = flag.String("scheme", "https", "URL scheme")
cdnPattern = regexp.MustCompile("https://cdn.googlesource.com/polygerrit_ui/[0-9.]*")
)
func main() {
flag.Parse()
fontsArchive, err := openDataArchive("fonts.zip")
if err != nil {
log.Fatal(err)
}
workspace := os.Getenv("BUILD_WORKSPACE_DIRECTORY")
if err := os.Chdir(filepath.Join(workspace, "polygerrit-ui")); err != nil {
log.Fatal(err)
}
compiledSrcPath := filepath.Join(workspace, "./.ts-out/server-go")
tsInstance := newTypescriptInstance(
filepath.Join(workspace, "./node_modules/.bin/tsc"),
filepath.Join(workspace, "./polygerrit-ui/app/tsconfig.json"),
compiledSrcPath,
)
if err := tsInstance.StartWatch(); err != nil {
log.Fatal(err)
}
dirListingMux := http.NewServeMux()
dirListingMux.Handle("/styles/", http.StripPrefix("/styles/", http.FileServer(http.Dir("app/styles"))))
dirListingMux.Handle("/samples/", http.StripPrefix("/samples/", http.FileServer(http.Dir("app/samples"))))
dirListingMux.Handle("/elements/", http.StripPrefix("/elements/", http.FileServer(http.Dir("app/elements"))))
dirListingMux.Handle("/behaviors/", http.StripPrefix("/behaviors/", http.FileServer(http.Dir("app/behaviors"))))
http.HandleFunc("/",
func(w http.ResponseWriter, req *http.Request) {
// If typescript compiler hasn't finished yet, wait for it
tsInstance.WaitForCompilationComplete()
handleSrcRequest(compiledSrcPath, dirListingMux, w, req)
})
http.Handle("/fonts/",
addDevHeadersMiddleware(http.FileServer(httpfs.New(zipfs.New(fontsArchive, "fonts")))))
http.HandleFunc("/index.html", handleIndex)
http.HandleFunc("/changes/", handleProxy)
http.HandleFunc("/accounts/", handleProxy)
http.HandleFunc("/config/", handleProxy)
http.HandleFunc("/projects/", handleProxy)
http.HandleFunc("/static/", handleProxy)
http.HandleFunc("/accounts/self/detail", handleAccountDetail)
if len(*plugins) > 0 {
http.Handle("/plugins/", http.StripPrefix("/plugins/",
http.FileServer(http.Dir("../plugins"))))
log.Println("Local plugins from", "../plugins")
} else {
http.HandleFunc("/plugins/", handleProxy)
// Serve local plugins from `plugins_`
http.Handle("/plugins_/", http.StripPrefix("/plugins_/",
http.FileServer(http.Dir("../plugins"))))
}
log.Println("Serving on port", *port)
log.Fatal(http.ListenAndServe(*port, &server{}))
}
func addDevHeadersMiddleware(h http.Handler) http.Handler {
return http.HandlerFunc(func(writer http.ResponseWriter, req *http.Request) {
addDevHeaders(writer)
h.ServeHTTP(writer, req)
})
}
func addDevHeaders(writer http.ResponseWriter) {
writer.Header().Set("Access-Control-Allow-Origin", "*")
writer.Header().Set("Access-Control-Allow-Headers", "cache-control,x-test-origin")
writer.Header().Set("Cache-Control", "public, max-age=10, must-revalidate")
}
func handleSrcRequest(compiledSrcPath string, dirListingMux *http.ServeMux, writer http.ResponseWriter, originalRequest *http.Request) {
parsedUrl, err := url.Parse(originalRequest.RequestURI)
if err != nil {
writer.WriteHeader(500)
return
}
if parsedUrl.Path != "/" && strings.HasSuffix(parsedUrl.Path, "/") {
dirListingMux.ServeHTTP(writer, originalRequest)
return
}
normalizedContentPath := parsedUrl.Path
if !strings.HasPrefix(normalizedContentPath, "/") {
normalizedContentPath = "/" + normalizedContentPath
}
isJsFile := strings.HasSuffix(normalizedContentPath, ".js") || strings.HasSuffix(normalizedContentPath, ".mjs")
isTsFile := strings.HasSuffix(normalizedContentPath, ".ts")
// Source map in a compiled js file point to a file inside /app/... directory
// Browser tries to load original file from the directory when debugger is
// activated. In this case we return original content without any processing
isOriginalFileRequest := strings.HasPrefix(normalizedContentPath, "/polygerrit-ui/app/") && (isTsFile || isJsFile)
data, err := getContent(compiledSrcPath, normalizedContentPath, isOriginalFileRequest)
if err != nil {
if !isOriginalFileRequest {
data, err = getContent(compiledSrcPath, normalizedContentPath+".js", false)
}
if err != nil {
writer.WriteHeader(404)
return
}
isJsFile = true
}
if isOriginalFileRequest {
// Explicitly set text/html Content-Type. If live code tries
// to import javascript from the /app/ folder accidentally, browser fails
// with the import error, so we can catch this problem easily.
writer.Header().Set("Content-Type", "text/html")
} else if isJsFile {
// import ... from '@polymer/decorators'
// must be transformed into
// import ... from '@polymer/decorators/lib/decorators.js'
// The correct way to do it is to use value of the "main" property
// from the @polymer/decorators/package.json. However, parsing package.json
// is overcomplicated right now, hard-code exact path here.
moduleImportRegexp := regexp.MustCompile("(?m)^(import.*)'@polymer/decorators';$")
data = moduleImportRegexp.ReplaceAll(data, []byte("$1 '@polymer/decorators/lib/decorators.js';"))
// The following code updates import statements.
// 1. if an in imported file has .js or .mjs extension, the code keeps
// the file extension unchanged. Otherwise, it adds .js extension
// 2. For module imports it adds '/node_modules/' prefix.
// Examples:
// '@polymer/polymer.js' -> '/node_modules/@polymer/polymer.js'
// 'page/page.mjs' -> '/node_modules/page.mjs'
// '@polymer/iron-icon' -> '/node_modules/@polymer/iron-icon.js'
// './element/file' -> './element/file.js'
moduleImportRegexp = regexp.MustCompile(`(import[^'";]*|export[^'";]*from ?)['"]([^;\s]*?)(\.(m?)js)?['"];`)
data = moduleImportRegexp.ReplaceAll(data, []byte("$1'$2.${4}js';"))
moduleImportRegexp = regexp.MustCompile(`(import[^'";]*|export[^'";]*from ?)['"]([^/.;\s][^;\s]*)['"];`)
data = moduleImportRegexp.ReplaceAll(data, []byte("$1'/node_modules/$2';"))
// The es module version of rxjs can be found in the _esm2015/ directory.
moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/rxjs)(.*).js(';)$")
data = moduleImportRegexp.ReplaceAll(data, []byte("$1/_esm2015$3/index.js$4"))
// The es module version of tslib.js can be found in tslib.es6.js.
moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/)tslib.js';$")
data = moduleImportRegexp.ReplaceAll(data, []byte("${1}tslib/tslib.es6.js';"))
// 'lit.js' has to be resolved as 'lit/index.js'.
moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/)lit.js';$")
data = moduleImportRegexp.ReplaceAll(data, []byte("${1}lit/index.js';"))
// Some lit imports 'a.js' have to be resolved as 'a/a.js'.
moduleImportRegexp = regexp.MustCompile(`((import|export)[^'";]*'/node_modules/(@lit/)?)(lit-element|lit-html|reactive-element).js';`)
data = moduleImportRegexp.ReplaceAll(data, []byte("${1}${4}/${4}.js';"))
// 'immer' imports and exports have to be resolved to 'immer/dist/immer.esm.js'.
moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/)immer.js';$")
data = moduleImportRegexp.ReplaceAll(data, []byte("${1}/immer/dist/immer.esm.js';"))
// 'webvital' imports
moduleImportRegexp = regexp.MustCompile("(?m)^((import|export).*'/node_modules/)web-vitals.js';$")
data = moduleImportRegexp.ReplaceAll(data, []byte("${1}/web-vitals/dist/web-vitals.js';"))
if strings.HasSuffix(normalizedContentPath, "/node_modules/page/page.js") {
// Can't import page.js directly, because this is undefined.
// Replace it with window
// The same replace exists in karma.conf.js
// Rollup makes this replacement automatically
pageJsRegexp := regexp.MustCompile(`(?m)^}\(this, \(function \(\) { 'use strict';$`)
newData := pageJsRegexp.ReplaceAll(data, []byte("}(window, (function () { 'use strict';"))
if len(newData) == len(data) {
log.Fatal("The page.js was updated. Please update regexp/replace accordingly")
}
data = newData
}
writer.Header().Set("Content-Type", "application/javascript")
} else if strings.HasSuffix(normalizedContentPath, ".css") {
writer.Header().Set("Content-Type", "text/css")
} else if strings.HasSuffix(normalizedContentPath, "_test.html") {
moduleImportRegexp := regexp.MustCompile("(?m)^(import.*)'([^/.].*)';$")
data = moduleImportRegexp.ReplaceAll(data, []byte("$1 '/node_modules/$2';"))
writer.Header().Set("Content-Type", "text/html")
} else if strings.HasSuffix(normalizedContentPath, ".html") {
writer.Header().Set("Content-Type", "text/html")
}
writer.WriteHeader(200)
addDevHeaders(writer)
writer.Write(data)
}
func getContent(compiledSrcPath string, normalizedContentPath string, isOriginalFileRequest bool) ([]byte, error) {
// normalizedContentPath must always starts with '/'
if isOriginalFileRequest {
data, err := ioutil.ReadFile(normalizedContentPath[len("/polygerrit-ui/"):])
if err != nil {
return nil, errors.New("File not found")
}
return data, nil
}
// gerrit loads gr-app.js as an ordinary script, without type="module" attribute.
// If server.go serves this file as is, browser shows the error:
// Uncaught SyntaxError: Cannot use import statement outside a module
//
// To load non-bundled gr-app.js as a module, we "virtually" renames original
// gr-app.js to gr-app.mjs and load it with dynamic import.
//
// Another option is to patch rewriteHostPage function and add type="module" attribute
// to <script src=".../elements/gr-app.js"> tag, but this solution is incompatible
// with --dev-cdn options. If you run local gerrit instance with --dev-cdn parameter,
// the server.go is used as cdn and it doesn't handle host page (i.e. rewriteHostPage
// method is not called).
if normalizedContentPath == "/elements/gr-app.js" {
return []byte("import('./gr-app.mjs')"), nil
}
if normalizedContentPath == "/elements/gr-app.mjs" {
normalizedContentPath = "/elements/gr-app.js"
}
pathsToTry := []string{compiledSrcPath + normalizedContentPath, "app" + normalizedContentPath}
bowerComponentsSuffix := "/bower_components/"
nodeModulesPrefix := "/node_modules/"
testComponentsPrefix := "/components/"
if strings.HasPrefix(normalizedContentPath, testComponentsPrefix) {
pathsToTry = append(pathsToTry, "node_modules/wct-browser-legacy/node_modules/"+normalizedContentPath[len(testComponentsPrefix):])
pathsToTry = append(pathsToTry, "node_modules/"+normalizedContentPath[len(testComponentsPrefix):])
}
if strings.HasPrefix(normalizedContentPath, bowerComponentsSuffix) {
pathsToTry = append(pathsToTry, "node_modules/@webcomponents/"+normalizedContentPath[len(bowerComponentsSuffix):])
}
if strings.HasPrefix(normalizedContentPath, nodeModulesPrefix) {
pathsToTry = append(pathsToTry, "node_modules/"+normalizedContentPath[len(nodeModulesPrefix):])
}
for _, path := range pathsToTry {
data, err := ioutil.ReadFile(path)
if err == nil {
return data, nil
}
}
return nil, errors.New("File not found")
}
func openDataArchive(path string) (*zip.ReadCloser, error) {
absBinPath, err := resourceBasePath()
if err != nil {
return nil, err
}
return zip.OpenReader(absBinPath + ".runfiles/gerrit/polygerrit-ui/" + path)
}
func resourceBasePath() (string, error) {
return filepath.Abs(os.Args[0])
}
func handleIndex(writer http.ResponseWriter, originalRequest *http.Request) {
fakeRequest := &http.Request{
URL: &url.URL{
Path: "/",
RawQuery: originalRequest.URL.RawQuery,
},
}
handleProxy(writer, fakeRequest)
}
func handleProxy(writer http.ResponseWriter, originalRequest *http.Request) {
patchedRequest := &http.Request{
Method: "GET",
URL: &url.URL{
Scheme: *scheme,
Host: *host,
Opaque: originalRequest.URL.EscapedPath(),
RawQuery: originalRequest.URL.RawQuery,
},
}
response, err := http.DefaultClient.Do(patchedRequest)
if err != nil {
http.Error(writer, err.Error(), http.StatusInternalServerError)
return
}
defer response.Body.Close()
for name, values := range response.Header {
for _, value := range values {
if name != "Content-Length" {
writer.Header().Add(name, value)
}
}
}
writer.WriteHeader(response.StatusCode)
if _, err := io.Copy(writer, patchResponse(originalRequest, response)); err != nil {
log.Println("Error copying response to ResponseWriter:", err)
return
}
}
func getJsonPropByPath(json map[string]interface{}, path []string) interface{} {
prop, path := path[0], path[1:]
if json[prop] == nil {
return nil
}
switch json[prop].(type) {
case map[string]interface{}: // map
return getJsonPropByPath(json[prop].(map[string]interface{}), path)
case []interface{}: // array
return json[prop].([]interface{})
default:
return json[prop].(interface{})
}
}
func setJsonPropByPath(json map[string]interface{}, path []string, value interface{}) {
prop, path := path[0], path[1:]
if json[prop] == nil {
return // path not found
}
if len(path) > 0 {
setJsonPropByPath(json[prop].(map[string]interface{}), path, value)
} else {
json[prop] = value
}
}
func patchResponse(req *http.Request, res *http.Response) io.Reader {
switch req.URL.EscapedPath() {
case "/":
return rewriteHostPage(res.Body)
case "/config/server/info":
return injectLocalPlugins(res.Body)
default:
return res.Body
}
}
func rewriteHostPage(reader io.Reader) io.Reader {
buf := new(bytes.Buffer)
buf.ReadFrom(reader)
original := buf.String()
// Simply remove all CDN references, so files are loaded from the local file system or the proxy
// server instead.
replaced := cdnPattern.ReplaceAllString(original, "")
// Modify window.INITIAL_DATA so that it has the same effect as injectLocalPlugins. To achieve
// this let's add JavaScript lines at the end of the <script>...</script> snippet that also
// contains window.INITIAL_DATA=...
// Here we rely on the fact that the <script> snippet that we want to append to is the first one.
if len(*plugins) > 0 {
insertionPoint := strings.Index(replaced, "</script>")
builder := new(strings.Builder)
builder.WriteString(
"window.INITIAL_DATA['/config/server/info'].plugin.js_resource_paths = []; ")
for _, p := range strings.Split(*plugins, ",") {
if filepath.Ext(p) == ".js" {
builder.WriteString(
"window.INITIAL_DATA['/config/server/info'].plugin.js_resource_paths.push('" + p + "'); ")
}
}
replaced = replaced[:insertionPoint] + builder.String() + replaced[insertionPoint:]
}
return strings.NewReader(replaced)
}
func injectLocalPlugins(reader io.Reader) io.Reader {
if len(*plugins) == 0 {
return reader
}
// Skip escape prefix
io.CopyN(ioutil.Discard, reader, 5)
dec := json.NewDecoder(reader)
var response map[string]interface{}
err := dec.Decode(&response)
if err != nil {
log.Fatal(err)
}
// Configuration path in the JSON server response
jsPluginsPath := []string{"plugin", "js_resource_paths"}
jsResources := getJsonPropByPath(response, jsPluginsPath).([]interface{})
for _, p := range strings.Split(*plugins, ",") {
if filepath.Ext(p) == ".js" {
jsResources = append(jsResources, p)
}
}
setJsonPropByPath(response, jsPluginsPath, jsResources)
reader, writer := io.Pipe()
go func() {
defer writer.Close()
io.WriteString(writer, ")]}'") // Write escape prefix
err := json.NewEncoder(writer).Encode(&response)
if err != nil {
log.Fatal(err)
}
}()
return reader
}
func handleAccountDetail(w http.ResponseWriter, r *http.Request) {
http.Error(w, http.StatusText(http.StatusForbidden), http.StatusForbidden)
}
type gzipResponseWriter struct {
io.WriteCloser
http.ResponseWriter
}
func newGzipResponseWriter(w http.ResponseWriter) *gzipResponseWriter {
gz := gzip.NewWriter(w)
return &gzipResponseWriter{WriteCloser: gz, ResponseWriter: w}
}
func (w gzipResponseWriter) Write(b []byte) (int, error) {
return w.WriteCloser.Write(b)
}
func (w gzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
h, ok := w.ResponseWriter.(http.Hijacker)
if !ok {
return nil, nil, errors.New("gzipResponseWriter: ResponseWriter does not satisfy http.Hijacker interface")
}
return h.Hijack()
}
type server struct{}
// Any path prefixes that should resolve to index.html.
var (
fePaths = []string{"/q/", "/c/", "/id/", "/p/", "/x/", "/dashboard/", "/admin/", "/settings/"}
issueNumRE = regexp.MustCompile(`^\/\d+\/?$`)
)
func (_ *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
log.Printf("%s %s %s %s\n", r.Proto, r.Method, r.RemoteAddr, r.URL)
for _, prefix := range fePaths {
if strings.HasPrefix(r.URL.Path, prefix) || r.URL.Path == "/" {
r.URL.Path = "/index.html"
log.Println("Redirecting to /index.html")
break
} else if match := issueNumRE.Find([]byte(r.URL.Path)); match != nil {
r.URL.Path = "/index.html"
log.Println("Redirecting to /index.html")
break
}
}
if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
http.DefaultServeMux.ServeHTTP(w, r)
return
}
w.Header().Set("Content-Encoding", "gzip")
addDevHeaders(w)
gzw := newGzipResponseWriter(w)
defer gzw.Close()
http.DefaultServeMux.ServeHTTP(gzw, r)
}
// Typescript compiler support
// The code below runs typescript compiler in watch mode and redirect
// all output from the compiler to the standard logger with the prefix "TSC -"
// Additionally, the code analyzes messages produced by the typescript compiler
// and allows to wait until compilation is finished.
var (
tsStartingCompilation = "- Starting compilation in watch mode..."
tsFileChangeDetectedMsg = "- File change detected. Starting incremental compilation..."
// If there is only one error typescript outputs:
// Found 1 error
// In all other cases it outputs
// Found X errors
tsStartWatchingMsg = regexp.MustCompile(`^.* - Found \d+ error(s)?\. Watching for file changes\.$`)
waitForNextChangeInterval = 1 * time.Second
)
// typescriptLogWriter implements Writer interface and receives output
// (stdout and stderr) from the typescript compiler. It reads incoming
// data line-by-line, analyzes each line and updates compilationDoneWaiter
// according to the current compiler state. Additionally, the
// typescriptLogWriter passes all incoming lines to the underlying logger.
type typescriptLogWriter struct {
// unfinishedLine stores the portion of line which was partially received
// (i.e. all text received after the last EOL (\n) mark.
unfinishedLine string
// logger is used to pass-through all received strings
logger *log.Logger
// when WaitGroup counter is 0 the compilation is complete
compilationDoneWaiter *sync.WaitGroup
}
func newTypescriptLogWriter(compilationCompleteWaiter *sync.WaitGroup) *typescriptLogWriter {
return &typescriptLogWriter{
logger: log.New(log.Writer(), "TSC - ", log.Flags()),
compilationDoneWaiter: compilationCompleteWaiter,
}
}
func (lw typescriptLogWriter) Write(p []byte) (n int, err error) {
// The input p can contain several lines and/or the partial line
// Code splits the input by EOL marker (\n) and stores the unfinished line
// for the next call to Write.
partialText := lw.unfinishedLine + string(p)
lines := strings.Split(partialText, "\n")
fullLines := lines
if strings.HasSuffix(partialText, "\n") {
lw.unfinishedLine = ""
} else {
fullLines = lines[:len(lines)-1]
lw.unfinishedLine = lines[len(lines)-1]
}
for _, fullLine := range fullLines {
text := strings.TrimSpace(fullLine)
if text == "" {
continue
}
if strings.HasSuffix(text, tsFileChangeDetectedMsg) ||
strings.HasSuffix(text, tsStartingCompilation) {
lw.compilationDoneWaiter.Add(1)
}
if tsStartWatchingMsg.MatchString(text) {
// A source code can be changed while previous compiler run is in progress.
// In this case typescript reruns compilation again almost immediately
// after the previous run finishes. To detect this situation, we are
// waiting waitForNextChangeInterval before decreasing the counter.
// If another compiler run is started in this interval, we will wait
// again until it finishes.
go func() {
time.Sleep(waitForNextChangeInterval)
lw.compilationDoneWaiter.Done()
}()
}
lw.logger.Print(text)
}
return len(p), nil
}
type typescriptInstance struct {
cmd *exec.Cmd
compilationCompleteWaiter *sync.WaitGroup
}
func newTypescriptInstance(tscBinaryPath string, projectPath string, outdir string) *typescriptInstance {
cmd := exec.Command(tscBinaryPath,
"--watch",
"--preserveWatchOutput",
"--project",
projectPath,
"--outDir",
outdir)
compilationCompleteWaiter := &sync.WaitGroup{}
logWriter := newTypescriptLogWriter(compilationCompleteWaiter)
// Note 1: (from https://golang.org/pkg/os/exec/#Cmd)
// If Stdout and Stderr are the same writer, and have a type that can
// be compared with ==, at most one goroutine at a time will call Write.
//
// Note 2: The typescript compiler reports all compilation errors to
// stdout by design (see https://github.com/microsoft/TypeScript/issues/615)
// It writes to stderr only when something unexpected happens (like internal
// exceptions). To print such errors in the same way as standard typescript
// error, the same logWriter is used both for Stdout and Stderr.
//
// If Stderr arrives in the middle of ordinary typescript output (i.e.
// something unexpected happens), the server.go can stop respond to http
// requests. However, this is not a problem for us: typescript compiler and
// server.go must be restarted anyway.
cmd.Stdout = logWriter
cmd.Stderr = logWriter
return &typescriptInstance{
cmd: cmd,
compilationCompleteWaiter: compilationCompleteWaiter,
}
}
func (ts *typescriptInstance) StartWatch() error {
err := ts.cmd.Start()
if err != nil {
return err
}
go func() {
ts.cmd.Wait()
log.Fatal("Typescript exits unexpected")
}()
return nil
}
func (ts *typescriptInstance) WaitForCompilationComplete() {
ts.compilationCompleteWaiter.Wait()
}