chore: add pubsub example

.github/workflows/ci.yml

@@ -20,6 +20,7 @@ jobs:
       fail-fast: false
       matrix:
         project:
+          - js-libp2p-example-browser-pubsub
           - js-libp2p-example-chat
           - js-libp2p-example-circuit-relay
           - js-libp2p-example-connection-encryption
@@ -70,6 +71,7 @@ jobs:
       fail-fast: true
       matrix:
         project:
+          - js-libp2p-example-browser-pubsub
           - js-libp2p-example-chat
           - js-libp2p-example-circuit-relay
           - js-libp2p-example-connection-encryption

examples/js-libp2p-example-browser-pubsub/.github/pull_request_template.md

@@ -0,0 +1,17 @@
+# ⚠️ IMPORTANT ⚠️
+
+# Please do not create a Pull Request for this repository
+
+The contents of this repository are automatically synced from the parent [js-libp2p Examples Project](https://github.com/libp2p/js-libp2p-examples) so any changes made to the standalone repository will be lost after the next sync.
+
+Please open a PR against [js-libp2p Examples](https://github.com/libp2p/js-libp2p-examples) instead.
+
+## Contributing
+
+Contributions are what make the open source community such an amazing place to be learn, inspire, and create. Any contributions you make are **greatly appreciated**.
+
+1. Fork the [js-libp2p Examples Project](https://github.com/libp2p/js-libp2p-examples)
+2. Create your Feature Branch (`git checkout -b feature/amazing-example`)
+3. Commit your Changes (`git commit -a -m 'feat: add some amazing example'`)
+4. Push to the Branch (`git push origin feature/amazing-example`)
+5. Open a Pull Request

examples/js-libp2p-example-browser-pubsub/.github/workflows/sync.yml

@@ -0,0 +1,19 @@
+name: pull
+
+on:
+  workflow_dispatch
+
+jobs:
+  sync:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Pull from another repository
+        uses: ipfs-examples/actions-pull-directory-from-repo@main
+        with:
+          source-repo: libp2p/js-libp2p-examples
+          source-folder-path: examples/${{ github.event.repository.name }}
+          source-branch: main
+          target-branch: main
+          git-username: github-actions
+          git-email: github-actions@github.com

examples/js-libp2p-example-browser-pubsub/README.md

@@ -0,0 +1,104 @@
+# @libp2p/example-browser-pubsub <!-- omit in toc -->
+
+[![libp2p.io](https://img.shields.io/badge/project-libp2p-yellow.svg?style=flat-square)](http://libp2p.io/)
+[![Discuss](https://img.shields.io/discourse/https/discuss.libp2p.io/posts.svg?style=flat-square)](https://discuss.libp2p.io)
+[![codecov](https://img.shields.io/codecov/c/github/libp2p/js-libp2p-examples.svg?style=flat-square)](https://codecov.io/gh/libp2p/js-libp2p-examples)
+[![CI](https://img.shields.io/github/actions/workflow/status/libp2p/js-libp2p-examples/ci.yml?branch=main\&style=flat-square)](https://github.com/libp2p/js-libp2p-examples/actions/workflows/ci.yml?query=branch%3Amain)
+
+> User libp2p pubsub in browsers
+
+This example leverages the [vite bundler](https://vitejs.dev/) to compile and serve the libp2p code in the browser. You can use other bundlers such as Webpack, but we will not be covering them here.
+
+## Table of contents <!-- omit in toc -->
+
+- [Setup](#setup)
+- [Running](#running)
+  - [Why do I need a Relay Server?](#why-do-i-need-a-relay-server)
+  - [Start the Relay Server](#start-the-relay-server)
+  - [Running the Example](#running-the-example)
+- [License](#license)
+- [Contribution](#contribution)
+
+## Setup
+
+1. Install example depenedencies and build the project
+    ```console
+    $ npm install
+    $ npm run build
+    ```
+2. Open 2 terminal windows in the `./src` directory.
+
+## Running
+
+This example has three components.  Two browser windows which will send pubsub messages and a relay server that they will use to establish the initial connection.
+
+### Why do I need a Relay Server?
+
+The only transport available to browser nodes that lets them be dialed by remote peers is the [WebRTC](https://www.npmjs.com/package/@libp2p/webrtc) transport.
+
+This transport requires an initial [handshake](https://en.wikipedia.org/wiki/Session_Description_Protocol) to be done out-of-band, during which the two peers exchange their capabilities, addresses and open ports.
+
+We use a [Circuit Relay](https://docs.libp2p.io/concepts/nat/circuit-relay/) server to establish an initial communication channel between the two browsers for this process, after which they will have negotiated a peer-to-peer connection and the relay will no longer be used.
+
+```mermaid
+sequenceDiagram
+    Browser A->>Relay: Create reservation
+    activate Relay
+    Browser B->>Relay: Dial Browser A
+    Relay->>Browser A: Relayed dial from Browser B
+    Browser B->>Relay: WebRTC handshake request
+    Relay->>Browser A: Relayed WebRTC handshake request
+    Browser A->>Relay: WebRTC handshake response
+    Relay->>Browser B: Relayed WebRTC handshake response
+    deactivate Relay
+    Browser B->>Browser A: WebRTC connection
+```
+
+### Start the Relay Server
+
+For browsers to communicate, we first need to run the libp2p relay server:
+
+```console
+$ npm run relay
+```
+
+Copy one of the multiaddresses in the output.
+
+### Running the Example
+
+Start the Vite server:
+
+```console
+$ npm start
+```
+
+A browser window will automatically open. Let's call this `Browser A`.
+
+1. Paste the copied multiaddress from the relay server, paste it into the `Dial MultiAddr` input and click the `Connect` button
+2. `Browser A` is now connected to the relay server
+3. Copy the multiaddress located after the `Listening on` message
+
+Now open a second browser with the url `http://localhost:5173/`. Let's call this `Browser B`.
+
+1. Using the copied multiaddress from `Listening on` section in `Browser A`, paste it into the `Remote MultiAddress` input and click the `Connect` button
+2. `Browser B` is now connected to `Browser A`
+
+You can now shut down the relay server if you wish.
+
+1. In both `Browser A` and `Browser B`, enter the same topic name in the "Subscribe to topic" input and click the "Subscribe" button
+2. In either browser, enter a message in the `Send Message to Topic` field and click "Send"
+
+You should see the message appear in the output section towards the bottom of the other browser window.
+
+## License
+
+Licensed under either of
+
+- Apache 2.0, ([LICENSE-APACHE](LICENSE-APACHE) / <http://www.apache.org/licenses/LICENSE-2.0>)
+- MIT ([LICENSE-MIT](LICENSE-MIT) / <http://opensource.org/licenses/MIT>)
+
+## Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.

examples/js-libp2p-example-browser-pubsub/index.html

@@ -0,0 +1,84 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>js-libp2p browser pubsub</title>
+    <style>
+      label,
+      button {
+        display: block;
+        font-weight: bold;
+        margin: 5px 0;
+      }
+      div {
+        margin-bottom: 20px;
+      }
+      #send-section {
+        display: none;
+      }
+      input[type="text"] {
+        width: 800px;
+      }
+    </style>
+  </head>
+  <body>
+    <h1>libp2p Browser PubSub example</h1>
+    <p>This example demonstrates the pubsub API running in a browser</p>
+    <ol>
+      <li>Start a relay using the command line: <pre>$ node ./relay.js
+Relay listening on multiaddr(s):  [
+  '${multiaddr}'
+]
+      </pre></li>
+      <li>Copy the relay's multiaddr and use the "Dial Multaddr" section to dial the relay</li>
+      <li>Wait for a WebRTC address to appear in the "Listening Addresses" area</li>
+      <li>Open the same page in another browser window</li>
+      <li>Use the "Dial Multiaddr" section in the second window to dial the WebRTC address from the first</li>
+      <li>Subscribe both windows to the same topic using the "PubSub" section</li>
+      <li>Send messages between the windows using the "PubSub" section</li>
+    </ol>
+    <hr />
+    <div>
+      <h2>Node</h2>
+      <label for="relay">Dial MultiAddr</label>
+      <input type="text" id="dial-multiaddr-input" placeholder="/ip4/127.0.0.1/tcp/1234/ws/p2p/123Foo" />
+      <button id="dial-multiaddr-button">Connect</button>
+
+      <h4>PeerId</h4>
+      <p id="peer-id"></p>
+
+      <h4>Listening Addresses</h4>
+      <ul id="listening-addresses">
+        <li>None</li>
+      </ul>
+
+      <h4>Connected Peers</h4>
+      <ul id="peer-connections">
+        <li>None</li>
+      </ul>
+    </div>
+    <hr />
+    <div>
+      <h2>PubSub</h2>
+      <label for="topic">Subscribe to topic</label>
+      <input type="text" id="subscribe-topic-input" placeholder="my-topic" />
+      <button id="subscribe-topic-button">Subscribe</button>
+
+      <h4>Topic Peers</h4>
+      <ul id="topic-peers">
+        <li>None</li>
+      </ul>
+
+      <label for="topic">Send Message to Topic</label>
+      <input type="text" id="send-topic-message-input" placeholder="hello world" disabled="disabled" />
+      <button id="send-topic-message-button" disabled="disabled">Send</button>
+    </div>
+    <hr />
+    <div>
+      <h2>Output</h2>
+      <pre id="output"></pre>
+    </div>
+    <script type="module" src="./index.js"></script>
+  </body>
+</html>