Applies To: Construct 2, jQuery

jsMessage is a Construct 2 plugin that enables sending and receiving messages through jQuery events. I’ve just released it over on CodePlex where you can download it and a sample game to show you how to use it. You can use it in the free edition as well as all paid editions. The license is totally open so feel free to use it in your commercial or personal projects, etc. No attribution necessary (although always appreciated).

You can find out how to install it by checking out the documentation on CodePlex (It’s a c2addon, so just drag and drop).

What

jsMessage is a cool little plugin that adds 2 conditions (Message Received, Command Received), 1 Action (Send Message), 5 Expressions (Message Raw, ValueCount, Command, Value, Separator) and 1 Property (Value Separator).

You can use these to respond to external messages coming through the browser.

Why

There are several other plugins that allow network communication and generally this is the way you’re going to want to go. If you are trying to have games talk to each other or download things, etc. – this is not the plugin for you. The only way to communicate to the game using this plugin is to trigger jQuery events and to register to receive them as well.

I had a specific need to communicate to a running game in a browser I control. I will be demonstrating this technique in an upcoming post and hopefully it will make more sense then. However, there are lots of other uses and I’m excited to see what other people end up using it for.

How

There is some more in-depth documentation available on the CodePlex site and I’ll be posting an elaborate walkthough using the basic example game in an upcoming post. In the meantime, here’s an overview.

To communicate to a running game you can send messages by triggering the CKjsMessageSend event. Here’s a one-liner perfect for the console window:

$(document).trigger('CKjsMessageSend','SomeCommand');

This will trigger both the Message Received and Command Received conditions in your game. Command Received allows you to respond to a specific phrase. Message Received is more general and you’ll have to do some comparisons to see if it was the message you were looking for.

You can also send values by using a delimiter. The default delimiter is the pipe | but this can be changed as a game setting. To find out what the separator has been set to you can use the CKjsMessageSeparatorQ and CKjsMessageSeparatorA events. It might look something like the following:

$(document).ready(function(){
    var jsSeparator = '';

    //Prepare to respond to the Separator Answer
    $(document).on('CKjsMessageSeparatorA',function(e,m){
        jsSeparator = m;

        //Send a message with values
        $(document).trigger('CKjsMessageSend','MyCommand' + jsSeparator + 'Value1' + jsSeparator + 'Value2');
    });

    //Ask the game what the Separator is
    $(document).trigger('CKjsMessageSeparatorQ','');
});

In other words, register to respond to the CKjsMessageSeparatorA event and then trigger the CKjsMessageSeparatorQ event to have the game respond.

Within the Message Received or Command Received condition you can get a count of the values sent with the jsMessage.ValueCount expression and then request those values using the jsMessage.Value(0) expression. There are also expressions to get the raw message (jsMessage.MessageRaw), just the command (jsMessage.Command) and even the configured separator (jsMessage.Separator).

The game can also send messages using the Send Message action. Here’s a quick example of how to register to receive these messages:

$(document).on('CKjsMessageReceive',function(e,m){
    console.log(m);
});

This will simply print out whatever message was sent directly to the console.

 

That’s the basic overview of the plugin. If you have a need for this kind of interaction then go download it and check out the example “game” (it’s free!). In my next post we’ll make this a little clearer by walking through the example game in detail.