client03.ts

/**
 *
 * Copyright 2018 Google LLC
 *
 * 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
 *
 *     https://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.
 *
 */
import * as grpcWeb from 'grpc-web';

import {EchoRequest, EchoResponse} from './generated/echo_pb';
import {EchoServiceClient} from './generated/echo_grpc_web_pb';

// The StreamInterceptor interface is for the callback-based client.
class MyStreamInterceptor implements grpcWeb.StreamInterceptor<
  EchoRequest, EchoResponse> {
  intercept(
    request: grpcWeb.Request<EchoRequest, EchoResponse>,
    invoker: (request: grpcWeb.Request<EchoRequest, EchoResponse>) =>
      grpcWeb.ClientReadableStream<EchoResponse>) {
    class InterceptedStream implements grpcWeb.ClientReadableStream<
      EchoResponse> {
      stream: grpcWeb.ClientReadableStream<EchoResponse>;
      constructor(stream: grpcWeb.ClientReadableStream<EchoResponse>) {
        this.stream = stream;
      };
      on(eventType: string, callback: any) {
        if (eventType == 'data') {
          const newCallback = (response: EchoResponse) => {
            response.setMessage('[-in-]'+response.getMessage());
            callback(response);
          };
          this.stream.on(eventType, newCallback);
        } else if (eventType == 'error') {
          this.stream.on('error', callback);
        } else if (eventType == 'metadata') {
          this.stream.on('metadata', callback);
        } else if (eventType == 'status') {
          this.stream.on('status', callback);
        } else if (eventType == 'end') {
          this.stream.on('end', callback);
        }
        return this;
      };
      removeListener(eventType: string, callback: any) {
      }
      cancel() {}
    }
    var reqMsg = request.getRequestMessage();
    reqMsg.setMessage('[-out-]'+reqMsg.getMessage());
    return new InterceptedStream(invoker(request));
  };
}

var opts = {'streamInterceptors' : [new MyStreamInterceptor()]};

const echoService = new EchoServiceClient('http://localhost:8080', null, opts);

export {echoService, EchoRequest}