From da4037df770027c8f7163595a29ec434f705f8b1 Mon Sep 17 00:00:00 2001
From: Brent Shaffer <betterbrent@google.com>
Date: Thu, 1 Sep 2022 11:07:07 -0600
Subject: [PATCH] fix: add eager refresh (#411)

* fix: add eager refresh

* add test
---
 src/FetchAuthTokenCache.php       |  7 ++++-
 tests/FetchAuthTokenCacheTest.php | 46 ++++++++++++++++++++++++++++++-
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/src/FetchAuthTokenCache.php b/src/FetchAuthTokenCache.php
index 0f870977f..28caea3b9 100644
--- a/src/FetchAuthTokenCache.php
+++ b/src/FetchAuthTokenCache.php
@@ -37,6 +37,11 @@ class FetchAuthTokenCache implements
      */
     private $fetcher;
 
+    /**
+     * @var int
+     */
+    private $eagerRefreshThresholdSeconds = 10;
+
     /**
      * @param FetchAuthTokenInterface $fetcher A credentials fetcher
      * @param array<mixed> $cacheConfig Configuration for the cache
@@ -250,7 +255,7 @@ private function fetchAuthTokenFromCache($authUri = null)
                 // (for JwtAccess and ID tokens)
                 return $cached;
             }
-            if (time() < $cached['expires_at']) {
+            if ((time() + $this->eagerRefreshThresholdSeconds) < $cached['expires_at']) {
                 // access token is not expired
                 return $cached;
             }
diff --git a/tests/FetchAuthTokenCacheTest.php b/tests/FetchAuthTokenCacheTest.php
index 088540d34..e88470eed 100644
--- a/tests/FetchAuthTokenCacheTest.php
+++ b/tests/FetchAuthTokenCacheTest.php
@@ -251,7 +251,7 @@ public function testShouldReturnValueWhenNotExpired()
     {
         $cacheKey = 'myKey';
         $token = '2/abcdef1234567890';
-        $expiresAt = time() + 10;
+        $expiresAt = time() + 20;
         $cachedValue = [
             'access_token' => $token,
             'expires_at' => $expiresAt,
@@ -328,6 +328,50 @@ public function testShouldNotReturnValueWhenExpired()
         $this->assertEquals($newToken, $accessToken);
     }
 
+    public function testShouldNotReturnValueWhenExpiredWithinEagerThreshold()
+    {
+        $cacheKey = 'myKey';
+        $token = '2/abcdef1234567890';
+        $expiresAt = time() + 5;
+        $cachedValue = [
+            'access_token' => $token,
+            'expires_at' => $expiresAt,
+        ];
+        $newToken = ['access_token' => '3/abcdef1234567890'];
+        $this->mockCacheItem->isHit()
+            ->shouldBeCalledTimes(1)
+            ->willReturn(true);
+        $this->mockCacheItem->get()
+            ->shouldBeCalledTimes(1)
+            ->willReturn($cachedValue);
+        $this->mockCacheItem->set($newToken)
+            ->shouldBeCalledTimes(1)
+            ->willReturn($this->mockCacheItem->reveal());
+        $this->mockCacheItem->expiresAfter(1500)
+            ->shouldBeCalledTimes(1)
+            ->willReturn($this->mockCacheItem->reveal());
+        $this->mockCache->getItem($cacheKey)
+            ->shouldBeCalledTimes(2)
+            ->willReturn($this->mockCacheItem->reveal());
+        $this->mockFetcher->fetchAuthToken(null)
+            ->shouldBeCalledTimes(1)
+            ->willReturn($newToken);
+        $this->mockFetcher->getCacheKey()
+            ->shouldBeCalled()
+            ->willReturn($cacheKey);
+        $this->mockCache->save($this->mockCacheItem)
+            ->shouldBeCalledTimes(1);
+
+        // Run the test.
+        $cachedFetcher = new FetchAuthTokenCache(
+            $this->mockFetcher->reveal(),
+            null,
+            $this->mockCache->reveal()
+        );
+        $accessToken = $cachedFetcher->fetchAuthToken();
+        $this->assertEquals($newToken, $accessToken);
+    }
+
     public function testGetsCachedAuthTokenUsingCachePrefix()
     {
         $prefix = 'test_prefix_';