Add app engine and compute engine examples.

google/example_test.go

@@ -5,12 +5,13 @@ import (
 	"net/http"
 
 	"github.com/golang/oauth2"
+	"google.golang.org/appengine"
 )
 
 func Example_webServer() {
 	// Your credentials should be obtained from the Google
 	// Developer Console (https://console.developers.google.com).
-	config, err := NewConfig(&oauth2.Opts{
+	config, err := NewConfig(&oauth2.Options{
 		ClientID:     "YOUR_CLIENT_ID",
 		ClientSecret: "YOUR_CLIENT_SECRET",
 		RedirectURL:  "YOUR_REDIRECT_URL",
@@ -57,13 +58,70 @@ func Example_webServer() {
 }
 
 func Example_serviceAccounts() {
+	// Your credentials should be obtained from the Google
+	// Developer Console (https://console.developers.google.com).
+	config, err := NewServiceAccountConfig(&oauth2.JWTOptions{
+		Email: "xxx@developer.gserviceaccount.com",
+		// The path to the pem file. If you have a p12 file instead, you
+		// can use `openssl` to export the private key into a pem file.
+		// $ openssl pkcs12 -in key.p12 -out key.pem -nodes
+		PemFilename: "/path/to/pem/file.pem",
+		Scopes: []string{
+			"https://www.googleapis.com/auth/bigquery",
+		},
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
 
+	// Initiate an http.Client, the following GET request will be
+	// authorized and authenticated on the behalf of
+	// xxx@developer.gserviceaccount.com.
+	client := http.Client{Transport: conf.NewTransport()}
+	client.Get("...")
+
+	// If you would like to impersonate a user, you can
+	// create a transport with a subject. The following GET
+	// request will be made on the behalf of user@example.com.
+	client = http.Client{Transport: conf.NewTransportWithUser("user@example.com")}
+	client.Get("...")
+
+	// Alternatively you can iniate a transport with
+	// a token read from the cache.
+	// If the existing access token expires, and a new access token is
+	// retrieved, the newly fetched token will be written to the cache.
+	cache := NewFileCache("/path/to/file")
+	t, err := conf.NewTransportWithCache(cache)
+	if err != nil {
+		log.Fatal(err)
+	}
+	client = http.Client{Transport: t}
+	// The following request will be authorized by the token
+	// retrieved from the cache.
+	client.Get("...")
 }
 
 func Example_appEngine() {
+	context := appengine.NewContext(nil)
+	config, err := NewAppEngineConfig(context, []string{
+		"https://www.googleapis.com/auth/bigquery",
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
 
+	// The following client will be authorized by the App Engine
+	// app's service account for the provided scopes.
+	client := http.Client{Transport: config.NewTransport()}
+	client.Get("...")
 }
 
 func Example_computeEngine() {
-
+	// If no other account is specified, "default" is in use.
+	config, err := NewComputeEngineConfig("")
+	if err != nil {
+		log.Fatal(err)
+	}
+	client := http.Client{Transport: config.NewTransport()}
+	client.Get("...")
 }