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How to better implement the call transfer function #10

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estvita opened this issue Jan 9, 2025 · 7 comments
Open

How to better implement the call transfer function #10

estvita opened this issue Jan 9, 2025 · 7 comments

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@estvita
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estvita commented Jan 9, 2025

Hello! In my personal project, where I started using the connector, I realized I needed to implement a function to transfer a call from assistant to a live operator (or an operator queue). On the voice assistant’s side, I understand that I need to create a new “call transfer” feature, which the assistant can invoke at the subscriber’s request. This function would obtain the destination number (for example, from a database or configuration) and then instruct OpenSIPS to redirect the call. From what I’ve gathered, I can use either the callops module or the call-api module to accomplish this. Am I moving in the right direction?
@razvancrainea
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call-api/callops is not the right tool to do this, as they do not work with B2B calls - however, you can manually issue a REFER message using ua_session_update within the dialog to achieve the transfer.

@estvita
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estvita commented Jan 9, 2025

@razvancrainea
ok, thanks for the tip
i did it like this

def mi_update(params):
    resp = mi_conn.execute('ua_session_update', params)
    print(resp)

...
elif msg["name"] == "transfer_call":
    params = {
        "key": self.call.b2b_key,
        "method": "REFER",
        "body": "Refer-To: <sip:999@asterisk>\r\n"
                "Referred-By: <sip:openai@opensips>\r\n"
    }
    mi_update(params)

the request goes to asterisk, but in response I get a message about an invalid request


2025/01/09 17:52:10.651996 opensips:5060 -> asterisk:5060
REFER sip:separator@asterisk:5060 SIP/2.0
Via: SIP/2.0/UDP opensips:5060;branch=z9hG4bKf3d1.3f5ac9f7.0
To: <sip:separator@opensips>;tag=e6bf1cd2-2893-4dbe-9c49-e8fb5a066430
From: <sip:openai@opensips>;tag=B2B.9.0.1736434314.2002050160
CSeq: 2 REFER
Call-ID: dad060bb-feab-4c22-b743-4095f9c10d77
Max-Forwards: 70
Content-Length: 81
User-Agent: OpenSIPS (3.5.3 (x86_64/linux))
Content-Type: application/sdp
Contact: <sip:opensips:5060>

Refer-To: <sip:999@asterisk>
Referred-By: <sip:openai@opensips>



2025/01/09 17:52:10.652489 asterisk:5060 -> opensips:5060
SIP/2.0 400 Bad Request
Via: SIP/2.0/UDP opensips:5060;rport=5060;received=opensips;branch=z9hG4bKf3d1.3f5ac9f7.0
Call-ID: dad060bb-feab-4c22-b743-4095f9c10d77
From: <sip:openai@opensips>;tag=B2B.9.0.1736434314.2002050160
To: <sip:separator@opensips>;tag=e6bf1cd2-2893-4dbe-9c49-e8fb5a066430
CSeq: 2 REFER
Reason: Q.850;cause=16
Server: FPBX-17.0.19.23(21.5.0)
Content-Length:  0

@razvancrainea
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The Refer-To and Referred-By should not be in body, but rather in extra_headers argument of the ua_session_update MI command.
It would be nice to have the values of Refer-To configurable as well when doing the transfer. I believe the Referred-By header can be extracted from the To header of the call, right?

@estvita
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estvita commented Jan 10, 2025

yes, I understand about dynamic parameters that I will extract from headers, now I want to work out the call transfer scenario on static data

@estvita
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estvita commented Jan 11, 2025

@razvancrainea
I did the following

                elif msg["name"] == "transfer_call":
                    params = {
                        "key": self.call.b2b_key,
                        "method": "REFER",
                        "extra_headers": (
                            "Refer-To: <sip:999@asterisk>\r\n"
                            "Referred-By: <sip:openai@opensips>\r\n"
                        )
                    }
                    mi_update(params)

and this is what happens next:

2025/01/11 15:35:22.886174 opensips:5060 -> asterisk:5060
REFER sip:separator@asterisk:5060 SIP/2.0
Via: SIP/2.0/UDP opensips:5060;branch=z9hG4bK7e55.f2fc7467.0
To: <sip:separator@opensips>;tag=00e49590-18f0-48a9-a846-c7905d5d8fd2
From: <sip:openai@opensips>;tag=B2B.387.358.1736591714.815896195
CSeq: 2 REFER
Call-ID: 29ee759d-3552-4944-b120-ca8242785208
Max-Forwards: 70
Content-Length: 0
User-Agent: OpenSIPS (3.5.3 (x86_64/linux))
Content-Type: application/sdp
  1. Request-Line - REFER sip:separator@asterisk:5060 SIP/2.0 does not contain the number to which I am directing the call, it displays the name of the account in Asterisk from which the call is made
  2. no sip headers Refer-To and Referred-By which are specified in the code

@estvita
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estvita commented Jan 18, 2025

I launched the connector in debug mode, and there I see that ua_session_update passes the necessary headers (Refer-To and Referred-By ) to opensips, but for some reason opensips does not pass them to asterisk, so I get a 408 error

ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:mi_datagram:mi_datagram_callback: received 244 |{"jsonrpc": "2.0", "id": "12979", "method": "ua_session_update", "params": {"key": "B2B.267.105.1737119835.749594385", "method": "REFER", "extra_headers": "Refer-To: <sip:999@asterisk_ip>\r\nReferred-By: <sip:openai@opensips_ip>\r\n"}}|
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:b2b_entities:b2b_parse_key: hash_index = [267]  - local_index= [105]
ai-voice-connector-engine    | 2025-01-17 13:17:22,064 - tid: 140368651212608 - INFO - response.output_item.done
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:b2b_entities:b2b_parse_key: hash_index = [267]  - local_index= [105]
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:b2b_entities:_b2b_send_request: Send request [REFER] for entity type [0] for dlg[0x7fa5682de740]->[B2B.267.105.1737119835.749594385]
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:tm:t_uac: next_hop=<sip:asterisk@asterisk_ip:5060>
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:core:mk_proxy: doing DNS lookup...
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:tm:t_uac: sending socket is opensips_ip 
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:tm:print_request_uri: sip:asterisk@asterisk_ip:5060
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:tm:set_timer: relative timeout is 500000
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:tm:insert_timer_unsafe: [4]: 0x7fa5682e0ab0 (21300000)
ai-voice-connector-engine    | 2025-01-17 13:17:22,074 - tid: 140368651212608 - INFO - response.done
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:tm:insert_timer_unsafe: [0]: 0x7fa5682e0ae0 (22)
ai-voice-connector-opensips  | Jan 17 13:17:22 [8] DBG:mi_datagram:mi_datagram_callback: the response: {"jsonrpc":"2.0","result":"OK","id":"12979"} has been sent in 44 octets
ai-voice-connector-opensips  | Jan 17 13:17:22 [66] DBG:tm:utimer_routine: timer routine:4,tl=0x7fa5682e0ab0 next=(nil), timeout=21300000
ai-voice-connector-opensips  | Jan 17 13:17:22 [66] DBG:tm:retransmission_handler: retransmission_handler : request resending (t=0x7fa5682e0890, REFER sip ... )
ai-voice-connector-opensips  | Jan 17 13:17:22 [66] DBG:tm:set_timer: relative timeout is 1000000
ai-voice-connector-opensips  | Jan 17 13:17:22 [66] DBG:tm:insert_timer_unsafe: [5]: 0x7fa5682e0ab0 (22300000)
ai-voice-connector-opensips  | Jan 17 13:17:22 [66] DBG:tm:retransmission_handler: retransmission_handler : done
ai-voice-connector-engine    | 2025-01-17 13:17:22,813 - tid: 140368651212608 - INFO - Speaker: Please connect me to the operator
ai-voice-connector-opensips  | Jan 17 13:17:23 [55] DBG:tm:utimer_routine: timer routine:5,tl=0x7fa5682e0ab0 next=(nil), timeout=22300000
ai-voice-connector-opensips  | Jan 17 13:17:23 [55] DBG:tm:retransmission_handler: retransmission_handler : request resending (t=0x7fa5682e0890, REFER sip ... )
ai-voice-connector-opensips  | Jan 17 13:17:23 [55] DBG:tm:set_timer: relative timeout is 2000000
ai-voice-connector-opensips  | Jan 17 13:17:23 [55] DBG:tm:insert_timer_unsafe: [6]: 0x7fa5682e0ab0 (24300000)
ai-voice-connector-opensips  | Jan 17 13:17:23 [55] DBG:tm:retransmission_handler: retransmission_handler : done
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:timer_routine: timer routine:0,tl=0x7fa5682e0ae0 next=(nil), timeout=22
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:final_response_handler: Cancel sent out, sending 408 (0x7fa5682e0890)
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:t_should_relay_response: T_code=0, new_code=408
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:t_pick_branch: picked branch 0, code 408 (prio=800)
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:is_3263_failure: dns-failover test: branch=0, last_recv=408, flags=0
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:t_should_relay_response: trying DNS-based failover
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:local_reply: branch=0, save=0, winner=0
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:local_reply: local transaction completed
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:run_any_trans_callbacks: trans=0x7fa5682e0890, callback type 256, id 0 entered
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:b2b_entities:b2b_tm_cback: tm [0x7fa5682e0890] notification cb for [408] reply
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:b2b_entities:b2b_parse_key: hash_index = [267]  - local_index= [105]
ai-voice-connector-engine    | 2025-01-17 13:17:23,942 - tid: 140368651212608 - ERROR - Failed to send reply: Error executing command: 500: Failed to send reply
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:b2b_entities:b2b_tm_cback: Received reply [408] for dialog [0x7fa5682de740], method [REFER]
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_to_param: tag=809b5324-c0a9-4cf4-8fba-e741a6f122d7
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_to_param: end of header reached, state=11
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:_parse_to: end of header reached, state=29
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:_parse_to: display={"990"}, ruri={sip:990@asterisk_ip}
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_to_param: tag=B2B.267.105.1737119835.749594385
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_to_param: end of header reached, state=13
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:_parse_to: end of header reached, state=29
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:_parse_to: display={}, ruri={sip:openai@opensips_ip}
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str key='B2B.267.105.1737119835.749594385'
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str entity_type='UAS'
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str event_type='REJECTED'
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str method='REFER'
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set int status=408
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str reason='Timeout'
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str body=''
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_headers_aux: flags=ffffffffffffffff
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str headers='From: <sip:openai@opensips_ip>;tag=B2B.267.105.1737119835.749594385
ai-voice-connector-opensips  | '
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_param_set: set str extra_params=''
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:get_dummy_sip_msg: allocating new sip msg
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_msg: SIP Request:
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_msg:  method:  <DUMMY>
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_msg:  uri:     <sip:[email protected]>
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_msg:  version: <SIP/2.0>
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_headers_aux: flags=ffffffffffffffff
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_via_param: found param type 232, <branch> = <z9hG4bKdummy>; state=16
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_via: end of header reached, state=5
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_headers_aux: via found, flags=ffffffffffffffff
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_headers_aux: this is the first via
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:_parse_to: end of header reached, state=10
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:_parse_to: display={}, ruri={sip:[email protected]}
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:get_hdr_field_aux: <To> [20]; uri=[sip:[email protected]] 
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:get_hdr_field_aux: to body [<sip:[email protected]>
ai-voice-connector-opensips  | ]
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:get_hdr_field_aux: cseq <CSeq>: <1> <DUMMY>
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:get_hdr_field_aux: found end of header
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:parse_headers_aux: flags=ffffffffffffffff
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:get_dummy_sip_msg: setting as static to 0x7fa56a158448
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:evi_raise_event_msg: found subscriber 127.0.0.1
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:release_dummy_sip_msg: cleaning the static sip msg 0x7fa56a158448
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:core:destroy_avp_list: destroying list (nil)
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:insert_timer_unsafe: [2]: 0x7fa5682e0910 (27)
ai-voice-connector-opensips  | Jan 17 13:17:23 [13] DBG:tm:final_response_handler: done
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] DBG:mi_datagram:mi_datagram_callback: received 184 |{"jsonrpc": "2.0", "id": "32236", "method": "ua_session_reply", "params": {"key": "B2B.267.105.1737119835.749594385", "method": "REFER", "code": 405, "reason": "Method not supported"}}|
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] DBG:b2b_entities:b2b_parse_key: hash_index = [267]  - local_index= [105]
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] DBG:b2b_entities:_b2b_send_reply: For server entity
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] DBG:b2b_entities:b2b_parse_key: hash_index = [267]  - local_index= [105]
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] DBG:b2b_entities:_b2b_send_reply: code = 405, last_method= 4096
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] ERROR:b2b_entities:_b2b_send_reply: Tm transaction not saved!
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] ERROR:b2b_entities:b2b_ua_mi_reply: Failed to send reply
ai-voice-connector-opensips  | Jan 17 13:17:23 [8] DBG:mi_datagram:mi_datagram_callback: the response: {"jsonrpc":"2.0","error":{"code":500,"message":"Failed to send reply"},"id":"32236"} has been sent in 84 octets

@estvita
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estvita commented Jan 26, 2025

hi
i found a temporary solution - if i substitute an empty parameter "body" then the extra_headers Refer-To and Referred-By are passed in the request

elif msg["name"] == "transfer_call":
    params = {
        'key': self.call.b2b_key,
        'method': "REFER",
        'extra_headers': ( "Refer-To: <sip:999@asterisk>\r\n"
                            "Referred-By: <sip:openai@opensips>\r\n"),
        'body': ""
    }
    mi_conn.execute('ua_session_update', params)

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@razvancrainea @estvita