Inject a singleton Gson instead of creating it many times (#3058)

Creation of Gson objects is nontrivial and it's thread-safe so we might
as well just use some singleton objects as much as possible rather than
recreating them.

core/src/main/java/google/registry/bsa/api/BsaCredential.java

@@ -68,6 +68,8 @@ public class BsaCredential {
 
   private final Keyring keyring;
 
+  private final Gson gson;
+
   private final Clock clock;
 
   @Nullable private String authToken;
@@ -79,11 +81,13 @@ public class BsaCredential {
       @Config("bsaAuthUrl") String authUrl,
       @Config("bsaAuthTokenExpiry") Duration authTokenExpiry,
       Keyring keyring,
+      Gson gson,
       Clock clock) {
     this.urlConnectionService = urlConnectionService;
     this.authUrl = authUrl;
     this.authTokenExpiry = authTokenExpiry;
     this.keyring = keyring;
+    this.gson = gson;
     this.clock = clock;
   }
 
@@ -143,8 +147,7 @@ public class BsaCredential {
       // TODO: catch json syntax exception
       @SuppressWarnings("unchecked")
       String idToken =
-          new Gson()
-              .fromJson(new String(getResponseBytes(connection), UTF_8), Map.class)
+          gson.fromJson(new String(getResponseBytes(connection), UTF_8), Map.class)
               .getOrDefault(ID_TOKEN, "")
               .toString();
       if (idToken.isEmpty()) {

core/src/main/java/google/registry/request/Modules.java

@@ -18,8 +18,10 @@ import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
 import com.google.api.client.http.javanet.NetHttpTransport;
 import com.google.api.client.json.JsonFactory;
 import com.google.api.client.json.gson.GsonFactory;
+import com.google.gson.Gson;
 import dagger.Module;
 import dagger.Provides;
+import google.registry.tools.GsonUtils;
 import jakarta.inject.Singleton;
 import java.net.HttpURLConnection;
 import javax.net.ssl.HttpsURLConnection;
@@ -49,9 +51,16 @@ public final class Modules {
   @Module
   public static final class GsonModule {
     @Provides
+    @Singleton
     static JsonFactory provideJsonFactory() {
       return GsonFactory.getDefaultInstance();
     }
+
+    @Provides
+    @Singleton
+    public static Gson provideGson() {
+      return GsonUtils.provideGson();
+    }
   }
 
   /** Dagger module that provides standard {@link NetHttpTransport}. */

core/src/main/java/google/registry/request/RequestModule.java

@@ -44,7 +44,6 @@ import google.registry.request.HttpException.UnsupportedMediaTypeException;
 import google.registry.request.auth.AuthResult;
 import google.registry.request.lock.LockHandler;
 import google.registry.request.lock.LockHandlerImpl;
-import google.registry.tools.GsonUtils;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import jakarta.servlet.http.HttpSession;
@@ -74,13 +73,6 @@ public final class RequestModule {
     this.authResult = authResult;
   }
 
-  @RequestScope
-  @VisibleForTesting
-  @Provides
-  public static Gson provideGson() {
-    return GsonUtils.provideGson();
-  }
-
   @Provides
   @Parameter(RequestParameters.PARAM_TLD)
   static String provideTld(HttpServletRequest req) {

core/src/main/java/google/registry/tools/AuthModule.java

@@ -146,20 +146,20 @@ public class AuthModule {
   @LocalCredentialJson
   public static String provideLocalCredentialJson(
       Lazy<GoogleClientSecrets> clientSecrets,
+      Gson gson,
       @StoredCredential Lazy<Credential> credential,
       @Nullable @Config("credentialFilePath") String credentialFilePath) {
     try {
       if (credentialFilePath != null) {
         return Files.readString(Paths.get(credentialFilePath));
       } else {
-        return new Gson()
-            .toJson(
-                ImmutableMap.<String, String>builder()
-                    .put("type", "authorized_user")
-                    .put("client_id", clientSecrets.get().getDetails().getClientId())
-                    .put("client_secret", clientSecrets.get().getDetails().getClientSecret())
-                    .put("refresh_token", credential.get().getRefreshToken())
-                    .build());
+        return gson.toJson(
+            ImmutableMap.<String, String>builder()
+                .put("type", "authorized_user")
+                .put("client_id", clientSecrets.get().getDetails().getClientId())
+                .put("client_secret", clientSecrets.get().getDetails().getClientSecret())
+                .put("refresh_token", credential.get().getRefreshToken())
+                .build());
       }
     } catch (IOException e) {
       throw new RuntimeException(e);

core/src/test/java/google/registry/bsa/api/BsaCredentialTest.java

@@ -28,9 +28,11 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import com.google.gson.Gson;
 import google.registry.keyring.api.Keyring;
 import google.registry.request.UrlConnectionService;
 import google.registry.testing.FakeClock;
+import google.registry.tools.GsonUtils;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -49,6 +51,7 @@ import org.mockito.junit.jupiter.MockitoExtension;
 class BsaCredentialTest {
 
   private static final Duration AUTH_TOKEN_EXPIRY = Duration.ofMinutes(30);
+  private static final Gson GSON = GsonUtils.provideGson();
 
   @Mock OutputStream connectionOutputStream;
   @Mock HttpsURLConnection connection;
@@ -60,7 +63,8 @@ class BsaCredentialTest {
   @BeforeEach
   void setup() throws Exception {
     credential =
-        new BsaCredential(connectionService, "https://authUrl", AUTH_TOKEN_EXPIRY, keyring, clock);
+        new BsaCredential(
+            connectionService, "https://authUrl", AUTH_TOKEN_EXPIRY, keyring, GSON, clock);
   }
 
   void setupHttp() throws Exception {

core/src/test/java/google/registry/testing/ConsoleApiParamsUtils.java

@@ -20,7 +20,7 @@ import static org.mockito.Mockito.when;
 import com.google.common.collect.ImmutableList;
 import google.registry.groups.GmailClient;
 import google.registry.model.console.User;
-import google.registry.request.RequestModule;
+import google.registry.request.Modules;
 import google.registry.request.auth.AuthResult;
 import google.registry.security.XsrfTokenManager;
 import google.registry.ui.server.SendEmailUtils;
@@ -50,6 +50,6 @@ public final class ConsoleApiParamsUtils {
         authResult,
         sendEmailUtils,
         xsrfTokenManager,
-        RequestModule.provideGson());
+        Modules.GsonModule.provideGson());
   }
 }

core/src/test/java/google/registry/tools/AuthModuleTest.java

@@ -55,6 +55,8 @@ class AuthModuleTest {
   private static final String ACCESS_TOKEN = "FakeAccessToken";
   private static final String REFRESH_TOKEN = "FakeReFreshToken";
 
+  private static final Gson GSON = GsonUtils.provideGson();
+
   @SuppressWarnings("WeakerAccess")
   @TempDir
   Path folder;
@@ -166,7 +168,7 @@ class AuthModuleTest {
   void test_provideLocalCredentialJson() {
     String credentialJson =
         AuthModule.provideLocalCredentialJson(
-            AuthModuleTest::getSecrets, this::getCredential, null);
+            AuthModuleTest::getSecrets, GSON, this::getCredential, null);
     Map<String, String> jsonMap =
         new Gson().fromJson(credentialJson, new TypeToken<Map<String, String>>() {}.getType());
     assertThat(jsonMap.get("type")).isEqualTo("authorized_user");
@@ -182,7 +184,10 @@ class AuthModuleTest {
     Files.writeString(credentialFile.toPath(), "{some_field: some_value}");
     String credentialJson =
         AuthModule.provideLocalCredentialJson(
-            AuthModuleTest::getSecrets, this::getCredential, credentialFile.getCanonicalPath());
+            AuthModuleTest::getSecrets,
+            GSON,
+            this::getCredential,
+            credentialFile.getCanonicalPath());
     assertThat(credentialJson).isEqualTo("{some_field: some_value}");
   }