dataportal

Share JSON across websockets

Installation

npm install dataportal

Getting started

Create a dataportal server in node, eg:

require('dataportal')();

And run it with node - it should now be running on port 32827 - to use the client side:

<script type="text/javascript" src="node_modules/dataportal/build/dataportal.js?url=http://local.mac:32827/dataPortal"></script>
<script>
var obj = {"hello": "world"};
 
//	Create a portal for this topic
mp = dataPortal(obj, "myobject", {
    onready: function(portal){
        //	Modify our object and publish it
        obj.time = (new Date()).getTime();
        portal.subscribe(function(value){console.log(value);});
        portal.publish(obj);
    }
});
</script>
 
</body>
</html>

Note: Change "http://local.mac:32827/dataPortal" to the IP address or URL of where you're running your dataportal server. This example should log out a message each time the object is published for the "myobject" topic - it should show the same value on the last console.log line in each browser.

Um, why?

Curiosity - I've seen many other implementations - including what they do in MeteorJS - they all seem unnecessarily complex for something as simple as syncing JSON across a websocket, so this is just an experiment to see if it can be done a little simpler. Obviously this means we haven't implemented any protocols (such as DDP), but rather just allow object to be synchronized, using https://github.com/benjamine/jsondiffpatch for efficiency. As I said, this is an experiment, and so is not meant for production code.

Usage

You create an object you want to share, and then a data portal with a topic:

dataPortal(Object, Topic, [Arguments]);

• Object {object}: The object you want to track
• Topic {string}: The name of the topic - make sure this is unique per data portal server
• Arguments {object}: Optional arguments

Arguments include:

• onready {function(portal)}: Callback function for when the portal has been initialised and is connected - passes back the portal object
• onpatch {function(object, diff)}: Manually handle the patching process - the difference has what the new object changes are as per the diffs used in https://github.com/benjamine/jsondiffpatch.
• onclose {function(portal)}: Callback for when the server closes the connection, you can try to re-establish the connection by reloading the page, or the portal.

Portal object

The portal object controls how your data is shared with the server, you

• publish {function(newObjectValue)}: If you change the object, use this to publish the new object value
• subscribe {function(func{function(object)})}: Callback function that receives the object when it is changed
• close {function(func{function(object)})}: Subscribe a callback for when the server closes the connection, you can try to re-establish the connection by reloading the page, or the portal.

Examples:

See the examples folder in this repository.

Note: The examples included with Dataportal have the URL of the server set to "http://local.mac:32827/dataPortal", be sure to adjust that to it uses the IP address or URL of where you're running your dataportal server, for when you test on separate machines.