The core of NowJS operation lies inside the now item. The now item is special as it exists within the server as well as customer.
This means variables you established within the now item are immediately synced concerning the consumer and the server. Also server features can be specifically known as over the consumer and shopper features is usually referred to as directly from the server.
You may have a working HTTP server up and managing in NodeJS with just a few traces of code. For example:
var http = call for('http');
http.createServer(function (req, res)
res.writeHead(two hundred, 'Content material-Form': 'text/basic');
res.end('Hi Worldn');
).listen(8080);
This minor snippet of code will produce an HTTP server, pay attention on port 8080, and send back again "Hello Entire world" For each and every request. Which is it. Nothing at all extra necessary.
Applying NowJS, communication in between the customer and server facet is just as very simple.
Consumer Aspect:
Within this code snippet, the customer facet sets a variable to 'someValue' and calls serverSideFunction(), and that is declared only around the server.
Server Aspect:
Anyone.now.serverSideFunction = operate()
console.log(this.now.clientSideVariable);
The server side is then capable to obtain clientSideVariable, which can be declared only to the client.
All the small print which include setting up connections and speaking improve of data involving the server and client are handed automagically through the framework.
In truth writing code making use of this framework is so very simple, the NowJS hi there entire world case in point is really a Doing work chat shopper and server created in safety deposit boxes for sale beneath a dozen strains of code. Go check it out.
As an easy exercising to get comfy Along with the NowJS API, we can easily modify the chat client illustration to guidance multiple chat rooms. Let's Examine how quick it's.
Server Aspect (multiroom_server.js)
one. The first thing we need to do is modify the distributeMessage() operate to only send out messages to users in the identical chat place given that the user.
// Deliver concept to All people in the customers group
All people.now.distributeMessage = functionality(concept)
var team = nowjs.getGroup(this.now.serverRoom);
team.now.receiveMessage(this.now.identify+'@'+this.now.serverRoom, message);
;
We retailer the title with the server home around the consumer aspect (this.now.serverRoom). If the shopper calls the distributeMessage() perform we ship the concept to All people in a similar chat room by utilizing getGroup() and using the team.now item in lieu of theeveryone.now item. (everyone is just a group that contains all end users linked to the server).
two. Future we need to handle the consumer modifying chat rooms.
Absolutely everyone.now.changeRoom = purpose(newRoom)
var oldRoom = this.now.serverRoom;
//if aged room isn't null; then leave the previous area
if(oldRoom)
var oldGroup = nowjs.getGroup(oldRoom);
oldGroup.removeUser(this.person.clientId);
// sign up for The brand new home
var newGroup = nowjs.getGroup(newRoom);
newGroup.addUser(this.user.clientId);
// update the client's serverRoom variable
this.now.serverRoom = newRoom;
;
The getGroup() technique fetches the group object if it exists and generates a bunch if it will not exist already. We utilize the groups addUser() and removeUser() techniques to transfer the customer through the outdated place to The brand new place.
Which is over it over the server facet.
Client Side (multiroom.html)
3. 1st we insert a fall down While using the listing of server rooms.
four. Future we call the server facet changeRoom() functionality in the event the person to start with connects and Any time the fall down is improved.
// on creating 'now' relationship, established the server place
now.All set(purpose()
// By default decide the 1st chatroom
now.changeRoom($('#server-place').val());
);
// On transform of fall down, crystal clear textual content and alter server area
$('#server-area').modify(perform()
$("#messages").html(");
now.changeRoom($('#server-space').val());
);
5. For additional credit, we can allow the server to dynamically offer the list of rooms when the client connects.