1 files changed, 194 insertions, 0 deletions
diff --git a/java/com/android/voicemail/impl/transcribe/grpc/TranscriptionClientFactory.java b/java/com/android/voicemail/impl/transcribe/grpc/TranscriptionClientFactory.java
new file mode 100644
index 000000000..6101ed516
--- /dev/null
+++ b/java/com/android/voicemail/impl/transcribe/grpc/TranscriptionClientFactory.java
@@ -0,0 +1,194 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * 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 com.android.voicemail.impl.transcribe.grpc;
+
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.text.TextUtils;
+import com.android.dialer.common.Assert;
+import com.android.dialer.common.LogUtil;
+import com.android.voicemail.impl.transcribe.TranscriptionConfigProvider;
+import com.google.internal.communications.voicemailtranscription.v1.VoicemailTranscriptionServiceGrpc;
+import io.grpc.CallOptions;
+import io.grpc.Channel;
+import io.grpc.ClientCall;
+import io.grpc.ClientInterceptor;
+import io.grpc.ClientInterceptors;
+import io.grpc.ForwardingClientCall;
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+import io.grpc.Metadata;
+import io.grpc.MethodDescriptor;
+import io.grpc.okhttp.OkHttpChannelBuilder;
+import java.security.MessageDigest;
+
+/**
+ * Factory for creating grpc clients that talk to the transcription server. This allows all clients
+ * to share the same channel, which is relatively expensive to create.
+ */
+public class TranscriptionClientFactory {
+  private static final String DIGEST_ALGORITHM_SHA1 = "SHA1";
+  private static final char[] HEX_UPPERCASE = {
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+  };
+
+  private final TranscriptionConfigProvider configProvider;
+  private final ManagedChannel originalChannel;
+  private final String packageName;
+  private final String cert;
+
+  public TranscriptionClientFactory(Context context, TranscriptionConfigProvider configProvider) {
+    this(context, configProvider, getManagedChannel(configProvider));
+  }
+
+  public TranscriptionClientFactory(
+      Context context, TranscriptionConfigProvider configProvider, ManagedChannel managedChannel) {
+    this.configProvider = configProvider;
+    this.packageName = context.getPackageName();
+    this.cert = getCertificateFingerprint(context);
+    originalChannel = managedChannel;
+  }
+
+  public TranscriptionClient getClient() {
+    LogUtil.enterBlock("TranscriptionClientFactory.getClient");
+    Assert.checkState(!originalChannel.isShutdown());
+    Channel channel =
+        ClientInterceptors.intercept(
+            originalChannel,
+            new Interceptor(
+                packageName, cert, configProvider.getApiKey(), configProvider.getAuthToken()));
+    return new TranscriptionClient(VoicemailTranscriptionServiceGrpc.newBlockingStub(channel));
+  }
+
+  public void shutdown() {
+    LogUtil.enterBlock("TranscriptionClientFactory.shutdown");
+    originalChannel.shutdown();
+  }
+
+  private static ManagedChannel getManagedChannel(TranscriptionConfigProvider configProvider) {
+    ManagedChannelBuilder<OkHttpChannelBuilder> builder =
+        OkHttpChannelBuilder.forTarget(configProvider.getServerAddress());
+    // Only use plaintext for debugging
+    if (configProvider.shouldUsePlaintext()) {
+      // Just passing 'false' doesnt have the same effect as not setting this field
+      builder.usePlaintext(true);
+    }
+    return builder.build();
+  }
+
+  private static String getCertificateFingerprint(Context context) {
+    try {
+      PackageInfo packageInfo =
+          context
+              .getPackageManager()
+              .getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES);
+      if (packageInfo != null
+          && packageInfo.signatures != null
+          && packageInfo.signatures.length > 0) {
+        MessageDigest messageDigest = MessageDigest.getInstance(DIGEST_ALGORITHM_SHA1);
+        if (messageDigest == null) {
+          LogUtil.w(
+              "TranscriptionClientFactory.getCertificateFingerprint", "error getting digest.");
+          return null;
+        }
+        byte[] bytes = messageDigest.digest(packageInfo.signatures[0].toByteArray());
+        if (bytes == null) {
+          LogUtil.w(
+              "TranscriptionClientFactory.getCertificateFingerprint", "empty message digest.");
+          return null;
+        }
+
+        int length = bytes.length;
+        StringBuilder out = new StringBuilder(length * 2);
+        for (int i = 0; i < length; i++) {
+          out.append(HEX_UPPERCASE[(bytes[i] & 0xf0) >>> 4]);
+          out.append(HEX_UPPERCASE[bytes[i] & 0x0f]);
+        }
+        return out.toString();
+      } else {
+        LogUtil.w(
+            "TranscriptionClientFactory.getCertificateFingerprint",
+            "failed to get package signature.");
+      }
+    } catch (Exception e) {
+      LogUtil.e(
+          "TranscriptionClientFactory.getCertificateFingerprint",
+          "error getting certificate fingerprint.",
+          e);
+    }
+
+    return null;
+  }
+
+  private static final class Interceptor implements ClientInterceptor {
+    private final String packageName;
+    private final String cert;
+    private final String apiKey;
+    private final String authToken;
+
+    private static final Metadata.Key<String> API_KEY_HEADER =
+        Metadata.Key.of("X-Goog-Api-Key", Metadata.ASCII_STRING_MARSHALLER);
+    private static final Metadata.Key<String> ANDROID_PACKAGE_HEADER =
+        Metadata.Key.of("X-Android-Package", Metadata.ASCII_STRING_MARSHALLER);
+    private static final Metadata.Key<String> ANDROID_CERT_HEADER =
+        Metadata.Key.of("X-Android-Cert", Metadata.ASCII_STRING_MARSHALLER);
+    private static final Metadata.Key<String> AUTHORIZATION_HEADER =
+        Metadata.Key.of("authorization", Metadata.ASCII_STRING_MARSHALLER);
+
+    public Interceptor(String packageName, String cert, String apiKey, String authToken) {
+      this.packageName = packageName;
+      this.cert = cert;
+      this.apiKey = apiKey;
+      this.authToken = authToken;
+    }
+
+    @Override
+    public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(
+        MethodDescriptor<ReqT, RespT> method, CallOptions callOptions, Channel next) {
+      LogUtil.enterBlock(
+          "TranscriptionClientFactory.interceptCall, intercepted " + method.getFullMethodName());
+      ClientCall<ReqT, RespT> call = next.newCall(method, callOptions);
+
+      call =
+          new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(call) {
+            @Override
+            public void start(Listener<RespT> responseListener, Metadata headers) {
+              if (!TextUtils.isEmpty(packageName)) {
+                LogUtil.i(
+                    "TranscriptionClientFactory.interceptCall",
+                    "attaching package name: " + packageName);
+                headers.put(ANDROID_PACKAGE_HEADER, packageName);
+              }
+              if (!TextUtils.isEmpty(cert)) {
+                LogUtil.i("TranscriptionClientFactory.interceptCall", "attaching android cert");
+                headers.put(ANDROID_CERT_HEADER, cert);
+              }
+              if (!TextUtils.isEmpty(apiKey)) {
+                LogUtil.i("TranscriptionClientFactory.interceptCall", "attaching API Key");
+                headers.put(API_KEY_HEADER, apiKey);
+              }
+              if (!TextUtils.isEmpty(authToken)) {
+                LogUtil.i("TranscriptionClientFactory.interceptCall", "attaching auth token");
+                headers.put(AUTHORIZATION_HEADER, "Bearer " + authToken);
+              }
+              super.start(responseListener, headers);
+            }
+          };
+      return call;
+    }
+  }
+}