From e946e1da145e3d60c76512cd9982f49c8882744d Mon Sep 17 00:00:00 2001
From: Bochun Zhang <bochun@google.com>
Date: Tue, 30 Aug 2016 22:46:22 -0700
Subject: [PATCH] Add expiry to token in preparation for cache.

---
 go/src/oauth2client/oauth2client.go | 14 ++++++++++++--
 go/src/oauth2client/token.go        | 14 +++++++++++++-
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/go/src/oauth2client/oauth2client.go b/go/src/oauth2client/oauth2client.go
index 3f6a9e66..5132f4c4 100644
--- a/go/src/oauth2client/oauth2client.go
+++ b/go/src/oauth2client/oauth2client.go
@@ -75,9 +75,19 @@ func retrieveAccessToken(url string, params url.Values) (*Token, error) {
 	if err != nil {
 		return nil, err
 	}
+
 	var token *Token
-	err := json.Unmarshal(body, &token)
-	return token, err
+
+	if err := json.Unmarshal(body, &token); err != nil {
+		return nil, err
+	}
+
+	if token.ExpiresIn != nil {
+		expiry := int64(time.Now().Unix()) + int64(*token.ExpiresIn)
+		token.Expiry = time.Unix(expiry, 0)
+		token.ExpiresIn = nil
+	}
+	return token, nil
 }
 
 // Run 3LO verification. Sends a request to auth_uri with a verification code.
diff --git a/go/src/oauth2client/token.go b/go/src/oauth2client/token.go
index fb03ba4d..17ef287c 100644
--- a/go/src/oauth2client/token.go
+++ b/go/src/oauth2client/token.go
@@ -1,5 +1,9 @@
 package oauth2client
 
+import (
+	"time"
+)
+
 // Definition for OAuth2 token type.
 // Referenced from https://godoc.org/golang.org/x/oauth2#Token
 type Token struct {
@@ -16,6 +20,14 @@ type Token struct {
 	// if it expires.
 	RefreshToken string `json:"refresh_token,omitempty"`
 
+	// Expiry is the optional expiration time of the access token.
+	//
+	// If zero, TokenSource implementations will reuse the same
+	// token forever and RefreshToken or equivalent
+	// mechanisms for that TokenSource will not be used.
+	Expiry time.Time `json:"expiry,omitempty"`
+	// contains filtered or unexported fields
+
 	// ExpiresIn is the optional expiration time in seconds.
-	ExpiresIn int `json:"expires_in,omitempty"`
+	ExpiresIn *int `json:"expires_in,omitempty"`
 }