问题
I am developing a real-time text editor with paragraph locking property similar to https://quip.com/. in socket.io and nodejs.
It means when you write onto a given paragraph, other collaborators cant edit it.
Moment you hit enter or move cursor to a new line that paragraph becomes Editable for other Collaborators.
I am quite stuck after this. I am thinking a nice approach to move further. Suggestions please.
Below is my code which works perfectly. Till now i can get list of all collaborators and broadcast the content of editor to other collaborators.
index.html
<!DOCTYPE html>
<html>
<head>
<title>Connected Clients</title>
<!--<meta charset="UTF-8"> -->
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<!--<script type="text/javascript" src="jquery.js"></script> -->
<script src="/socket.io/socket.io.js"></script>
</head>
<body>
<textarea id="editor" style="height:200px;width:300px">
Thinknest Pragraph locking Test sample !
</textarea>
<script>
function msgReceived(msg){
//clientCounter.html(msg.clients);
document.getElementById('people').innerHTML=msg.uid;
//console.log(msg.id);
}
var clientCounter;
$(document).ready(function () {
clientCounter = $("#client_count");
var socket = io.connect(
'http://localhost:5000',
{'sync disconnect on unload':true}
);
var uId=prompt("enter your userId",'');
socket.emit('collabrator',uId);
socket.on('message', function(msg){
msgReceived(msg);
});
socket.on('online_collabs',function(data){
$('#online_ppl').html(data);
clientCounter.html(data.length);
});
socket.on('remained_collabs',function(data){
$('#online_ppl').html(data);
clientCounter.html(data.length);
});
socket.on('note_collabs',function(data){
$('#note_colabs').html(data);
});
socket.on('updated_para',function(data){
//$('#editor').append(data);
document.getElementById('editor').innerHTML=data;
});
$('#editor').on('keydown',function(){
//var para=$('#editor').value;
var para= $('#editor').val();
//var para=document.querySelector('[contenteditable]');
// var text=para.textContent;
socket.emit('para',{paragraph:para});
});
});
</script>
<p><span id="client_count">0</span> connected clients</p><br/>
<ul id="people"></ul>
<h3>Online Collaborators</h3>
<span id="online_ppl"></span> <br>
<h3>Note Collaborators</h3>
<span id="note_colabs"></span>
</body>
</html>
server.js
var app = require('express')()
, server = require('http').createServer(app)
, io = require('socket.io').listen(server);
server.listen(5000);
app.get('/',function(req,res){
res.sendfile("./index.html");
});
var activeClients = 0;
var Collaborators=['Colab1','Colab2','Colab3'];
var people=[];
io.sockets.on('connection', function(socket){
clientConnect(socket);
socket.on('disconnect', function(){
clientDisconnect(socket);
});
socket.on('para',function(data){
//io.sockets.emit('updated_para',data.paragraph);
socket.broadcast.emit('updated_para',data.paragraph);
});
});
function clientConnect(socket){
//activeClients +=1;
var userSocketId=socket.id;
check_Collaborator(socket);
io.sockets.emit('message', {uid:userSocketId});
}
var online_collabs=[];
function check_Collaborator(socket){
socket.on('collabrator',function(data){
if(Collaborators.indexOf(data)!=-1){
socket.data=data;
if(online_collabs.indexOf(data)==-1) {
online_collabs.push(data);
}
io.sockets.emit('online_collabs',online_collabs);
io.sockets.emit('note_collabs',Collaborators);
} else {
console.log("collabrator not found");
}
});
}
function clientDisconnect(socket){
var index=online_collabs.indexOf(socket.data)
if(index>-1)
online_collabs.splice(index,1);
//activeClients -=1;
//io.sockets.emit('message', {clients:activeClients});
io.sockets.emit('remained_collabs',online_collabs);
}
回答1:
I saw this yesterday already. What exactly is your question? Do you want to know how to 'lock' a text area with javascript? I am confused as to why you put such a strong emphasis on node/socket.io in your question.
Also, next time please format your code. You want help, I get it, but then make it easier for others to help you.
What you have to do in order to make a paragraph not editable by others, I don't know. But let me suggest what I'ld do in socket.io:
Store each paragraph separately and remember who has a lock on it. For locking, I would use the sessionID in case users don't have to register. This would look something like this:
var paragraphs = {
data : [
{
text: "this is an unlocked paragraph",
lock: ""
},
{
text: "this is a locked paragraph",
lock: "oWEALlLx5E-VejicAAAC"
}
]
}
Now, users will likely be allowed to add a paragraph before an existing one. Therefore you should keep an additional index like:
var paragraphs = {
index : [
1,
0
],
data : [
{
text: "this the second paragraph",
lock: "oWEALlLx5E-VejicAAAC"
},
{
text: "this is the first paragraph",
lock: ""
}
]
}
The amount of data being sent over the sockets should now be very small - altough with additional client/server-side logic.
回答2:
Paragraph lock can be easily achieved by adding a class to the currently editing paragraph. Transfer this paragraph with the class to the other user. so that if the user tries to write over that prevent him by validate with the class.
Generate a class name look like - className_userid (className_1).
来源：https://stackoverflow.com/questions/24260302/realtime-collaborative-text-editor-in-nodejs-socket-io