// Copyright 2011 Google Inc. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package main import ( "context" "encoding/gob" "errors" "flag" "fmt" "hash/fnv" "io/ioutil" "log" "net/http" "net/http/httptest" "net/url" "os" "os/exec" "path/filepath" "runtime" "strings" "time" "golang.org/x/oauth2" "golang.org/x/oauth2/google" ) // Flags var ( clientID = flag.String("clientid", "", "OAuth 2.0 Client ID. If non-empty, overrides --clientid_file") clientIDFile = flag.String("clientid-file", "clientid.dat", "Name of a file containing just the project's OAuth 2.0 Client ID from https://developers.google.com/console.") secret = flag.String("secret", "", "OAuth 2.0 Client Secret. If non-empty, overrides --secret_file") secretFile = flag.String("secret-file", "clientsecret.dat", "Name of a file containing just the project's OAuth 2.0 Client Secret from https://developers.google.com/console.") cacheToken = flag.Bool("cachetoken", true, "cache the OAuth 2.0 token") debug = flag.Bool("debug", false, "show HTTP traffic") ) func usage() { fmt.Fprintf(os.Stderr, "Usage: go-api-demo [api name args]\n\nPossible APIs:\n\n") for n := range demoFunc { fmt.Fprintf(os.Stderr, " * %s\n", n) } os.Exit(2) } func main() { flag.Parse() if flag.NArg() == 0 { usage() } name := flag.Arg(0) demo, ok := demoFunc[name] if !ok { usage() } config := &oauth2.Config{ ClientID: valueOrFileContents(*clientID, *clientIDFile), ClientSecret: valueOrFileContents(*secret, *secretFile), Endpoint: google.Endpoint, Scopes: []string{demoScope[name]}, } ctx := context.Background() if *debug { ctx = context.WithValue(ctx, oauth2.HTTPClient, &http.Client{ Transport: &logTransport{http.DefaultTransport}, }) } c := newOAuthClient(ctx, config) demo(c, flag.Args()[1:]) } var ( demoFunc = make(map[string]func(*http.Client, []string)) demoScope = make(map[string]string) ) func registerDemo(name, scope string, main func(c *http.Client, argv []string)) { if demoFunc[name] != nil { panic(name + " already registered") } demoFunc[name] = main demoScope[name] = scope } func osUserCacheDir() string { switch runtime.GOOS { case "darwin": return filepath.Join(os.Getenv("HOME"), "Library", "Caches") case "linux", "freebsd": return filepath.Join(os.Getenv("HOME"), ".cache") } log.Printf("TODO: osUserCacheDir on GOOS %q", runtime.GOOS) return "." } func tokenCacheFile(config *oauth2.Config) string { hash := fnv.New32a() hash.Write([]byte(config.ClientID)) hash.Write([]byte(config.ClientSecret)) hash.Write([]byte(strings.Join(config.Scopes, " "))) fn := fmt.Sprintf("go-api-demo-tok%v", hash.Sum32()) return filepath.Join(osUserCacheDir(), url.QueryEscape(fn)) } func tokenFromFile(file string) (*oauth2.Token, error) { if !*cacheToken { return nil, errors.New("--cachetoken is false") } f, err := os.Open(file) if err != nil { return nil, err } t := new(oauth2.Token) err = gob.NewDecoder(f).Decode(t) return t, err } func saveToken(file string, token *oauth2.Token) { f, err := os.Create(file) if err != nil { log.Printf("Warning: failed to cache oauth token: %v", err) return } defer f.Close() gob.NewEncoder(f).Encode(token) } func newOAuthClient(ctx context.Context, config *oauth2.Config) *http.Client { cacheFile := tokenCacheFile(config) token, err := tokenFromFile(cacheFile) if err != nil { token = tokenFromWeb(ctx, config) saveToken(cacheFile, token) } else { log.Printf("Using cached token %#v from %q", token, cacheFile) } return config.Client(ctx, token) } func tokenFromWeb(ctx context.Context, config *oauth2.Config) *oauth2.Token { ch := make(chan string) randState := fmt.Sprintf("st%d", time.Now().UnixNano()) ts := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) { if req.URL.Path == "/favicon.ico" { http.Error(rw, "", 404) return } if req.FormValue("state") != randState { log.Printf("State doesn't match: req = %#v", req) http.Error(rw, "", 500) return } if code := req.FormValue("code"); code != "" { fmt.Fprintf(rw, "

Success

Authorized.") rw.(http.Flusher).Flush() ch <- code return } log.Printf("no code") http.Error(rw, "", 500) })) defer ts.Close() config.RedirectURL = ts.URL authURL := config.AuthCodeURL(randState) go openURL(authURL) log.Printf("Authorize this app at: %s", authURL) code := <-ch log.Printf("Got code: %s", code) token, err := config.Exchange(ctx, code) if err != nil { log.Fatalf("Token exchange error: %v", err) } return token } func openURL(url string) { try := []string{"xdg-open", "google-chrome", "open"} for _, bin := range try { err := exec.Command(bin, url).Run() if err == nil { return } } log.Printf("Error opening URL in browser.") } func valueOrFileContents(value string, filename string) string { if value != "" { return value } slurp, err := ioutil.ReadFile(filename) if err != nil { log.Fatalf("Error reading %q: %v", filename, err) } return strings.TrimSpace(string(slurp)) }