Add extensible custom logic to the domain info flow

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=139584129

java/google/registry/flows/custom/CustomLogicFactory.java

@@ -40,4 +40,9 @@ public class CustomLogicFactory {
       EppInput eppInput, SessionMetadata sessionMetadata) {
     return new DomainCheckFlowCustomLogic(eppInput, sessionMetadata);
   }
+
+  public DomainInfoFlowCustomLogic forDomainInfoFlow(
+      EppInput eppInput, SessionMetadata sessionMetadata) {
+    return new DomainInfoFlowCustomLogic(eppInput, sessionMetadata);
+  }
 }

java/google/registry/flows/custom/CustomLogicModule.java

@@ -34,4 +34,10 @@ public class CustomLogicModule {
       CustomLogicFactory factory, EppInput eppInput, SessionMetadata sessionMetadata) {
     return factory.forDomainCheckFlow(eppInput, sessionMetadata);
   }
+
+  @Provides
+  static DomainInfoFlowCustomLogic provideDomainInfoFlowCustomLogic(
+      CustomLogicFactory factory, EppInput eppInput, SessionMetadata sessionMetadata) {
+    return factory.forDomainInfoFlow(eppInput, sessionMetadata);
+  }
 }

java/google/registry/flows/custom/DomainInfoFlowCustomLogic.java

@@ -0,0 +1,140 @@
+// Copyright 2016 The Nomulus Authors. All Rights Reserved.
+//
+// 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 google.registry.flows.custom;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import google.registry.flows.EppException;
+import google.registry.flows.SessionMetadata;
+import google.registry.flows.domain.DomainInfoFlow;
+import google.registry.model.ImmutableObject;
+import google.registry.model.domain.DomainResource;
+import google.registry.model.eppinput.EppInput;
+import google.registry.model.eppoutput.EppResponse.ResponseExtension;
+
+/**
+ * A no-op base class for {@link DomainInfoFlow} custom logic.
+ *
+ * <p>Extend this class and override the hook(s) to perform custom logic.
+ */
+public class DomainInfoFlowCustomLogic extends BaseFlowCustomLogic {
+
+  protected DomainInfoFlowCustomLogic(EppInput eppInput, SessionMetadata sessionMetadata) {
+    super(eppInput, sessionMetadata);
+  }
+
+  /** A hook that runs before any validation. This is useful to e.g. add allowable extensions. */
+  @SuppressWarnings("unused")
+  public void beforeValidation() throws EppException {
+    // Do nothing.
+  }
+
+  /** A hook that runs at the end of the validation step to perform additional validation. */
+  @SuppressWarnings("unused")
+  public void afterValidation(AfterValidationParameters parameters) throws EppException {
+    // Do nothing.
+  }
+
+  /**
+   * A hook that runs before the response is returned.
+   *
+   * <p>This takes the {@link DomainResource} and {@link ResponseExtension}s as input and returns
+   * them, potentially with modifications.
+   */
+  @SuppressWarnings("unused")
+  public BeforeResponseReturnData beforeResponse(BeforeResponseParameters parameters)
+      throws EppException {
+    return BeforeResponseReturnData.newBuilder()
+        .setResData(parameters.resData())
+        .setResponseExtensions(parameters.responseExtensions())
+        .build();
+  }
+
+  /** A class to encapsulate parameters for a call to {@link #afterValidation}. */
+  @AutoValue
+  public abstract static class AfterValidationParameters extends ImmutableObject {
+
+    public abstract DomainResource domain();
+
+    public static Builder newBuilder() {
+      return new AutoValue_DomainInfoFlowCustomLogic_AfterValidationParameters.Builder();
+    }
+
+    /** Builder for {@link AfterValidationParameters}. */
+    @AutoValue.Builder
+    public abstract static class Builder {
+
+      public abstract Builder setDomain(DomainResource domain);
+
+      public abstract AfterValidationParameters build();
+    }
+  }
+
+  /** A class to encapsulate parameters for a call to {@link #beforeResponse}. */
+  @AutoValue
+  public abstract static class BeforeResponseParameters extends ImmutableObject {
+
+    public abstract DomainResource domain();
+
+    public abstract DomainResource resData();
+
+    public abstract ImmutableList<? extends ResponseExtension> responseExtensions();
+
+    public static Builder newBuilder() {
+      return new AutoValue_DomainInfoFlowCustomLogic_BeforeResponseParameters.Builder();
+    }
+
+    /** Builder for {@link BeforeResponseParameters}. */
+    @AutoValue.Builder
+    public abstract static class Builder {
+
+      public abstract Builder setDomain(DomainResource domain);
+
+      public abstract Builder setResData(DomainResource resData);
+
+      public abstract Builder setResponseExtensions(
+          ImmutableList<? extends ResponseExtension> responseExtensions);
+
+      public abstract BeforeResponseParameters build();
+    }
+  }
+
+  /**
+   * A class to encapsulate parameters for the return values from a call to {@link #beforeResponse}.
+   */
+  @AutoValue
+  public abstract static class BeforeResponseReturnData extends ImmutableObject {
+
+    public abstract DomainResource resData();
+
+    public abstract ImmutableList<? extends ResponseExtension> responseExtensions();
+
+    public static Builder newBuilder() {
+      return new AutoValue_DomainInfoFlowCustomLogic_BeforeResponseReturnData.Builder();
+    }
+
+    /** Builder for {@link BeforeResponseReturnData}. */
+    @AutoValue.Builder
+    public abstract static class Builder {
+
+      public abstract Builder setResData(DomainResource resData);
+
+      public abstract Builder setResponseExtensions(
+          ImmutableList<? extends ResponseExtension> responseExtensions);
+
+      public abstract BeforeResponseReturnData build();
+    }
+  }
+}

java/google/registry/flows/domain/DomainInfoFlow.java

@@ -29,6 +29,10 @@ import google.registry.flows.ExtensionManager;
 import google.registry.flows.Flow;
 import google.registry.flows.FlowModule.ClientId;
 import google.registry.flows.FlowModule.TargetId;
+import google.registry.flows.custom.DomainInfoFlowCustomLogic;
+import google.registry.flows.custom.DomainInfoFlowCustomLogic.AfterValidationParameters;
+import google.registry.flows.custom.DomainInfoFlowCustomLogic.BeforeResponseParameters;
+import google.registry.flows.custom.DomainInfoFlowCustomLogic.BeforeResponseReturnData;
 import google.registry.model.domain.DomainCommand.Info;
 import google.registry.model.domain.DomainCommand.Info.HostsRequest;
 import google.registry.model.domain.DomainResource;
@@ -72,19 +76,31 @@ public final class DomainInfoFlow implements Flow {
   @Inject @TargetId String targetId;
   @Inject Clock clock;
   @Inject EppResponse.Builder responseBuilder;
-  @Inject DomainInfoFlow() {}
+  @Inject DomainInfoFlowCustomLogic customLogic;
+
+  @Inject
+  DomainInfoFlow() {}
 
   @Override
   public final EppResponse run() throws EppException {
     extensionManager.register(FeeInfoCommandExtensionV06.class);
+    customLogic.beforeValidation();
     extensionManager.validate();
     validateClientIsLoggedIn(clientId);
     DateTime now = clock.nowUtc();
     DomainResource domain = loadAndVerifyExistence(DomainResource.class, targetId, now);
     verifyOptionalAuthInfo(authInfo, domain);
+    customLogic.afterValidation(AfterValidationParameters.newBuilder().setDomain(domain).build());
+    BeforeResponseReturnData responseData =
+        customLogic.beforeResponse(
+            BeforeResponseParameters.newBuilder()
+                .setDomain(domain)
+                .setResData(getResourceInfo(domain))
+                .setResponseExtensions(getDomainResponseExtensions(domain, now))
+                .build());
     return responseBuilder
-        .setResData(getResourceInfo(domain))
-        .setExtensions(getDomainResponseExtensions(domain, now))
+        .setResData(responseData.resData())
+        .setExtensions(responseData.responseExtensions())
         .build();
   }
 
@@ -126,24 +142,21 @@ public final class DomainInfoFlow implements Flow {
     }
     FeeInfoCommandExtensionV06 feeInfo =
         eppInput.getSingleExtension(FeeInfoCommandExtensionV06.class);
-    if (feeInfo != null) {  // Fee check was requested.
+    if (feeInfo != null) { // Fee check was requested.
       FeeInfoResponseExtensionV06.Builder builder = new FeeInfoResponseExtensionV06.Builder();
       handleFeeRequest(
-          feeInfo,
-          builder,
-          InternetDomainName.from(targetId),
-          clientId,
-          null,
-          now,
-          eppInput);
+          feeInfo, builder, InternetDomainName.from(targetId), clientId, null, now, eppInput);
       extensions.add(builder.build());
     }
     // If the TLD uses the flags extension, add it to the info response.
     Optional<RegistryExtraFlowLogic> extraLogicManager =
         RegistryExtraFlowLogicProxy.newInstanceForDomain(domain);
     if (extraLogicManager.isPresent()) {
-      Set<String> flags = extraLogicManager.get().getExtensionFlags(
-          domain, clientId, now); // As-of date is always now for info commands.
+      Set<String> flags =
+          extraLogicManager
+              .get()
+              .getExtensionFlags(
+                  domain, clientId, now); // As-of date is always now for info commands.
       if (!flags.isEmpty()) {
         extensions.add(FlagsInfoResponseExtension.create(ImmutableList.copyOf(flags)));
       }