123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172 |
- // Copyright (C) 2019 The Syncthing Authors.
- //
- // This Source Code Form is subject to the terms of the Mozilla Public
- // License, v. 2.0. If a copy of the MPL was not distributed with this file,
- // You can obtain one at https://mozilla.org/MPL/2.0/.
- package main
- import (
- "bytes"
- "encoding/json"
- "fmt"
- "io"
- "log"
- "net/http"
- "os"
- "sort"
- "strings"
- "time"
- "github.com/alecthomas/kong"
- "github.com/prometheus/client_golang/prometheus/promhttp"
- _ "github.com/syncthing/syncthing/lib/automaxprocs"
- "github.com/syncthing/syncthing/lib/httpcache"
- "github.com/syncthing/syncthing/lib/upgrade"
- )
- type cli struct {
- Listen string `default:":8080" help:"Listen address"`
- MetricsListen string `default:":8081" help:"Listen address for metrics"`
- URL string `short:"u" default:"https://api.github.com/repos/syncthing/syncthing/releases?per_page=25" help:"GitHub releases url"`
- Forward []string `short:"f" help:"Forwarded pages, format: /path->https://example/com/url"`
- CacheTime time.Duration `default:"15m" help:"Cache time"`
- }
- func main() {
- var params cli
- kong.Parse(¶ms)
- if err := server(¶ms); err != nil {
- fmt.Printf("Error: %v\n", err)
- os.Exit(1)
- }
- }
- func server(params *cli) error {
- if params.MetricsListen != "" {
- mux := http.NewServeMux()
- mux.Handle("/metrics", promhttp.Handler())
- go func() {
- log.Println("Listening for metrics on", params.MetricsListen)
- if err := http.ListenAndServe(params.MetricsListen, mux); err != nil {
- log.Fatalf("Failed to start metrics server: %v", err)
- }
- }()
- }
- mux := http.NewServeMux()
- mux.Handle("/meta.json", httpcache.SinglePath(&githubReleases{url: params.URL}, params.CacheTime))
- for _, fwd := range params.Forward {
- path, url, ok := strings.Cut(fwd, "->")
- if !ok {
- return fmt.Errorf("invalid forward: %q", fwd)
- }
- log.Println("Forwarding", path, "to", url)
- mux.Handle(path, httpcache.SinglePath(&proxy{url: url}, params.CacheTime))
- }
- srv := &http.Server{
- Addr: params.Listen,
- Handler: mux,
- ReadTimeout: 5 * time.Second,
- WriteTimeout: 10 * time.Second,
- }
- srv.SetKeepAlivesEnabled(false)
- return srv.ListenAndServe()
- }
- type githubReleases struct {
- url string
- }
- func (p *githubReleases) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
- log.Println("Fetching", p.url)
- rels := upgrade.FetchLatestReleases(p.url, "")
- if rels == nil {
- http.Error(w, "no releases", http.StatusInternalServerError)
- return
- }
- sort.Sort(upgrade.SortByRelease(rels))
- rels = filterForLatest(rels)
- // Move the URL used for browser downloads to the URL field, and remove
- // the browser URL field. This avoids going via the GitHub API for
- // downloads, since Syncthing uses the URL field.
- for _, rel := range rels {
- for j, asset := range rel.Assets {
- rel.Assets[j].URL = asset.BrowserURL
- rel.Assets[j].BrowserURL = ""
- }
- }
- buf := new(bytes.Buffer)
- _ = json.NewEncoder(buf).Encode(rels)
- w.Header().Set("Content-Type", "application/json; charset=utf-8")
- w.Header().Set("Access-Control-Allow-Origin", "*")
- w.Header().Set("Access-Control-Allow-Methods", "GET")
- w.Write(buf.Bytes())
- }
- type proxy struct {
- url string
- }
- func (p *proxy) ServeHTTP(w http.ResponseWriter, req *http.Request) {
- log.Println("Fetching", p.url)
- req, err := http.NewRequestWithContext(req.Context(), http.MethodGet, p.url, nil)
- if err != nil {
- http.Error(w, err.Error(), http.StatusInternalServerError)
- return
- }
- resp, err := http.DefaultClient.Do(req)
- if err != nil {
- http.Error(w, err.Error(), http.StatusInternalServerError)
- return
- }
- defer resp.Body.Close()
- ct := resp.Header.Get("Content-Type")
- w.Header().Set("Content-Type", ct)
- if resp.StatusCode == http.StatusOK {
- w.Header().Set("Cache-Control", "public, max-age=900")
- w.Header().Set("Access-Control-Allow-Origin", "*")
- w.Header().Set("Access-Control-Allow-Methods", "GET")
- }
- w.WriteHeader(resp.StatusCode)
- if strings.HasPrefix(ct, "application/json") {
- // Special JSON handling; clean it up a bit.
- var v interface{}
- if err := json.NewDecoder(resp.Body).Decode(&v); err != nil {
- http.Error(w, err.Error(), http.StatusInternalServerError)
- return
- }
- _ = json.NewEncoder(w).Encode(v)
- } else {
- _, _ = io.Copy(w, resp.Body)
- }
- }
- // filterForLatest returns the latest stable and prerelease only. If the
- // stable version is newer (comes first in the list) there is no need to go
- // looking for a prerelease at all.
- func filterForLatest(rels []upgrade.Release) []upgrade.Release {
- var filtered []upgrade.Release
- var havePre bool
- for _, rel := range rels {
- if !rel.Prerelease {
- // We found a stable version, we're good now.
- filtered = append(filtered, rel)
- break
- }
- if rel.Prerelease && !havePre {
- // We remember the first prerelease we find.
- filtered = append(filtered, rel)
- havePre = true
- }
- }
- return filtered
- }
|