feat: Enable REST transport for most of Java and Go clients

README.md

@@ -57,13 +57,13 @@ implementation 'com.google.cloud:google-cloud-document-ai'
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-document-ai:2.5.1'
+implementation 'com.google.cloud:google-cloud-document-ai:2.5.2'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-document-ai" % "2.5.1"
+libraryDependencies += "com.google.cloud" % "google-cloud-document-ai" % "2.5.2"
 ```
 
 ## Authentication

google-cloud-document-ai/pom.xml

@@ -70,6 +70,10 @@
       <groupId>com.google.api</groupId>
       <artifactId>gax-grpc</artifactId>
     </dependency>
+    <dependency>
+      <groupId>com.google.api</groupId>
+      <artifactId>gax-httpjson</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.threeten</groupId>
       <artifactId>threetenbp</artifactId>
@@ -103,12 +107,24 @@
     </dependency>
 
     <!-- Need testing utility classes for generated gRPC clients tests -->
+    <dependency>
+      <groupId>com.google.api</groupId>
+      <artifactId>gax</artifactId>
+      <classifier>testlib</classifier>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>com.google.api</groupId>
       <artifactId>gax-grpc</artifactId>
       <classifier>testlib</classifier>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.google.api</groupId>
+      <artifactId>gax-httpjson</artifactId>
+      <classifier>testlib</classifier>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <profiles>

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceClient.java

@@ -17,13 +17,13 @@
 package com.google.cloud.documentai.v1;
 
 import com.google.api.gax.core.BackgroundResource;
+import com.google.api.gax.httpjson.longrunning.OperationsClient;
 import com.google.api.gax.longrunning.OperationFuture;
 import com.google.api.gax.rpc.OperationCallable;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.documentai.v1.stub.DocumentProcessorServiceStub;
 import com.google.cloud.documentai.v1.stub.DocumentProcessorServiceStubSettings;
 import com.google.longrunning.Operation;
-import com.google.longrunning.OperationsClient;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
@@ -99,13 +99,29 @@
  *     DocumentProcessorServiceClient.create(documentProcessorServiceSettings);
  * }</pre>
  *
+ * <p>To use REST (HTTP1.1/JSON) transport (instead of gRPC) for sending and receiving requests over
+ * the wire:
+ *
+ * <pre>{@code
+ * // This snippet has been automatically generated for illustrative purposes only.
+ * // It may require modifications to work in your environment.
+ * DocumentProcessorServiceSettings documentProcessorServiceSettings =
+ *     DocumentProcessorServiceSettings.newBuilder()
+ *         .setTransportChannelProvider(
+ *             DocumentProcessorServiceSettings.defaultHttpJsonTransportProviderBuilder().build())
+ *         .build();
+ * DocumentProcessorServiceClient documentProcessorServiceClient =
+ *     DocumentProcessorServiceClient.create(documentProcessorServiceSettings);
+ * }</pre>
+ *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
 @Generated("by gapic-generator-java")
 public class DocumentProcessorServiceClient implements BackgroundResource {
   private final DocumentProcessorServiceSettings settings;
   private final DocumentProcessorServiceStub stub;
-  private final OperationsClient operationsClient;
+  private final OperationsClient httpJsonOperationsClient;
+  private final com.google.longrunning.OperationsClient operationsClient;
 
   /** Constructs an instance of DocumentProcessorServiceClient with default settings. */
   public static final DocumentProcessorServiceClient create() throws IOException {
@@ -139,13 +155,17 @@ protected DocumentProcessorServiceClient(DocumentProcessorServiceSettings settin
       throws IOException {
     this.settings = settings;
     this.stub = ((DocumentProcessorServiceStubSettings) settings.getStubSettings()).createStub();
-    this.operationsClient = OperationsClient.create(this.stub.getOperationsStub());
+    this.operationsClient =
+        com.google.longrunning.OperationsClient.create(this.stub.getOperationsStub());
+    this.httpJsonOperationsClient = OperationsClient.create(this.stub.getHttpJsonOperationsStub());
   }
 
   protected DocumentProcessorServiceClient(DocumentProcessorServiceStub stub) {
     this.settings = null;
     this.stub = stub;
-    this.operationsClient = OperationsClient.create(this.stub.getOperationsStub());
+    this.operationsClient =
+        com.google.longrunning.OperationsClient.create(this.stub.getOperationsStub());
+    this.httpJsonOperationsClient = OperationsClient.create(this.stub.getHttpJsonOperationsStub());
   }
 
   public final DocumentProcessorServiceSettings getSettings() {
@@ -160,10 +180,18 @@ public DocumentProcessorServiceStub getStub() {
    * Returns the OperationsClient that can be used to query the status of a long-running operation
    * returned by another API method call.
    */
-  public final OperationsClient getOperationsClient() {
+  public final com.google.longrunning.OperationsClient getOperationsClient() {
     return operationsClient;
   }
 
+  /**
+   * Returns the OperationsClient that can be used to query the status of a long-running operation
+   * returned by another API method call.
+   */
+  public final OperationsClient getHttpJsonOperationsClient() {
+    return httpJsonOperationsClient;
+  }
+
   // AUTO-GENERATED DOCUMENTATION AND METHOD.
   /**
    * Processes a single document.

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceSettings.java

@@ -21,6 +21,7 @@
 import com.google.api.gax.core.GoogleCredentialsProvider;
 import com.google.api.gax.core.InstantiatingExecutorProvider;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
+import com.google.api.gax.httpjson.InstantiatingHttpJsonChannelProvider;
 import com.google.api.gax.rpc.ApiClientHeaderProvider;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.ClientSettings;
@@ -128,11 +129,18 @@ public static GoogleCredentialsProvider.Builder defaultCredentialsProviderBuilde
     return DocumentProcessorServiceStubSettings.defaultCredentialsProviderBuilder();
   }
 
-  /** Returns a builder for the default ChannelProvider for this service. */
+  /** Returns a builder for the default gRPC ChannelProvider for this service. */
   public static InstantiatingGrpcChannelProvider.Builder defaultGrpcTransportProviderBuilder() {
     return DocumentProcessorServiceStubSettings.defaultGrpcTransportProviderBuilder();
   }
 
+  /** Returns a builder for the default REST ChannelProvider for this service. */
+  @BetaApi
+  public static InstantiatingHttpJsonChannelProvider.Builder
+      defaultHttpJsonTransportProviderBuilder() {
+    return DocumentProcessorServiceStubSettings.defaultHttpJsonTransportProviderBuilder();
+  }
+
   public static TransportChannelProvider defaultTransportChannelProvider() {
     return DocumentProcessorServiceStubSettings.defaultTransportChannelProvider();
   }
@@ -142,11 +150,17 @@ public static ApiClientHeaderProvider.Builder defaultApiClientHeaderProviderBuil
     return DocumentProcessorServiceStubSettings.defaultApiClientHeaderProviderBuilder();
   }
 
-  /** Returns a new builder for this class. */
+  /** Returns a new gRPC builder for this class. */
   public static Builder newBuilder() {
     return Builder.createDefault();
   }
 
+  /** Returns a new REST builder for this class. */
+  @BetaApi
+  public static Builder newHttpJsonBuilder() {
+    return Builder.createHttpJsonDefault();
+  }
+
   /** Returns a new builder for this class. */
   public static Builder newBuilder(ClientContext clientContext) {
     return new Builder(clientContext);
@@ -185,6 +199,11 @@ private static Builder createDefault() {
       return new Builder(DocumentProcessorServiceStubSettings.newBuilder());
     }
 
+    @BetaApi
+    private static Builder createHttpJsonDefault() {
+      return new Builder(DocumentProcessorServiceStubSettings.newHttpJsonBuilder());
+    }
+
     public DocumentProcessorServiceStubSettings.Builder getStubSettingsBuilder() {
       return ((DocumentProcessorServiceStubSettings.Builder) getStubSettings());
     }

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStub.java

@@ -41,7 +41,11 @@
 public abstract class DocumentProcessorServiceStub implements BackgroundResource {
 
   public OperationsStub getOperationsStub() {
-    throw new UnsupportedOperationException("Not implemented: getOperationsStub()");
+    return null;
+  }
+
+  public com.google.api.gax.httpjson.longrunning.stub.OperationsStub getHttpJsonOperationsStub() {
+    return null;
   }
 
   public UnaryCallable<ProcessRequest, ProcessResponse> processDocumentCallable() {

google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStubSettings.java

@@ -25,6 +25,9 @@
 import com.google.api.gax.grpc.GrpcTransportChannel;
 import com.google.api.gax.grpc.InstantiatingGrpcChannelProvider;
 import com.google.api.gax.grpc.ProtoOperationTransformers;
+import com.google.api.gax.httpjson.GaxHttpJsonProperties;
+import com.google.api.gax.httpjson.HttpJsonTransportChannel;
+import com.google.api.gax.httpjson.InstantiatingHttpJsonChannelProvider;
 import com.google.api.gax.longrunning.OperationSnapshot;
 import com.google.api.gax.longrunning.OperationTimedPollAlgorithm;
 import com.google.api.gax.retrying.RetrySettings;
@@ -139,6 +142,11 @@ public DocumentProcessorServiceStub createStub() throws IOException {
         .equals(GrpcTransportChannel.getGrpcTransportName())) {
       return GrpcDocumentProcessorServiceStub.create(this);
     }
+    if (getTransportChannelProvider()
+        .getTransportName()
+        .equals(HttpJsonTransportChannel.getHttpJsonTransportName())) {
+      return HttpJsonDocumentProcessorServiceStub.create(this);
+    }
     throw new UnsupportedOperationException(
         String.format(
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
@@ -171,30 +179,56 @@ public static GoogleCredentialsProvider.Builder defaultCredentialsProviderBuilde
         .setUseJwtAccessWithScope(true);
   }
 
-  /** Returns a builder for the default ChannelProvider for this service. */
+  /** Returns a builder for the default gRPC ChannelProvider for this service. */
   public static InstantiatingGrpcChannelProvider.Builder defaultGrpcTransportProviderBuilder() {
     return InstantiatingGrpcChannelProvider.newBuilder()
         .setMaxInboundMessageSize(Integer.MAX_VALUE);
   }
 
+  /** Returns a builder for the default REST ChannelProvider for this service. */
+  @BetaApi
+  public static InstantiatingHttpJsonChannelProvider.Builder
+      defaultHttpJsonTransportProviderBuilder() {
+    return InstantiatingHttpJsonChannelProvider.newBuilder();
+  }
+
   public static TransportChannelProvider defaultTransportChannelProvider() {
     return defaultGrpcTransportProviderBuilder().build();
   }
 
   @BetaApi("The surface for customizing headers is not stable yet and may change in the future.")
-  public static ApiClientHeaderProvider.Builder defaultApiClientHeaderProviderBuilder() {
+  public static ApiClientHeaderProvider.Builder defaultGrpcApiClientHeaderProviderBuilder() {
     return ApiClientHeaderProvider.newBuilder()
         .setGeneratedLibToken(
             "gapic", GaxProperties.getLibraryVersion(DocumentProcessorServiceStubSettings.class))
         .setTransportToken(
             GaxGrpcProperties.getGrpcTokenName(), GaxGrpcProperties.getGrpcVersion());
   }
 
-  /** Returns a new builder for this class. */
+  @BetaApi("The surface for customizing headers is not stable yet and may change in the future.")
+  public static ApiClientHeaderProvider.Builder defaultHttpJsonApiClientHeaderProviderBuilder() {
+    return ApiClientHeaderProvider.newBuilder()
+        .setGeneratedLibToken(
+            "gapic", GaxProperties.getLibraryVersion(DocumentProcessorServiceStubSettings.class))
+        .setTransportToken(
+            GaxHttpJsonProperties.getHttpJsonTokenName(),
+            GaxHttpJsonProperties.getHttpJsonVersion());
+  }
+
+  public static ApiClientHeaderProvider.Builder defaultApiClientHeaderProviderBuilder() {
+    return DocumentProcessorServiceStubSettings.defaultGrpcApiClientHeaderProviderBuilder();
+  }
+
+  /** Returns a new gRPC builder for this class. */
   public static Builder newBuilder() {
     return Builder.createDefault();
   }
 
+  /** Returns a new REST builder for this class. */
+  public static Builder newHttpJsonBuilder() {
+    return Builder.createHttpJsonDefault();
+  }
+
   /** Returns a new builder for this class. */
   public static Builder newBuilder(ClientContext clientContext) {
     return new Builder(clientContext);
@@ -312,6 +346,19 @@ private static Builder createDefault() {
       return initDefaults(builder);
     }
 
+    private static Builder createHttpJsonDefault() {
+      Builder builder = new Builder(((ClientContext) null));
+
+      builder.setTransportChannelProvider(defaultHttpJsonTransportProviderBuilder().build());
+      builder.setCredentialsProvider(defaultCredentialsProviderBuilder().build());
+      builder.setInternalHeaderProvider(defaultHttpJsonApiClientHeaderProviderBuilder().build());
+      builder.setEndpoint(getDefaultEndpoint());
+      builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
+      builder.setSwitchToMtlsEndpointAllowed(true);
+
+      return initDefaults(builder);
+    }
+
     private static Builder initDefaults(Builder builder) {
       builder
           .processDocumentSettings()