There are four types of REST methods

connect
direct invocatons
event
incoming invocations

The connect method determines behavior of all other methods.
The connect method should return in the response only those data that it really received from WCS with an exception of the case when some field in the response should be explicitly overwritten or another status must be returned.
Other methods are recommended to return in the response only those data that they received with an exception of the case when some field in the response should be explicitly overwritten or another status must be returned.
All methods should return the 200 OK HTTP status with an exception of the case when another status should be explicitly returned, for example, 403 Forbidden.

Direct invocations from WCS JavaScript API

These events may be interrupted by web server:

call - outgoing call may be forbidden
answer - incoming call answer may be forbidden
hold - call hold may be forbidden
unhold - call hold may be forbidden
transfer - call transfer may be forbidden
sendDTMF - DTMF sending may be forbidden
sendMessage - message sending may be forbidden
sendIMDN - IMDN sending may be forbidden
subscribe - SIP subscription may be forbidden
sendXcapRequest - XCAP sending may be forbidden
publishStream - stream publishing may be forbidden
playStream - stream playing may be forbidden
playHLS - HLS stream playing may be forbidden
playRTSP - RTSP stream playing may be forbidden
OnDataEvent - data sent may be rejected
sendBugReport - bug report sending may be forbidden

These events may be interrupted, but it is impractical:

hangup - call hangup may be forbidden
unPublishStream - stream unpublishing may be forbidden
stopStream - stream stopping may be forbidden

Events that have already happened and can not be forbidden by web server

This events can not be cancelled by web server because the event has already happened on WCS side, and only notification is sent to web server

ConnectionStatusEvent
RegistrationStatusEvent
CallStatusEvent
TransferStatusEvent
MessageStatusEvent
SubscriptionStatusEvent
XcapStatusEvent
StreamStatusEvent
DataStatusEvent
BugReportStatusEvent
StreamKeepAliveEvent
sendStreamEvent
StreamEvent

Incoming calls

Incoming calls may be interrupted by web server. WCS notifies caller in this case.

OnCallEvent - incoming call
OnMessageEvent - incoming message
OnTransferEvent - incoming call transfer

If REST method was initiated using REST API

If REST method of any type was initiated using REST API, it should not be declined by web server.

Actions taken when web server interaction error is occurred

An interaction error occurs when web server returns status other than 200 OK, or some error prevents access to web server. Actions taken depending on restOnError field of restClientConfig object and method type, described below:

restOnError	Connect	Direct invocations	Events	Incoming calls
FAIL	Decline Return FAIL to a client	Log the error Break execution Deliver error to a client in corresponding event	Log the error Continue execution Deliver error to a client in special event ErrorEvent	Log the error Break execution Response to caller with status 403 FORBIDDEN Deliver error to client in corresponding event
LOG	Decline Return FAIL to a client	Log the error Continue execution	Log the error Continue execution	Log the error Continue execution

Actions taken when other error is occurred

When SIP status 4xx, 5xx, 6xx is received, or other error not concerning to REST is occured, an appropriate event will be initiated with FAILED status and error description in 'info' field. This event will be delivered to web server and then to client according to the rules defined in restClientConfig.

For example, if SIP server returns 403 FORBIDDEN on outgoing call then CallStatusEvent event with status='FAILED', info='SIP 403 FORBIDDEN' and sipMessageRaw='the original SIP message' will be sent to the web server and to the client.

If the error can not be correlated with any of the existing events then ErrorEvent event will be initiated with error description in 'info' field.

Let’s review one method of each type (the remaining methods behave similarly within the corresponding type).