Dialogic Global Call IP Benutzerhandbuch

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4.14.4
Receiving Responses to OPTIONS Requests
When the Dialogic
®
 Global Call API library’s SIP stack receives a response to a SIP OPTIONS 
request, it generates a GCEV_EXTENSION event of type IPEXTID_RECEIVEMSG. 
The GC_PARM_BLK associated with the Extension event will contain a parameter element as 
follows:
IPSET_MSG_SIP
IPPARM_MSGTYPE parameter ID
and one of the following values:
IP_MSGTYPE_SIP_OPTIONS_OK
IP_MSGTYPE_SIP_OPTIONS_FAILED
The application can also retrieve the specific SIP response code from the event’s parameter block 
using the IPSET_MSG_SIP set ID and the IPPARM_MSG_SIP_RESPONSE_CODE parameter 
ID.
In the case of an IP_MSGTYPE_SIP_OPTIONS_OK response, the application can use the 
techniques described in 
 to retrieve message 
header fields of interest, including:
Request-URI 
To header field 
From header field 
Contact URI 
Accept header field 
Accept-encoding header field 
Accept-language header field 
Supported header field 
Allow header field 
Require header field 
Call-ID header field 
The application can also extract any MIME information from the message body using the 
techniques described in 
responses to OPTIONS requests are the single case where the MIME part containing SDP 
information is exposed to the application rather than handled internally by the Dialogic
®
 Global 
Call API library. The SDP information is identified by the string “Content-Type: application/sdp”.
In the case of an IP_MSGTYPE_SIP_OPTIONS_FAILED response, the application can use the 
techniques described in 
 to retrieve the 
following message header fields:
Request-URI 
To header field 
From header field