websocket
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小牛编辑
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2023-12-01
websocket在开发上有两条路径。第一条是自行处理消息，第二条是由服务器自动处理。前者需要开发者使用c/c++语言，后者则只需开发者使用javascript语言。
路径一
#include <mongols/ws_server.hpp>
int main(int, char**)
{
int port = 9090;
const char* host = "127.0.0.1";
mongols::ws_server server(host, port, 5000, 8096, std::thread::hardware_concurrency() /*0*/);
// if (!server.set_openssl("openssl/localhost.crt", "openssl/localhost.key")) {
// return -1;
// }
auto f = [](const std::string& input, bool& keepalive, bool& send_to_other, mongols::tcp_server::client_t& client, mongols::tcp_server::filter_handler_function& send_to_other_filter, mongols::ws_server::ws_message_t& ws_msg_type) -> std::string {
keepalive = KEEPALIVE_CONNECTION;
send_to_other = true;
if (ws_msg_type == mongols::ws_server::ws_message_t::BINARY) {
ws_msg_type = mongols::ws_server::ws_message_t::TEXT;
goto ws_close;
}
if (input == "close") {
ws_close:
keepalive = CLOSE_CONNECTION;
send_to_other = false;
return "close";
}
return input;
};
//server.set_enable_origin_check(true);
//server.set_origin("http://localhost");
//server.set_max_send_limit(5);
server.run(f);
//server.run();
}
以上代码中的f是一个handler,它是实现开发者自行处理消息的关键。以上实现是说，如果客户端发送close或者二进制消息到服务器，服务器就关闭它的连接，并且不转发该消息；除此而外，服务器会保持连接，并转发消息到所有在线客户端。这是走第一条路径的一个例子，它没有实现聊天群组功能和其他特性。
浏览器测试代码:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>WebSocket Test</title>
</head>
<body>
<h2>WebSocket Test</h2>
<div id="req_output"></div><br />
<div id="res_output"></div><br />
<div id="err_output"></div><br />
<script language="javascript" type="text/javascript">
var wsUri = "ws://127.0.0.1:9090";
var req_output, res_output, err_output;
var j;
function ab2str(buf) {
return String.fromCharCode.apply(null, new Uint8Array(buf));
}
function str2ab(str) {
var buf = new ArrayBuffer(str.length);
var bufView = new Uint8Array(buf);
for (var i = 0; i < str.length; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
function init() {
req_output = document.getElementById("req_output");
res_output = document.getElementById('res_output');
err_output = document.getElementById('err_output')
testWebSocket();
var i = 0, max_i = 1000;
j = setInterval(function () {
if (i < max_i) {
var data = {};
data.gid = 0;
data.uid = 0;
data.gfilter = [];
data.ufilter = [];
data.name = 'Bugger';
data.message = "websocket test: " + i;
data.room = 'cpp';
data.time = ((new Date()).toLocaleString());
doSend(JSON.stringify(data))
i++;
}
}, 10)
}
function testWebSocket() {
websocket = new WebSocket(wsUri);
websocket.onopen = function (evt) { onOpen(evt) };
websocket.onclose = function (evt) { onClose(evt) };
websocket.onmessage = function (evt) { onMessage(evt) };
websocket.onerror = function (evt) { onError(evt) };
}
function onOpen(evt) {
writeToScreen("CONNECTED", err_output);
doSend("WebSocket rocks");
}
function onClose(evt) {
clearInterval(j);
writeToScreen("DISCONNECTED", err_output);
}
function onMessage(evt) {
writeToScreen('<span style="color: blue;">RESPONSE: ' + (evt.data) + '</span>', res_output);
}
function onError(evt) {
writeToScreen('<span style="color: red;">ERROR:</span> ' + evt.data, err_output);
}
function doSend(message) {
writeToScreen("SENT: " + message, req_output);
websocket.send((message));
}
function writeToScreen(message, ele) {
var pre = document.createElement("p");
pre.style.wordWrap = "break-word";
pre.innerHTML = message;
if (ele.childNodes.length == 0) {
ele.appendChild(pre);
} else {
ele.replaceChild(pre, ele.childNodes[0]);
}
}
window.addEventListener("load", init, false);
</script>
</body>
</html>
路径二
走第二条路径就简单多了。没有参数的 run可调用内置的群组管理机制，开发者仅仅在前端使用javascript即可完成对群组的控制和管理。是不是太方便！
怎么用？每一次用javascript向服务器发送的消息应该是一个用JSON.stringify处理的json数据。该数据应该包含以下是个字段：
- uid，表示连接id，默认是0。
- gid, 表示连接所属群组id或群组id数组，默认是0。如果需退出某群组，用负的gid表示即可。
- gfilter，表示可接受该消息的群组gid数组。如果为空数组，则表示转发至所有在线群组。
- ufilter，表示可接受该消息的的uid数组。如果为空数组，则表示转发至所有在线连接。
其他字段为自选。服务器收到数据后，会解析该数据，根据以上四个字段作相应处理，并返回该数据。
基本实现，可参考demo,基本体验可访问：浮生beta
利用websocket上传文件
首先是服务器代码:
#include <fstream>
#include <memory>
#include <mongols/util.hpp>
#include <mongols/ws_server.hpp>
int main(int, char**)
{
int port = 9090;
const char* host = "127.0.0.1";
mongols::ws_server server(host, port, 5000, 8192, std::thread::hardware_concurrency() /*0*/);
// if (!server.set_openssl("openssl/localhost.crt", "openssl/localhost.key")) {
// return -1;
// }
std::unordered_map<size_t, std::pair<std::string, std::shared_ptr<std::ofstream>>> file_manage;
auto f = [&](const std::string& input, bool& keepalive, bool& send_to_other, mongols::tcp_server::client_t& client, mongols::tcp_server::filter_handler_function& send_to_other_filter, mongols::ws_server::ws_message_t& ws_msg_type) -> std::string {
keepalive = KEEPALIVE_CONNECTION;
send_to_other = false;
if (ws_msg_type == mongols::ws_server::ws_message_t::BINARY) {
*file_manage[client.sid].second << input;
ws_msg_type = mongols::ws_server::ws_message_t::TEXT;
return "continue";
}
std::vector<std::string> v = mongols::split(input, ':');
if (v.size() > 1 && v[0] == "name") {
file_manage[client.sid].first = v.back();
file_manage[client.sid].second = std::make_shared<std::ofstream>("upload/" + file_manage[client.sid].first, std::ios::binary | std::ios::out | std::ios::ate);
return "start upload";
}
if (input == "upload success") {
file_manage.erase(client.sid);
}
return input;
};
//server.set_enable_origin_check(true);
//server.set_origin("http://localhost");
//server.set_max_send_limit(5);
server.run(f);
//server.run();
}
接着是客户端代码:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>WebSocket Upload Test</title>
</head>
<body>
<h2>WebSocket Update File Test</h2>
<form id='upload_form'>
<input type="file" id="my_file" multiple>
</form>
<div>
<ul id=box></ul>
</div>
<div id="log"></div>
<script src="http://cdn.bootcss.com/jquery/3.4.0/jquery.min.js"></script>
<script language="javascript" type="text/javascript">
var ws = new Array(), ws_uri = "ws://127.0.0.1:9090";
var tpl = "<li><div>名称：<strong class='name'>NULL</strong> 信息：<strong class='info'>准备</strong> 进度: <strong class='tag'>0%</strong> 耗时：<strong class='time'>0 ms</strong></div></li>"
var tag, ttag, info, fname, box = $('#box')
var default_step = 8092;
var upload_info = new Array()
var files;
function upload(i) {
if (upload_info[i].uploaded + upload_info[i].step > upload_info[i].size) {
upload_info[i].step = upload_info[i].size - upload_info[i].uploaded;
}
var buffer = files[i].slice(upload_info[i].uploaded, upload_info[i].uploaded + upload_info[i].step)
var reader = new FileReader();
reader.readAsArrayBuffer(buffer);
reader.onload = function (e) {
ws[i].send(e.target.result);
info.eq(i).html('正在上传数据');
}
reader.onloadend = function (e) {
tag.eq(i).html(upload_info[i].uploaded / upload_info[i].size * 100 + '%');
upload_info[i].uploaded = upload_info[i].uploaded + upload_info[i].step;
}
}
$('#my_file').on('change', function (event) {
files = document.getElementById("my_file").files;
for (var i = 0; i < files.length; ++i) {
upload_info.push({ size: files[i].size, name: files[i].name, uploaded: 0, step: default_step, t: 0 })
box.append(tpl)
ws.push(new WebSocket(ws_uri))
}
tag = $('.tag');
ttag = $('.time');
info = $('.info');
fname = $('.name');
ws.forEach(function (item, j) {
fname.eq(j).html(files[j].name);
ws[j].onopen = function () {
info.eq(j).html('已连接上');
ws[j].send("name:" + upload_info[j].name);
}
ws[j].onclose = function () {
info.eq(j).html('连接已关闭');
}
ws[j].onmessage = function (e) {
if (e.data == 'start upload') {
info.eq(j).html('开始上传文件');
upload_info[j].t = new Date().getTime();
upload(j);
} else if (e.data == 'continue') {
if (upload_info[j].size > upload_info[j].uploaded) {
ttag.eq(j).html((new Date().getTime() - upload_info[j].t) + " ms");
upload(j);
} else {
ws[j].send('upload success');
}
} else if (e.data == 'upload success') {
info.eq(j).html('上传完成');
tag.eq(j).html(upload_info[j].uploaded / upload_info[j].size * 100 + ' %');
ttag.eq(j).html((new Date().getTime() - upload_info[j].t) + " ms");
ws[j].close();
}
}
});
});
</script>
</body>
</html>
以上代码给出一个利用websocket进行文件分片上传的基本实现。该实现不限文件大小，只要合理配置default_step即分片大小，再大的文件也可轻松上传。
注意：分片大小应该小于服务器缓冲大小(默认值为8192)，一般不能超过(服务器缓冲大小-100)；分片大小越大，上传越快；但不是越大越好，还要考虑客户端的分片发送能力，一般情况下，default_step配置为8092即可满足绝大多数大文件上传需求。
安全
ws_server自带安全检查方法。 通过set_enable_origin_check方法启用OriginHTTP头部检查，默认不检查。该方法需配合set_origin方法来配置连接请求需要匹配的Origin值。
另外，所有对tcp_server进行的安全配置对ws_server都是有效的。
关于客户端
不要使用firefox等非chrome系浏览器测试、调试websocket应用，如果你不想莫名其妙地恼火、头疼的话。