Support token cache for OAuth and JWT token

go/oauth2l/README.md

@@ -170,3 +170,12 @@ $ oauth2l test ya29.justkiddingmadethisoneup
 $ echo $?
 1
 ```
+
+### reset
+
+Reset all tokens cached locally. We cache previously retrieved tokens in the
+file `~/.oauth2l.token`.
+
+```bash
+$ oauth2l reset
+```

go/oauth2l/main.go

@@ -31,7 +31,7 @@ var (
 )
 
 func help() {
-	fmt.Println("Usage: oauth2l {fetch|header|info|test} " +
+	fmt.Println("Usage: oauth2l {fetch|header|info|test|reset} " +
 		"[--jwt] [--json] [--sso] [--ssocli] {scope|aud|email}")
 }
 
@@ -69,7 +69,7 @@ func parseScopes(scopes []string) string {
 }
 
 func main() {
-	if len(os.Args) < 3 {
+	if len(os.Args) < 2 {
 		help()
 		return
 	}
@@ -144,6 +144,8 @@ func main() {
 		}
 	} else if task, ok := infoTasks[cmd]; ok {
 		task(flagSet.Args()[len(flagSet.Args()) - 1])
+	} else if cmd == "reset" {
+		util.Reset()
 	} else {
 		// Unknown command, print usage.
 		help()

go/oauth2l/util/cache.go

@@ -0,0 +1,131 @@
+//
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package util
+
+import (
+	"log"
+	"io/ioutil"
+	"encoding/json"
+	"os"
+	"github.com/google/oauth2l/go/sgauth"
+	"os/user"
+)
+
+const (
+	cacheFileName = ".oauth2l.token"
+)
+
+// The key struct that used to identify an auth token fetch operation.
+type CacheKey struct {
+	// The JSON credentials content downloaded from Google Cloud Console.
+	CredentialsJSON string
+	// If specified, use OAuth. Otherwise, JWT.
+	Scope string
+	// The audience field for JWT auth
+	Audience string
+	// The Google API key
+	APIKey string
+}
+
+func LookupCache(settings *sgauth.Settings) (*sgauth.Token, error) {
+	var token sgauth.Token
+	var cache, err = loadCache()
+	if err != nil {
+		return nil, err
+	}
+	key, err := json.Marshal(createKey(settings))
+	if err != nil {
+		return nil, err
+	}
+	val := cache[string(key)]
+	err = json.Unmarshal(val, &token)
+	if err != nil {
+		return nil, err
+	}
+	return &token, nil
+}
+
+func InsertCache(settings *sgauth.Settings, token *sgauth.Token) error {
+	var cache, err = loadCache()
+	if err != nil {
+		return err
+	}
+	val, err := json.Marshal(*token)
+	if err != nil {
+		return err
+	}
+	key, err := json.Marshal(createKey(settings))
+	if err != nil {
+		return err
+	}
+	cache[string(key)] = val
+	data, err := json.Marshal(cache)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(cacheLocation(), data, 0666)
+}
+
+func ClearCache() error {
+	if _, err := os.Stat(cacheLocation()); os.IsNotExist(err) {
+		// Noop if file does not exist.
+		return nil
+	}
+	return os.Remove(cacheLocation())
+}
+
+func loadCache() (map[string][]byte, error) {
+	if _, err := os.Stat(cacheLocation()); os.IsNotExist(err) {
+		// Create the cache file if not existing.
+		f, err := os.OpenFile(cacheLocation(), os.O_RDONLY|os.O_CREATE, 0666)
+		if err != nil {
+			log.Fatal(err)
+			return nil, err
+		}
+		f.Close()
+	}
+	data, err := ioutil.ReadFile(cacheLocation())
+	if err != nil {
+		log.Fatal(err)
+		return nil, err
+	}
+	m := map[string][]byte{}
+	if len(data) > 0 {
+		err = json.Unmarshal(data, &m)
+		if err != nil {
+			log.Fatal(err)
+			return nil, err
+		}
+	}
+	return m, nil
+}
+
+func cacheLocation() string {
+	usr, err := user.Current()
+	if err != nil {
+		log.Fatal( err )
+	}
+	return usr.HomeDir + "/" + cacheFileName
+}
+
+func createKey(settings *sgauth.Settings) CacheKey {
+	return CacheKey{
+		CredentialsJSON: settings.CredentialsJSON,
+		Scope: settings.Scope,
+		Audience: settings.Audience,
+		APIKey: settings.APIKey,
+	}
+}
+

go/oauth2l/util/tasks.go

@@ -41,20 +41,14 @@ func PrintToken(tokenType string, token string, headerFormat bool) {
 // Fetches and prints the token in plain text with the given settings
 // using Google Authenticator.
 func Fetch(settings *sgauth.Settings) {
-	token, err := sgauth.FetchToken(context.Background(), settings)
-	if err != nil {
-		fmt.Println(err)
-	}
+	token := fetchToken(settings)
 	PrintToken(token.TokenType, token.AccessToken, false)
 }
 
 // Fetches and prints the token in header format with the given settings
 // using Google Authenticator.
 func Header(settings *sgauth.Settings) {
-	token, err := sgauth.FetchToken(context.Background(), settings)
-	if err != nil {
-		fmt.Println(err)
-	}
+	token := fetchToken(settings)
 	PrintToken(token.TokenType, token.AccessToken, true)
 }
 
@@ -79,6 +73,14 @@ func Test(token string) {
 	}
 }
 
+// Reset the cache
+func Reset() {
+	err := ClearCache()
+	if err != nil {
+		fmt.Print(err)
+	}
+}
+
 func getTokenInfo(token string) (string, error) {
 	c := http.DefaultClient
 	resp, err := c.Get(googleTokenInfoURLPrefix + token)
@@ -91,3 +93,19 @@ func getTokenInfo(token string) (string, error) {
 	}
 	return string(data), err
 }
+
+func fetchToken(settings *sgauth.Settings) (*sgauth.Token) {
+	token, _ := LookupCache(settings)
+	if token != nil {
+		return token
+	}
+	token, err := sgauth.FetchToken(context.Background(), settings)
+	if err != nil {
+		fmt.Println(err)
+	}
+	err = InsertCache(settings, token)
+	if err != nil {
+		fmt.Println(err)
+	}
+	return token
+}