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最简单完整的libwebsockets的例子
发布时间：2023/12/20
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最简单完整的libwebsockets的例子
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/** simplest_websocket_example - 最简单且完整的使用libwebsocket的例子** Copyright (C) 2020 Zhu Nengjie <dotphoenix@qq.com>* This library is free software; you can redistribute it and/or* modify it under the terms of the GNU Lesser General Public* License as published by the Free Software Foundation:* version 2.1 of the License.** This library is distributed in the hope that it will be useful,* but WITHOUT ANY WARRANTY; without even the implied warranty of* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU* Lesser General Public License for more details.** You should have received a copy of the GNU Lesser General Public* License along with this library; if not, write to the Free Software* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,* MA 02110-1301 USA
*/#include <libwebsockets.h>
#include <glib.h>
#include <string.h>
#include <stdio.h>//这个例子的主要功能是:
//1. ws客户端会定期向ws服务器更新一个数字,该数字递增,见:LWS_CALLBACK_CLIENT_WRITEABLE;
//2. ws服务器收到该数字之后,见:LWS_CALLBACK_RECEIVE,会保存下来;
//3. 当server可写的时候,会向所有的客户端发送这个数字(包括发送数字的客户端),见:LWS_CALLBACK_SERVER_WRITEABLE
//4. 客户端收到数字的时候,会显示出来,见:LWS_CALLBACK_CLIENT_RECEIVE
//5. 浏览器访问http://localhost:8000, ws服务器(因为它同时也是一个标准的http服务器)会返回一个自动创建的一个html文件,
// 该html文件的内容就是html_contenti变量里面的内容,它的主要功能是通过js建立一个ws客户端,并连接到localhost:8000这个
// ws服务器,并且在收到数据的时候,更新到页面.当有人向localhost:8000请求发送http请求时,返回该文件,见:LWS_CALLBACK_RECEIVE//编译: 必须先安装libwebsocket和glib-2.0, ssl应该不是必须的,但没有的话可能编译不通过,注意修改下ssl的路径为你自己电脑的路径
//gcc -g -Wall simplest_websocket_example.c -o simplest_websocket_example `pkg-config --libs --cflags glib-2.0 libwebsockets` -I/usr/local/Cellar/openssl@1.1/1.1.1d/include//这个内容会自动写到一个html文件里面, 他的功能是使用js创建一个websocket客户端,当收到数据的时候,刷新页面
const char *html_content = " <!DOCTYPE html>"
"<html> \n"
"<title>Websocket example</title>\n"
"<script>\n"" var socket = new WebSocket( \"ws://\" + document.domain + ':' + location.port, \"ws-protocol-example\" );\n"
" function update(msg) { document.getElementById(\"num\").innerHTML = msg; }\n"" socket.onopen = function() { console.log(\"socket open\"); update(\"open\"); }\n"" socket.onclose = function() { console.log(\"socket close\"); update(\"closed\"); }\n"
" socket.onmessage = function(msg) { console.log(\"socket message: \" + msg.data); update(msg.data); }\n"
"</script>\n"
"<body>\n"
"<p id=\"num\"></p>\n"
"</body>\n"
"</html>\n";//创建html文件的路径
static char example_html_file_path[512] = {0};//返回html文件的路径,会自动获取当前运行的路径
static const char* get_html_file_path()
{if(strlen(example_html_file_path) == 0){getcwd(example_html_file_path, 512);strcat(example_html_file_path, "/websocket_example.html");}return (const char*)example_html_file_path;
}//写入内容到html文件里面,此处每次打开页面都会重新创建一次,可以考虑做个判断,不用每次都创建
static void create_html_file()
{FILE *f;const char* pathname = get_html_file_path();if ((f = fopen(pathname, "w+")) == NULL){printf("open file error");return ;}fwrite(html_content, 1, strlen(html_content), f);fflush(f);fclose(f);
}//html协议的回调函数
static int callback_http( struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len )
{switch( reason ){case LWS_CALLBACK_HTTP:create_html_file();printf("%s->%s\n", "LWS_CALLBACK_HTTP", get_html_file_path());lws_serve_http_file( wsi, get_html_file_path(), "text/html", NULL, 0 );break;default:break;}return 0;
}#define EXAMPLE_RX_BUFFER_BYTES (10)
//定义的一个payload结构,用于存储ws发送和接收的数据
struct payload
{unsigned char data[LWS_SEND_BUFFER_PRE_PADDING + EXAMPLE_RX_BUFFER_BYTES + LWS_SEND_BUFFER_POST_PADDING];size_t len;
} ;struct payload server_received_payload;//ws服务端的ws(ws-protocol-example)协议的回调函数
static int callback_example_server( struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len )
{switch( reason ){case LWS_CALLBACK_RECEIVE: //收到数据memset(&server_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING], 0, len + 1);memcpy( &server_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING], in, len );server_received_payload.len = len;printf("\033[31mserver callback: %s->%s\n", "LWS_CALLBACK_RECEIVE", &server_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING]);lws_callback_on_writable_all_protocol( lws_get_context( wsi ), lws_get_protocol( wsi ) );break;case LWS_CALLBACK_SERVER_WRITEABLE: //可写 //会朝所有的连接写入数据,此处至少是2个连接(发送数字的ws客户端和html里面建立的一个ws客户端),所以log可以看到2条printf("\033[31mserver callback: %s->%s\n", "LWS_CALLBACK_SERVER_WRITEABLE", &server_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING]);lws_write( wsi, &server_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING], server_received_payload.len, LWS_WRITE_TEXT );break;default:break;}return 0;
}//ws服务端在同一个端口支持2种协议,http和ws(具体是ws-protocol-example,实际上可以再多几个ws协议)
static struct lws_protocols server_protocols[] =
{/* The first protocol must always be the HTTP handler */{"http-only", /* name */callback_http, /* callback */0, /* No per session data. */0, /* max frame size / rx buffer */},{"ws-protocol-example",callback_example_server,0,EXAMPLE_RX_BUFFER_BYTES,},{ NULL, NULL, 0, 0 } /* terminator */
};//s停止服务器
static int stop_server = 0;
int main_server()
{struct lws_context_creation_info info;memset( &info, 0, sizeof(info) );info.port = 8000;//监听端口info.protocols = server_protocols; //支持哪些协议info.gid = -1;info.uid = -1;struct lws_context *context = lws_create_context( &info );printf("websockets server starts at %d \n", info.port);while( stop_server == 0 ){lws_service( context, /* timeout_ms = */ 1000000 );}lws_context_destroy( context );return 0;
}///以下为ws客户端的内容 /
///
//用于保存客户端与服务端的连接
static struct lws *web_socket = NULL;struct payload client_received_payload; //保存客户端收到的数据static int report_count = 0; //客户端发送的数据//客户端回调
static int callback_example_client( struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len )
{switch( reason ){case LWS_CALLBACK_CLIENT_ESTABLISHED: //建立连接成功printf("\033[34mclient callback: %s->%s\n", "LWS_CALLBACK_CLIENT_ESTABLISHED", "");lws_callback_on_writable( wsi );break;case LWS_CALLBACK_CLIENT_RECEIVE://回显服务器发回来的数据memset(&client_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING], 0, len + 1);memcpy( &client_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING], in, len );client_received_payload.len = len;printf("\033[34mclient callback: %s->%s\n", "LWS_CALLBACK_CLIENT_RECEIVE", &client_received_payload.data[LWS_SEND_BUFFER_PRE_PADDING]);break;case LWS_CALLBACK_CLIENT_WRITEABLE: //每次回调,count加一,发送给服务器{unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + EXAMPLE_RX_BUFFER_BYTES + LWS_SEND_BUFFER_POST_PADDING];unsigned char *p = &buf[LWS_SEND_BUFFER_PRE_PADDING];size_t n = sprintf( (char *)p, "%u", report_count++ );printf("\033[34mclient callback: %s->%s\n", "LWS_CALLBACK_CLIENT_WRITEABLE", p);lws_write( wsi, p, n, LWS_WRITE_TEXT );break;}case LWS_CALLBACK_CLOSED:case LWS_CALLBACK_CLIENT_CONNECTION_ERROR://连接失败或者中断,置空,便于重新连接web_socket = NULL;break;default:break;}return 0;
}//客户端只需要支持ws(ws-protocol-example)
enum client_protocols_type
{WS_PROTOCOL_EXAMPLE = 0,PROTOCOL_COUNT
};
static struct lws_protocols client_protocols[] =
{{"ws-protocol-example", //协议名称,一个端口可以建立多个ws协议callback_example_client,0,EXAMPLE_RX_BUFFER_BYTES,},{ NULL, NULL, 0, 0 } /* terminator */
};static int stop_client = 0;
int main_client()
{struct lws_context_creation_info info;memset( &info, 0, sizeof(info) );info.port = CONTEXT_PORT_NO_LISTEN;info.protocols = client_protocols;info.gid = -1;info.uid = -1;struct lws_context *context = lws_create_context( &info );time_t old = 0;while( stop_client == 0 ){struct timeval tv;gettimeofday( &tv, NULL );/* Connect if we are not connected to the server. */if( !web_socket && tv.tv_sec != old ){struct lws_client_connect_info ccinfo = {0};ccinfo.context = context;ccinfo.address = "localhost";ccinfo.port = 8000;ccinfo.path = "/";ccinfo.host = lws_canonical_hostname( context );ccinfo.origin = "origin";ccinfo.protocol = client_protocols[WS_PROTOCOL_EXAMPLE].name;web_socket = lws_client_connect_via_info(&ccinfo);}if( tv.tv_sec != old ){/* Send a random number to the server every second. */lws_callback_on_writable( web_socket );old = tv.tv_sec;}lws_service( context, /* timeout_ms = */ 250 );//在V3.2之后,timeout的值已经废弃,底层自己调度;所以这个地方怎么控制频率,不清楚}lws_context_destroy( context );return 0;
}//运行server的线程函数
void thread_func_server(void *p)
{main_server();
}int main( int argc, char *argv[] )
{//server在work thread里面调用,客户端运行在main threadGThread* server_thread = g_thread_new("server_thread", (GThreadFunc)(thread_func_server), NULL);main_client();g_thread_join(server_thread); //等待,无限循环
}
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