@eropple/temporal-fastify-codec-server

A Fastify plugin that serves a Temporal.io PayloadCodec over HTTP.

This plugin provides a simple way to expose a PayloadCodec from the Temporal SDK as a web service. It is useful for scenarios where a remote system needs to encode or decode Temporal payloads without having direct access to the codec implementation, such as in a polyglot environment or for a remote UI.

Installation

pnpm add @eropple/temporal-fastify-codec-server

Usage

Register the plugin with your Fastify instance and provide it with a configured PayloadCodec.

import { KeySealedEnvelopeRSACodec } from "@eropple/temporal-payload-codec";
import fastify from "fastify";
import { temporalCodecPlugin } from "@eropple/temporal-fastify-codec-server";

// 1. Create and configure your payload codec
const codec = new KeySealedEnvelopeRSACodec({
  // ... your key configuration
});

// 2. Create a Fastify server
const server = fastify();

// 3. Register the plugin
await server.register(temporalCodecPlugin, {
  codec: codec,
});

// 4. Start the server
await server.listen({ port: 8888 });

Options

• codec (required): An instance of a class that implements the Temporal PayloadCodec interface.

API

The plugin exposes two POST endpoints for handling payload transformations.

Payload Format

Both endpoints expect a JSON body with a payloads key, which is an array of JSONPayload objects. The metadata and data properties of these payloads should be base64-encoded strings.

{
  "payloads": [
    {
      "metadata": {
        "encoding": "anNvbi9wbGFpbg=="
      },
      "data": "eyJoZWxsbyI6IndvcmxkIn0="
    }
  ]
}

POST /encode

Takes an array of decoded JSONPayload objects and returns them in their encoded form.

POST /decode

Takes an array of encoded JSONPayload objects and returns them in their decoded form.