authhandler: Rename to CmdAuthorizationHandler and add example_test.go

authhandler/cmd_authhandler.go

@@ -8,7 +8,7 @@ import (
 	"fmt"
 )
 
-// DefaultAuthorizationHandler returns a command line auth handler
+// CmdAuthorizationHandler returns a command line auth handler
 // that prints the auth URL on the console and prompts the user to
 // authorize in the browser and paste the auth code back via stdin.
 //
@@ -19,18 +19,10 @@ import (
 // instead of asking the user to additionally paste the state from
 // the auth response. In order for this to work, the state
 // configured here must match the state used in authCodeURL.
-//
-// Usage example:
-//
-// state := uuid.New().String()
-// tokenSource:= authhandler.TokenSource(ctx, conf
-//     authhandler.DefaultAuthorizationHandler(state), state)
-// pubsubService, err := pubsub.NewService(ctx,
-//     option.WithTokenSource(tokenSource))
-func DefaultAuthorizationHandler(state string) AuthorizationHandler {
+func CmdAuthorizationHandler(state string) AuthorizationHandler {
 	return func(authCodeURL string) (string, string, error) {
 		fmt.Printf("Go to the following link in your browser:\n\n   %s\n\n", authCodeURL)
-		fmt.Println("Enter authorization code: ")
+		fmt.Println("Enter authorization code:")
 		var code string
 		fmt.Scanln(&code)
 		return code, state, nil

authhandler/example_test.go

@@ -0,0 +1,56 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package authhandler_test
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/authhandler"
+)
+
+func ExampleCmdAuthorizationHandler() {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r.ParseForm()
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{
+				"access_token": "90d64460d14870c08c81352a05dedd3465940a7c",
+				"scope": "pubsub",
+				"token_type": "bearer",
+				"expires_in": 3600
+			}`))
+	}))
+	defer ts.Close()
+
+	ctx := context.Background()
+	conf := &oauth2.Config{
+		ClientID: "testClientID",
+		Scopes:   []string{"pubsub"},
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  "testAuthCodeURL",
+			TokenURL: ts.URL,
+		},
+	}
+	state := "unique_state"
+
+	token, err := authhandler.TokenSource(ctx, conf, authhandler.CmdAuthorizationHandler(state), state).Token()
+
+	if err != nil {
+		fmt.Println(err)
+	}
+
+	fmt.Printf("AccessToken: %s", token.AccessToken)
+
+	// Output:
+	// Go to the following link in your browser:
+	//
+	//    testAuthCodeURL?client_id=testClientID&response_type=code&scope=pubsub&state=unique_state
+	//
+	// Enter authorization code:
+	// AccessToken: 90d64460d14870c08c81352a05dedd3465940a7c
+}