一个最简单的WebSocket hello world demo
服务器端代码不超过42行：
const WSServer = require("./server.js");
var counter = 0;
function createWebsocket() {
var host = "127.0.0.1";
var port = "9999";
var wsServer = WSServer.startServer(host, port);
console.log("WebSocket server listens to: " + host + ":" + port);
wsServer.on('open', (data) => {
console.log('WS Client has connected: ' + data);
setInterval(function(){
counter++;
WSServer.broadcast("Jerry: " + counter );
}, 3000);
});
wsServer.on('dataWS', (data) => {
console.log('Receive Data from WebUI : ' + data);
});
wsServer.on('disconnect', (data) => {
console.log('WSServer disconnect:' + data.name);
});
wsServer.on('close', (data) => {
console.log('WSServer close: ' + data.name);
});
wsServer.on('end', (data) => {
console.log('WSServer Close: '+data.name);
});
wsServer.on('error', (data) => {
});
}
createWebsocket();
代码第10行创建一个WebSocket服务器，监听在9999端口上：
第15～18行每隔3秒发送一个字符串到浏览器，用一个计数器标识每次发送的请求。
代码里所需的server.js我已经上传到我的Github上了：
https://github.com/i042416/KnowlegeRepository/blob/master/practice/nodejs/server.js
使用nodejs启动这个服务器：
网页端代码：
<html>
<script src="socket.io.dev.js">
</script>
<script>
console.log("1");
var socket = io('ws://127.0.0.1:9999');
socket.on('connect', function(){
console.log("connected!");
});
socket.on('event', function(data){
console.log("event: " + data);
});
socket.on('news', function(data){
console.log("data from server: " + JSON.stringify(data,2,2));
});
socket.on('disconnect', function(){
console.log("disconnect...");
});
</script>
</html>
浏览器端每隔三秒收到服务器推送的消息，打印在console上：
首先通过下面的链接下载openSSL
https://slproweb.com/products/Win32OpenSSL.html
下载完毕后，执行openssl进入交互式界面：
使用命令生成privatekey.pem 1024意思是1024位长度。
openssl genrsa -out privatekey.pem 1024
生成的privatekey.pem，打开看一看长啥样：
什么是pem文件？
.pem - Defined in RFCs 1421 through 1424, this is a container format that may include just the public certificate (such as with Apache installs, and CA certificate files /etc/ssl/certs), or may include an entire certificate chain including public key, private key, and root certificates. Confusingly, it may also encode a CSR (e.g. as used here) as the PKCS10 format can be translated into PEM. The name is from Privacy Enhanced Mail (PEM), a failed method for secure email but the container format it used lives on, and is a base64 translation of the x509 ASN.1 keys.
简单的说，就是一个密钥文件。
第二步，基于第一步生成的密钥文件生成一个证书请求：
openssl req -new -key privatekey.pem -out certrequest.csr
如果懒得维护证书明细，直接敲回车，会自动填入默认值：
最后基于第一步生成的密钥和证书请求生成一个数字证书：当然颁发机构就是自己了，仅用于测试目的。
openssl x509 -req -in certrequest.csr -signkey privatekey.pem -out certificate.pem
至此我们有了privatekey.pem和Certificate.pem两个证书了。
下面是我https服务器的代码，很简单，只有50几行：
var app = require('express')();
var fs = require('fs');
var https = require('https');
var httpOptions = {
key: fs.readFileSync("keys/privatekey.pem"),
cert: fs.readFileSync("keys/certificate.pem")
}
var server = https.createServer(httpOptions, app);
var io = require('socket.io')(server);
console.log("https server listens on port 8080...");
server.listen(8080);
function print_env(){
console.log(process.env);
}
app.get('/', function (req, res) {
var response = "Hello World";
res.send(response);
});
app.get('/env', function (req, res) {
print_env();
// res.sendFile(__dirname + '/index.html');
var response = JSON.stringify(process.env);
res.send(response);
});
app.get('/redis', function (req, res) {
var redisClient = require("./redisClient");
function callback(response){
// var response = "ok";//JSON.stringify(process.env);
res.send(response);
}
redisClient.test(callback);
});
io.on('connection', function (socket) {
console.log("connect comming from client: " + socket.id);
socket.emit('messages_jerry', { hello: 'world greeting from Server!' });
socket.on('messages', function (data) {
console.log("data received from Client:" + JSON.stringify(data,2,2));
});
});
从代码里不难理解这两个pem文件是如何用在https服务器里的。
最后在浏览器里测试。因为是自己颁发的证书，没有经过CA验证，所以浏览器会显示一个警告。
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