### Initialize PartyKit Project

Source: https://docs.partykit.io/reference/partykit-cli

Add PartyKit to an existing npm project. This installs PartyKit, creates a `partykit.json` configuration file, and generates example `client.ts` and `server.ts` files.

```bash
npx partykit init
```

--------------------------------

### Install Partysocket

Source: https://docs.partykit.io/tutorials/2-adding-realtime-cursors

Install the partysocket library, which simplifies WebSocket connection management for PartyKit.

```bash
npm install partysocket@beta
```

--------------------------------

### Load Data on Server Start with PartyKit Storage

Source: https://docs.partykit.io/tutorials/add-partykit-to-a-nextjs-app/6-add-storage

Implement the `onStart` method to load data from PartyKit storage when the server starts or the first connection is made. This ensures that existing data is available.

```typescript
async onStart() {
    this.poll = await this.room.storage.get<Poll>("poll");
  }
```

--------------------------------

### Install PartyKit CLI

Source: https://docs.partykit.io/reference/partykit-cli

Install the latest version of the PartyKit CLI using npm.

```bash
npm install partykit@latest
```

--------------------------------

### Start Local Development Server

Source: https://docs.partykit.io/reference/partykit-cli

Start a local development server that watches for code changes and restarts automatically. Uses the `main` field in `partykit.json` or a specified entry point.

```bash
npx partykit dev
```

```bash
npx partykit dev src/server.ts
```

--------------------------------

### Install PartySocket

Source: https://docs.partykit.io/reference/partysocket-api

Install the PartySocket package using npm.

```bash
npm install partysocket@latest

```

--------------------------------

### Install PartyKit CLI

Source: https://docs.partykit.io/tutorials/add-partykit-to-a-nextjs-app/2-set-up-server

Run this command in your app directory to add PartyKit to a new project. It installs necessary packages and creates a 'party' directory for server code.

```bash
npx partykit@latest init

```

--------------------------------

### Start PartyKit Dev Server

Source: https://docs.partykit.io/add-to-existing-project

Execute this command in your project's directory to launch the local development server for PartyKit.

```bash
npx partykit dev
```

--------------------------------

### Example PartyKit Token Output

Source: https://docs.partykit.io/guides/setting-up-ci-cd-with-github-actions

This is an example of the output you will receive after generating a PartyKit token. The PARTYKIT_TOKEN is sensitive and should be kept secure.

```bash
PARTYKIT_LOGIN=your_username
PARTYKIT_TOKEN=eyJhb...YR7Bw
```

--------------------------------

### Install partykit-ai Package

Source: https://docs.partykit.io/reference/partykit-ai

Install the partykit-ai package to use AI models in your PartyKit project.

```bash
npm install partykit-ai
```

--------------------------------

### Basic PartyKit Server Setup

Source: https://docs.partykit.io/guides

Defines a basic PartyKit server that accepts WebSocket connections. No additional setup is required for WebSocket functionality.

```typescript
import type * as Party from "partykit/server";


export default class WebSocketServer implements Party.Server {}
```

--------------------------------

### Initialize PartyKit in Project

Source: https://docs.partykit.io/add-to-existing-project

Run this command in your project's root directory to install PartyKit packages and add the necessary 'party' directory with a server template.

```bash
npx partykit@latest init
```

--------------------------------

### Create a new PartyKit app

Source: https://docs.partykit.io/quickstart

Run this command in your terminal to initialize a new PartyKit project. Ensure you have Node.js v17 or higher installed.

```bash
npm create partykit@latest
```

--------------------------------

### Deploy PartyKit App

Source: https://docs.partykit.io/add-to-existing-project

Use this command to deploy your PartyKit server. Refer to the deployment guide for more details.

```bash
npx partykit deploy
```

--------------------------------

### Generate Text Description with Llama 2

Source: https://docs.partykit.io/reference/partykit-ai

Example fetch handler using the text-generation model to get a description for a word. Ensure the model name and messages are correctly formatted.

```typescript
import { Ai } from "partykit-ai";
import type * as Party from "partykit/server";


export default class {
  static async onFetch(request: Party.Request, lobby: Party.FetchLobby) {
    const ai = new Ai(lobby.ai);
    const result = await ai.run("@cf/meta/llama-2-7b-chat-int8", {
      messages: [
        { role: "system", content: "You are a friendly assistant" },
        {
          role: "user",
          content: "What is the origin of the phrase Hello, World"
        }
      ],
      stream: true
    });


    return new Response(result, {
      headers: { "content-type": "text/event-stream" }
    });
  }
}
```

--------------------------------

### Configure Custom Build Commands

Source: https://docs.partykit.io/reference/partykit-configuration

Define custom commands to run before starting the server, on code changes, or before deployment. Includes options for watching directories.

```json
{
  "build": {
    "command": "npm run build",
    "watch": "src"
  }
}
```

--------------------------------

### Set up a Yjs Server with PartyKit

Source: https://docs.partykit.io/reference/y-partykit-api

Implement the PartyKit Server interface to host Yjs documents. This basic setup handles incoming connections and integrates with the onConnect function from y-partykit.

```typescript
import type * as Party from "partykit/server";
import { onConnect } from "y-partykit";


export default class YjsServer implements Party.Server {
  constructor(public party: Party.Room) {}
  onConnect(conn: Party.Connection) {
    return onConnect(conn, this.party, {
      // ...options
    });
  }
}
```

--------------------------------

### Party.Server onStart Lifecycle Method

Source: https://docs.partykit.io/reference/partyserver-api

The onStart method is called when the server starts or wakes from hibernation, prior to the first onConnect or onRequest. Use it for asynchronous initialization like loading data from storage.

```typescript
import type * as Party from "partykit/server";


export default class Server implements Party.Server {
  async onStart() {}
}
```

--------------------------------

### Configure Vectorize Index in partykit.json

Source: https://docs.partykit.io/reference/partykit-ai

Example configuration for a Vectorize index named 'myIndex' within the partykit.json file.

```json
{
  // ...
  "vectorize": {
    "myIndex": {
      "index_name": "my-index"
    }
  }
}
```

--------------------------------

### Run PartyKit Dev Server

Source: https://docs.partykit.io/tutorials/add-partykit-to-a-nextjs-app/2-set-up-server

Start the PartyKit development server in a separate terminal tab to handle server logic during development.

```bash
npx partykit dev

```

--------------------------------

### Handling String Messages

Source: https://docs.partykit.io/guides/handling-binary-messages

Examples of parsing incoming string messages and broadcasting stringified JSON.

```typescript
onMessage(message: string) {
  const data = JSON.parse(message);
}
```

```typescript
onConnect(connection: Party.Connection) {
  this.room.broadcast(JSON.stringify({ type: "join", id: connection.id }));
}
```

--------------------------------

### Stateful Party Server Implementation

Source: https://docs.partykit.io/how-partykit-works

Implement a stateful server for a PartyKit room. This example demonstrates managing in-memory messages and broadcasting them to connected clients, while also sending message history on new connections.

```typescript
export default class Server implements PartyServer {
  this.messages = [];
  onMessage(message: string) {
    // keep track of messages in-memory
    this.messages.push(message);
    // send them to all connected clients
    this.room.broadcast(JSON.stringify({ messages: [message]} ));
  }
  onConnect(connection: PartyConnection) {
    // when a new client connects, send them the full message history
    connection.send(JSON.stringify({ messages: this.messages }));
  }

}
```

--------------------------------

### Handling String or Binary Messages

Source: https://docs.partykit.io/guides/handling-binary-messages

A basic example of checking the message type and broadcasting binary data directly.

```typescript
onMessage(message: string | ArrayBufferLike) {
  if (typeof message !== string) {
    this.room.broadcast(message);
  }
}
```

--------------------------------

### Read data up front in onStart

Source: https://docs.partykit.io/guides/persisting-state-into-storage

Load data from storage into memory when the server starts. This is useful for frequent reads and infrequent writes, or when joining multiple data sets. Assumes data fits within storage limits.

```typescript
export default class Main implements Party.Server {
  constructor(public room: Party.Room) {}
  messages: string[] = [];


  // You can use this to load data from storage and perform other
  // asynchronous initialization. The Room will wait until `onStart` completes before
  // processing any connections or requests.
  async onStart() {
    this.messages = (await this.room.storage.get<string[]>(
```

```typescript
messages")) ?? [];
  }


  async onConnect(connection: Party.Connection) {
    connection.send(JSON.stringify(this.messages));
  }


  async onMessage(message: string) {
    this.messages.push(message);
    this.room.storage.put("messages", this.messages);
    connection.send(message);
  }
}
```

--------------------------------

### Accessing Defined Constants in Code

Source: https://docs.partykit.io/reference/partykit-configuration

Example of how to access constants defined in the `define` section of `partykit.json` within your PartyKit server code.

```javascript
export default {
  onConnect(connection, room) {
    console.log(MY_CONSTANT); // -> "my value"
    console.log(process.env.MY_MAGIC_NUMBER) -> // 1
  },
};
```

--------------------------------

### PartyKit Vectorize CLI Commands

Source: https://docs.partykit.io/reference/partykit-ai

Command-line interface commands for managing Vectorize indexes, including create, delete, get, list, and insert.

```bash
🎈 PartyKit
------------
Usage: partykit vectorize [options] [command]


Manage vectorize indexes


Options:
  -h, --help               display help for command

Commands:
  create [options] <name>  Create a vectorize index
  delete [options] <name>  Delete a vectorize index
  get [options] <name>     Get a vectorize index by name
  list [options]           List all vectorize indexes
  insert [options] [name]  Insert vectors into a Vectorize index

```

--------------------------------

### Accessing Environment Variables in Code

Source: https://docs.partykit.io/reference/partykit-configuration

Example of how to access environment variables defined in `partykit.json` within your PartyKit server code.

```javascript
export default {
  onConnect(connection, room) {
    console.log(room.env.MY_VAR); // "my value"
    console.log(room.env["some-nested-object"].a); // 123
  }
};
```

--------------------------------

### Handle Custom HTTP Endpoints with static onFetch

Source: https://docs.partykit.io/reference/partyserver-api

Configure a custom HTTP endpoint using the static `onFetch` method. This example demonstrates returning a response with a specific status code.

```typescript
import type * as Party from "partykit/server";


export default class Server implements Party.Server {
  static async onFetch(
    req: Party.Request,
    lobby: Party.FetchLobby,
    ctx: Party.ExecutionContext
  ) {
    return new Response(req.url, { status: 403 });
  }
}


Server satisfies Party.Worker;
```

--------------------------------

### GitHub Action Workflow for PartyKit Deployment

Source: https://docs.partykit.io/guides/setting-up-ci-cd-with-github-actions

This YAML file defines a GitHub Action that deploys your PartyKit project on every push to the 'main' branch. It checks out the code, sets up Node.js, installs dependencies, and then deploys using the PartyKit CLI.

```yaml
name: Deploy

on:
  push:
    branches:
      - main

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - uses: actions/setup-node@v4
        with:
          node-version: 18
          cache: "npm"
      - run: npm ci
      - run: npx partykit deploy
        env:
          PARTYKIT_TOKEN: ${{ secrets.PARTYKIT_TOKEN }}
          PARTYKIT_LOGIN: ${{ secrets.PARTYKIT_LOGIN  }}
```

--------------------------------

### Implement Incremental Back-off Rate Limiter

Source: https://docs.partykit.io/guides/rate-limiting-messages

Apply a rate limiter to incoming messages with a specified interval and a callback for actions. This example uses a `rateLimit` function, likely from a utility or library.

```typescript
onMessage(message: string, sender: Party.Connection) {
  // rate limit incoming messages to every 100ms with an incremental back-off
  rateLimit(sender, 100, () => {
    // do things
  });
}
```

--------------------------------

### List all items in storage

Source: https://docs.partykit.io/guides/persisting-state-into-storage

Use `storage.list()` to retrieve all key-value pairs. This operation can be memory-intensive and should be used only when iteration is necessary. Consider using `get` for individual items.

```typescript
const items = await this.room.storage.list();
for (const [key, value] of items) {
  console.log(key, value);
}
```

--------------------------------

### Party.Server.onStart

Source: https://docs.partykit.io/reference/partyserver-api

The `onStart` method is called when the server begins execution or resumes from hibernation, prior to any client connections or requests.

```APIDOC
## Party.Server.onStart

Called when the server is started or after waking up from hibernation, before first `onConnect` or `onRequest`.
You can use this to load data from storage and perform other asynchronous initialization, such as retrieving data or configuration from other services or databases.
```typescript
import type * as Party from "partykit/server";

export default class Server implements Party.Server {
  async onStart() {}
}
```
```

--------------------------------

### Deploy to a Preview Environment

Source: https://docs.partykit.io/guides/preview-environments

Use the `--preview` flag with `partykit deploy` to deploy your project to a custom URL. This is ideal for creating isolated environments for testing.

```bash
partykit deploy --preview my-preview
```

--------------------------------

### Get all connections or filter by tag

Source: https://docs.partykit.io/reference/partyserver-api

Use `room.getConnections()` to get an iterable of all connected clients, or `room.getConnections("tag")` to filter by a specific tag. This can be used to send messages or count players.

```typescript
const playerCount = [...this.room.getConnections()].length;
for (const everyone of this.room.getConnections()) {
  everyone.send(`Let's play!`);
}
for (const tagged of this.room.getConnections("some-tag")) {
  tagged.send(`You're it!`);
}
```

--------------------------------

### Get Vectorize Index Details

Source: https://docs.partykit.io/reference/partykit-ai

Command to retrieve details of a specific Vectorize index by its name.

```bash
npx partykit vectorize get my-index
```

--------------------------------

### Configure Main Entry Point

Source: https://docs.partykit.io/reference/partykit-configuration

Specify the main entry point file for your PartyKit project.

```json
{
  "main": "src/server.ts"
}
```

--------------------------------

### Vector Object Example

Source: https://docs.partykit.io/reference/partykit-ai

Defines the structure of a vector object, including its ID, embedding values, and optional metadata.

```javascript
let vectorExample = {
  id: "12345",
  values: [32.4, 6.55, 11.2, 10.3, 87.9],
  metadata: {
    key: "value",
    hello: "world",
    url: "r2://bucket/some/object.json"
  }
};
```

--------------------------------

### Deploy PartyKit Project

Source: https://docs.partykit.io/reference/partykit-cli

Deploy your code to the PartyKit platform. Uses the `main` and `name` fields from `partykit.json` or specified arguments.

```bash
npx partykit deploy
```

```bash
npx partykit deploy src/server.ts --name my-project
```

--------------------------------

### Metadata Filter - Explicit Operator

Source: https://docs.partykit.io/reference/partykit-ai

Example of a metadata filter using an explicit operator, '$ne' (not equals), to exclude a boolean value.

```json
{ "someKey": { "$ne": true } }
```

--------------------------------

### Party.Server Constructor with Room Access

Source: https://docs.partykit.io/reference/partyserver-api

Demonstrates the Party.Server constructor, which receives a Party.Room instance for accessing room state, storage, connections, and more.

```typescript
import type * as Party from "partykit/server";


export default class Server implements Party.Server {
  constructor(readonly room: Party.Room) {
    // ...
  }
}
```

--------------------------------

### Metadata Filter - Implicit Equals

Source: https://docs.partykit.io/reference/partykit-ai

Example of a metadata filter using the implicit '$eq' operator for exact matching on a string value.

```json
{ "streaming_platform": "netflix" }
```

--------------------------------

### Detailed Build Configuration for Asset Compilation

Source: https://docs.partykit.io/guides/serving-static-assets

Fine-tune the build process with options for entry points, bundling, splitting, output directory, minification, format, sourcemaps, and more.

```json
{
  // ...
  "serve": {
    "path": "path/to/assets",
    // ...
    "build": {
      "entry": "path/to/entry.ts", // can also be an array of paths
      "bundle": true, // bundle all dependencies, defaults to true
      "splitting": true, // split bundles, defaults to true
      "outdir": "path/to/outdir", // defaults to serve.path + "dist"
      "minify": true, // minify bundles, defaults to false in dev and to true in deploy
      "format": "esm", // "esm" | "cjs" | "iife", default "esm"
      "sourcemap": true, // generate sourcemaps, defaults to true
      "define": {
        // define global constants, defaults to {}
        "process.env.xyz": "123"
        // you can pass values via the CLI with --define key=value
      },
      "external": ["react", "react-dom"], // externalize modules, defaults to []
      "loader": {
        // configure loaders, defaults to {}
        ".png": "file" // see https://esbuild.github.io/content-types/ for more info
      }
    }
  }
}
```

--------------------------------

### Party.Server Constructor

Source: https://docs.partykit.io/reference/partyserver-api

The constructor for Party.Server receives a Party.Room instance, providing access to room state, storage, connections, and other resources.

```APIDOC
## Party.Server (constructor)

The `Party.Server` constructor receives an instance of `Party.Room`, which gives you access to the room state and resources such as storage, connections, id, and more.
```typescript
import type * as Party from "partykit/server";

export default class Server implements Party.Server {
  constructor(readonly room: Party.Room) {
    // ...
  }
}
```
```

--------------------------------

### Configure Static Asset Serving

Source: https://docs.partykit.io/reference/partykit-configuration

Configure PartyKit to serve static assets or a static website from your project's root. Includes options for build process customization.

```json
{
  "serve": {
    "path": "path/to/assets",
    // ...
    "build": {
      "entry": "path/to/entry.ts", // can also be an array of paths
      "bundle": true, // bundle all dependencies, defaults to true
      "splitting": true, // split bundles, defaults to true
      "outdir": "path/to/outdir", // defaults to serve.path + "dist"
      "minify": true, // minify bundles, defaults to false in dev and to true in deploy
      "format": "esm", // "esm" | "cjs" | "iife", default "esm"
      "sourcemap": true, // generate sourcemaps, defaults to true
      "define": {
        // define global constants, defaults to {}
        "process.env.xyz": "123"
        // you can pass values via the CLI with --define key=value
      },
      "external": ["react", "react-dom"], // externalize modules, defaults to []
      "loader": {
        // configure loaders, defaults to {}
        ".png": "file" // see https://esbuild.github.io/content-types/ for more info
      }
    }
  }
}
```

--------------------------------

### Access and interact with other parties from within a party

Source: https://docs.partykit.io/guides/using-multiple-parties-per-project

Retrieve handles to other parties defined in the project and get specific room instances for communication.

```typescript
const userParty = this.room.context.parties.user;
const userRoom = userParty.get(userId);


// make an HTTP request to the room
const res = await userRoom.fetch({ method: "GET" });


// or open a WebSocket connection to the room to listen to messages
const socket = await userRoom.socket();
```

--------------------------------

### Connecting to a PartyKit Server with PartySocket

Source: https://docs.partykit.io/guides

Demonstrates how to connect to a PartyKit WebSocket server using the PartySocket client library. It shows how to send messages and listen for incoming messages.

```typescript
import PartySocket from "partysocket";


// connect to our server
const partySocket = new PartySocket({
  host: "localhost:1999",
  room: "my-room"
});


// send a message to the server
partySocket.send("Hello everyone");


// print each incoming message from the server to console
partySocket.addEventListener("message", (e) => {
  console.log(e.data);
});
```

--------------------------------

### Good: On-Demand Data Loading and Individual Updates

Source: https://docs.partykit.io/guides/scaling-partykit-servers-with-hibernation

This snippet demonstrates the recommended approach for handling data in a hibernating PartyKit server. It avoids loading all data on startup and instead fetches and updates individual items as needed, improving performance and reducing memory usage.

```typescript
type AllItems = Record<string, any>;


export default class Server implements Party.Server {
  options: Party.ServerOptions = { hibernate: true };
  constructor(readonly room: Party.Room) {}
  // GOOD: no data loading on startup
  // onStart() {}


  async onMessage(websocketMessage: string) {
    const event = JSON.parse(websocketMessage);
    if (event.type === "create") {
      this.room.broadcast(event.data);
      // store each item under a separate key
      this.room.storage.put(`item:${event.id}`, event.data);
    };


    if (event.type === "update") {
      // GOOD: read stored state on-demand when needed
      const item = (await this.room.storage.get(`item:${event.id}`)) ?? {};
      const updatedItem = {
        ...item,
        ...event.data,
      };


      // GOOD: now we need to write only to a single key
      this.room.storage.put(`item:${event.id}`, updatedItem);
    };
  };
};
```

--------------------------------

### Metadata Filter - Logical AND

Source: https://docs.partykit.io/reference/partykit-ai

Example of a metadata filter combining multiple conditions using an implicit logical AND. Both conditions must be met for a vector to be included.

```json
{ "pandas.nice": 42, "someKey": { "$ne": true } }
```

--------------------------------

### Deploy PartyKit Project to Cloudflare

Source: https://docs.partykit.io/guides/deploy-to-cloudflare

Run this command to deploy your project to your own Cloudflare account. Ensure you have set the CLOUDFLARE_ACCOUNT_ID and CLOUDFLARE_API_TOKEN environment variables or pass them directly.

```bash
CLOUDFLARE_ACCOUNT_ID=<your account id> CLOUDFLARE_API_TOKEN=<your api token> npx partykit deploy --domain partykit.domain.com
```

--------------------------------

### List Environment Variables

Source: https://docs.partykit.io/reference/partykit-cli

List all environment variable keys configured for your PartyKit project.

```bash
npx partykit env list
```

--------------------------------

### Get Vectors by IDs

Source: https://docs.partykit.io/reference/partykit-ai

Retrieves vectors from a Vectorize index based on their unique IDs. Returns an array of vector objects matching the provided IDs.

```javascript
const result = await myIndex.getByIds(["1", "2"]);
```

--------------------------------

### FetchLobby.env

Source: https://docs.partykit.io/reference/partyserver-api

Environment variables defined for this project.

```APIDOC
## FetchLobby.env

### Description
Environment variables defined for this project.

### Related Reading
Managing environment variables with PartyKit.
```

--------------------------------

### Set and get connection state

Source: https://docs.partykit.io/reference/partyserver-api

Use `connection.setState()` to store small, non-persistent data (up to 2KB) on a connection for its lifetime. Access this data later using `connection.state`.

```typescript
connection.setState({ username: "jani" });
```

```typescript
const user = connection.state?.username;
```

--------------------------------

### Access other parties via Room.context.parties

Source: https://docs.partykit.io/reference/partyserver-api

Use `this.room.context.parties` to access and interact with other parties within the same project. You can get a specific party instance and make fetch requests to it.

```typescript
const otherParty = this.room.context.parties.other;
const otherPartyInstance = otherParty.other.get("room-id");
const req = await otherRoom.fetch({ method: "GET" });
const res = await req.json();
```

--------------------------------

### Configure Project Name

Source: https://docs.partykit.io/reference/partykit-configuration

Set the name of your project, used for identification and URL generation.

```json
{
  "name": "my-project"
}
```

--------------------------------

### Configure Build Process for Static Assets

Source: https://docs.partykit.io/guides/serving-static-assets

Integrate a build process for compiling assets like TypeScript or JSX by specifying the 'build' field in your partykit.json.

```json
{
  // ...
  "serve": {
    "path": "path/to/assets",
    // ...
    "build": "path/to/entry.ts"
  }
}
```

--------------------------------

### Metadata Filter - Nested Keys

Source: https://docs.partykit.io/reference/partykit-ai

Example demonstrating how to filter on nested metadata keys using dot notation. This targets a specific key within a nested object.

```json
{ "pandas.nice": 42 }


// looks for { "pandas": { "nice": 42 } }
```

--------------------------------

### List Published Projects

Source: https://docs.partykit.io/reference/partykit-cli

List all projects you have published on the PartyKit platform.

```bash
npx partykit list
```

--------------------------------

### Store Room ID on Startup

Source: https://docs.partykit.io/guides/scheduling-tasks-with-alarms

Saves the room ID to storage when the room starts from a connection or request. This is a workaround for accessing the room ID within the onAlarm callback.

```typescript
onStart() {
  if (this.room.id) {
    // save id when room starts from a connection or request
    await this.room.storage.put<string>("id", this.id);
  }
}
```

--------------------------------

### List All Vectorize Indexes

Source: https://docs.partykit.io/reference/partykit-ai

Command to list all available Vectorize indexes.

```bash
npx partykit vectorize list
```

--------------------------------

### Basic PartySocket Usage

Source: https://docs.partykit.io/reference/partysocket-api

Demonstrates how to instantiate and use PartySocket to connect to a PartyKit room, including optional client identification and party specification.

```APIDOC
## Basic PartySocket Usage

### Description
Instantiate `PartySocket` to connect to a PartyKit server. You can specify the host, room, a unique client ID, and the target party. Query parameters can also be dynamically provided.

### Constructor
`new PartySocket(options: { host: string; room: string; id?: string; party?: string; query?: () => Record<string, string> | Promise<Record<string, string>>; })`

### Parameters
*   **host** (string) - The hostname of the PartyKit server or `localhost` for development.
*   **room** (string) - The name of the room to connect to.
*   **id** (string, optional) - A unique identifier for this specific connection. If not provided, a random ID is generated.
*   **party** (string, optional) - The name of the party to connect to. Defaults to "main" if not specified.
*   **query** (function, optional) - A function that returns an object of query parameters to be appended to the connection URL. Can be synchronous or asynchronous.

### Request Example
```typescript
import PartySocket from "partysocket";

const ws = new PartySocket({
  host: "project-name.username.partykit.dev", // or localhost:1999 in dev
  room: "my-room",
  id: "some-connection-id",
  party: "main",
  query: async () => ({
    token: await getAuthToken()
  })
});
```
```

--------------------------------

### Fetch poll data from PartyKit server

Source: https://docs.partykit.io/tutorials/add-partykit-to-a-nextjs-app/3-hook-up-data-to-the-server

Fetches poll data from the PartyKit server using an HTTP GET request. Caching is disabled to ensure data is always current.

```typescript
const req = await fetch(`${PARTYKIT_URL}/party/${pollId}`, {
  method: "GET",
  next: {
    revalidate: 0
  }
});


if (!req.ok) {
  if (req.status === 404) {
    notFound();
  } else {
    throw new Error("Something went wrong.");
  }
}
```

--------------------------------

### Deploy PartyKit with Variables from .env File

Source: https://docs.partykit.io/guides/managing-environment-variables

This command deploys your PartyKit application and includes environment variables defined in a local `.env` file. This method takes precedence over globally deployed secrets for this specific deployment.

```bash
npx partykit deploy --with-vars
```

--------------------------------

### Bad: Loading All State on Startup and Persisting Entire State

Source: https://docs.partykit.io/guides/scaling-partykit-servers-with-hibernation

This snippet illustrates an inefficient pattern for hibernating PartyKit servers. It loads the entire state on startup and persists the whole state on every update, which can lead to significant performance issues and high costs with large datasets.

```typescript
type AllItems = Record<string, any>;


export default class Server implements Party.Server {
  options: Party.ServerOptions = { hibernate: true };
  constructor(readonly room: Party.Room) {}
  async onStart() {
    // BAD
    // we load full state from storage on start (may be big)
    this.items = await this.room.storage.get<AllItems>("state");
  };


  async onMessage(websocketMessage: string) {
    const event = JSON.parse(websocketMessage);
    if (event.type === "create") {
      this.items[event.id] = event.data;
      this.room.broadcast(event.data);
    };


    if (event.type === "update") {
      const item = this.items[event.id];
      this.items[event.id] = {
        ...item,
        ...event.data,
      };
    };


    // BAD
    // we need to persist the whole state again (expensive)
    await this.room.storage.put("items", this.items);
  };
};
```

--------------------------------

### Verify HTTP Request Token with Clerk

Source: https://docs.partykit.io/guides/authentication

Implement the `onBeforeRequest` handler to verify the `Authorization` header. This example uses Clerk for JWT verification. Returns an unauthorized response if verification fails.

```typescript
import type * as Party from "partykit/server";
import { verifyToken } from "@clerk/backend";


const DEFAULT_CLERK_ENDPOINT = "https://clerk.yourdomain.com";


export default class Server implements Party.Server {
  static async onBeforeRequest(request: Party.Request) {
    try {
      // get authentication server url from environment variables (optional)
      const issuer = lobby.env.CLERK_ENDPOINT || DEFAULT_CLERK_ENDPOINT;
      // get token from request headers
      const token = request.headers.get("Authorization") ?? "";
      // verify the JWT (in this case using clerk)
      await verifyToken(token, { issuer });
      // forward the request onwards on onRequest
      return request;
    } catch (e) {
      // authentication failed!
      // short-circuit the request before it's forwarded to the party
      return new Response("Unauthorized", { status: 401 });
    }
  }


  onRequest(req: Party.Request) {
    return new Response(`Hello from party!`);
  }
}
```

--------------------------------

### Custom WebSocket Options

Source: https://docs.partykit.io/reference/partysocket-api

Explains how to provide custom options, such as a different WebSocket constructor or connection timeouts, when creating a `WebSocket` instance.

```APIDOC
## Custom WebSocket Options

### Description
Pass an `options` object to the `WebSocket` constructor to customize its behavior, such as specifying a custom WebSocket implementation or setting connection timeouts and retry limits.

### Parameters
*   **WebSocket** (constructor, optional) - A custom WebSocket constructor to use (e.g., `ws` from the `ws` package).
*   **connectionTimeout** (number, optional) - The timeout in milliseconds for establishing a connection.
*   **maxRetries** (number, optional) - The maximum number of times to retry the connection upon failure.

### Request Example
```typescript
import { WebSocket } from "partysocket";
import WS from "ws";

const options = {
  WebSocket: WS, // custom WebSocket constructor
  connectionTimeout: 1000,
  maxRetries: 10
};
const ws = new WebSocket("wss://my.site.com", [], options);
```
```

--------------------------------

### Define the main party in partykit.json

Source: https://docs.partykit.io/guides/using-multiple-parties-per-project

This is the default configuration for a single party project.

```json
{
  "name": "multiparty",
  "main": "src/server.ts"
}
```

--------------------------------

### Handle Incoming HTTP Requests in PartyKit Server

Source: https://docs.partykit.io/guides/responding-to-http-requests

Implement the `onRequest` handler in a PartyKit server to process incoming HTTP requests. Supports POST for adding messages and GET for retrieving them.

```typescript
import type * as Party from "partykit/server";


export default class MessageServer implements Party.Server {
  messages: string[] = [];
  constructor(readonly room: Party.Room) {}


  async onRequest(request: Party.Request) {
    // push new message
    if (request.method === "POST") {
      const payload = await request.json<{ message: string }>();
      this.messages.push(payload.message);
      this.room.broadcast(payload.message);
      return new Response("OK");
    }


    // get all messages
    if (request.method === "GET") {
      return new Response(JSON.stringify(this.messages));
    }


    return new Response("Method not allowed", { status: 405 });
  }
}
```

--------------------------------

### Deploy to a Custom Domain with Preview

Source: https://docs.partykit.io/guides/preview-environments

When deploying to your own Cloudflare account, you can specify a custom domain and a preview environment name. This allows for more control over your deployment URLs.

```bash
partykit deploy --domain mydomain.com --preview my-preview
```

--------------------------------

### Update Alarm on Data Read

Source: https://docs.partykit.io/guides/scheduling-tasks-with-alarms

This example shows how to update the storage expiry alarm when data is read from the room. This ensures that storage persists for 30 days since the last read operation.

```typescript
  onConnect(connection: Party.Connection) {
    // do something, and save to storage
    connection.send(await this.room.storage.get(data.id));
    await this.room.storage.setAlarm(Date.now() + EXPIRY_PERIOD_MILLISECONDS);
  }

```

--------------------------------

### Tail Project Logs

Source: https://docs.partykit.io/reference/partykit-cli

View live logs for your PartyKit project, useful for debugging. You can specify the project name.

```bash
npx partykit tail
```

```bash
npx partykit tail --name my-project
```

--------------------------------

### Configure Yjs Server with Persistence and Read-Only Options

Source: https://docs.partykit.io/reference/y-partykit-api

Enhance the Yjs server setup with options for persistence and read-only mode. The `persist` option can be set to 'snapshot' or 'history', and `readOnly` can disable editing.

```typescript
import type * as Party from "partykit/server";
import { onConnect } from "y-partykit";


export default class YjsServer implements Party.Server {
  constructor(public room: Party.Room) {}
  onConnect(conn: Party.Connection) {
    return onConnect(conn, this.room, {
      // experimental: persists the document to partykit's room storage
      persist: { mode: "snapshot" },


      // enable read only access to true to disable editing, default: false
      readOnly: true,


      // Or, you can load/save to your own database or storage
      async load() {
        // load a document from a database, or some remote resource
        // and return a Y.Doc instance here (or null if no document exists)
      },


      callback: {
        async handler(yDoc) {
          // called every few seconds after edits
          // you can use this to write to a database
          // or some external storage
        },
        // control how often handler is called with these options
        debounceWait: 10000, // default: 2000 ms
        debounceMaxWait: 20000, // default: 10000 ms
        timeout: 5000 // default: 5000 ms
      }
    });
  }
}
```

--------------------------------

### Authenticate with PartyKit

Source: https://docs.partykit.io/reference/partykit-cli

Authenticate with the PartyKit service by opening a browser window for GitHub authentication. Automatic login occurs on first `deploy` or `env` command usage if not manually logged in.

```bash
npx partykit login
```

--------------------------------

### Type Safety Example for Zod Schemas

Source: https://docs.partykit.io/guides/validating-client-inputs

Demonstrates how Zod's TypeScript inference provides type safety within switch statements, ensuring that message properties are correctly typed based on their schema.

```typescript
case "remove":
  // @ts-expect-error RemoveMessage does not have `item`
  data.item;
  break;

```

--------------------------------

### Create a Vectorize Index

Source: https://docs.partykit.io/reference/partykit-ai

Commands to create a new Vectorize index, specifying dimensions and metric, or using a preset model.

```bash
npx partykit vectorize create my-index --dimensions <dimensions> --metric <type>


# or


npx partykit vectorize create my-index --preset <preset>
# where <preset> is one of:
# - @cf/baai/bge-small-en-v1.5
# - @cf/baai/bge-base-en-v1.5
# - @cf/baai/bge-large-en-v1.5
# - openai/text-embedding-ada-002

```

--------------------------------

### Set and Clear Room Storage with Alarms

Source: https://docs.partykit.io/guides/scheduling-tasks-with-alarms

This example demonstrates how to set an alarm to expire room storage after a defined period of inactivity. The alarm is updated on every data save. If the alarm triggers, all storage in the room is cleared.

```typescript
const EXPIRY_PERIOD_MILLISECONDS = 30 * 24 * 60 * 60 * 1000; // 30 days


export default class UserSession implements Party.Server {
  onMessage(message: string) {
    const data = JSON.parse(message);
    // do something, and save to storage
    await this.room.storage.put(data.id, data);
    await this.room.storage.setAlarm(Date.now() + EXPIRY_PERIOD_MILLISECONDS);
  }


  onAlarm() {
    // clear all storage in this room
    await this.room.storage.deleteAll();
  }
}
```

--------------------------------

### Basic Party.Server Implementation

Source: https://docs.partykit.io/reference/partyserver-api

The fundamental structure for a PartyKit server, implementing the Party.Server interface. Assumes TypeScript.

```typescript
import type * as Party from "partykit/server";


export default class Server implements Party.Server {}
```

--------------------------------

### PartyKit Server Implementation

Source: https://docs.partykit.io/tutorials/add-partykit-to-a-nextjs-app/2-set-up-server

This TypeScript code defines the PartyKit server for handling HTTP requests. It manages poll data in memory and responds to POST requests to create polls and GET requests to retrieve poll data.

```typescript
import type * as Party from "partykit/server";


import type { Poll } from "@/app/types";


export default class Server implements Party.Server {
  constructor(readonly room: Party.Room) {}


  poll: Poll | undefined;


  async onRequest(req: Party.Request) {
    if (req.method === "POST") {
      const poll = (await req.json()) as Poll;
      this.poll = { ...poll, votes: poll.options.map(() => 0) };
    }


    if (this.poll) {
      return new Response(JSON.stringify(this.poll), {
        status: 200,
        headers: { "Content-Type": "application/json" }
      });
    }


    return new Response("Not found", { status: 404 });
  }
}


Server satisfies Party.Worker;

```

--------------------------------

### Create a vector index

Source: https://docs.partykit.io/reference/partykit-ai

Use this command to create a new vector index with specified dimensions and metric.

```bash
$ npx partykit vectorize create tutorial-index --dimensions=3 --metric=cosine
```

--------------------------------

### Party.Server.options

Source: https://docs.partykit.io/reference/partyserver-api

The `options` field allows customization of PartyServer behavior, such as enabling or disabling hibernation.

```APIDOC
## Party.Server.options

You can define an `options` field to customise the PartyServer behaviour.
```typescript
import type * as Party from "partykit/server";

export default class Server implements Party.Server {
  readonly options = {
    hibernate: false
  };
}
```

##### Party.Server.options.hibernate
Whether the PartyKit platform should remove the server from memory between HTTP requests and WebSocket messages. The default value is `false`.
**Related guide:** Scaling PartyKit Servers with Hibernation
```

--------------------------------

### Connecting to Other WebSocket Servers

Source: https://docs.partykit.io/reference/partysocket-api

Demonstrates using the `WebSocket` class from `partysocket` to connect to any standard WebSocket server.

```APIDOC
## Connecting to Other WebSocket Servers

### Description
Utilize the `WebSocket` class exported from `partysocket` to establish connections with any WebSocket server, not limited to PartyKit.

### Constructor
`new WebSocket(url: string | (() => string) | (() => Promise<string>), protocols?: string | string[] | (() => string | string[] | null) | (() => Promise<string | string[] | null>), options?: object)`

### Request Example (Basic)
```typescript
import { WebSocket } from "partysocket";

const ws = new WebSocket("wss://my.site.com");

ws.addEventListener("open", () => {
  ws.send("hello!");
});
```
```

--------------------------------

### Verify WebSocket Connection Token with Clerk

Source: https://docs.partykit.io/guides/authentication

Implement the `onBeforeConnect` handler to verify the JWT token received in the query string. This example uses Clerk for verification and sets a user ID header for subsequent handlers. Returns an unauthorized response if verification fails.

```typescript
import * as Party from "partykit/server";
import { verifyToken } from "@clerk/backend";


const DEFAULT_CLERK_ENDPOINT = "https://clerk.yourdomain.com";


export default class Server implements Party.Server {
  static async onBeforeConnect(request: Party.Request, lobby: Party.Lobby) {
    try {
      // get authentication server url from environment variables (optional)
      const issuer = lobby.env.CLERK_ENDPOINT || DEFAULT_CLERK_ENDPOINT;
      // get token from request query string
      const token = new URL(request.url).searchParams.get("token") ?? "";
      // verify the JWT (in this case using clerk)
      const session = await verifyToken(token, { issuer });
      // pass any information to the onConnect handler in headers (optional)
      request.headers.set("X-User-ID", session.sub);
      // forward the request onwards on onConnect
      return request;
    } catch (e) {
      // authentication failed!
      // short-circuit the request before it's forwarded to the party
      return new Response("Unauthorized", { status: 401 });
    }
  }


  onConnect(
    connection: Party.Connection,
    { request }: Party.ConnectionContext
  ) {
    const userId = request.headers.get("X-User-ID");
    connection.send(`Hello ${userId} from party!`);
  }
}
```

--------------------------------

### Push Environment Variables to Platform

Source: https://docs.partykit.io/reference/partykit-cli

Deploy environment variables from `partykit.json` to the PartyKit platform. A subsequent `npx partykit deploy` is required for the variables to take effect.

```bash
npx partykit env push
```

--------------------------------

### Basic PartySocket Usage

Source: https://docs.partykit.io/reference/partysocket-api

Connect to a PartyKit server using PartySocket. Configure host, room, and optionally an ID, party, or query parameters.

```typescript
import PartySocket from "partysocket";


const ws = new PartySocket({
  host: "project-name.username.partykit.dev", // or localhost:1999 in dev
  room: "my-room",
  // add an optional id to identify the client,
  // if not provided, a random id will be generated
  // note that the id needs to be unique per connection,
  // not per user, so e.g. multiple devices or tabs need a different id
  id: "some-connection-id",


  // optionally, specify the party to connect to.
  // if not provided, will connect to the "main" party defined in partykit.json
  party: "main",


  // optionally, pass an object of query string parameters to add to the request
  query: async () => ({
    token: await getAuthToken()
  })
});


// optionally, update the properties of the connection
// (e.g. to change the host or room)
ws.updateProperties({
  host: "another-project.username.partykit.dev",
  room: "my-new-room"
});


ws.reconnect(); // make sure to call reconnect() after updating the properties

```

--------------------------------

### Party.Server.onBeforeRequest

Source: https://docs.partykit.io/reference/partyserver-api

Runs before any HTTP request is made to the party. It can modify the request or return a Response to short-circuit it.

```APIDOC
## `static` onBeforeRequest

### Description
Runs before any HTTP request is made to the party. You can modify the `request` before it is forwarded to the party, or return a `Response` to short-circuit it.
Receives an instance of `Party.Request`, and is expected to either return a request, or a standard Fetch API `Response`.

### Method Signature
```typescript
static async onBeforeRequest(req: Party.Request, lobby: Party.Lobby, ctx: Party.ExecutionContext): Promise<Party.Request | Response>
```

### Notes
Because the static `onBeforeRequest` method runs in an edge worker near the user instead of in the room, it doesn’t have access to `Party` room resources such as storage. Instead, you can access a subset of its properties via a `Party.Lobby`.

### Example Usage
```typescript
import type * as Party from "partykit/server";

export default class Server implements Party.Server {
  static async onBeforeRequest(
    req: Party.Request,
    lobby: Party.Lobby,
    ctx: Party.ExecutionContext
  ) {
    return new Response("Access denied", { status: 403 });
  }
  // ... other methods
}
```
```

--------------------------------

### Configure Global Constants

Source: https://docs.partykit.io/reference/partykit-configuration

Define global constants for your project, which will be substituted into your code. Values are provided as strings.

```json
{
  "define": {
    "MY_CONSTANT": "'my value'",
    "process.env.MY_MAGIC_NUMBER": "1"
  }
}
```

--------------------------------

### Dynamic Protocols Provider

Source: https://docs.partykit.io/reference/partysocket-api

Illustrates how to use functions to dynamically provide WebSocket subprotocols during connection.

```APIDOC
## Dynamic Protocols Provider

### Description
The `protocols` parameter can be a function that returns the desired subprotocols. This supports returning `null`, a single `string`, an array of `string`s, or a `Promise` resolving to any of these.

### Usage
Provide `null`, a `string`, `string[]`, a function returning any of these, or a function returning a `Promise` resolving to any of these.

### Request Example (String Protocol)
```typescript
import { WebSocket } from "partysocket";

const ws = new WebSocket("wss://your.site.com", "your protocol");
```

### Request Example (Round Robin Protocols)
```typescript
import WebSocket from 'partysocket';

const protocols = ['p1', 'p2', ['p3.1', 'p3.2']];
let protocolsIndex = 0;

const protocolsProvider = () => protocols[protocolsIndex++ % protocols.length];

const ws = new WebSocket('wss://your.site.com', protocolsProvider);
```
```

--------------------------------

### Connect a Yjs Client to the Server

Source: https://docs.partykit.io/reference/y-partykit-api

Use the YPartyKitProvider to connect a Yjs document to a running y-partykit server. Ensure the host and document name match the server configuration.

```typescript
import YPartyKitProvider from "y-partykit/provider";
import * as Y from "yjs";


const yDoc = new Y.Doc();


const provider = new YPartyKitProvider(
  "localhost:1999",
  "my-document-name",
  yDoc
);
```

--------------------------------

### Configure Static Assets Path in partykit.json

Source: https://docs.partykit.io/guides/serving-static-assets

Specify the directory containing static assets to be served by PartyKit using the 'serve' field in your partykit.json.

```json
{
  //...
  "serve": "path/to/assets"
}
```

--------------------------------

### PartySocket Constructor

Source: https://docs.partykit.io/reference/partysocket-api

Initializes a new PartySocket client. Provide the WebSocket URL and optionally protocols and configuration options.

```typescript
constructor(url: UrlProvider, protocols?: ProtocolsProvider, options?: Options)

```

--------------------------------

### Deploy PartyKit with Inline Environment Variables

Source: https://docs.partykit.io/guides/managing-environment-variables

Specify environment variables directly on the command line during deployment. This is useful for CI environments or when not using a `.env` file. These variables will override any previously deployed secrets for this deployment.

```bash
npx partykit deploy --var API_KEY=$API_KEY --var HOST=$HOST
```

--------------------------------

### Accessing Other Parties in FetchLobby

Source: https://docs.partykit.io/reference/partyserver-api

Demonstrates how to access and interact with other parties within the same project using FetchLobby. Useful for inter-party communication.

```javascript
const otherParty = lobby.parties.other;
const otherPartyInstance = otherParty.other.get("room-id");
const req = await otherRoom.fetch({ method: "GET" });
const res = await req.json();

```

--------------------------------

### Implement PartyKit Server Logic

Source: https://docs.partykit.io/how-partykit-works

Define the behavior of your PartyKit server using the `Party.Server` interface. Implement methods like `onRequest`, `onConnect`, and `onMessage` to handle different types of interactions.

```typescript
export default class Server implements Party.Server {
  constructor(readonly room: Party.Room) {}
  onRequest(req: PartyRequest) {
    return new Response("Hello via HTTP");
  },
  onConnect(connection: PartyConnection) {
    connection.send("Hello via WebSockets");
  },
  onMessage(message: string) {
    this.room.broadcast(`Received ${message} via WebSockets`);
  }
}
```

--------------------------------

### Send HTTP Request using PartySocket.fetch Utility

Source: https://docs.partykit.io/guides/responding-to-http-requests

Utilize the PartySocket.fetch utility to simplify constructing URLs and sending HTTP requests to a PartyKit room. It automatically handles protocol and host details.

```javascript
PartySocket.fetch(
  { host: PARTYKIT_HOST, room: roomId },
  {
    method: "POST",
    body: JSON.stringify({ message: "Hello!" })
  }
);
```