websocket fails in simple app after websocket is created 4 times.

[Daniel-Trevitz]

I am working on an application that uses esphttpd to provide a single webpage and uses websocket for life updating. After four connections a websocket would no longer be created.

[Daniel-Trevitz]

I'm not super motivated to find the right way to do this... My solution is as follows:

httpd.c -- perform a complete cleanup when retiring a connection
//Retires a connection for re-use
static void ICACHE_FLASH_ATTR httpdRetireConn(HttpdConnData *conn)
{
if (conn->post->buff != NULL)
os_free(conn->post->buff);

if(conn->cleanup)
    conn->cleanup(conn);

//Find the matching conndata in pool
int i;
for (i = 0; i < MAX_CONN; i++) 
{
    if (&connData[i] == conn) 
    {
        break;
    }
}

if(i < 0 || i >= MAX_CONN)
{
    os_printf("Failed to find the connection to clear\n");
}

os_memset(&connPrivData[i], 0, sizeof(HttpdPriv));
os_memset(&connData[i],     0, sizeof(HttpdConnData));
os_memset(&connPostData[i], 0, sizeof(HttpdPostData));

}

httpd.h -- Add the cleanup callback
typedef void (* cgiCleanupCallback)(HttpdConnData connData);
typedef int ( cgiSendCallback)(HttpdConnData connData);
typedef int ( cgiRecvHandler)(HttpdConnData *connData, char *data, int len);

//A struct describing a http connection. This gets passed to cgi functions.
struct HttpdConnData {
struct espconn *conn;
char requestType;
char *url;
char *getArgs;
const void *cgiArg;
void *cgiData;
void *cgiPrivData; // Used for streaming handlers storing state between requests
char *hostName;
HttpdPriv *priv;
cgiCleanupCallback cleanup;
cgiSendCallback cgi;
cgiRecvHandler recvHdl;
HttpdPostData *post;
int remote_port;
uint8 remote_ip[4];
};

cgiwebsocket.c --- Add the cleanup function and set the callback.

static void ws_cleanup()
{
llStart = NULL;
}

--- Within cgiWebsocket ---
//Set data receive handler
connData->recvHdl = cgiWebSocketRecv;
// Set the cleanup handler
connData->cleanup = ws_cleanup;

Because llStart points to data that we clean the fatal call to the websocket causes some kind of crash instead of re-initializing llStart.

If anything like that exists in the other cgi's it probabbly needs a cleanup function as well.

[Charlie-Chan]

Thanks for this, I was suffering with a similar problem - I'd found that just refreshing my browser would reliably kill the webSocket -
1/ browse to webSocket start - starts ok
2/ refresh - still ok
3/ refresh - still ok
4/ refresh - broken.

Your solution mostly fixes my problem, but not quite. The 4th refresh would still break, but a 5th would get it going again. I think that the problem is where you jump on the llStart pointer rather thank delinking the appropriate item in the linked-list. I've used exactly as you describe above, except I created a new function RemoveFromll, which is called from ws_cleanup, and I found that ws_cleanup needed to remove itself from the parent structure in case that got used reused by a handle which wasn't the same websocket (maybe it should get initialised when a socket is first connected?):

int RemoveFromll(HttpdConnData *connData)
{
    if (llStart)
    {
        if (llStart->conn==connData)
        {
            llStart=llStart->priv->next;
        }
        else
        {
            Websock *lwsPrior=NULL;
            Websock *lws=llStart;
            //Find ws that links to this one.
            while (lws!=NULL && lws->conn!=connData)
            {
                lwsPrior=lws;
                lws=lws->priv->next;
            }
            if (lwsPrior!=NULL)
            {
                lwsPrior->priv->next=lws->priv->next;
            }
            else
            {
                return 1;
            }
        }
    }
    return 0;
}

int ICACHE_FLASH_ATTR ws_cleanup(HttpdConnData *connData)
{
    int llStatus=0;
    llStatus=RemoveFromll(connData);
    connData->cleanup=0;
    return llStatus;
    }

I also commented out the linked-list removal in cgiWebsocket, because now its done in the cleanup:

int ICACHE_FLASH_ATTR cgiWebsocket(HttpdConnData *connData) {
    char buff[256];
    int i;
    sha1nfo s;
    if (connData->conn==NULL) {
        //Connection aborted. Clean up.
//      os_printf("WS: Cleanup\n");
        if (connData->cgiPrivData) {
            Websock *ws=(Websock*)connData->cgiPrivData;
            if (ws->closeCb) ws->closeCb(ws);
            //Clean up linked list
            //if (llStart==ws) {
            //  llStart=ws->priv->next;
            //} else if (llStart) {
            //  Websock *lws=llStart;
                //Find ws that links to this one.
            //  while (lws!=NULL && lws->priv->next!=ws) lws=lws->priv->next;
            //  if (lws!=NULL) lws->priv->next=ws->priv->next;
            //}
            if (ws->priv) os_free(ws->priv);
            os_free(connData->cgiPrivData);
            connData->cgiPrivData=NULL;
        }
        return HTTPD_CGI_DONE;
    }