Append HF don't work in event_route

[Eulnono76]

Description

Hello,

I'm trying to connect kamailio to Microsoft Teams.
Dispatch is correctly configured and send SIP OPTION correctly.
Following this tutorial : https://skalatan.de/en/blog/kamailio-sbc-teams, I added an Event_Route to add contact header to SIP OPTION from dispath to MS :

event_route[tm:local-request] {
xlog("*** tm:local-request *** ");
if(is_method("OPTIONS") && $ru =~ "pstnhub.microsoft.com") {
xlog("L_INFO", "Append new contact !\n");
append_hf("Contact: sip:MY_SBC_NAME.COM:5061;transport=tls\r\n");
}
xlog("L_INFO", "Sent out tm request: $mb\n");
}

When I check the log to see my sended frame, I don't see a contact header field :
INFO: <script>: Append new contact !
INFO: <script>: Sent out tm request :
OPTIONS sip:sip.pstnhub.microsoft.com;transport=tls SIP/2.0
Via: SIP/2.0/TLS MY_SBC_NAME.COM:5061;branch=z9hG4bK4497.f3e5e754000000000000000000000000.0
To: sip:sip.pstnhub.microsoft.com;transport=tls
From: sip:MY_SBC_NAME.COM.fr;tag=a76e006ace3802951ed860e08df964af-7971
CSeq: 10 OPTIONS
Call-ID: 2e1278ea77796160-9837@MY_SBC_IP
Max-Forwards: 70
Content-Length: 0
User-Agent: kamailio (5.2.1 (x86_64/linux))

According the documentation about textop, append_hf(txt[, hdr]) :
This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

So my question is append HF can be used in Event_route ?
Is there any other way to add contact header ?

Regards,
Arnaud

Troubleshooting

Reproduction

Can be easily reproducted with the following code (don t forget to set SBC NAME)

event_route[tm:local-request] {
xlog("*** tm:local-request *** ");
if(is_method("OPTIONS") && $ru =~ "pstnhub.microsoft.com") {
xlog("L_INFO", "Append new contact !\n");
append_hf("Contact: sip:MY_SBC_NAME.COM:5061;transport=tls\r\n");
}
xlog("L_INFO", "Sent out tm request: $mb\n");
}

Log Messages

INFO: <script>: Append new contact !
INFO: <script>: Sent out tm request :
OPTIONS sip:sip.pstnhub.microsoft.com;transport=tls SIP/2.0
Via: SIP/2.0/TLS MY_SBC_NAME.COM:5061;branch=z9hG4bK4497.f3e5e754000000000000000000000000.0
To: sip:sip.pstnhub.microsoft.com;transport=tls
From: sip:MY_SBC_NAME.COM.fr;tag=a76e006ace3802951ed860e08df964af-7971
CSeq: 10 OPTIONS
Call-ID: 2e1278ea77796160-9837@MY_SBC_IP
Max-Forwards: 70
Content-Length: 0
User-Agent: kamailio (5.2.1 (x86_64/linux))

#### SIP Traffic

Traffic is in TLS, can't be easily readed.

### Additional Information

version: kamailio 5.3.9 (x86_64/linux) a5fd0a
flags: USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES, TLS_PTHREAD_MUTEX_SHARED
ADAPTIVE_WAIT_LOOPS 1024, MAX_RECV_BUFFER_SIZE 262144, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
id: a5fd0a
compiled on 15:59:30 Jan 10 2022 with gcc 8.3.0

* **Operating System**:

No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 10 (buster)
Release:        10
Codename:       buster

Linux debian 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux

[henningw]

The bug tracker is for tracking of bugs in Kamailio, not for discussing user related questions. Please contact our sr-users list instead.
The append_hf can be used in event_route. If you want to see it in logs, you could use the textops msg_apply_changes() function.

[Eulnono76]

Didn't try to see it in log, I see the complete frame with $mb and I see my append is missing.
Also when I try msg_apply_changes(), getting unknown command, missing loadmodule, textops is correctly loaded (loadmodule "textops.so").
Are you really sure there is no issue ?

[henningw]

https://www.kamailio.org/docs/modules/devel/modules/textopsx.html#textopsx.f.msg_apply_changes

[Eulnono76]

when I try msg_apply_changes(), getting unknown command, missing loadmodule, textops is correctly loaded (loadmodule "textops.so").

[henningw]

Please read the quoted link, its textopsx module. For more question please consult the mailing list.