[SR-Users] Re: evapi not processing received messages

Message boundary challenges are an innate part of the architecture of raw TCP services. How does Kamailio know when a complete message has been read from the socket, with a transport where the number of bytes available for reading is decoupled from message delimiters?

Normally, CRLF/newline would be the expected delimiter, and I would guess that's true of EVAPI too. If your Python script's responses aren't terminated with a newline, I would guess that they probably need to be.

However, I haven't run into this issue because I use the netstring approach to the boundary problem:

https://kamailio.org/docs/modules/5.8.x/modules/evapi.html#evapi.p.netstring...

-- Alex

On Jan 8, 2025, at 12:25 pm, Sergio Charrua via sr-users sr-users@lists.kamailio.org wrote:

Hi all!

I have implemented evapi module on Kamailio 5.8.4, calling a python script. Python script is listening to a socket. It receives messages (JSON) from Kamailio, makes an HTTP request somewhere, and sends the response back to Kamailio. The Python script is working fine: it connects to Kamailio, sends HTTP requests, and forwards a response back to Kamailio: I have confirmed using TCPDump that, in fact, the data is received and forwarded back. However, despite showing messages that the Python client script is correctly connected to Kamailio, the event_route[evapi:message-received] is never executed.

Probably there is some detail that I am missing, but the docs and online info for evapi are very rare, and they all show very similar configuration. And as I wrote, I have confirmed using TCPDump that the data is received from Python client script to Kamailio node. What am I missing?

This is my Kamailio cfg:

[loads modules] [sets modparams]

modparam("evapi","bind_addr","10.20.20.1:8888")

debug=2 children=16 log_facility=LOG_LOCAL0 log_prefix="{$mt $hdr(CSeq) $ci} " disable_sctp = yes force_rport = yes rundir="/tmp"

request_route {

    if ( is_method("ACK") ) {
            if ( t_check_trans() ) {
                t_relay();
            }
            exit;
    }

    if(is_method("OPTIONS")){
            sl_reply("200", "OK");
            exit;
    }

    if(is_method("CANCEL")){
            sl_reply("200","OK");
            sl_reply("487","Request Terminated");
            exit;
    }

    route(TOEVAPI);
   exit;

}

event_route[evapi:connection-new] { xlog("LINFO","new connection from [$evapi(srcaddr):$evapi(srcport)]\n"); if($evapi(srcaddr)!="10.20.0.1") { evapi_close(); exit; } }

event_route[evapi:connection-closed] { xlog("LINFO","connection closed by $evapi(srcaddr):$evapi(srcport)\n"); }

event_route[evapi:message-received] { xlog("LINFO","received [$evapi(msg)] from $evapi(srcaddr):$evapi(srcport)\n"); jansson_get("t-index", "$evapi(msg)", "$var(t-index)"); jansson_get("t-label", "$evapi(msg)", "$var(t-label)"); $var(evmsg) = $evapi(msg); xlog("L_INFO", "preparing to resume transaction for processing: $var(tindex) / $var(tlabel)\n"); t_continue("$var(tindex)", "$var(tlabel)", "EVAPIRESPONSE"); }

route[EVAPIRESPONSE] { xlog("L_INFO", "resumed transaction for processing: $T(id_index) / $T(id_label)\n"); [do stuff] }

route[TOEVAPI]{

    xlog("L_INFO", "suspended transaction: $T(id_index) / $T(id_label)\n");

    evapi_async_relay( [some JSON string] );

    exit;

}

Thanks in advance!

Atenciosamente / Kind Regards / Cordialement / Un saludo,

Sérgio Charrua __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- sr-users@lists.kamailio.org To unsubscribe send an email to sr-users-leave@lists.kamailio.org Important: keep the mailing list in the recipients, do not reply only to the sender!