libuv
libuv简介
1: 开源跨平台的异步IO库, 主要功能有网络异步，文件异步等。
2: libuv主页: http://libuv.org/
3: libuv是node.js的底层库;
4: libuv的事件循环模型:
epoll, kqueue, IOCP, event ports;
异步 TCP 与 UDP sockets;
DNS 解析
异步文件读写;
信号处理;
高性能定时器;
进程/线程池;
libuv原理
1:异步: 在用户层同时管理多个句柄请求。
2: loop循环等待所有的事件和句柄,管理好所有的这些请求。
3: 当其中一个请求完成后，loop就会监测得到然后调用用户指定的回掉函数处理;
4: 例如loop监听所有的socket,有数据来了后，loop就会处理，然后转到用户指定的回调函数。
5: libuv编写思想:
1> 创建一个对象, 例如socket;
2> 给loop管理这个对象;
3> 并指定一个回调函数,当有事件发生的时候调用这个回调函数, callback;
6: 1>向loop发送请求;
2>指定结束后的回调函数;
3>当请求结束后，调用调函数;
TCP服务器搭建
首先需要下载libuv库，导入到工程中，设置好include的路径和链接上对应的库
代码如下：
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "uv.h"
/*
uv_handle_s 数据结构:
UV_HANDLE_FIELDS
uv_stream_t 数据结构;
UV_HANDLE_FIELDS
UV_STREAM_FIELDS
uv_tcp_t 数据结构;
UV_HANDLE_FIELDS
UV_STREAM_FIELDS
UV_TCP_PRIVATE_FIELDS
uv_tcp_t is uv_stream_t is uv_handle_t;
*/
static uv_loop_t* loop = NULL;
static uv_tcp_t l_server; // 监听句柄;
// 当我们的event loop检车到handle上有数据可以读的时候,
// 就会调用这个函数, 让这个函数给event loop准备好读入数据的内存;
// event loop知道有多少数据,suggested_size,
// handle: 发生读时间的handle;
// suggested_size: 建议我们分配多大的内存来保存这个数据;
// uv_buf_t: 我们准备好的内存，通过uv_buf_t,告诉even loop;
static void
uv_alloc_buf(uv_handle_t* handle,
size_t suggested_size,
uv_buf_t* buf) {
if (handle->data != NULL) {
free(handle->data);
handle->data = NULL;
}
buf->base = malloc(suggested_size + 1);
buf->len = suggested_size;
handle->data = buf->base;
}
static void
on_close(uv_handle_t* handle) {
printf("close client\n");
if (handle->data) {
free(handle->data);
handle->data = NULL;
}
}
static void
on_shutdown(uv_shutdown_t* req, int status) {
uv_close((uv_handle_t*)req->handle, on_close);
free(req);
}
static void
after_write(uv_write_t* req, int status) {
if (status == 0) {
printf("write success\n");
}
uv_buf_t* w_buf = req->data;
if (w_buf) {
free(w_buf);
}
free(req);
}
// 参数:
// uv_stream_t* handle --> uv_tcp_t;
// nread: 读到了多少字节的数据;
// uv_buf_t: 我们的数据都读到到了哪个buf里面, base;
static void after_read(uv_stream_t* stream,
ssize_t nread,
const uv_buf_t* buf) {
// 连接断开了;
if (nread < 0) {
uv_shutdown_t* reg = malloc(sizeof(uv_shutdown_t));
memset(reg, 0, sizeof(uv_shutdown_t));
uv_shutdown(reg, stream, on_shutdown);
return;
}
// end
buf->base[nread] = 0;
printf("recv %d\n", nread);
printf("%s\n", buf->base);
// 测试发送给我们的 客户端;
uv_write_t* w_req = malloc(sizeof(uv_write_t));
uv_buf_t* w_buf = malloc(sizeof(uv_buf_t));
w_buf->base = buf->base;
w_buf->len = nread;
w_req->data = w_buf;
uv_write(w_req, stream, w_buf, 1, after_write);
}
static void
uv_connection(uv_stream_t* server, int status) {
printf("new client comming\n");
// 接入客户端;
uv_tcp_t* client = malloc(sizeof(uv_tcp_t));
memset(client, 0, sizeof(uv_tcp_t));
uv_tcp_init(loop, client);
uv_accept(server, (uv_stream_t*)client);
// end
// 告诉event loop,让他帮你管理哪个事件;
uv_read_start((uv_stream_t*)client, uv_alloc_buf, after_read);
}
int main(int argc, char** argv) {
int ret;
loop = uv_default_loop();
// Tcp 监听服务;
uv_tcp_init(loop, &l_server); // 将l_server监听句柄加入到event loop里面;
// 你需要event loop来给你做那种管理呢？配置你要的管理类型;
struct sockaddr_in addr;
uv_ip4_addr("0.0.0.0", 6080, &addr); // ip地址, 端口
ret = uv_tcp_bind(&l_server, (const struct sockaddr*) &addr, 0);
if (ret != 0) {
goto failed;
}
// 让event loop来做监听管理，当我们的l_server句柄上有人连接的时候;
// event loop就会调用用户指定的这个处理函数uv_connection;
uv_listen((uv_stream_t*)&l_server, SOMAXCONN, uv_connection);
uv_run(loop, UV_RUN_DEFAULT);
failed:
printf("end\n");
system("pause");
return 0;
}
UDP服务器搭建
客户端
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")
int main(int argc, char** argv) {
WSADATA ws;
WSAStartup(MAKEWORD(2, 2), &ws);
SOCKET client = socket(AF_INET, SOCK_DGRAM, 0);
// 可以bind也可以不绑,如果不要求别人先发给你可以不bind;
// end
SOCKADDR_IN addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(6080);
addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
int len = sizeof(SOCKADDR_IN);
int send_len = sendto(client, "Hello", 5, 0, (const SOCKADDR*)&addr, len);
printf("send_len = %d\n", send_len);
char buf[128];
SOCKADDR_IN sender_addr; // 收到谁发的数据包的地址;
int recv_len = recvfrom(client, buf, 128, 0, &sender_addr, &len);
if (recv_len > 0) {
buf[recv_len] = 0; // 加上结尾符号;
printf("%s\n", buf);
}
WSACleanup();
system("pause");
return 0;
}
不用libuv版本的服务器
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")
int main(int argc, char** argv) {
WSADATA ws;
WSAStartup(MAKEWORD(2, 2), &ws);
SOCKET client = socket(AF_INET, SOCK_DGRAM, 0);
// 可以bind也可以不绑,如果不要求别人先发给你可以不bind;
// end
SOCKADDR_IN addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(6080);
addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
int len = sizeof(SOCKADDR_IN);
int send_len = sendto(client, "Hello", 5, 0, (const SOCKADDR*)&addr, len);
printf("send_len = %d\n", send_len);
char buf[128];
SOCKADDR_IN sender_addr; // 收到谁发的数据包的地址;
int recv_len = recvfrom(client, buf, 128, 0, &sender_addr, &len);
if (recv_len > 0) {
buf[recv_len] = 0; // 加上结尾符号;
printf("%s\n", buf);
}
WSACleanup();
system("pause");
return 0;
}
libuv的UDP服务器
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "uv.h"
static uv_loop_t* event_loop = NULL;
static uv_udp_t server; // UDP的句柄;
static void
uv_alloc_buf(uv_handle_t* handle,
size_t suggested_size,
uv_buf_t* buf) {
if (handle->data != NULL) {
free(handle->data);
handle->data = NULL;
}
handle->data = malloc(suggested_size + 1); // +1测试的时候，我要收字符串，所以呢要加上1来访结尾符号;
buf->base = handle->data;
buf->len = suggested_size;
}
static void
on_uv_udp_send_end(uv_udp_send_t* req, int status) {
if (status == 0) {
printf("send sucess\n");
}
free(req);
}
static void
after_uv_udp_recv(uv_udp_t* handle,
ssize_t nread,
const uv_buf_t* buf,
const struct sockaddr* addr, // 发过来数据包的IP地址 + 端口;
unsigned flags) {
char ip_addr[128];
uv_ip4_name((struct sockaddr_in*)addr, ip_addr, 128);
int port = ntohs(((struct sockaddr_in*)addr)->sin_port);
printf("ip: %s:%d nread = %d\n", ip_addr, port, nread);
char* str_buf = handle->data;
str_buf[nread] = 0;
printf("recv %s\n", str_buf);
uv_buf_t w_buf;
w_buf = uv_buf_init("PING", 4);
// 写数据;
uv_udp_send_t* req = malloc(sizeof(uv_udp_send_t));
uv_udp_send(req, handle, &w_buf, 1, addr, on_uv_udp_send_end);
// end
}
int main(int argc, char** argv) {
event_loop = uv_default_loop();
memset(&server, 0 ,sizeof(uv_udp_t));
uv_udp_init(event_loop, &server);
// bind端口;
struct sockaddr_in addr;
uv_ip4_addr("0.0.0.0", 6080, &addr);
uv_udp_bind(&server, (const struct sockaddr*)&addr, 0);
// end
// 告诉事件循环,你要他管理recv事件;
uv_udp_recv_start(&server, uv_alloc_buf, after_uv_udp_recv);
uv_run(event_loop, UV_RUN_DEFAULT);
system("pause");
return 0;
}
定时器设计
源码
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "uv.h"
#include "time_list.h"
#define my_malloc malloc
#define my_free free
struct timer {
uv_timer_t uv_timer; // libuv timer handle
void(*on_timer)(void* udata);
void* udata;
int repeat_count; // -1一直循环;
};
static struct timer*
alloc_timer(void(*on_timer)(void* udata),
void* udata, int repeat_count) {
struct timer* t = my_malloc(sizeof(struct timer));
memset(t, 0, sizeof(struct timer));
t->on_timer = on_timer;
t->repeat_count = repeat_count;
t->udata = udata;
uv_timer_init(uv_default_loop(), &t->uv_timer);
return t;
}
static void
free_timer(struct timer* t) {
my_free(t);
}
static void
on_uv_timer(uv_timer_t* handle) {
struct timer* t = handle->data;
if (t->repeat_count < 0) { // 不断的触发;
t->on_timer(t->udata);
}
else {
t->repeat_count --;
t->on_timer(t->udata);
if (t->repeat_count == 0) { // 函数time结束
uv_timer_stop(&t->uv_timer); // 停止这个timer
free_timer(t);
}
}
}
struct timer*
schedule(void(*on_timer)(void* udata),
void* udata,
int after_msec,
int repeat_count) {
struct timer* t = alloc_timer(on_timer, udata, repeat_count);
// 启动一个timer;
t->uv_timer.data = t;
uv_timer_start(&t->uv_timer, on_uv_timer, after_msec, after_msec);
// end
return t;
}
void
cancel_timer(struct timer* t) {
if (t->repeat_count == 0) { // 全部触发完成，;
return;
}
uv_timer_stop(&t->uv_timer);
free_timer(t);
}
struct timer*
schedule_once(void(*on_timer)(void* udata),
void* udata,
int after_msec) {
return schedule(on_timer, udata, after_msec, 1);
}
#ifndef __MY_TIMER_LIST_H__
#define __MY_TIMER_LIST_H__
// on_timer是一个回掉函数,当timer触发的时候调用;
// udata: 是用户传的自定义的数据结构;
// on_timer执行的时候 udata,就是你这个udata;
// after_sec: 多少秒开始执行;
// repeat_count: 执行多少次, repeat_count == -1一直执行;
// 返回timer的句柄;
struct timer;
struct timer*
schedule(void(*on_timer)(void* udata),
void* udata,
int after_msec,
int repeat_count);
// 取消掉这个timer;
void
cancel_timer(struct timer* t);
struct timer*
schedule_once(void(*on_timer)(void* udata),
void* udata,
int after_msec);
#endif
使用
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "uv.h"
// 获取当前系统从开机到现在运行了多少毫秒;
#ifdef WIN32
#include <windows.h>
static unsigned int
get_cur_ms() {
return GetTickCount();
}
#else
#include <sys/time.h>
#include <time.h>
#include <limits.h>
static unsigned int
get_cur_ms() {
struct timeval tv;
// struct timezone tz;
gettimeofday(&tv, NULL);
return ((tv.tv_usec / 1000) + tv.tv_sec * 1000);
}
#endif
static uv_loop_t* event_loop = NULL;
#include "time_list.h"
struct timer* t = NULL;
static void
on_time_func(void* udata) {
static int count = 0;
char* str = (udata);
printf("%s\n", str);
count++;
if (count == 10) {
cancel_timer(t);
}
}
static void
on_time_func2(void* udata) {
char* str = (udata);
printf("%s\n", str);
}
int main(int argc, char** argv) {
event_loop = uv_default_loop();
// 每隔5秒掉一次，掉4次;
t = schedule(on_time_func, "HelloWorld!!!", 1000, -1);
//
schedule_once(on_time_func2, "CallFunc!!!", 1000);
uv_run(event_loop, UV_RUN_DEFAULT);
system("pause");
return 0;
}
异步文件读写
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include "uv.h"
/*
uv_fs_open:
loop: 事件循环,
uv_fs_t req请求对象;
path: 文件路径
flags: 标志0
mode: 可读，可写... O_RDONLY O_RDWR...
*/
static uv_loop_t* event_loop = NULL;
static uv_fs_t req;
static uv_fs_t w_req;
static uv_file fs_handle;
static char mem_buffer[1024];
/*
uv_file
文件句柄对象: 打开文件以后的文件handle
uv_fs_t
result,每次请求的结果都是这个值来返回;
打开文件: result返回打开文件句柄对象uv_file;
读文件: result读到的数据长度;
写文件: result为写入的数据长度;
*/
/*
释放掉这个请求req所占的资源
uv_req_cleanup(req);
*/
/*
stdin: 标注的输入文件, scanf, cin>>
stdout: 标准的输出文件 printf;
fprintf(stdout, "xxxxxxx");
每个进程在运行的时候:
stdin文件句柄与stdout这个文件句柄始终是打开的;
stdin:标准的输入文件,
stdout: 标准的输出;
*/
static void
after_read(uv_fs_t* req) {
printf("read %d byte\n", req->result);
mem_buffer[req->result] = 0; // 字符串结尾;
printf("%s\n", mem_buffer);
uv_fs_req_cleanup(req);
uv_fs_close(event_loop, req, fs_handle, NULL);
uv_fs_req_cleanup(req);
}
static void
on_open_fs_cb(uv_fs_t* req) {
// 打开文件
fs_handle = req->result;
uv_fs_req_cleanup(req);
printf("open success end\n");
uv_buf_t buf = uv_buf_init(mem_buffer, 1024);
uv_fs_read(event_loop, req,
fs_handle, &buf, 1, 0,
after_read);
}
int main(int argc, char** argv) {
event_loop = uv_default_loop();
// step1:打开文件:
uv_fs_open(event_loop, &req,
"./test.txt", 0,
O_RDONLY, on_open_fs_cb);
uv_buf_t w_buf = uv_buf_init("Good! BYCW!!!!", 12);
uv_fs_write(event_loop, &w_req, (uv_file)1, &w_buf, 1, 0, NULL);
uv_fs_req_cleanup(&w_req);
uv_run(event_loop, UV_RUN_DEFAULT);
system("pause");
return 0;
}
websocket协议
1: websocket是基于TCP的一种协议,是H5的一种传输协议;
2: websocket连接协议;
3: websocket 发送数据协议;
4: websocket 接受数据协议;
5: websocket 关闭协议;
建立连接
1:客户端向服务器发送http报文,服务器处理后回客户端连接报文;
2: 客户端发过来的报文:
GET /chat HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Origin: http://example.com
Sec-WebSocket-Protocol: chat, superchat
Sec-WebSocket-Version: 13
3: 服务器回应客户端报文:
:key+migic ， SHA-1 加密， base-64 加密
key=”来自客户端的随机”, migic = “258EAFA5-E914-47DA-95CA-C5AB0DC85B11”;
static char *wb_accept = “HTTP/1.1 101 Switching Protocols\r\n”
“Upgrade:websocket\r\n”
“Connection: Upgrade\r\n”
“Sec-WebSocket-Accept: %s\r\n”
“WebSocket-Protocol:chat\r\n\r\n”;
Sec-WebSocket-Key/Accept的作用
- 避免服务端收到非法的websocket连接（比如http客户端不小心请求连接websocket服务，此时服务端可以直接拒绝连接）
- 确保服务端理解websocket连接。因为ws握手阶段采用的是http协议，因此可能ws连接是被一个http服务器处理并返回的，此时客户端可以通过Sec-WebSocket-Key来确保服务端认识ws协议。（并非百分百保险，比如总是存在那么些无聊的http服务器，光处理Sec-WebSocket-Key，但并没有实现ws协议。。。）
- 用浏览器里发起ajax请求，设置header时，Sec-WebSocket-Key以及其他相关的header是被禁止的。这样可以避免客户端发送ajax请求时，意外请求协议升级（websocket upgrade）
可以防止反向代理（不理解ws协议）返回错误的数据。比如反向代理前后收到两次ws连接的升级请求，反向代理把第一次请求的返回给cache住，然后第二次请求到来时直接把cache住的请求给返回（无意义的返回）。 - Sec-WebSocket-Key主要目的并不是确保数据的安全性，因为Sec-WebSocket-Key、Sec-WebSocket-Accept的转换计算公式是公开的，而且非常简单，最主要的作用是预防一些常见的意外情况（非故意的）。
关闭连接
1: 主动关闭socket
2: 客户端关闭socket:
收到 0x88 开头的数据包;
收到tcp socket关闭事件;
发送数据
- 固定字节(0x81)
- 包长度字节
- 原始数据
接收数据
1)固定字节(1000 0001或1000 0010);
2)包长度字节, 去掉最高位, 剩下7为得到一个整数(0, 127);125以内的长度直接表示就可以了；
126表示后面两个字节表示大小,127表示后面的8个字节是数据的长度;(高位存在低地址)
3)mark 掩码为包长之后的 4 个字节
4)兄弟数据：
得到真实数据的方法：将兄弟数据的每一字节 x ，和掩码的第 i%4 字节做 xor 运算，其中 i 是 x 在兄弟数据中的索引
代码
客户端网页
<!DOCTYPE html>
<html>
<head>
<title>skynet WebSocket example</title>
</head>
<body>
<script>
var ws = new WebSocket('ws://127.0.0.1:8001/ws');
ws.onopen = function(){
alert("open");
ws.send('WebSocket');
};
ws.onmessage = function(ev){
alert(ev.data);
};
ws.onclose = function(ev){
alert("close");
};
ws.onerror = function(ev){
console.log(ev);
alert("error");
};
</script>
</body>
</html>
服务器
该代码在前面的TCP服务器的基础上修改
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "../3rd/http_parser/http_parser.h"
#include "../3rd/crypto/sha1.h"
#include "../3rd/crypto/base64_encoder.h"
#include "uv.h"
struct ws_context {
int is_shake_hand; // 是否已经握手
char* data; // 读取数据的buf
};
static uv_loop_t* loop = NULL;
static uv_tcp_t l_server; // 监听句柄;
static void
uv_alloc_buf(uv_handle_t* handle,
size_t suggested_size,
uv_buf_t* buf) {
struct ws_context* wc = handle->data;
if (wc->data != NULL) {
free(wc->data);
wc->data = NULL;
}
buf->base = malloc(suggested_size + 1);
buf->len = suggested_size;
wc->data = buf->base;
}
static void
on_close(uv_handle_t* handle) {
printf("close client\n");
if (handle->data) {
struct ws_context* wc = handle->data;
free(wc->data);
wc->data = NULL;
free(wc);
handle->data = NULL;
}
free(handle);
}
static void
on_shutdown(uv_shutdown_t* req, int status) {
uv_close((uv_handle_t*)req->handle, on_close);
free(req);
}
static void
after_write(uv_write_t* req, int status) {
if (status == 0) {
printf("write success\n");
}
uv_buf_t* w_buf = req->data;
if (w_buf) {
free(w_buf->base);
free(w_buf);
}
free(req);
}
static void
send_data(uv_stream_t* stream, unsigned char* send_data, int send_len) {
uv_write_t* w_req = malloc(sizeof(uv_write_t));
uv_buf_t* w_buf = malloc(sizeof(uv_buf_t));
unsigned char* send_buf = malloc(send_len);
memcpy(send_buf, send_data, send_len);
w_buf->base = send_buf;
w_buf->len = send_len;
w_req->data = w_buf;
uv_write(w_req, stream, w_buf, 1, after_write);
}
static char filed_sec_key[512];
static char value_sec_key[512];
static int is_sec_key = 0;
static int has_sec_key = 0;
static int
on_ws_header_field(http_parser* p, const char *at, size_t length) {
if (strncmp(at, "Sec-WebSocket-Key", length) == 0) {
is_sec_key = 1;
}
else {
is_sec_key = 0;
}
return 0;
}
static int
on_ws_header_value(http_parser* p, const char *at, size_t length) {
if (!is_sec_key) {
return 0;
}
strncpy(value_sec_key, at, length);
value_sec_key[length] = 0;
has_sec_key = 1;
return 0;
}
//
static char* wb_migic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
// base64(sha1(key + wb_migic))
static char *wb_accept = "HTTP/1.1 101 Switching Protocols\r\n"
"Upgrade:websocket\r\n"
"Connection: Upgrade\r\n"
"Sec-WebSocket-Accept: %s\r\n"
"WebSocket-Protocol:chat\r\n\r\n";
static void
ws_connect_shake_hand(uv_stream_t* stream, unsigned char* data, int data_len) {
http_parser_settings settings;
http_parser_settings_init(&settings);
settings.on_header_field = on_ws_header_field;
settings.on_header_value = on_ws_header_value;
http_parser p;
http_parser_init(&p, HTTP_REQUEST);
is_sec_key = 0;
has_sec_key = 0;
http_parser_execute(&p, &settings, data, data_len);
if (has_sec_key) { // 解析到了websocket里面的Sec-WebSocket-Key
printf("Sec-WebSocket-Key: %s\n", value_sec_key);
// key + migic
static char key_migic[512];
static char sha1_key_migic[SHA1_DIGEST_SIZE];
static char send_client[512];
int sha1_size;
sprintf(key_migic, "%s%s", value_sec_key, wb_migic);
crypt_sha1((unsigned char*)key_migic, strlen(key_migic), (unsigned char*)&sha1_key_migic, &sha1_size);
int base64_len;
char* base_buf = base64_encode(sha1_key_migic, sha1_size, &base64_len);
sprintf(send_client, wb_accept, base_buf);
base64_encode_free(base_buf);
send_data(stream, (unsigned char*)send_client, strlen(send_client));
}
}
static void
ws_send_data(uv_stream_t* stream, unsigned char* data, int len) {
int head_size = 2;
if (len > 125 && len < 65536) { // 两个字节[0, 65535]
head_size += 2;
}
else if (len >= 65536) { // 不做处理
head_size += 8;
}
unsigned char* data_buf = malloc(head_size + len);
data_buf[0] = 0x81;
if (len <= 125) {
data_buf[1] = len;
}
else if (len > 125 && len < 65536) {
data_buf[1] = 126;
data_buf[2] = (len & 0x0000ff00) >> 8;
data_buf[3] = (len & 0x000000ff);
}
else { // 127不写了
return;
}
memcpy(data_buf + head_size, data, len);
send_data(stream, data_buf, head_size + len);
free(data_buf);
}
// 收到的是一个数据包;
static void
ws_on_recv_data(uv_stream_t* stream,
unsigned char* data, unsigned int len) {
if (data[0] != 0x81 && data[0] != 0x82) {
return;
}
unsigned int data_len = data[1] & 0x0000007f;
int head_size = 2;
if (data_len == 126) { // 后面两个字节表示的是数据长度;data[2], data[3]
data_len = data[3] | (data[2] << 8);
head_size += 2;
}
else if (data_len == 127) { // 后面8个字节表示数据长度; 2, 3, 4, 5 | 6, 7, 8, 9
unsigned int low = data[5] | (data[4] << 8) | (data[3] << 16) | (data[2] << 24);
unsigned int hight = data[9] | (data[8] << 8) | (data[7] << 16) | (data[6] << 24);
data_len = low;
head_size += 8;
}
unsigned char* mask = data + head_size;
unsigned char* body = data + head_size + 4;
for (unsigned int i = 0; i < data_len; i++) { // 遍历后面所有的数据;
body[i] = body[i] ^ mask[i % 4];
}
// test
static char test_buf[4096];
memcpy(test_buf, body, data_len);
test_buf[data_len] = 0;
printf("%s\n", test_buf);
// 发送协议
ws_send_data(stream, "Hello", strlen("Hello"));
// end
}
static void after_read(uv_stream_t* stream,
ssize_t nread,
const uv_buf_t* buf) {
// 连接断开了;
if (nread < 0) {
uv_shutdown_t* reg = malloc(sizeof(uv_shutdown_t));
memset(reg, 0, sizeof(uv_shutdown_t));
uv_shutdown(reg, stream, on_shutdown);
return;
}
// end
printf("start websocket!!!\n");
struct ws_context* wc = stream->data;
// 如果没有握手，就进入websocket握手协议
if (wc->is_shake_hand == 0) {
ws_connect_shake_hand(stream, buf->base, buf->len);
wc->is_shake_hand = 1;
return;
}
// end
// 如果客户端主动关闭;0x88, 状态码
if ((unsigned char)(buf->base[0]) == 0x88) { // 关闭
printf("ws closing!!!!");
return;
}
// end
// ws正常的数据, 暂时不处理粘包这些问题;
// 假设我们一次性都可以收完websocket发过来的数据包;
ws_on_recv_data(stream, buf->base, nread);
// end
}
static void
uv_connection(uv_stream_t* server, int status) {
printf("new client comming\n");
uv_tcp_t* client = malloc(sizeof(uv_tcp_t));
memset(client, 0, sizeof(uv_tcp_t));
uv_tcp_init(loop, client);
uv_accept(server, (uv_stream_t*)client);
struct ws_context* wc = malloc(sizeof(struct ws_context));
memset(wc, 0, sizeof(struct ws_context));
client->data = wc;
uv_read_start((uv_stream_t*)client, uv_alloc_buf, after_read);
}
int main(int argc, char** argv) {
int ret;
loop = uv_default_loop();
uv_tcp_init(loop, &l_server);
struct sockaddr_in addr;
uv_ip4_addr("0.0.0.0", 8001, &addr); // ip地址, 端口
ret = uv_tcp_bind(&l_server, (const struct sockaddr*) &addr, 0);
if (ret != 0) {
goto failed;
}
uv_listen((uv_stream_t*)&l_server, SOMAXCONN, uv_connection);
uv_run(loop, UV_RUN_DEFAULT);
failed:
printf("end\n");
system("pause");
return 0;
}
总结
WebSocket是一种基于TCP协议的双向通信协议，与HTTP/HTTPS协议相比，具有更低的延迟和更高的实时性。使用WebSocket协议可以实现实时通信、数据推送、在线游戏等功能。但是，WebSocket协议并没有被广泛采用的原因有以下几个方面：
兼容性问题：WebSocket协议是HTML5标准中新增的协议，对于较老的浏览器可能不支持。虽然现代主流浏览器已经支持WebSocket协议，但是在一些特殊情况下（例如企业内部应用、旧版浏览器等），WebSocket协议的兼容性可能成为问题。
安全问题：由于WebSocket协议实现了双向通信，因此在网络安全方面需要更加关注。例如，在进行WebSocket通信时需要进行恰当的身份验证和加密，以避免数据泄露和劫持等问题。
部署和负载问题：WebSocket协议需要建立长连接，因此在部署WebSocket服务时需要考虑服务器负载和连接管理等问题。如果不恰当地部署WebSocket服务，可能会导致服务器资源浪费、连接管理不当等问题。
用处有限：对于大多数网站来说,HTTP请求已经能满足需求。使用WebSocket可以带来实时性改善,但对许多网站功能影响不大。所以如果没有实时交互等强需求,就不一定需要引入WebSocket。
尽管WebSocket协议存在一些问题，但是在特定的场景下仍然是一种非常有用的协议。例如，在实时通信、数据推送、在线游戏等场景下，WebSocket协议可以发挥出其优势。
HTTP服务器
步骤：
1: 等待socket 连接进来;
2: 接收socket发送过来的数据;–> http协议格式的请求数据包
3: http解析url
4: 根据url来找对应的响应处理;
5: 将要返回的数据打包成http响应格式，发给客户端;
6: 关闭客户端的连接;
以Get请求为例：
1: 客户端提交请求;
2: 服务端解析get的url找到对应的响应;
3: 服务端解析get参数;
5: 处理，返回结果给客户端:
“HTTP/1.1 %d %s\r\n” 状态码，状态描述
“transfer-encoding:%s\r\n”, “identity”
“content-length: %d\r\n\r\n” 内容长度
body数据
6: get携带参数格式?uname=xiaoming&key=18074532323
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "uv.h"
#include "../3rd/http_parser/http_parser.h"
/*
url 注册管理模块
*/
typedef void(*web_get_handle)(uv_stream_t* stream, char* url);
typedef void(*web_post_handle)(uv_stream_t* stream, char* url, char* body);
struct url_node {
char* url; // url地址
web_get_handle get; // url地址对应的处理函数;
web_post_handle post; // url地址对应的post函数
};
static struct url_node*
alloc_url_node(char* url, web_get_handle get, web_post_handle post) {
struct url_node* node = malloc(sizeof(struct url_node));
memset(node, 0, sizeof(struct url_node));
node->url = strdup(url);
node->get = get;
node->post = post;
return node;
}
static struct url_node* url_node[1024];
static int url_count = 0;
static void
register_web_handle(char* url, web_get_handle get, web_post_handle post) {
url_node[url_count] = alloc_url_node(url, get, post);
url_count ++;
}
static struct url_node*
get_url_node(char* url, int len) {
for (int i = 0; i < url_count; i++) {
if (strncmp(url, url_node[i]->url, len) == 0) {
return url_node[i];
}
}
return NULL;
}
/*
{
[100] = "Continue",
[101] = "Switching Protocols",
[200] = "OK",
[201] = "Created",
[202] = "Accepted",
[203] = "Non-Authoritative Information",
[204] = "No Content",
[205] = "Reset Content",
[206] = "Partial Content",
[300] = "Multiple Choices",
[301] = "Moved Permanently",
[302] = "Found",
[303] = "See Other",
[304] = "Not Modified",
[305] = "Use Proxy",
[307] = "Temporary Redirect",
[400] = "Bad Request",
[401] = "Unauthorized",
[402] = "Payment Required",
[403] = "Forbidden",
[404] = "Not Found",
[405] = "Method Not Allowed",
[406] = "Not Acceptable",
[407] = "Proxy Authentication Required",
[408] = "Request Time-out",
[409] = "Conflict",
[410] = "Gone",
[411] = "Length Required",
[412] = "Precondition Failed",
[413] = "Request Entity Too Large",
[414] = "Request-URI Too Large",
[415] = "Unsupported Media Type",
[416] = "Requested range not satisfiable",
[417] = "Expectation Failed",
[500] = "Internal Server Error",
[501] = "Not Implemented",
[502] = "Bad Gateway",
[503] = "Service Unavailable",
[504] = "Gateway Time-out",
[505] = "HTTP Version not supported",
}
*/
/*
uv_handle_s 数据结构:
UV_HANDLE_FIELDS
uv_stream_t 数据结构;
UV_HANDLE_FIELDS
UV_STREAM_FIELDS
uv_tcp_t 数据结构;
UV_HANDLE_FIELDS
UV_STREAM_FIELDS
UV_TCP_PRIVATE_FIELDS
uv_tcp_t is uv_stream_t is uv_handle_t;
*/
static uv_loop_t* loop = NULL;
static uv_tcp_t l_server; // 监听句柄;
// 当我们的event loop检车到handle上有数据可以读的时候,
// 就会调用这个函数, 让这个函数给event loop准备好读入数据的内存;
// event loop知道有多少数据,suggested_size,
// handle: 发生读时间的handle;
// suggested_size: 建议我们分配多大的内存来保存这个数据;
// uv_buf_t: 我们准备好的内存，通过uv_buf_t,告诉even loop;
static void
uv_alloc_buf(uv_handle_t* handle,
size_t suggested_size,
uv_buf_t* buf) {
if (handle->data != NULL) {
free(handle->data);
handle->data = NULL;
}
buf->base = malloc(suggested_size + 1);
buf->len = suggested_size;
handle->data = buf->base;
}
static void
on_close(uv_handle_t* handle) {
printf("close client\n");
if (handle->data) {
free(handle->data);
handle->data = NULL;
}
}
static void
on_shutdown(uv_shutdown_t* req, int status) {
uv_close((uv_handle_t*)req->handle, on_close);
free(req);
}
static void
after_write(uv_write_t* req, int status) {
if (status == 0) {
printf("write success\n");
}
uv_buf_t* w_buf = req->data;
if (w_buf) {
free(w_buf);
}
free(req);
}
static void
send_data(uv_stream_t* stream, unsigned char* send_data, int send_len) {
uv_write_t* w_req = malloc(sizeof(uv_write_t));
uv_buf_t* w_buf = malloc(sizeof(uv_buf_t));
unsigned char* send_buf = malloc(send_len);
memcpy(send_buf, send_data, send_len);
w_buf->base = send_buf;
w_buf->len = send_len;
w_req->data = w_buf;
uv_write(w_req, stream, w_buf, 1, after_write);
}
static char req_url[4096];
int on_url(http_parser* p, const char *at, size_t length) {
strncpy(req_url, at, length);
req_url[length] = 0;
return 0;
}
static int
filter_url(char* url) {
char* walk = url;
int len = 0;
while (*url != '?' && *url != '\0') {
len++;
url++;
}
return len;
}
static void
on_http_request(uv_stream_t* stream, char* req, int len) {
http_parser_settings settings;
http_parser_settings_init(&settings);
settings.on_url = on_url;
http_parser p;
http_parser_init(&p, HTTP_REQUEST);
http_parser_execute(&p, &settings, req, len);
// http get是可以携带参数的:
// http://www.baidu.com:6080/test?name=xiaoming&age=34
int url_len = filter_url(req_url);
struct url_node* node = get_url_node(req_url, url_len);
printf("%s\n", req_url);
if (node == NULL) {
return;
}
switch (p.method) { // 请求方法
case HTTP_GET:
if (node->get != NULL) {
node->get(stream, req_url);
}
break;
case HTTP_POST:
if (node->post != NULL) {
}
break;
}
}
// 参数:
// uv_stream_t* handle --> uv_tcp_t;
// nread: 读到了多少字节的数据;
// uv_buf_t: 我们的数据都读到到了哪个buf里面, base;
static void after_read(uv_stream_t* stream,
ssize_t nread,
const uv_buf_t* buf) {
// 连接断开了;
if (nread < 0) {
uv_shutdown_t* reg = malloc(sizeof(uv_shutdown_t));
memset(reg, 0, sizeof(uv_shutdown_t));
uv_shutdown(reg, stream, on_shutdown);
return;
}
// end
buf->base[nread] = 0;
printf("recv %d\n", nread);
printf("%s\n", buf->base);
// 处理
on_http_request(stream, buf->base, buf->len);
// end
}
static void
uv_connection(uv_stream_t* server, int status) {
printf("new client comming\n");
// 接入客户端;
uv_tcp_t* client = malloc(sizeof(uv_tcp_t));
memset(client, 0, sizeof(uv_tcp_t));
uv_tcp_init(loop, client);
uv_accept(server, (uv_stream_t*)client);
// end
// 告诉event loop,让他帮你管理哪个事件;
uv_read_start((uv_stream_t*)client, uv_alloc_buf, after_read);
}
static void
test_get(uv_stream_t* stream, char* url) {
printf("%s\n", url);
char* body = "SUCCESS TEST1";
static char respons_buf[4096];
char* walk = respons_buf;
sprintf(walk, "HTTP/1.1 %d %s\r\n", 200, "OK");
walk += strlen(walk);
sprintf(walk, "transfer-encoding:%s\r\n", "identity");
walk += strlen(walk);
sprintf(walk, "content-length: %d\r\n\r\n", strlen(body));
walk += strlen(walk);
sprintf(walk, "%s", body);
send_data(stream, respons_buf, strlen(respons_buf));
}
static void
test2_get(uv_stream_t* stream, char* url) {
printf("%s\n", url);
char* body = "SUCCESS TEST2";
static char respons_buf[4096];
char* walk = respons_buf;
sprintf(walk, "HTTP/1.1 %d %s\r\n", 200, "OK");
walk += strlen(walk);
sprintf(walk, "transfer-encoding:%s\r\n", "identity");
walk += strlen(walk);
sprintf(walk, "content-length: %d\r\n\r\n", strlen(body));
walk += strlen(walk);
sprintf(walk, "%s", body);
send_data(stream, respons_buf, strlen(respons_buf));
}
int main(int argc, char** argv) {
// 注册一下web请求函数
register_web_handle("/test", test_get, NULL);
register_web_handle("/test2", test2_get, NULL);
// end
int ret;
loop = uv_default_loop();
// Tcp 监听服务;
uv_tcp_init(loop, &l_server); // 将l_server监听句柄加入到event loop里面;
// 你需要event loop来给你做那种管理呢？配置你要的管理类型;
struct sockaddr_in addr;
uv_ip4_addr("0.0.0.0", 6080, &addr); // ip地址, 端口
ret = uv_tcp_bind(&l_server, (const struct sockaddr*) &addr, 0);
if (ret != 0) {
goto failed;
}
// 让event loop来做监听管理，当我们的l_server句柄上有人连接的时候;
// event loop就会调用用户指定的这个处理函数uv_connection;
uv_listen((uv_stream_t*)&l_server, SOMAXCONN, uv_connection);
uv_run(loop, UV_RUN_DEFAULT);
failed:
printf("end\n");
system("pause");
return 0;
}
多线程与工作队列
1: 线程相关函数:
uv_thread_create: 创建一个线程;
uv_thread_self: 获取当前线程id号;
uv_thread_join: 等待线程结束;
2: 锁:
uv_mutex_init: 初始化锁;
uv_mutex_destroy: 销毁锁;
uv_mutex_lock: 获取锁，如果被占用，就等待;
uv_mutex_trylock: 尝试获取锁，如果获取不到，直接返回,不等待;
uv_mutex_unlock: 释放锁;
3: 等待/触发事件;
uv_cond_init: 创建条件事件;
uv_cond_destroy: 销毁条件事件;
uv_cond_signal: 触发条件事件;
uv_cond_broadcast: 广播条件事件;
uv_cond_wait/uv_cond_timedwait: 等待事件/等待事件超时;
工作队列：
1: libuv在启动的时候会创建一个线程池;
2: 线程池默认启动的线程数目是4个，最大是128个线程;
3: uv_queue_work工作队列原理:
step1: libuv启动线程池，等待任务的调度;
step2: 用户给工作队列一个执行函数，工作队列执行完后,通知主线程;
step3: 主线程在执行之前设置的回掉函数;
4: 工作队列的使用:
有很多操作，比如读文件，比如读数据库，比如读redis都会等待，所以使用工作队列，
可以工作队列来执行，然后通知主线程，这样就不会卡主线程了。给工作队列一个任务(函数)，并指定好任务完成的回掉函数,线程池就会调度去执行这个任务函数，完成后，通知主线程，主线程调用回掉函数;
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "uv.h"
// 工作队列的用处:
// 1：复杂的算法放到工作队列 ；
// 2：IO放到我们工作队列,获取数据库结果;
// ....
// 是在线程池里面另外一个线程里面调用，不在主线程;
static void
thread_work(uv_work_t* req) {
//
printf("user data = %d \n", (int)req->data);
printf("thread_work id 0x%d:\n", uv_thread_self());
}
// 当工作队列里面的线程执行完上面的任务后，通知主线程;
// 主线程调用这个函数;
static void
on_work_complete(uv_work_t* req, int status) {
printf("on_work_complete thread id 0x%d:\n", uv_thread_self());
}
int main(int argc, char** argv) {
uv_work_t uv_work;
printf("main id 0x%d:\n", uv_thread_self());
uv_work.data = (void*)6;
uv_queue_work(uv_default_loop(), &uv_work, thread_work, on_work_complete);
uv_run(uv_default_loop(), UV_RUN_DEFAULT);
system("pause");
return 0;
}