如何使用 libwebsockets C 库发送 JSON 数据？

Question

如何使用 libwebsockets C 库发送 JSON 数据？

我已经安装并尝试了示例代码，但是我看不到任何关于如何将数据发送到 localhost:someport 的示例。任何帮助将不胜感激。

这是 libwebsockets 的网站：http ://libwebsockets.org/trac/libwebsockets

这是 test-client.c 文件：http : //git.libwebsockets.org/cgi-bin/cgit/libwebsockets/tree/test-server

任何帮助将不胜感激。

Answer 1

我想这是你的例子 http://martinsikora.com/libwebsockets-simple-websocket-server

作者打开 localhost 服务器并使用 safari 连接到它。

如果您想使用 C 连接，这里是 C 中 HTTP 客户端的示例。

[编辑] [客户端]（通过 web.archive.org 恢复的死链接https://www.cs.utah.edu/~swalton/listings/sockets/programs/part1/chap4/http-client.c）

/* http-client.c
 *
 * Copyright (c) 2000 Sean Walton and Macmillan Publishers.  Use may be in
 * whole or in part in accordance to the General Public License (GPL).
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
*/

/*****************************************************************************/
/*** http-client.c                                                         ***/
/***                                                                       ***/
/*** This program shows what the HTTP server sends to the client.  First,  ***/
/*** it opens a TCP socket to the server.  Then, it sends the request      ***/
/*** "GET <resource> HTTP/1.0\n\n" (the second newline is needed for the   ***/
/*** "message-end" message.  Lastly it prints out the reply.               ***/
/*****************************************************************************/

#include <stdarg.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <resolv.h>
#include <errno.h>

#define MAXBUF  1024
void PANIC(char *msg);
#define PANIC(msg)  {perror(msg); abort();}

int main(int Count, char *Strings[])
{   int sockfd, bytes_read;
    struct sockaddr_in dest;
    char buffer[MAXBUF];

    /*---Make sure we have the right number of parameters---*/
    if ( Count != 3 )
        PANIC(stderr, "usage: testport <IP-addr> <send-msg>\n");
    if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
        PANIC("Socket");

    /*---Initialize server address/port struct---*/
    bzero(&dest, sizeof(dest));
    dest.sin_family = AF_INET;
    dest.sin_port = htons(80); /*default HTTP Server port */
    if ( inet_addr(Strings[1], &dest.sin_addr.s_addr) == 0 )
        PANIC(Strings[1]);

    /*---Connect to server---*/
    if ( connect(sockfd, (struct sockaddr*)&dest, sizeof(dest)) != 0 )
        PANIC("Connect");

    sprintf(buffer, "GET %s HTTP/1.0\n\n", Strings[2]);
    send(sockfd, buffer, strlen(buffer), 0);

    /*---While there's data, read and print it---*/
    do
    {
        bzero(buffer, sizeof(buffer));
        bytes_read = recv(sockfd, buffer, sizeof(buffer), 0);
        if ( bytes_read > 0 )
            printf("%s", buffer);
    }
    while ( bytes_read > 0 );

    /*---Clean up---*/
    close(sockfd);
    return 0;
}