func (t *transport) Refresh() error {
var scopes = strings.Join(t.Scopes, " ")
var client = urlfetch.Client(t.Context)
// get the key data for the service account
iss, key, err := t.Factory.CreateCredential(t.Context)
if err != nil {
return err
}
// fetch an access token
exchange := jwt.NewToken(iss, scopes, key)
if t.Token, err = exchange.Assert(client); err == nil && t.TokenCache != nil {
err = t.TokenCache.PutToken(t.Token)
}
return err
}
func main() {
flag.Parse()
if *secretsFile == "" || *pemFile == "" {
flag.Usage()
fmt.Println(usageMsg)
return
}
// Read the secret file bytes into the config.
secretBytes, err := ioutil.ReadFile(*secretsFile)
if err != nil {
log.Fatal("error reading secerets file:", err)
}
var config struct {
Web struct {
ClientEmail string `json:"client_email"`
ClientID string `json:"client_id"`
TokenURI string `json:"token_uri"`
}
}
err = json.Unmarshal(secretBytes, &config)
if err != nil {
log.Fatal("error unmarshalling secerets:", err)
}
// Get the project ID from the client ID.
projectID := strings.SplitN(config.Web.ClientID, "-", 2)[0]
// Read the pem file bytes for the private key.
keyBytes, err := ioutil.ReadFile(*pemFile)
if err != nil {
log.Fatal("error reading private key file:", err)
}
// Craft the ClaimSet and JWT token.
t := jwt.NewToken(config.Web.ClientEmail, scope, keyBytes)
t.ClaimSet.Aud = config.Web.TokenURI
// We need to provide a client.
c := &http.Client{}
// Get the access token.
o, err := t.Assert(c)
if err != nil {
log.Fatal("assertion error:", err)
}
// Refresh token will be missing, but this access_token will be good
// for one hour.
fmt.Printf("access_token = %v\n", o.AccessToken)
fmt.Printf("refresh_token = %v\n", o.RefreshToken)
fmt.Printf("expires %v\n", o.Expiry)
// Form the request to list Google Cloud Storage buckets.
req, err := http.NewRequest("GET", "https://storage.googleapis.com/", nil)
if err != nil {
log.Fatal("http.NewRequest:", err)
}
req.Header.Set("Authorization", "OAuth "+o.AccessToken)
req.Header.Set("x-goog-api-version", "2")
req.Header.Set("x-goog-project-id", projectID)
// Make the request.
r, err := c.Do(req)
if err != nil {
log.Fatal("API request error:", err)
}
defer r.Body.Close()
// Write the response to standard output.
res, err := ioutil.ReadAll(r.Body)
if err != nil {
log.Fatal("error reading API request results:", err)
}
fmt.Printf("\nRESULT:\n%s\n", res)
}