Node.js服务器和客户端之间的变量 [英] Variables between Node.js Server and Client
问题描述
我使用Node.js运行一个简单的http服务器：
I run a simple http server with Node.js:
var http = require('http');
var fs = require('fs');
var index = fs.readFileSync('index.html');
var sensor = require('ds18x20');
var temp = sensor.get('sensorID');
http.createServer(function(req,res) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(index);
}).listen(80);
console.log(temp);
我的index.html文件：
my index.html file:
<html>
<head>
</head>
<body>
My temperature:
//space for variable: temp
</body>
</html>
现在，我想在index.html文件中打印服务器端变量：temp。但是我不知道该怎么做。
Now, I want to print the server-side variable: temp in my index.html file. But I have no idea how to do it.
也许有人可以帮我从服务器到客户端交换变量。
Maybe somebody can help me with the exchange of Variables from the server to the client.
推荐答案
正如你可以在@WebServer的回答中看到的那样，节点中有各种各样的模板引擎。
我想给您使用其中一个示例 - EJS ：
As you can read in @WebServer's answer there is a variety of template engines in node.
I want to give you an example of using one of them - EJS:
首次安装它：
npm install ejs
server.js：
server.js:
var http = require('http');
var ejs = require('ejs');
var fs = require('fs');
http.createServer(function(req,res) {
res.writeHead(200, {'Content-Type': 'text/html'});
//since we are in a request handler function
//we're using readFile instead of readFileSync
fs.readFile('index.html', 'utf-8', function(err, content) {
if (err) {
res.end('error occurred');
return;
}
var temp = 'some temp'; //here you assign temp variable with needed value
var renderedHtml = ejs.render(content, {temp: temp}); //get redered HTML code
res.end(renderedHtml);
});
}).listen(80);
您的视图可能如下所示：
Your view might look like this:
<html>
<head>
</head>
<body>
My temperature: <%= temp %>
</body>
</html>
EJS也逃脱 temp （和其他变量）你传递给视图），所以你不必担心XSS攻击。
EJS also escapes temp (and other variables you pass to the view) for you, so you don't have to worry about XSS attacks.
编辑
如果您不想在每个请求中读取文件，也可以编译模板：
You can also compile the template if you don't want to read the file on each request:
var http = require('http');
var ejs = require('ejs');
var fs = require('fs');
//we are not in a request handler so we may use readFileSync
var content = fs.readFileSync('index.html', 'utf-8');
var compiled = ejs.compile(content);
http.createServer(function(req,res) {
var temp = 'some temp';
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(compiled({temp: temp}));
}).listen(80);
编辑2（回答您的评论问题）
以下是使用Express和AJAX的简单示例：
Here is a simple example of using Express and AJAX:
server.js：
var http = require('http');
var express = require('express');
var app = express();
app.configure(function() {
app.set('view engine', 'ejs'); //tell Express we're using EJS
app.set('views', __dirname + '/views'); //set path to *.ejs files
app.use(app.router);
//put your static files (js, css, images) into /public directory
app.use('/public', express.static(__dirname + '/public'));
});
//get some server data for sending it to the client
var getData = function() {
return Math.random().toString();
}
app.get('/', function(req, res) {
//render index.ejs file
res.render('index', {val: getData()});
});
app.get('/ajax', function(req, res) {
res.send(getData());
});
http.createServer(app).listen(80);
views / index.ejs：
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script src="/public/js/request.js"></script>
</head>
<body>
<h1>Val: <span id="val"><%=val%></span></h1>
<button id="loadRequest">Refresh</button>
</body>
</html>
public / js / request.js：
$(function() {
$('#loadRequest').click(function() {
$.get('/ajax', function(res) {
$('#val').text(res);
});
});
});
希望这会有所帮助
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