server

Client Challenge - Server Companion

This server is used as a companion for the client challenge.

The server will sometime be a bit capricious, you might observe:

• failure to receive a response
• timeouts when trying to send a message
• duplicate events being received in the messages stream

When that happens, you should retry and react accordingly.

Note: persistence is in-memory only, and restarting the server will reset its state.

How to start the server?

1. You need to install Go on your system: follow the official documentation
2. Then, execute the command: go run .

How to make the server reachable from another machine?

You might want to allow the server to be reached from another machine (a simulator or a phone for example). One way to do that is to use ngrok.

1. You need to install Ngrok on your system: follow the official documentation
2. Then, after having started the go server (see above), execute the command ngrok http 3000.

This will give you a public URL of the form https://9f98-62-194-145-77.ngrok.io, that can be used to reach your server from any system that has an internet connection.

API Documentation

This API exposes a few HTTP endpoints and an SSE stream. It allows to list chats, and read & write messages.

Notes

• All the POST endpoints expect an Idempotency-Key header, it must be a string unique to each request (and their respective retries). For more details, see here. A valid header could be: Idempotency-Key: 459cfe7e-5952-43a0-a0ff-b2d8f1f4cfad.

Endpoints

• GET /events?stream=messages: an SSE stream that sends you Message entities as they are ingested by the server
• GET /chats: returns a list of all Chat entities
• GET /chats/{chat_id}/messages: returns a list of the 100 most recent Message entities in a chat
• POST /chats/{chat_id}/messages: send a new message in a chat and returns the newly created Message entity. It expects a JSON payload of the form: { "text": "..." }

Entities

Chat

• id (number): the chat id
• name (string): the chat name

Message

• id (number): the message id
• chat_id (number): the id of the chat this message belongs to
• author (string): the message author (either the constant string "user" or "bot")
• text (string): the actual content of the message
• sent_at (string): the date at which the message was sent
• idempotency_key (string): the idempotency key that was passed during the message creation