ddp.js

#ddp.js

A javascript ddp client that runs both in the browser and in node.

##Why

This is the foundation of a project I'm working on to decouple meteor's client and server sides. It allows the to connect through ddp to a meteor server, and use all of the wonderful facilities meteor provides.

The project was inspired by ddp-browser-client, but I decided to re-implement the library from scratch to get a better understanding of the ddp protocol and to adapt it to run on node as well.

##Install

You can install the package for server-side usage via npm:

npm install ddp.js

For client-side usage, you can use bower:

bower install ddp.js

or you can just clone the repository and add ddp.js to your project.

##Example usage

var options = {
	endpoint: "http://localhost:3000/websocket",
	SocketConstructor: WebSocket
};
var ddp = new DDP(options);

ddp.on("connected", function () {
	console.log("Connected");

	ddp.sub("myCollection");
	ddp.on("added", function (data) {
		console.log(data.collection);
	});

	var myLoginParams = { ... };
	ddp.method("login", [myLoginParams], function (err, res) {
		if (err) throw err;
		console.log("Logged in!");
	});
});

##Tests

To run tests clone the repository

git clone https://github.com/mondora/ddp.js
cd ddp.js

install dependencies

npm install

and run tests

npm run test-node
npm run test-browser

##API

###new DDP(options)

Returns a new DDP instance.

Available options are:

• endpoint: the location of the websocket server. Its format depends on the type of socket you are using.

• SocketConstructor: the constructor function that will be used to construct the socket. Meteor (currently the only DDP server available) supports websockets and SockJS sockets. So, practically speaking, this means that on the browser you can use either the browser's native WebSocket constructor or the SockJS constructor provided by the SockJS library. On the server you can use whichever library implements the websocket protocol (e.g. faye-websocket).

• do_not_autoconnect: pass true if you do not wish to have the DDP instance to automatically connect itself to the server upon instantiation. In that case you'll need to explicitly call the connect method to do so.

• do_not_autoreconnect: pass true if you do not wish to have the DDP instance try reconnecting itself.

###DDP.connect()

Tries to connect to the DDP server. To connect to a DDP server a "connect" message needs to be sent. This function does not send the message itself. Instead, it opens a socket connection to the server and delegates sending the message to the "onopen" event handler of the socket instance.

connect also sets the readyState property of the DDP instance to 0 (connecting). If the user tries to send DDP messages before the connection is open (readyState equals 1), those messages get queued up and sent, in order, once the connection is established.

###DDP.method(name, params, onResult, onUpdated)

Calls a remote method and registers callbacks for the "result" and "updated" responses.

• name: name of the method to call.

• params: parameters to pass to the remote method. Pass an empty array if you do not wish to pass any parameters.

• onResult: callback for the "result" message corresponding to the method invocation.

• onUpdated: callback for the "updated" message corresponding to the method invocation.

###DDP.sub(name, params, onReady)

Subscribes the current DDP instance to a server publication.

• name: name of the server publication.

• params: parameters to pass to the server publish function. Pass an empty array if you do not wish to pass any parameters.

• onReady: callback for the "ready" message corresponding to this subscription.

###DDP.unsub(id)

Unsubscribes the current DDP instance to a server publication to which it was subscribed.

• id: id of the subscription.

###DDP.on(name, handler)

Registers a callback for the specified event. Built-in events are: connected, failed, error, added, removed, changed, socket_close, socket_error.

• name: name of the event.

• handler: handler for the event.

###DDP.off(name, handler)

Deregisters a previously registered callback for the specified event.

• name: name of the event.

• handler: handler for the event.

##DDP events

###"error"

###"connected"

###"failed"

###"socket_close"

###"socket_error"

###"added"

###"changed"

###"removed"