fix 修复返回了过期的匿名token

src/utils/cache.go

@@ -102,10 +102,18 @@ func ExtractTTLFromResponse(responseBody []byte) time.Duration {
 	defaultTTL := 30 * time.Minute
 
 	if json.Unmarshal(responseBody, &tokenResp) == nil && tokenResp.ExpiresIn > 0 {
-		safeTTL := time.Duration(tokenResp.ExpiresIn-300) * time.Second
+		expires := time.Duration(tokenResp.ExpiresIn) * time.Second
-		if safeTTL > 5*time.Minute {
+		skew := expires / 10
-			return safeTTL
+		if skew > 5*time.Minute {
+			skew = 5 * time.Minute
 		}
+		if skew < 10*time.Second {
+			skew = 10 * time.Second
+		}
+		if expires > skew {
+			return expires - skew
+		}
+		return expires / 2
 	}
 
 	return defaultTTL

src/utils/cache_test.go

@@ -34,6 +34,10 @@ func TestExtractTTLFromResponse(t *testing.T) {
 		t.Fatalf("TTL = %s, want 55m", ttl)
 	}
 
+	if ttl := ExtractTTLFromResponse([]byte(`{"expires_in":300}`)); ttl != 270*time.Second {
+		t.Fatalf("short TTL = %s, want 270s", ttl)
+	}
+
 	if ttl := ExtractTTLFromResponse([]byte(`{}`)); ttl != 30*time.Minute {
 		t.Fatalf("default TTL = %s", ttl)
 	}