2023-03-26 22:39:24 +00:00
|
|
|
---
|
|
|
|
|
title: Build a Chat App
|
|
|
|
|
---
|
|
|
|
|
|
|
|
|
|
# Build a Chat App
|
|
|
|
|
|
|
|
|
|
In this guide, you will learn how to receive and send messages using Waku by building an app from scratch.
|
|
|
|
|
If you want to learn how to add Waku to an existing app, check the [Quick Start](./quick-start) guide.
|
|
|
|
|
|
|
|
|
|
## Pre-Requisites
|
|
|
|
|
|
|
|
|
|
### 1. Set up Project
|
|
|
|
|
|
|
|
|
|
Setup a new npm package:
|
|
|
|
|
|
|
|
|
|
```shell
|
|
|
|
|
mkdir waku-app
|
|
|
|
|
cd waku-app
|
|
|
|
|
npm init -y
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
### 2. Set up Web Server
|
|
|
|
|
|
|
|
|
|
Use the `serve` package as a web server
|
|
|
|
|
|
|
|
|
|
```shell
|
|
|
|
|
npm i -D serve
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
Add a `start` script to the `package.json` file:
|
|
|
|
|
|
|
|
|
|
```json
|
|
|
|
|
{
|
|
|
|
|
"scripts": {
|
|
|
|
|
"start": "serve ."
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
### 3. Create Files
|
|
|
|
|
|
|
|
|
|
Finally, create empty files for your project:
|
|
|
|
|
|
|
|
|
|
```shell
|
|
|
|
|
touch index.html index.js
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## Write Your App
|
|
|
|
|
|
|
|
|
|
## 1. Add HTML Elements
|
|
|
|
|
|
|
|
|
|
In `index.html`, add a button, text box and `div` for messages to have a basic chat app.
|
|
|
|
|
Also, import the `index.js` file.
|
|
|
|
|
|
|
|
|
|
```html title=index.html
|
|
|
|
|
<!DOCTYPE html>
|
|
|
|
|
<html lang="en">
|
|
|
|
|
<head>
|
|
|
|
|
<meta charset="UTF-8"/>
|
|
|
|
|
<meta content="width=device-width, initial-scale=1.0" name="viewport"/>
|
|
|
|
|
<title>Waku Chat App</title>
|
|
|
|
|
</head>
|
|
|
|
|
<body>
|
|
|
|
|
<label for="textInput">Message text</label>
|
|
|
|
|
<input id="textInput" placeholder="Type your message here" type="text"/>
|
|
|
|
|
<button disabled id="send" type="button">
|
|
|
|
|
Send message using Light Push
|
|
|
|
|
</button>
|
|
|
|
|
<br/>
|
|
|
|
|
<div id="messages"></div>
|
|
|
|
|
<script src="./index.js" type="module"></script>
|
|
|
|
|
</body>
|
|
|
|
|
</html>
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 2. Access HTML Elements
|
|
|
|
|
|
|
|
|
|
::: note
|
|
|
|
|
|
|
|
|
|
From now on, all changes need to be done in the `index.js` file.
|
|
|
|
|
|
|
|
|
|
:::
|
|
|
|
|
|
|
|
|
|
Initialize variables to easily modify the HTML content:
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
const sendButton = document.getElementById("send")
|
|
|
|
|
const messagesDiv = document.getElementById("messages")
|
|
|
|
|
const textInput = document.getElementById("textInput")
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 3. Start a Waku Node
|
|
|
|
|
|
|
|
|
|
Create and start a Waku Node:
|
|
|
|
|
|
|
|
|
|
```js
|
2023-04-17 06:57:20 +00:00
|
|
|
import {createLightNode} from "https://unpkg.com/@waku/create@0.0.12/bundle/index.js"
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
const wakuNode = await createLightNode({defaultBootstrap: true})
|
|
|
|
|
await wakuNode.start()
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
:::info
|
|
|
|
|
|
|
|
|
|
Setting the `defaultBootstrap` option to true allows your Waku node to connect to a set of pre-defined nodes.
|
|
|
|
|
|
|
|
|
|
:::
|
|
|
|
|
|
|
|
|
|
## 4. Wait for Connection to be Established
|
|
|
|
|
|
|
|
|
|
Your Waku node needs to connect to a remote node in order to access the network.
|
|
|
|
|
To wait for this, use the `waitForRemotePeer` function:
|
|
|
|
|
|
|
|
|
|
```js
|
2023-04-17 06:57:20 +00:00
|
|
|
import * as waku from "https://unpkg.com/@waku/core@0.0.16/bundle/index.js"
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
await waku.waitForRemotePeer(wakuNode)
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 5. Define a Content Topic
|
|
|
|
|
|
|
|
|
|
The `contentTopic` is a metadata `string` used for categorizing messages on the Waku network.
|
|
|
|
|
Depending on your use case, you can create one or more new `contentTopic`(s).
|
2023-05-27 06:45:58 +00:00
|
|
|
Refer to our [How to Choose a Content Topic](/) guide more details.
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
For this guide, we'll use `/chat-app-guide/1/message/utf8`.
|
|
|
|
|
Note that our payload will be encoded using `utf-8`.
|
|
|
|
|
We recommended using Protobuf for production purposes.
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
const contentTopic = `/chat-app-guide/1/message/utf8`
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 6. Render Incoming Messages
|
|
|
|
|
|
|
|
|
|
Let's store incoming messages in an array and create a function to render them in the `messages` div:
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
const updateMessages = (msgs, div) => {
|
|
|
|
|
div.innerHTML = "<ul>"
|
|
|
|
|
msgs.forEach((msg) => (div.innerHTML += `<li>${msg}</li>`))
|
|
|
|
|
div.innerHTML += "</ul>"
|
2023-04-17 06:57:20 +00:00
|
|
|
}
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
const messages = []
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 7. Create a Decoder
|
|
|
|
|
|
|
|
|
|
Waku supports various encryption protocols.
|
|
|
|
|
A decoder allows you to specify the content topic to use and how to decrypt messages.
|
|
|
|
|
For the chosen content topic, create a plain text decoder (without encryption):
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
const decoder = waku.createDecoder(contentTopic)
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 8. Listen for Incoming Messages
|
|
|
|
|
|
|
|
|
|
Messages sent over the network are `Waku Message`s,
|
|
|
|
|
as defined in the [14/WAKU2-MESSAGE](https://rfc.vac.dev/spec/14/#wire-format) RFC.
|
|
|
|
|
|
|
|
|
|
Messages returned by the plain text decoder implement the [`DecodedMessage`](https://js.waku.org/classes/_waku_core.DecodedMessage.html) interface.
|
|
|
|
|
|
|
|
|
|
For now, we will just use the `payload` field.
|
|
|
|
|
It is a byte array field that can be used to encode any data.
|
|
|
|
|
We will store messages as a `utf-8` string.
|
|
|
|
|
|
|
|
|
|
Listen to messages using the decoder and add them to the `messages` div upon reception:
|
|
|
|
|
|
|
|
|
|
```ts
|
2023-04-17 06:57:20 +00:00
|
|
|
import * as utils from "https://unpkg.com/@waku/utils@0.0.4/bundle/bytes.js"
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
wakuNode.filter.subscribe([decoder], (message) => {
|
|
|
|
|
const str = utils.bytesToUtf8(message.payload)
|
|
|
|
|
messages.push(str)
|
|
|
|
|
updateMessages(messages, messagesDiv);
|
|
|
|
|
})
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
## 9. Send Messages
|
|
|
|
|
|
|
|
|
|
Finally, create a plain text encoder and set up the `send` button to send messages.
|
|
|
|
|
Users will be able to enter the message using the `textInput` div.
|
|
|
|
|
|
|
|
|
|
Once done, we can enable the `send` button.
|
|
|
|
|
|
|
|
|
|
```ts
|
2023-04-17 06:57:20 +00:00
|
|
|
const encoder = waku.createEncoder({contentTopic})
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
sendButton.onclick = async () => {
|
2023-04-17 06:57:20 +00:00
|
|
|
const text = textInput.value
|
2023-03-26 22:39:24 +00:00
|
|
|
|
2023-04-17 06:57:20 +00:00
|
|
|
await wakuNode.lightPush.send(encoder, {
|
2023-03-26 22:39:24 +00:00
|
|
|
payload: utils.utf8ToBytes(text),
|
|
|
|
|
});
|
2023-04-17 06:57:20 +00:00
|
|
|
textInput.value = null
|
2023-03-26 22:39:24 +00:00
|
|
|
};
|
|
|
|
|
sendButton.disabled = false
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
### 10. Run the App
|
|
|
|
|
|
|
|
|
|
You can now start a local web server to run the app:
|
|
|
|
|
|
|
|
|
|
```shell
|
|
|
|
|
npm start
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
Click on the link in the console (http://localhost:3000/) and send a message!
|
|
|
|
|
You can open your app in several tabs to see messages being sent around.
|
|
|
|
|
|
|
|
|
|
## Conclusion
|
|
|
|
|
|
|
|
|
|
Congratulations on building your first Waku chat app. You can find the complete files below:
|
|
|
|
|
|
|
|
|
|
```html title=index.html
|
|
|
|
|
<!DOCTYPE html>
|
|
|
|
|
<html lang="en">
|
|
|
|
|
<head>
|
|
|
|
|
<meta charset="UTF-8"/>
|
|
|
|
|
<meta content="width=device-width, initial-scale=1.0" name="viewport"/>
|
|
|
|
|
<title>JS-Waku Quick Start App</title>
|
|
|
|
|
</head>
|
|
|
|
|
<body>
|
|
|
|
|
<label for="textInput">Message text</label>
|
|
|
|
|
<input id="textInput" placeholder="Type your message here" type="text"/>
|
|
|
|
|
<button disabled id="send" type="button">
|
|
|
|
|
Send message using Light Push
|
|
|
|
|
</button>
|
|
|
|
|
<br/>
|
|
|
|
|
<div id="messages"></div>
|
|
|
|
|
<script src="./index.js" type="module"></script>
|
|
|
|
|
</body>
|
|
|
|
|
</html>
|
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
```js title=index.js
|
2023-04-17 06:57:20 +00:00
|
|
|
import {createLightNode} from "https://unpkg.com/@waku/create@0.0.12/bundle/index.js"
|
|
|
|
|
import * as waku from "https://unpkg.com/@waku/core@0.0.16/bundle/index.js"
|
|
|
|
|
import * as utils from "https://unpkg.com/@waku/utils@0.0.4/bundle/bytes.js"
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
const sendButton = document.getElementById("send")
|
|
|
|
|
const messagesDiv = document.getElementById("messages")
|
|
|
|
|
const textInput = document.getElementById("textInput")
|
|
|
|
|
|
|
|
|
|
const wakuNode = await createLightNode({defaultBootstrap: true})
|
|
|
|
|
await wakuNode.start()
|
|
|
|
|
|
|
|
|
|
await waku.waitForRemotePeer(wakuNode)
|
|
|
|
|
|
|
|
|
|
const contentTopic = `/chat-app-guide/1/message/utf8`
|
|
|
|
|
|
|
|
|
|
const updateMessages = (msgs, div) => {
|
|
|
|
|
div.innerHTML = "<ul>"
|
2023-04-17 06:57:20 +00:00
|
|
|
msgs.forEach((msg) => (div.innerHTML += `<li>${msg}</li>`))
|
2023-03-26 22:39:24 +00:00
|
|
|
div.innerHTML += "</ul>"
|
2023-04-17 06:57:20 +00:00
|
|
|
}
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
const messages = []
|
|
|
|
|
|
2023-04-17 06:57:20 +00:00
|
|
|
const decoder = waku.createDecoder(contentTopic)
|
|
|
|
|
|
2023-03-26 22:39:24 +00:00
|
|
|
wakuNode.filter.subscribe([decoder], (message) => {
|
2023-04-17 06:57:20 +00:00
|
|
|
console.log("message received", message)
|
2023-03-26 22:39:24 +00:00
|
|
|
const str = utils.bytesToUtf8(message.payload)
|
|
|
|
|
messages.push(str)
|
|
|
|
|
updateMessages(messages, messagesDiv);
|
|
|
|
|
})
|
|
|
|
|
|
2023-04-17 06:57:20 +00:00
|
|
|
const encoder = waku.createEncoder({contentTopic})
|
2023-03-26 22:39:24 +00:00
|
|
|
|
|
|
|
|
sendButton.onclick = async () => {
|
2023-04-17 06:57:20 +00:00
|
|
|
const text = textInput.value
|
2023-03-26 22:39:24 +00:00
|
|
|
|
2023-04-17 06:57:20 +00:00
|
|
|
await wakuNode.lightPush.send(encoder, {
|
2023-03-26 22:39:24 +00:00
|
|
|
payload: utils.utf8ToBytes(text),
|
2023-04-17 06:57:20 +00:00
|
|
|
})
|
|
|
|
|
textInput.value = null
|
|
|
|
|
}
|
2023-03-26 22:39:24 +00:00
|
|
|
sendButton.disabled = false
|
|
|
|
|
```
|
