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fastify-sse-v2

(★ 118)

Provide Server-Sent Events to Fastify

File Explorer

Download Latest Version (.zip)

- - ci.yaml
  - pr.yaml
- index.ts
- plugin.ts
- sse.ts
- types.ts
- util.ts
- - fastify4.spec.ts
  - utils.ts
- util.spec.ts
.codeclimate.yml
.codecov.yml
.eslintignore
.eslintrc.js
.gitignore
.nvmrc
.nycrc.json
CHANGELOG.md
example.ts
LICENSE
package.json
README.md
release-please-config.json
tsconfig.build.json
tsconfig.json
yarn.lock

# Installation Guide

1. Get the code

git clone https://github.com/mpetrunic/fastify-sse-v2

Downloads the entire project code from GitHub to your computer.

cd fastify-sse-v2

Moves into the project folder you just downloaded.

2. Node.js

Easy Recommended

Prerequisites

Git Needed to download the project code from GitHub.
Node.js Node.js must be installed to use npm. The LTS version is recommended.

yarn add fastify-sse-v2

Type this command into your terminal and run it.

✅ After running the command, open the address shown in the terminal (usually something like http://localhost:3000) in your browser.

Pulled directly from this repo's README.

// repository documentation

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# Fastify SSE Plugin

![CI check](https://github.com/NodeFactoryIo/fastify-sse-v2/workflows/CI%20check/badge.svg?branch=master)
[![npm version](https://badge.fury.io/js/fastify-sse-v2.svg)](https://badge.fury.io/js/fastify-sse-v2)

Fastify plugin for sending [Server-sent events](https://en.wikipedia.org/wiki/Server-sent_events).

For `fastify@2.x` use [fastify-sse-v2@1.x](https://github.com/NodeFactoryIo/fastify-sse-v2/tree/1.x)!

### How to use?

```terminal
yarn add fastify-sse-v2
```

Register fastify-sse-v2 plugin into your fastify instance:

```javascript
import { FastifySSEPlugin } from "fastify-sse-v2";

const server = fastify();
server.register(FastifySSEPlugin);
```

#### Sending events from AsyncIterable source

```javascript
import { FastifySSEPlugin } from "fastify-sse-v2";

const server = fastify();
server.register(FastifySSEPlugin);

server.get("/", function (req, res) {
  res.sse(
    (async function* source() {
      for (let i = 0; i < 10; i++) {
        sleep(2000);
        yield { id: String(i), data: "Some message" };
      }
    })()
  );
});
```

#### Sending individual events

```javascript
import { FastifySSEPlugin } from "fastify-sse-v2";

const server = fastify();
server.register(FastifySSEPlugin);

server.get("/", async function (req, res) {
  for (let i = 0; i < 10; i++) {
    await sleep(2000);
    res.sse({ id: String(i), data: "Some message" });
  }
});

fastify.get("/listenForChanges", {}, (request, reply) => {
  const listenStream = fastify.db
    .watch("doc-uuid")
    .on("data", (data) => reply.sse({ data: JSON.stringify(data) }))
    .on("delete", () => reply.sse({ event: "close" }));
  request.socket.on("close", () => listenStream.end());
});
```

##### Note

- When sending individual events, the connection is kept open until you call `reply.sseContext.source.end()` to terminate the stream.

##### Sending events from EventEmmiters

- [not supported in all nodejs versions](https://nodejs.org/api/events.html#events_events_on_emitter_eventname_options)

```javascript
import { FastifySSEPlugin } from "fastify-sse-v2";
import { on } from "events";

const server = fastify();
server.register(FastifySSEPlugin);

server.get("/", function (req, res) {
  res.sse(
    (async function* () {
      for await (const [event] of on(eventEmmitter, "update")) {
        yield {
          event: event.name,
          data: JSON.stringify(event),
        };
      }
    })()
  );
});
```

##### Note

- to remove event listeners (or some other cleanup) when client closes connection,
  you can listen on connection closing event: `request.socket.on('close', () => abortController.abort());
`

##### Change server send retry behavior

```javascript
import { FastifySSEPlugin } from "fastify-sse-v2";

const server = fastify();

server.register(FastifySSEPlugin) // retryDelay default 3000

server.register(FastifySSEPlugin, {
  retryDelay: false // disable retryDelay
  retryDelay: 5000 // override 5000
})
```

##### Change default highWaterMark

```javascript
import { FastifySSEPlugin } from "fastify-sse-v2";

const server = fastify();

server.register(FastifySSEPlugin) // highWaterMark defaults to 16384 bytes (16kb)

server.register(FastifySSEPlugin, {
  highWaterMark: 1024 // override default setting of 16384 (16kb) with 1024 (1kb)
})
```

##### Note

- You can set parameter `retryDelay` to `false` to disable the default behavior of sending retry, or set parameter `retryDelay` to `milliseconds` override the default 3000 retry interval .
- You can set parameter `highWaterMark` to define the buffer size (in bytes) that determines when the buffer is full and a 'flush' should be performed. Default is 16kb. (![Learn more](https://nodejs.org/en/learn/modules/backpressuring-in-streams#how-does-backpressure-resolve-these-issues))