How to call the Home Graph API with gRPC on Node.js - node.js

Question

Given the protocol buffers definition available at: https://github.com/googleapis/googleapis/blob/master/google/home/graph/v1/homegraph.proto
How can one call the Home Graph API RPC endpoint using gRPC on Node.js to multiplex concurrent API method calls over a single connection?

Answer 1

You can use #grpc-js in combination with Application Default Credentials to initialize the credentials.
$ npm install #grpc/grpc-js
$ npm install google-auth-library
$ export GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account-key.json
const grpc = require('#grpc/grpc-js');
const { GoogleAuth } = require('google-auth-library');
async function getCredentials() {
const sslCredentials = grpc.credentials.createSsl();
const googleAuth = new GoogleAuth({
scopes: 'https://www.googleapis.com/auth/homegraph'
});
const authClient = await googleAuth.getClient();
const callCredentials = grpc.credentials.createFromGoogleCredential(
authClient
);
const credentials = grpc.credentials.combineChannelCredentials(
sslCredentials,
callCredentials
);
return credentials;
}
Use google-proto-files with #grpc/proto-loader to load the Home Graph service protobuf definition with its dependencies.
const protoLoader = require('#grpc/proto-loader');
const protos = require('google-proto-files');
async function getHomegraph() {
const homegraphProto = await protoLoader.load(
protos.getProtoPath('home/graph', 'v1', 'homegraph.proto'), {
includeDirs: [protos.getProtoPath('..')]
}
);
const homegraph = grpc.loadPackageDefinition(
homegraphProto
).google.home.graph.v1;
return homegraph;
}
And finally initialize client stubs to call the HomeGraphApiService methods.
(async function() {
const credentials = await getCredentials();
const homegraph = await getHomegraph();
const homegraphService = new homegraph.HomeGraphApiService(
'homegraph.googleapis.com', credentials
);
homegraphService.sync({
agentUserId: 'AGENT_USER_ID'
}, function(err, result) {
if (err) {
console.error(err);
} else {
console.log(result);
}
});
// homegraphService.query();
// homegraphService.requestSyncDevices();
// homegraphService.reportStateAndNotification();
// homegraphService.deleteAgentUser();
})();
Note that by default the Channel implementation will reuse existing channels from a global pool if the parameters (address, credentials and options) are the same. You can alter this behavior with the grpc.use_local_subchannel_pool option.