c - C语言的noPoll Web套接字库总是连接不上

Question

我正在尝试为 C 开发人员构建一个开源 Cometd 库，以便能够在几乎任何给定设备下运行客户端。

我设法用 longPolling 技术完成了握手和数据传输，下一步逻辑上是给用户选择 Websocket 连接的选项。

为了简化工作，我决定为此使用一个库，我再次上网并找到了两个真正相关的库:

• WSlay库，它似乎运行良好但由于苹果不支持的 epoll.h 包含而不能在 OSX 下运行。

• NoPoll库，我认为这是最好用的。

问题是我不能让它正常运行，我总是连接失败。阅读完整文档后，我仍然不明白为什么？

这是我的代码:

    int main(void)
    {
      cometd        *cometd = cometd_new();
      JsonNode      *connect = json_node_new(JSON_NODE_OBJECT);
      noPollCtx     *ctx = nopoll_ctx_new(); //init the context of the lib
      noPollMsg     *msg; //variable to get messages

      if (!ctx) //check if the context is well inited
        puts("error ctx is nill");

      /*After the new you can enable or disable the Websocket simply do this, enabled by defautl*/
      cometd->config->webSockState = true;


      cometd_configure(cometd, COMETDOPT_URL, "http://m.zpush.ovh:8080/str/strd");
      cometd_configure(cometd, COMETDOPT_MAX_BACKOFF, 5000);
      struct _cometd_ext* logger = cometd_ext_logger_new();
      cometd_ext_add(&cometd->exts, logger);
      cometd_connect(cometd);
      connect = cometd_msg_connect_new(cometd);
      cometd_transport_send(cometd, connect); 
      //everything until here is for the handshake wich proceed well and the server returns a successful header

     //here i check if the user wants to Websocket upgrade his connection 
      if (cometd->config->webSockState == true)
        {
      // here i target the server
          noPollConn    *conn = nopoll_conn_new(ctx,  "54.171.156.38" , "8080" ,  "m.zpush.ovh:8080" , "ws://m.zpush.ovh:8080/str/strd", NULL, "null");
          if (!nopoll_conn_wait_until_connection_ready(conn, 5) ) 
      // here i check if the connection is ready
            {puts("nopoll_conn failed"); return (0);}
          if (nopoll_conn_send_text (conn, "hello how are you doing, do we connect ?", 40) != 40)
            {puts("send text just failed."); return(0);}
          else
            {
              while (nopoll_true) //the loop to receive and send messages
                {
                  msg = nopoll_conn_get_msg(conn);
                  if (msg)
                    break;

                  if (! nopoll_conn_is_ok (conn))
                    {
                      puts("connection failed during msg wait");
                      return nopoll_false;
                    }
                }
            }
        }
      cometd_subscribe(cometd, "/service/GmY-HuzW/6sd0/ls", handler);
      cometd_subscribe(cometd, "service/GmY-HuzW/6sd0/updateMeta", handler);
      cometd_subscribe(cometd, "/service/GmY-HuzW/6sd0/ls", handler);
      cometd_subscribe(cometd, "/service/GmY-HuzW/6sd0/newFile", handler);
      cometd_transport_send(cometd, cometd_ping_ls(cometd, "/service/GmY-HuzW/6sd0/ls"));

      cometd_listen(cometd);
      nopoll_ctx_unref(ctx);
      return 0;
    }

NoPoll 实现了一个调试选项，结果如下:

(proc 49413): (debug) nopoll_ctx.c:260 (nopoll_bool nopoll_ctx_register_conn(noPollCtx *, noPollConn *)) registered connection id 2, role: 0
(proc 49413): (debug) nopoll_conn.c:505 (noPollConn *__nopoll_conn_new_common(noPollCtx *, nopoll_bool, const char *, const char *, const char *, const char *, const char *, const char *)) Created noPoll conn-id=2 (ptr: 0x7f9d00501b60, context: 0x7f9d0041cdf0, socket: 3)
(proc 49413): (debug) nopoll_conn.c:284 (char *__nopoll_conn_get_client_init(noPollConn *)) Created Sec-WebSocket-Key nonce: Z0WLawAAAADGI3syAAAAAA==
(proc 49413): (debug) nopoll_conn.c:551 (noPollConn *__nopoll_conn_new_common(noPollCtx *, nopoll_bool, const char *, const char *, const char *, const char *, const char *, const char *)) Sending websocket client init: GET / HTTP/1.1
Host: 10.0.0.103
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: Z0WLawAAAADGI3syAAAAAA==
Origin: http://10.0.0.103
Sec-WebSocket-Version: 13


(proc 49413): (critical) nopoll_conn.c:643 (noPollConn *__nopoll_conn_new_common(noPollCtx *, nopoll_bool, const char *, const char *, const char *, const char *, const char *, const char *)) ***Failed to send websocket init message, error code was: 57 (2), closing session***
(proc 49413): (debug) nopoll_conn.c:1036 (void nopoll_conn_shutdown(noPollConn *)) shutting down connection id=2 (session: 3, role: client)
(proc 49413): (debug) nopoll_conn.c:651 (noPollConn *__nopoll_conn_new_common(noPollCtx *, nopoll_bool, const char *, const char *, const char *, const char *, const char *, const char *)) Web socket initial client handshake sent

-> 为了更好的阅读:发送 websocket 初始化消息失败，错误代码为:57 (2)，关闭 session

我真的希望有人已经成功地使用了这个库，并且可以给我一些提示或指南。任何帮助将不胜感激，并将让我有能力完成这个图书馆。

代码仍然有点乱，但如果您想全面了解我的代码，我可以上传到 GitHub。

--> 更新 :我发现了一个克服这个问题的恶作剧，我在 nopoll_conn.c 方法中注释了 N•845 nopoll_conn_shutdown(); 行，我想你已经猜到了，属于图书馆。然后进行安装，不再出现错误 57。

Answer 1

在您的示例中，我发现远程服务器正在通过报告以下错误来关闭连接:

INFO: conn=0x1238500, conn-id=2, nopoll_conn_is_ok (0x1238500)=1, nopoll_conn_is_ready (0x1238500)=1...sending content
ERROR: connection failed during msg wait, peer reported status=[1011] and reason=[java.text.ParseException: hello how are you doing, do we connect ?]

也就是说，您为此 WebSocket 发送了意外的应用程序格式，这导致连接关闭。但是，不支持 noPoll 对带有正文(包括状态代码和原因)的关闭帧的支持。

我已经更新了库，现在它得到了完全支持。您必须从此处获取库的副本(至少使用 SVN rev 227)。

• https://dolphin.aspl.es/svn/publico/nopoll/trunk/
• http://www.aspl.es/nopoll/downloads.html

除此之外，这里还有一个工作更新的示例，它直达我正在谈论的要点，还有一些功能可以让您获得远程对等方报告的状态和原因:

#include <nopoll.h>

int main (void) {

    /* init the context of the lib */
    noPollCtx     * ctx = nopoll_ctx_new(); 
    /* variable to get messages */
    noPollMsg     * msg; 
    noPollConn    * conn;

    /* nopoll_log_enable (ctx, nopoll_true);
       nopoll_log_color_enable (ctx, nopoll_true); */

    if (!ctx) {
        puts("error ctx is nill");
        return -1; /* do not continue */
    }

    /* here i target the server */
    conn = nopoll_conn_new (ctx,  "54.171.156.38" , 
                "8080" , 
                "m.zpush.ovh:8080" , 
                "ws://m.zpush.ovh:8080/str/strd", 
                NULL, "null");
    if (!nopoll_conn_wait_until_connection_ready (conn, 5) )  {
        /* here i check if the connection is ready */
        puts ("nopoll_conn failed"); 
        return -1;
    } /* end if */

    printf ("INFO: conn=%p, conn-id=%d, nopoll_conn_is_ok (%p)=%d, nopoll_conn_is_ready (%p)=%d...sending content\n",
        conn, nopoll_conn_get_id (conn), conn, 
        nopoll_conn_is_ok (conn), conn, 
        nopoll_conn_is_ready (conn));

    if (nopoll_conn_send_text (conn, "hello how are you doing, do we connect ?", 40) != 40) {
        puts("send text just failed."); 
        return - 1;
    } /* end if */

    while (nopoll_true) {

        /* the loop to receive and send messages */
        msg = nopoll_conn_get_msg(conn);
        if (msg)
            break;

        if (! nopoll_conn_is_ok (conn)) {
            printf ("ERROR: connection failed during msg wait, peer reported status=[%d] and reason=[%s]\n",
                nopoll_conn_get_close_status (conn), 
                nopoll_conn_get_close_reason (conn));

            return nopoll_false;
        }
    }

    /* close connection always */
    nopoll_conn_close (conn);
    /* release context */
    nopoll_ctx_unref (ctx);
    return 0;
}

最好的问候，