06 Run and inspect

You now have four files in your project:

greeter/
  greeter.proto
  load.js
  server.js
  client.js
  package.json
  node_modules/

Start the server

Open a terminal and run:

node server.js   # Greeter listening on :50051

The server blocks and listens on port 50051. Leave this terminal open.

Run the client

Open a second terminal in the same directory and run:

node client.js   # Hello, Ada

Expected output:

Hello, Ada

The client connects to localhost:50051, sends SayHello({ name: "Ada" }), receives the reply, prints response.message, and exits.

What just happened

client.js  →  HelloRequest { name: "Ada" }  →  server.js
           ←  HelloReply { message: "Hello, Ada" }  ←

1. The client serialized { name: "Ada" } into Protocol Buffers binary.
2. Sent it over HTTP/2 to localhost:50051.
3. The server deserialized the request, ran sayHello, and returned the reply.
4. The client deserialized the reply and printed message.

Stopping the server

Press Ctrl+C in the server terminal.

What's next

• Add a second method to greeter.proto (e.g., SayGoodbye) — wire up a new handler and observe how the proto change propagates through server and client.
• Swap createInsecure() for TLS credentials to secure the channel.
• Move to a server-streaming or bidirectional-streaming RPC to go beyond unary.