Google Speech Recognition with API key + gRPC

protos.diff

--- node_modules/@google-cloud/speech/protos/google/cloud/speech/v1/cloud_speech.proto.orig	2018-04-12 11:44:01.000000000 +0200
+++ node_modules/@google-cloud/speech/protos/google/cloud/speech/v1/cloud_speech.proto	2018-04-12 11:44:51.000000000 +0200
@@ -35,7 +35,7 @@
   // Performs synchronous speech recognition: receive results after all audio
   // has been sent and processed.
   rpc Recognize(RecognizeRequest) returns (RecognizeResponse) {
-    option (google.api.http) = { post: "/v1/speech:recognize" body: "*" };
+    option (google.api.http) = { post: "/v1/speech:recognize" };
   }
 
   // Performs asynchronous speech recognition: receive results via the
@@ -59,6 +59,8 @@
 
   // *Required* The audio data to be recognized.
   RecognitionAudio audio = 2;
+
+  string key = 3;
 }
 
 // The top-level message sent by the client for the `LongRunningRecognize`

testApiKeyAndGrpc.js

/**
* Make sure you're not already authenticated with gRPC, on MacOS you need
* to ensure the GOOGLE_APPLICATION_CREDENTIALS environment variable is not
* set : `unset GOOGLE_APPLICATION_CREDENTIALS`
*
* @google-cloud/speech and google-gax are used to load the necessary .proto files
*
* I tried to add the 'key' to the request itself, or as a metadata with the request
* and always getting the following error from gRPC :
*  Error: 7 PERMISSION_DENIED: The request is missing a valid API key.
*/
var PROTO_PATH = __dirname + '/node_modules/\@google-cloud/speech/protos/google/cloud/speech/v1/cloud_speech.proto';

const grpc = require('grpc');
const fs = require('fs');
const merge = require('lodash.merge');
const gax = require('google-gax');
const path = require('path');

const API_KEY = 'INSERT YOUR API KEY HERE';
const fileName = './audio.raw';

const metadata = new grpc.Metadata();
metadata.add('key', API_KEY);

// Load the applicable protos.
var protos = merge(
  {},
  gax.grpc().loadProto(
    path.join(__dirname, 'node_modules', '\@google-cloud', 'speech', 'protos'),
    'google/cloud/speech/v1/cloud_speech.proto'
  )
);

// Reads a local audio file and converts it to base64
const file = fs.readFileSync(fileName);
const audioBytes = file.toString('base64');

// The audio file's encoding, sample rate in hertz, and BCP-47 language code
const audio = {
  content: audioBytes,
};
const config = {
  encoding: 'LINEAR16',
  sampleRateHertz: 16000,
  languageCode: 'en-US',
};
const request = {
  audio: audio,
  config: config,
  key: API_KEY
};

const client = new protos.google.cloud.speech.v1.Speech('speech.googleapis.com:443', grpc.credentials.createSsl());

client.Recognize(request,
  metadata,
  function(err, response) {
    if (err) {
      console.log("ERR :", err);
      return;
    }
  
    console.log("RESPONSE :", response);
  });