rage-rpc

* Motivation
* Installation
* Examples
* Server to Client
* CEF to Server
* Client to Server
* API
* Universal
* register(name, callback)
* unregister(name)
* call(name, args)
* callServer(name, args)
* on(name, callback)
* off(name, callback)
* trigger(name, args)
* triggerServer(name, args)
* Server-side
* callClient(player, name, args)
* callBrowsers(player, name, args)
* triggerClient(player, name, args)
* triggerBrowsers(player, name, args)
* Client-side
* callBrowser(browser, name, args)
* triggerBrowser(browser, name, args)
* CEF or Client-side
* callBrowsers(name, args)
* callClient(name, args)
* triggerBrowsers(name, args)
* triggerClient(name, args)
* Options
* Events
* Changelog

Motivation

A very common workflow when developing with any kind of client-server platform is not only sending data between the server and clients, but also receiving data back after performing some kind of action. An example would be a client asking for information from a database in order to display to the user. One technique to achieve this is called remote procedure calls (RPC) which allows one application context to call code in a completely separate context and return the result back to the caller, as if it were local to begin with.

In RAGE Multiplayer, this kind of functionality is not supported natively. In order for a player to ask something of the server, the server must set up an event handler that the player calls remotely, then the server does its processing and calls _another_ event handler that resides on the client. There are many pitfalls to this approach, including but not limited to messy code and false identification (am i sending the response to the right caller instance?). Natively, the server cannot directly communicate with CEF instances at all. You have to route all requests through the client. Suddenly, you have 16 different events to handle one simple data request. It's horrible. And when your codebase starts growing, it becomes a huge hassle to deal with.

This is pretty much what everybody has learned to deal with, until now. rage-rpc simplifies two-way communication between the RAGE Multiplayer server, client, and browser instances by providing a easy-to-use API for calling remote code and retrieving results. Any context can call a function that resides in any other context and immediately get access to its return value without messing with events. This means any CEF instance can call code on the server, the client, or any other CEF instances and easily see the result.

---

Installation

#### Option 1

You can install via npm

``
npm i -S rage-rpc
`

From here, you can simply require the package in any RAGE context:

`javascript
const rpc = require('rage-rpc');

rpc.register('hi', () => 'hello!');
`

#### Option 2

In the dist/ folder of this repository is a single minified JS file that you can download and require into any RAGE context. It works the same as the above option, but you'll have to manually redownload the file when new versions are released.

`javascript
const rpc = require('./rage-rpc.min.js');

rpc.register('hi', () => 'hello!');
`

#### Option 3 (Browser Only)

In order to use require in the browser, you'll need either an AMD loader or some kind of bundler like Webpack. If those options don't suit your project, you can load the file into browser contexts with just a script tag before the code you use it in. It will expose a global rpc variable that you can use on your page.

`html







`

Examples

$3

Situation: The server wants to ask a specific player if they are currently climbing anything.

##### Client-side
`javascript
const rpc = require('rage-rpc');

rpc.register('getIsClimbing', () => mp.players.local.isClimbing());
`

##### Server-side
`javascript
const rpc = require('rage-rpc');

const player = mp.players.at(0);

rpc.callClient(player, 'getIsClimbing').then(climbing => {
if(climbing){
console.log('The player is climbing!');
}else{
console.log('The player is not climbing!');
}
});

// or even just this inside an async function:
const isClimbing = await rpc.callClient(player, 'getIsClimbing');
`

_That's it!_ No extra code to sort out who is asking for what, or setting up multiple events on each side just to send a single piece of data back to the caller.

---

$3

Situation: A CEF instance wants a list of all vehicle license plates directly from the server.

##### Server-side
`javascript
const rpc = require('rage-rpc');

rpc.register('getAllLicensePlates', () => mp.vehicles.toArray().map(vehicle => vehicle.numberPlate));
`

##### Client-side
`javascript
// even if not using RPC on the client, it must be required somewhere before CEF can send any events
require('rage-rpc');
`

##### Browser
`javascript
const rpc = require('rage-rpc');

rpc.callServer('getAllLicensePlates').then(plates => {
alert(plates.join(', '));
});
`

With rage-rpc, CEF can directly communicate with the server and vice-versa, without having to pass everything through the client-side JS.

###### In vanilla RAGE, you would have to set up multiple events for sending/receiving on the client-side, call them from CEF, then resend the data to the server and back. It's a huge hassle.

---

$3

Situation: Give the clients/CEF the ability to log to the server's console.

##### Server-side
`javascript
const rpc = require('rage-rpc');

rpc.register('log', (message, info) => {
/*
the second argument, info, gives information about the request such as
- the internal ID of the request
- the environment in which the request was sent (server, client, or cef)
- the player who sent the request, if any
*/

console.log(info.player.name+': '+message);
});
`

##### Client-side OR Browser
`javascript
const rpc = require('rage-rpc');

function log(message){
return rpc.callServer('log', message);
}

// send it and forget it
log("Hello, Server!");

// send it again, but make sure it was successfully received
log("Hello again!").then(() => {
// the server acknowledged and processed the message
}).catch(() => {
// the message either timed out or the procedure was never registered
});
`

Note: Once any side of the game registers a procedure, any context can immediately start accessing it. You could call rpc.callServer('log', message); from any CEF instance or anywhere in the client without any further setup.

API

This library is universal to RAGE, which means you can load the same package into all 3 contexts: browser, client JS, and server JS.

There are only 7 functions that you can use almost anywhere around your game. However, depending on the current context, the usage of some functions might differ slightly.

$3

#### register(name, callback)

Registers a procedure in the current context.

The return value of the callback will be sent back to the caller, even if it fails. If a Promise is returned, it will finish before returning its result or error to the caller.

The return value must be JSON-able in order to be sent over the network. This doesn't matter if the procedure call is local.

##### Parameters

* name string - The unique identifier, relative to the current context, of the procedure.
* callback function - The procedure. This function will receive 2 arguments.
* args - The arguments that were provided by the caller. This parameter's type will be the same that was sent by the caller. undefined if no arguments were sent.
* info object - Various information about the caller.
* id string - The internal ID used to keep track of this request.
* environment string - The caller's environment. Can be cef, client, or server.
player Player - The caller. Only exists in the server context if remotely called from cef or client.*

##### Examples

`javascript
rpc.register('hello', () => 'hi!');
`

Returns hi! to the caller.

---

`javascript
rpc.register('getUser', async (id) => {
const user = await someLongOperationThatReturnsUserFromId(id);
return user;
});
`

Waits for the returned Promise to finish before returning the resolved user to the caller.

---

`javascript
rpc.register('echo', (message, info) => {
console.log(${info.player.name} via ${info.environment}: ${message});
});
`

Server-side example only. The passed argument will be logged to the console along with the caller's name and the environment which they called from.

#### unregister(name)

Unregisters a procedure from the current context. It will no longer take requests unless it is re-registered.

* name string - The unique identifier, relative to the current context, of the procedure.

#### call(name, args?, options?)

Calls a procedure that has been registered in the current context.

* name string - The name of the previously registered procedure.
* args? - Optional arguments to pass to the procedure. Can be of any type, since call does not traverse the network.
* options? - Optional options to control how the procedure is called.

##### Example

`javascript
rpc.register('hi', () => 'hello!');

rpc.call('hi').then(result => {
// result = hello!
console.log(result);
}).catch(err => {
console.error(err);
});
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

#### callServer(name, args?, options?)

Calls a procedure that has been registered on the server.

* name string - The name of the previously registered procedure.
* args? - Optional arguments to pass to the procedure. Must be JSON-able if the current context is not the server. Use an array or object to pass multiple arguments.
* options? - Optional options to control how the procedure is called.

##### Example

Server-side:
`javascript
rpc.register('getWeather', () => mp.world.weather);
`

Client-side OR Browser OR Server:
`javascript
rpc.callServer('getWeather').then(weather => {
mp.gui.chat.push(The current weather is ${weather}.);
}).catch(err => {
// handle error
});
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

$3

#### callClient(player, name, args?)

Calls a procedure that has been registered on a specific client.

* player Player - The player to call the procedure on.
* name string - The name of the registered procedure.
* args? - Optional arguments to pass to the procedure. Must be JSON-able. Use an array or object to pass multiple arguments.
* options? - Optional options to control how the procedure is called.

##### Example

Client-side:
`javascript
rpc.register('toggleChat', toggle => {
mp.gui.chat.show(toggle);
});
`

Server-side:
`javascript
mp.players.forEach(player => {
rpc.callClient(player, 'toggleChat', false);
});
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

#### callBrowsers(player, name, args?, options?)

Calls a procedure that has been registered in any CEF instance on a specific client.

Any CEF instance can register the procedure. The client will iterate through each instance and call the procedure on the first instance that it exists on.

* player Player - The player to call the procedure on.
* name string - The name of the registered procedure.
* args? - Optional arguments to pass to the procedure. Must be JSON-able. Use an array or object to pass multiple arguments.
* options? - Optional options to control how the procedure is called.

##### Example

Browser:
`javascript
rpc.register('toggleHUD', toggle => {
// if jQuery is your thing
$('#hud').toggle(toggle);
});
`

Server-side:
`javascript
mp.players.forEach(player => {
rpc.callClient(player, 'toggleChat', false);
});
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

$3

#### callBrowser(browser, name, args?, options?)

Calls a procedure that has been registered in a specific CEF instance.

* browser Browser - The browser to call the procedure on.
* name string - The name of the registered procedure.
* args? - Optional arguments to pass to the procedure. Must be JSON-able. Use an array or object to pass multiple arguments.
* options? - Optional options to control how the procedure is called.

##### Example

Browser:
`javascript
rpc.register('getInputValue', () => {
// if jQuery is your thing
return $('#input').val();
});
`

Client-side:
`javascript
const browser = mp.browsers.at(0);

rpc.callBrowser(browser, 'getInputValue').then(value => {
mp.gui.chat.push(The CEF input value is: ${value});
}).catch(err => {
// handle errors
});
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

$3

#### callBrowsers(name, args?, options?)

Calls a procedure that has been registered in any CEF instance on a specific client.

Any CEF instance can register the procedure. The client will iterate through each instance and call the procedure on the first instance that it exists on.

* name string - The name of the registered procedure.
* args? - Optional arguments to pass to the procedure. Must be JSON-able. Use an array or object to pass multiple arguments.
* options? - Optional options to control how the procedure is called.

##### Example

Browser:
`javascript
rpc.register('toggleHUD', toggle => {
// if jQuery is your thing
$('#hud').toggle(toggle);
});
`

Client-side OR Browser:
`javascript
rpc.callBrowsers('toggleChat', false);
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

#### callClient(name, args?, options?)

Calls a procedure that has been registered on the local client.

* name string - The name of the registered procedure.
* args? - Optional arguments to pass to the procedure. Must be JSON-able if the current context is not this client. Use an array or object to pass multiple arguments.
* options? - Optional options to control how the procedure is called.

##### Example

Client-side:
`javascript
rpc.register('toggleChat', toggle => {
mp.gui.chat.show(toggle);
});
`

Client-side OR Browser:
`javascript
rpc.callClient('toggleChat', false);
`

###### Returns Promise resolving or failing due to the procedure's result. If the procedure called does not exist, PROCEDURE_NOT_FOUND will be thrown.

Options

For remote procedure calling functions, there are optional options you can pass as the last parameter:

* timeout (number): The amount of time in milliseconds to reject the call automatically
* noRet (boolean): Prevent the remote context from sending data back. Saves bandwidth, but the promise will never return or reject. Similar to using trigger.

Events

You can now use rage-rpc as a full on replacement for mp.events. API functions that start with "trigger" use the same syntax as the ones that start with "call", except they do not return anything. They call remote events on any context where there can be many handlers or none.

Changelog

Check the releases tab for an up-to-date changelog.

#### 0.1.0

* ADD: Bundled Typescript definitions
* IMPROVE: CEF outgoing call returning performance
* IMRPOVE: callBrowsers` performance on all contexts
* FIX: Some code simplifications

#### 0.0.3

* ADD: Extra player verification for outgoing server calls
* FIX: Bug that prevented multiple resources from using RPC at the same time
* FIX: False alarm for multiple CEF instances receiving the same result

#### 0.0.2

* FIX: UMD exposing for correct Node.js importing

#### 0.0.1

* Initial commit