Add Making A Terminal App guide

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Tobias Baunbaek
2024-02-13 15:02:21 +01:00
parent cf76bfc7c8
commit 74f73c0ecb
3 changed files with 126 additions and 14 deletions

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## Step 2. Module dependencies ## Step 2. Module dependencies
**Note**: Close the app before installing dependencies. If dependencies are installed while the app is running, an error is thrown. **Note**: Close the app before installing dependencies. If dependencies are installed while the app is running, an error is thrown.
The app uses these modules: The app uses these modules:

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# Making a Pear Terminal Application # Making a Pear Terminal Application
This guide demonstrates how to build a peer-to-peer chat application.
It continues where [Starting a Pear Terminal Project](./starting-a-pear-terminal-project.md) left off.
> [Build with Pear - Episode 04: Pear Terminal Applications]https://www.youtube.com/watch?v=73KVE0wocTE > [Build with Pear - Episode 04: Pear Terminal Applications]https://www.youtube.com/watch?v=73KVE0wocTE
## Step 1. Install modules ## Step 1. Install modules
This app uses these modules: `hyperswarm`, `hypercore-crypto`, and `b4a`. For the chat part of the app, the same modules are needed as in [Making a Pear Desktop Application](./making-a-pear-desktop-app.md), `hyperswarm`, `b4a`, `hypercore-crypto`.
To read input we will want to use `readline`, but it's important that Pear does not run on Node.js. Instead it runs on `Bare`. Bare is a lightweight javascript runtime which means it does not include a lot of the standard library modules as Node.js does. To use the `bare` equivalent the modules `bare-readline` and `bare-tty` are needed
``` ```
npm i hyperswarm hypercore-crypto b4a npm i bare-readline bare-tty hyperswarm b4a hypercore-crypto
``` ```
**Note**: If the modules are installed while the app is running an error is thrown similar to `Cannot find package 'hyperswarm' imported from /app.js`. When installing modules, close down the app, before they can be installed. ## Step 2. JavaScript
- [hyperswarm](https://www.npmjs.com/package/hyperswarm). One of the main building blocks. Find peers that share a "topic". Replace `index.js` with
- [hypercore-crypto](https://www.npmjs.com/package/hypercore-crypto). A set of crypto function used in Pear.
- [b4a](https://www.npmjs.com/package/b4a). A set of functions for bridging the gap between the Node.js `Buffer` class and the `Uint8Array` class.
## Step 2. ``` js
import Hyperswarm from 'hyperswarm'
import b4a from 'b4a'
import crypto from 'hypercore-crypto'
import readline from 'bare-readline'
import tty from 'bare-tty'
const { teardown, config } = Pear
const key = config.args.pop()
const shouldCreateSwarm = !key
const swarm = new Hyperswarm()
const log = console.log
const rl = readline.createInterface({
input: new tty.ReadStream(0),
output: new tty.WriteStream(1)
})
swarm.on('connection', peer => {
const name = b4a.toString(peer.remotePublicKey, 'hex').substr(0, 6)
console.log(`[info] New peer joined, ${name}`)
peer.on('data', message => appendMessage({ name, message }))
})
swarm.on('update', () => {
console.log(`[info] Number of connections is now ${swarm.connections.size}`)
})
if (shouldCreateSwarm) {
await createChatRoom()
} else {
await joinChatRoom(key)
}
rl.input.setMode(tty.constants.MODE_RAW)
rl.on('data', line => {
sendMessage(line)
rl.prompt()
})
rl.prompt()
async function createChatRoom () {
const topicBuffer = crypto.randomBytes(32)
await joinSwarm(topicBuffer)
const topic = b4a.toString(topicBuffer, 'hex')
console.log(`[info] Created new chat room: ${topic}`)
}
async function joinChatRoom (topicStr) {
const topicBuffer = b4a.from(topicStr, 'hex')
await joinSwarm(topicBuffer)
console.log(`[info] Joined chat room`)
}
async function joinSwarm (topicBuffer) {
const discovery = swarm.join(topicBuffer, { client: true, server: true })
await discovery.flushed()
}
function sendMessage (message) {
const peers = [...swarm.connections]
for (const peer of peers) peer.write(message)
}
function appendMessage ({ name, message }) {
console.log(`[${name}] ${message}`)
}
```
## Step 3. Run in dev mode
To test this chat app, in one terminal run `pear dev .`.
The app will output something similar to:
```
[info] Created new chat room: a1b2c35fbeb452bc900c5a1c00306e52319a3159317312f54fe5a246d634f51a
```
In another terminal use this key as input, `pear dev . a1b2c35fbeb452bc900c5a1c00306e52319a3159317312f54fe5a246d634f51a`.
The app will output:
```
[info] Number of connections is now 0
[info] New peer joined, 6193ec
[info] Number of connections is now 1
[info] Joined chat room
```
Type something in one app, and see that the two apps are now connected and can talk!
## Next
* [Sharing a Pear Application](./sharing-a-pear-app.md)

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## Step 1. Init ## Step 1. Init
First create a new project using `pear init`. First create a new project using `pear init --type terminal`.
``` ```
mkdir chat-bot mkdir chat-app
cd chat-bot cd chat-app
pear init --yes pear init --yes --type terminal
``` ```
This creates the base project structure. This creates the base project structure.
- `package.json`. App configuration. Notice the `pear` property. - `package.json`. App configuration. Notice the `pear` property.
- `index.js`. App entrypoint. - `index.js`. App entrypoint.
- `app.js`. Main code.
- `test/index.test.js`. Test skeleton. ## Step 2. Verify Everything Works
Use `pear dev` to see that it works.
```
pear dev
```
The app will now run. Note that it will keep running until you exit with `ctrl + c`.
That's all there is to it!
## Next
* [Making a Pear Terminal Application](./making-a-pear-terminal-app.md)