Mist

A barebones library for interacting with cloud variable servers.

What Mist will do for you:

• A simple event-driven API
• Automatic reconnection if the server restarts
• Strict input validation to detect bad code early
• Forces you to provide a valid User-Agent (if used in Node.js)

What Mist won't do for you:

• Encode or decode strings/lists/etc. as numbers. We just provide the means to talk to talk to cloud variables. You have to provide encoding and decoding on your own.
• Authentication, for example to connect to clouddata.scratch.mit.edu.
• Interacting with any other API. It's just cloud variables.
• A lot of customization options. We're trying to keep it simple. Mist is small enough and has few enough dependencies that forking it to meet your needs shouldn't be that hard.
• Rate limiting. Be reasonable, okay?

You are expected to read https://docs.turbowarp.org/cloud-variables#advanced before using Mist.

Usage in Node.js

Install:

npm install @turbowarp/mist

Simple usage:

const Mist = require('@turbowarp/mist');

const connection = new Mist({
    // Can be any text, not just numbers
    projectId: '',

    // You must add your contact information here; see https://docs.turbowarp.org/cloud-variables#user-agent
    userAgent: '',

    // You can also send a username if you want but we recommend just using the default which is guaranteed
    // to always work.
    // username: 'player2345',

    // You can specify a different cloud host here:
    // cloudHost: 'wss://clouddata.turbowarp.org',
});

connection.on('connected', () => {
    // Event is fired each time a connection is successfully opened
    // Note that at this point **no variables have any values yet**
    console.log('Connected!');
});

connection.on('reconnecting', () => {
    // Event is fired each time a connection is lost (server restart, internet outage, etc.)
    console.log('Connection lost, trying to reconnect...');
});

connection.on('set', (name, value) => {
    // Event is fired each time a value is received for a variable
    console.log(name, 'was set to', value);
});

connection.on('error', (error) => {
    // Event is fired when there is an unrecoverable error. At this point the connection
    // is permanently terminated and will not automatically reconnect. Examples include
    // an invalid username or invalid User-Agent but do not include a server restart
    // (as that will trigger the reconnection logic instead).
    console.error(error);
});

const interval = setInterval(() => {
    // Instead of event-driven APIs, you can also use get() which returns the most recently
    // received or set value of a given variable. If you don't include "☁ " then we will add
    // it for you. Unknown variables return `undefined`.
    const value = connection.get('my variable') || 0;

    if (value >= 30) {
        // close() will immediately end the connection. No events will be fired.
        connection.close();
        console.log('Closing!');
        clearInterval(interval);
    } else {
        // Update a variable by calling set() anywhere. Like get(), if you don't include "☁ "
        // then we will add it for you. If called before the connection is opened, it will be
        // saved in a queue to be sent when the connection opens.
        connection.set('my variable', value + 1);
        console.log('☁ my variable is being set to', connection.get('☁ my variable'));
    }
}, 1000);

Usage in browsers

It should work if you use a build tool like webpack. Only difference is that the User-Agent is not required (and is in fact ignored). Standalone script tag version to come eventually.

License

This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.