How to control and steer calls with Call Automation

Call Automation uses a REST API interface to receive requests for actions and provide responses to notify whether the request was successfully submitted or not. Due to the asynchronous nature of calling, most actions have corresponding events that are triggered when the action completes successfully or fails. This guide covers the actions available for steering calls, like CreateCall, Transfer, Redirect, and managing participants. Actions are accompanied with sample code on how to invoke the said action and sequence diagrams describing the events expected after invoking an action. These diagrams help you visualize how to program your service application with Call Automation.

Call Automation supports various other actions to manage call media and recording that have separate guides.

Note

Call Automation currently doesn't support Rooms calls.

As a prerequisite, we recommend you to read these articles to make the most of this guide:

1. Call Automation concepts guide that describes the action-event programming model and event callbacks.
2. Learn about user identifiers like CommunicationUserIdentifier and PhoneNumberIdentifier used in this guide.

For all the code samples, client is CallAutomationClient object that can be created as shown and callConnection is the CallConnection object obtained from Answer or CreateCall response. You can also obtain it from callback events received by your application.

csharp

var client = new CallAutomationClient("<resource_connection_string>"); 

Java

 CallAutomationClient client = new CallAutomationClientBuilder().connectionString("<resource_connection_string>").buildClient();

JavaScript

const client = new CallAutomationClient("<resource_connection_string>");

Python

call_automation_client = CallAutomationClient.from_connection_string("<resource_connection_string>")

Make an outbound call

You can place a 1:1 or group call to a communication user or phone number (public or Communication Services owned number). When calling a PSTN endpoint, you also need to provide a phone number that is used as the source caller ID and shown in the call notification to the target PSTN endpoint. To place a call to a Communication Services user, you need to provide a CommunicationUserIdentifier object instead of PhoneNumberIdentifier.

csharp

Uri callbackUri = new Uri("https://<myendpoint>/Events"); //the callback endpoint where you want to receive subsequent events 
var callerIdNumber = new PhoneNumberIdentifier("+16044561234"); // This is the Azure Communication Services provisioned phone number for the caller  
var callThisPerson = new CallInvite(new PhoneNumberIdentifier("+16041234567"), callerIdNumber); // person to call
CreateCallResult response = await client.CreateCallAsync(callThisPerson, callbackUri);

Java

String callbackUri = "https://<myendpoint>/Events"; //the callback endpoint where you want to receive subsequent events
PhoneNumberIdentifier callerIdNumber = new PhoneNumberIdentifier("+18001234567"); // This is the Azure Communication Services provisioned phone number for the caller  
CallInvite callInvite = new CallInvite(new PhoneNumberIdentifier("+16471234567"), callerIdNumber); // person to call
CreateCallResult response = client.createCall(callInvite, callbackUri).block();

JavaScript

const callInvite = {
    targetParticipant: { phoneNumber: "+18008008800" }, // person to call
    sourceCallIdNumber: { phoneNumber: "+18888888888" } // This is the Azure Communication Services provisioned phone number for the caller
};
const callbackUri = "https://<myendpoint>/Events"; // the callback endpoint where you want to receive subsequent events 
const response = await client.createCall(callInvite, callbackUri);

Python

callback_uri = "https://<myendpoint>/Events"  # the callback endpoint where you want to receive subsequent events
caller_id_number = PhoneNumberIdentifier(
    "+18001234567"
)  # This is the Azure Communication Services provisioned phone number for the caller
call_invite = CallInvite(
    target=PhoneNumberIdentifier("+16471234567"),
    source_caller_id_number=caller_id_number,
)
call_connection_properties = client.create_call(call_invite, callback_uri)

When making a group call that includes a phone number, you must provide a phone number that is used as a caller ID number to the PSTN endpoint.

csharp

Uri callbackUri = new Uri("https://<myendpoint>/Events"); //the callback endpoint where you want to receive subsequent events 
var pstnEndpoint = new PhoneNumberIdentifier("+16041234567");
var voipEndpoint = new CommunicationUserIdentifier("<user_id_of_target>"); //user id looks like 8:a1b1c1-...
var groupCallOptions = new CreateGroupCallOptions(new List<CommunicationIdentifier>{ pstnEndpoint, voipEndpoint }, callbackUri)
{
    SourceCallerIdNumber = new PhoneNumberIdentifier("+16044561234"), // This is the Azure Communication Services provisioned phone number for the caller
};
CreateCallResult response = await client.CreateGroupCallAsync(groupCallOptions);

Java

String callbackUri = "https://<myendpoint>/Events"; //the callback endpoint where you want to receive subsequent events
PhoneNumberIdentifier callerIdNumber = new PhoneNumberIdentifier("+18001234567"); // This is the Azure Communication Services provisioned phone number for the caller
List<CommunicationIdentifier> targets = new ArrayList<>(Arrays.asList(new PhoneNumberIdentifier("+16471234567"), new CommunicationUserIdentifier("<user_id_of_target>")));
CreateGroupCallOptions groupCallOptions = new CreateGroupCallOptions(targets, callbackUri);
groupCallOptions.setSourceCallIdNumber(callerIdNumber);
Response<CreateCallResult> response = client.createGroupCallWithResponse(createGroupCallOptions).block();

JavaScript

const callbackUri = "https://<myendpoint>/Events"; // the callback endpoint where you want to receive subsequent events 
const participants = [
    { phoneNumber: "+18008008800" },
    { communicationUserId: "<user_id_of_target>" }, //user id looks like 8:a1b1c1-...
];
const createCallOptions = {
    sourceCallIdNumber: { phoneNumber: "+18888888888" }, // This is the Azure Communication Services provisioned phone number for the caller
};
const response = await client.createGroupCall(participants, callbackUri, createCallOptions);

Python

callback_uri = "https://<myendpoint>/Events"  # the callback endpoint where you want to receive subsequent events
caller_id_number = PhoneNumberIdentifier(
    "+18888888888"
)  # This is the Azure Communication Services provisioned phone number for the caller
pstn_endpoint = PhoneNumberIdentifier("+18008008800")
voip_endpoint = CommunicationUserIdentifier(
    "<user_id_of_target>"
)  # user id looks like 8:a1b1c1-...
call_connection_properties = client.create_group_call(
    target_participants=[voip_endpoint, pstn_endpoint],
    callback_url=callback_uri,
    source_caller_id_number=caller_id_number,
)

The response provides you with CallConnection object that you can use to take further actions on this call once it's connected. Once the call is answered, two events are published to the callback endpoint you provided earlier:

1. CallConnected event notifying that the call has been established with the callee.
2. ParticipantsUpdated event that contains the latest list of participants in the call.

Answer an incoming call

Once you've subscribed to receive incoming call notifications to your resource, you will answer an incoming call. When answering a call, it's necessary to provide a callback url. Communication Services post all subsequent events about this call to that url.

csharp

string incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>"; 
Uri callBackUri = new Uri("https://<myendpoint_where_I_want_to_receive_callback_events"); 

var answerCallOptions = new AnswerCallOptions(incomingCallContext, callBackUri);  
AnswerCallResult answerResponse = await client.AnswerCallAsync(answerCallOptions);
CallConnection callConnection = answerResponse.CallConnection; 

Java

String incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>";
String callbackUri = "https://<myendpoint>/Events"; 
 
AnswerCallOptions answerCallOptions = new AnswerCallOptions(incomingCallContext, callbackUri); 
Response<AnswerCallResult> response = client.answerCallWithResponse(answerCallOptions).block(); 

JavaScript

const incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>";
const callbackUri = "https://<myendpoint>/Events";

const { callConnection } = await client.answerCall(incomingCallContext, callbackUri);

Python

incoming_call_context = "<IncomingCallContext_From_IncomingCall_Event>"
callback_uri = "https://<myendpoint>/Events"  # the callback endpoint where you want to receive subsequent events
call_connection_properties = client.answer_call(
    incoming_call_context=incoming_call_context, callback_url=callback_uri
)

The response provides you with CallConnection object that you can use to take further actions on this call once it's connected. Once the call is answered, two events are published to the callback endpoint you provided earlier:

1. CallConnected event notifying that the call has been established with the caller.
2. ParticipantsUpdated event that contains the latest list of participants in the call.

Reject a call

You can choose to reject an incoming call as shown below. You can provide a reject reason: none, busy or forbidden. If nothing is provided, none is chosen by default.

csharp

string incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>"; 
var rejectOption = new RejectCallOptions(incomingCallContext); 
rejectOption.CallRejectReason = CallRejectReason.Forbidden; 
_ = await client.RejectCallAsync(rejectOption); 

Java

String incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>";  
RejectCallOptions rejectCallOptions = new RejectCallOptions(incomingCallContext) 
        .setCallRejectReason(CallRejectReason.BUSY); 
Response<Void> response = client.rejectCallWithResponse(rejectCallOptions).block(); 

JavaScript

const incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>";
const rejectOptions = {
    callRejectReason: KnownCallRejectReason.Forbidden,
};
await client.rejectCall(incomingCallContext, rejectOptions);

Python

incoming_call_context = "<IncomingCallContext_From_IncomingCall_Event>"
client.reject_call(
    incoming_call_context=incoming_call_context,
    call_reject_reason=CallRejectReason.FORBIDDEN,
)

No events are published for reject action.

Redirect a call

You can choose to redirect an incoming call to another endpoint without answering it. Redirecting a call removes your application's ability to control the call using Call Automation.

csharp

string incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>"; 
var target = new CallInvite(new CommunicationUserIdentifier("<user_id_of_target>")); //user id looks like 8:a1b1c1-... 
_ = await client.RedirectCallAsync(incomingCallContext, target); 

Java

String incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>"; 
CallInvite target = new CallInvite(new CommunicationUserIdentifier("<user_id_of_target>")); //user id looks like 8:a1b1c1-... 
RedirectCallOptions redirectCallOptions = new RedirectCallOptions(incomingCallContext, target); 
Response<Void> response = client.redirectCallWithResponse(redirectCallOptions).block();

JavaScript

const incomingCallContext = "<IncomingCallContext_From_IncomingCall_Event>";
const target = { targetParticipant: { communicationUserId: "<user_id_of_target>" } }; //user id looks like 8:a1b1c1-...
await client.redirectCall(incomingCallContext, target);

Python

incoming_call_context = "<IncomingCallContext_From_IncomingCall_Event>"
call_invite = CallInvite(
    CommunicationUserIdentifier("<user_id_of_target>")
  )  # user id looks like 8:a1b1c1-...
client.redirect_call(
    incoming_call_context=incoming_call_context, target_participant=call_invite
)

To redirect the call to a phone number, construct the target and caller ID with PhoneNumberIdentifier.

csharp

var callerIdNumber = new PhoneNumberIdentifier("+16044561234"); // This is the Azure Communication Services provisioned phone number for the caller
var target = new CallInvite(new PhoneNumberIdentifier("+16041234567"), callerIdNumber);

Java

PhoneNumberIdentifier callerIdNumber = new PhoneNumberIdentifier("+16044561234"); // This is the Azure Communication Services provisioned phone number for the caller
CallInvite target = new CallInvite(new PhoneNumberIdentifier("+18001234567"), callerIdNumber);

JavaScript

const callerIdNumber = { phoneNumber: "+16044561234" };
const target = {
    targetParticipant: { phoneNumber: "+16041234567" }, 
    sourceCallIdNumber: callerIdNumber,
};

Python

caller_id_number = PhoneNumberIdentifier(
    "+18888888888"
)  # This is the Azure Communication Services provisioned phone number for the caller
call_invite = CallInvite(
    target=PhoneNumberIdentifier("+16471234567"),
    source_caller_id_number=caller_id_number,
)

No events are published for redirect. If the target is a Communication Services user or a phone number owned by your resource, it generates a new IncomingCall event with 'to' field set to the target you specified.

Transfer a participant in call

When your application answers a call or places an outbound call to an endpoint, that endpoint can be transferred to another destination endpoint. Transferring a 1:1 call removes your application from the call and hence remove its ability to control the call using Call Automation. The call invite to the target will display the caller ID of the endpoint being transferred. Providing a custom caller ID is not supported.

csharp

var transferDestination = new CommunicationUserIdentifier("<user_id>"); 
var transferOption = new TransferToParticipantOptions(transferDestination) {
    OperationContext = "<Your_context>",
    OperationCallbackUri = new Uri("<uri_endpoint>") // Sending event to a non-default endpoint.
};
// adding customCallingContext
transferOption.CustomCallingContext.AddVoip("customVoipHeader1", "customVoipHeaderValue1");
transferOption.CustomCallingContext.AddVoip("customVoipHeader2", "customVoipHeaderValue2");

TransferCallToParticipantResult result = await callConnection.TransferCallToParticipantAsync(transferOption);

Java

CommunicationIdentifier transferDestination = new CommunicationUserIdentifier("<user_id>");
TransferCallToParticipantOptions options = new TransferCallToParticipantOptions(transferDestination)
                .setOperationContext("<operation_context>")
                .setOperationCallbackUrl("<url_endpoint>"); // Sending event to a non-default endpoint.
// set customCallingContext
options.getCustomCallingContext().addVoip("voipHeaderName", "voipHeaderValue");

Response<TransferCallResult> transferResponse = callConnectionAsync.transferToParticipantCallWithResponse(options).block();

JavaScript

const transferDestination = { communicationUserId: "<user_id>" };
const options = { operationContext: "<Your_context>", operationCallbackUrl: "<url_endpoint>" };
// adding customCallingContext
const customCallingContext: CustomCallingContext = [];
customCallingContext.push({ kind: "voip", key: "customVoipHeader1", value: "customVoipHeaderValue1" })
options.customCallingContext = customCallingContext;

const result = await callConnection.transferCallToParticipant(transferDestination, options);

Python

transfer_destination = CommunicationUserIdentifier("<user_id>")
call_connection_client = call_automation_client.get_call_connection("<call_connection_id_from_ongoing_call>")
# set custom context
voip_headers = {"customVoipHeader1", "customVoipHeaderValue1"}

result = call_connection_client.transfer_call_to_participant(
    target_participant=transfer_destination,
    voip_headers=voip_headers,
    opration_context="Your context",
    operationCallbackUrl="<url_endpoint>"
)

When your application answers a group call or places an outbound group call to an endpoint or added a participant to a 1:1 call, an endpoint can be transferred from the call to another destination endpoint, except call automation endpoint. Transferring a participant in a group call removes the endpoint being transferred from the call. The call invite to the target will display the caller ID of the endpoint being transferred. Providing a custom caller ID is not supported.

csharp

// Transfer User
var transferDestination = new CommunicationUserIdentifier("<user_id>");
var transferee = new CommunicationUserIdentifier("<transferee_user_id>"); 
var transferOption = new TransferToParticipantOptions(transferDestination);
transferOption.Transferee = transferee;

// adding customCallingContext
transferOption.CustomCallingContext.AddVoip("customVoipHeader1", "customVoipHeaderValue1");
transferOption.CustomCallingContext.AddVoip("customVoipHeader2", "customVoipHeaderValue2");

transferOption.OperationContext = "<Your_context>";
transferOption.OperationCallbackUri = new Uri("<uri_endpoint>");
TransferCallToParticipantResult result = await callConnection.TransferCallToParticipantAsync(transferOption);

// Transfer PSTN User
var transferDestination = new PhoneNumberIdentifier("<target_phoneNumber>");
var transferee = new PhoneNumberIdentifier("<transferee_phoneNumber>"); 
var transferOption = new TransferToParticipantOptions(transferDestination);
transferOption.Transferee = transferee;

// adding customCallingContext
transferOption.CustomCallingContext.AddSipUui("uuivalue");
transferOption.CustomCallingContext.AddSipX("header1", "headerValue");

transferOption.OperationContext = "<Your_context>";

// Sending event to a non-default endpoint.
transferOption.OperationCallbackUri = new Uri("<uri_endpoint>");

TransferCallToParticipantResult result = await callConnection.TransferCallToParticipantAsync(transferOption);

Java

// Transfer User
CommunicationIdentifier transferDestination = new CommunicationUserIdentifier("<user_id>");
CommunicationIdentifier transferee = new CommunicationUserIdentifier("<transferee_user_id>"); 
TransferCallToParticipantOptions options = new TransferCallToParticipantOptions(transferDestination);
options.setTransferee(transferee);
options.setOperationContext("<Your_context>");
options.setOperationCallbackUrl("<url_endpoint>");

// set customCallingContext
options.getCustomCallingContext().addVoip("voipHeaderName", "voipHeaderValue");

Response<TransferCallResult> transferResponse = callConnectionAsync.transferToParticipantCallWithResponse(options).block();

// Transfer Pstn User
CommunicationIdentifier transferDestination = new PhoneNumberIdentifier("<taget_phoneNumber>");
CommunicationIdentifier transferee = new PhoneNumberIdentifier("<transferee_phoneNumber>"); 
TransferCallToParticipantOptions options = new TransferCallToParticipantOptions(transferDestination);
options.setTransferee(transferee);
options.setOperationContext("<Your_context>");
options.setOperationCallbackUrl("<url_endpoint>");

// set customCallingContext
options.getCustomCallingContext().addSipUui("UUIvalue");
options.getCustomCallingContext().addSipX("sipHeaderName", "value");

Response<TransferCallResult> transferResponse = callConnectionAsync.transferToParticipantCallWithResponse(options).block();

JavaScript

// Transfer User
const transferDestination = { communicationUserId: "<user_id>" };
const transferee = { communicationUserId: "<transferee_user_id>" };
const options = { transferee: transferee, operationContext: "<Your_context>", operationCallbackUrl: "<url_endpoint>" };

// adding customCallingContext
const customCallingContext: CustomCallingContext = [];
customContext.push({ kind: "voip", key: "customVoipHeader1", value: "customVoipHeaderValue1" })
options.customCallingContext = customCallingContext;

const result = await callConnection.transferCallToParticipant(transferDestination, options);

// Transfer pstn User
const transferDestination = { phoneNumber: "<taget_phoneNumber>" };
const transferee = { phoneNumber: "<transferee_phoneNumber>" };
const options = { transferee: transferee, operationContext: "<Your_context>", operationCallbackUrl: "<url_endpoint>" };

// adding customCallingContext
const customCallingContext: CustomCallingContext = [];
customContext.push({ kind: "sipuui", key: "", value: "uuivalue" });
customContext.push({ kind: "sipx", key: "headerName", value: "headerValue" })
options.customCallingContext = customCallingContext;

const result = await callConnection.transferCallToParticipant(transferDestination, options);

Python

# Transfer to user
transfer_destination = CommunicationUserIdentifier("<user_id>")
transferee = CommnunicationUserIdentifer("transferee_user_id")
call_connection_client = call_automation_client.get_call_connection("<call_connection_id_from_ongoing_call>")

# create custom context
voip_headers = {"customVoipHeader1", "customVoipHeaderValue1"}

result = call_connection_client.transfer_call_to_participant(
    target_participant=transfer_destination,
    transferee=transferee,
    voip_headers=voip_headers,
    opration_context="Your context",
    operationCallbackUrl="<url_endpoint>"
)

# Transfer to PSTN user
transfer_destination = PhoneNumberIdentifer("<target_phoneNumber>")
transferee = PhoneNumberIdentifer("transferee_phoneNumber")

# create custom context
sip_headers={}
sip_headers.add("X-MS-Custom-headerName", "headerValue")
sip_headers.add("User-To-User","uuivale")

call_connection_client = call_automation_client.get_call_connection("<call_connection_id_from_ongoing_call>")
result = call_connection_client.transfer_call_to_participant(
    target_participant=transfer_destination,
    transferee=transferee,
    sip_headers=sip_headers,
    opration_context="Your context",
    operationCallbackUrl="<url_endpoint>"
)

The sequence diagram shows the expected flow when your application places an outbound call and then transfers it to another endpoint.

Add a participant to a call

You can add a participant (Communication Services user or phone number) to an existing call. When adding a phone number, it's mandatory to provide a caller ID. This caller ID is shown on call notification to the participant being added.

csharp

// Add user
var addThisPerson = new CallInvite(new CommunicationUserIdentifier("<user_id>"));
// add custom calling context
addThisPerson.CustomCallingContext.AddVoip("myHeader", "myValue");
AddParticipantsResult result = await callConnection.AddParticipantAsync(addThisPerson);

// Add PSTN user
var callerIdNumber = new PhoneNumberIdentifier("+16044561234"); // This is the Azure Communication Services provisioned phone number for the caller
var addThisPerson = new CallInvite(new PhoneNumberIdentifier("+16041234567"), callerIdNumber);
// add custom calling context
addThisPerson.CustomCallingContext.AddSipUui("value");
addThisPerson.CustomCallingContext.AddSipX("header1", "customSipHeaderValue1");

// Use option bag to set optional parameters
var addParticipantOptions = new AddParticipantOptions(new CallInvite(addThisPerson))
{
    InvitationTimeoutInSeconds = 60,
    OperationContext = "operationContext",
    OperationCallbackUri = new Uri("uri_endpoint"); // Sending event to a non-default endpoint.
};

AddParticipantsResult result = await callConnection.AddParticipantAsync(addParticipantOptions); 

Java

// Add user
CallInvite callInvite = new CallInvite(new CommunicationUserIdentifier("<user_id>"));
// add custom calling context
callInvite.getCustomCallingContext().addVoip("voipHeaderName", "voipHeaderValue");
AddParticipantOptions addParticipantOptions = new AddParticipantOptions(callInvite)
                .setOperationContext("<operation_context>")
                .setOperationCallbackUrl("<url_endpoint>");
Response<AddParticipantResult> addParticipantResultResponse = callConnectionAsync.addParticipantWithResponse(addParticipantOptions).block();

// Add PSTN user
PhoneNumberIdentifier callerIdNumber = new PhoneNumberIdentifier("+16044561234"); // This is the Azure Communication Services provisioned phone number for the caller
CallInvite callInvite = new CallInvite(new PhoneNumberIdentifier("+16041234567"), callerIdNumber);
// add custom calling context
callInvite.getCustomCallingContext().addSipUui("value");
callInvite.getCustomCallingContext().addSipX("header1", "customSipHeaderValue1");
AddParticipantOptions addParticipantOptions = new AddParticipantOptions(callInvite)
                .setOperationContext("<operation_context>")
                .setOperationCallbackUrl("<url_endpoint>");
Response<AddParticipantResult> addParticipantResultResponse = callConnectionAsync.addParticipantWithResponse(addParticipantOptions).block();

JavaScript

// Add user
// add custom calling context
const customCallingContext: CustomCallingContext = [];
customContext.push({ kind: "voip", key: "voipHeaderName", value: "voipHeaderValue" })

const addThisPerson = {
    targetParticipant: { communicationUserId: "<acs_user_id>" },
    customCallingContext: customCallingContext,
};
const addParticipantResult = await callConnection.addParticipant(addThisPerson, {
            operationCallbackUrl: "<url_endpoint>",
            operationContext: "<operation_context>"
});

// Add PSTN user
const callerIdNumber = { phoneNumber: "+16044561234" }; // This is the Azure Communication Services provisioned phone number for the caller
// add custom calling context
const customCallingContext: CustomCallingContext = [];
customContext.push({ kind: "sipuui", key: "", value: "value" });
customContext.push({ kind: "sipx", key: "headerName", value: "headerValue" })
const addThisPerson = {
    targetParticipant: { phoneNumber: "+16041234567" }, 
    sourceCallIdNumber: callerIdNumber,
    customCallingContext: customCallingContext,
};
const addParticipantResult = await callConnection.addParticipant(addThisPerson, {
            operationCallbackUrl: "<url_endpoint>",
            operationContext: "<operation_context>"
});

Python

# Add user
voip_headers = {"voipHeaderName", "voipHeaderValue"}
target = CommunicationUserIdentifier("<acs_user_id>")

call_connection_client = call_automation_client.get_call_connection(
    "<call_connection_id_from_ongoing_call>"
)
result = call_connection_client.add_participant(
    target,
    voip_headers=voip_headers,
    opration_context="Your context",
    operationCallbackUrl="<url_endpoint>"
)

# Add PSTN user
caller_id_number = PhoneNumberIdentifier(
    "+18888888888"
) # This is the Azure Communication Services provisioned phone number for the caller
sip_headers = {}
sip_headers["User-To-User"] = "value"
sip_headers["X-MS-Custom-headerName"] = "headerValue"
target = PhoneNumberIdentifier("+18008008800"),

call_connection_client = call_automation_client.get_call_connection(
    "<call_connection_id_from_ongoing_call>"
)
result = call_connection_client.add_participant(
    target,
    sip_headers=sip_headers,
    opration_context="Your context",
    operationCallbackUrl="<url_endpoint>",
    source_caller_id_number=caller_id_number
)

To add a Communication Services user, provide a CommunicationUserIdentifier instead of PhoneNumberIdentifier. Caller ID isn't mandatory in this case.

AddParticipant publishes a AddParticipantSucceeded or AddParticipantFailed event, along with a ParticipantUpdated providing the latest list of participants in the call.

Cancel an add participant request

csharp

// add a participant
var addThisPerson = new CallInvite(new CommunicationUserIdentifier("<user_id>"));
var addParticipantResponse = await callConnection.AddParticipantAsync(addThisPerson);

// cancel the request with optional parameters
var cancelAddParticipantOperationOptions = new CancelAddParticipantOperationOptions(addParticipantResponse.Value.InvitationId)
{
    OperationContext = "operationContext",
    OperationCallbackUri = new Uri("uri_endpoint"); // Sending event to a non-default endpoint.
}
await callConnection.CancelAddParticipantOperationAsync(cancelAddParticipantOperationOptions);

Java

// Add user
CallInvite callInvite = new CallInvite(new CommunicationUserIdentifier("<user_id>"));
AddParticipantOperationOptions addParticipantOperationOptions = new AddParticipantOptions(callInvite);
Response<AddParticipantResult> addParticipantOperationResultResponse = callConnectionAsync.addParticipantWithResponse(addParticipantOptions).block();

// cancel the request
CancelAddParticipantOperationOptions cancelAddParticipantOperationOptions = new CancelAddParticipantOperationOptions(addParticipantResultResponse.invitationId)
                .setOperationContext("<operation_context>")
                .setOperationCallbackUrl("<url_endpoint>");
callConnectionAsync.cancelAddParticipantOperationWithResponse(cancelAddParticipantOperationOptions).block();

JavaScript

// Add user
const addThisPerson = {
    targetParticipant: { communicationUserId: "<acs_user_id>" },
};
const { invitationId } = await callConnection.addParticipant(addThisPerson, {
            operationCallbackUrl: "<url_endpoint>",
            operationContext: "<operation_context>"
});

// cancel the request
await callConnection.cancelAddParticipantOperation(invitationId, {
            operationCallbackUrl: "<url_endpoint>",
            operationContext: "<operation_context>"
});

Python

# Add user
target = CommunicationUserIdentifier("<acs_user_id>")

call_connection_client = call_automation_client.get_call_connection(
    "<call_connection_id_from_ongoing_call>"
)
result = call_connection_client.add_participant(target)

# cancel the request
call_connection_client.cancel_add_participant_operation(result.invitation_id, opration_context="Your context", operationCallbackUrl="<url_endpoint>")

Remove a participant from a call

csharp

var removeThisUser = new CommunicationUserIdentifier("<user_id>"); 

// remove a participant from the call with optional parameters
var removeParticipantOptions = new RemoveParticipantOptions(removeThisUser)
{
    OperationContext = "operationContext",
    OperationCallbackUri = new Uri("uri_endpoint"); // Sending event to a non-default endpoint.
}

RemoveParticipantsResult result = await callConnection.RemoveParticipantAsync(removeParticipantOptions);

Java

CommunicationIdentifier removeThisUser = new CommunicationUserIdentifier("<user_id>");
RemoveParticipantOptions removeParticipantOptions = new RemoveParticipantOptions(removeThisUser)
                .setOperationContext("<operation_context>")
                .setOperationCallbackUrl("<url_endpoint>");
Response<RemoveParticipantResult> removeParticipantResultResponse = callConnectionAsync.removeParticipantWithResponse(removeParticipantOptions).block();

JavaScript

const removeThisUser = { communicationUserId: "<user_id>" };
const removeParticipantResult = await callConnection.removeParticipant(removeThisUser, {
            operationCallbackUrl: "<url_endpoint>",
            operationContext: "<operation_context>"
});

Python

remove_this_user = CommunicationUserIdentifier("<user_id>")
call_connection_client = call_automation_client.get_call_connection(
    "<call_connection_id_from_ongoing_call>"
)
result = call_connection_client.remove_participant(remove_this_user, opration_context="Your context", operationCallbackUrl="<url_endpoint>")

RemoveParticipant will publish a RemoveParticipantSucceeded or RemoveParticipantFailed event, along with a ParticipantUpdated event providing the latest list of participants in the call. The removed participant is omitted from the list.

Hang up on a call

Hang Up action can be used to remove your application from the call or to terminate a group call by setting forEveryone parameter to true. For a 1:1 call, hang up terminates the call with the other participant by default.

csharp

_ = await callConnection.HangUpAsync(forEveryone: true); 

Java

Response<Void> response = callConnectionAsync.hangUpWithResponse(true).block();

JavaScript

await callConnection.hangUp(true);

Python

call_connection_client.hang_up(is_for_everyone=True)

CallDisconnected event is published once the hangUp action has completed successfully.

Get information about a call participant

csharp

CallParticipant participantInfo = await callConnection.GetParticipantAsync(new CommunicationUserIdentifier("<user_id>"));

Java

CallParticipant participantInfo = callConnection.getParticipant(new CommunicationUserIdentifier("<user_id>")).block();

JavaScript

const participantInfo = await callConnection.getParticipant({ communicationUserId: "<user_id>" });

Python

participant_info = call_connection_client.get_participant(
    CommunicationUserIdentifier("<user_id>")
)

Get information about all call participants

csharp

List<CallParticipant> participantList = (await callConnection.GetParticipantsAsync()).Value.ToList(); 

Java

List<CallParticipant> participantList = Objects.requireNonNull(callConnection.listParticipants().block()).getValues();

JavaScript

const participantList = await callConnection.listParticipants();

Python

participant_list = call_connection_client.list_participants()

Get latest info about a call

csharp

CallConnectionProperties callConnectionProperties = await callConnection.GetCallConnectionPropertiesAsync(); 

Java

CallConnectionProperties callConnectionProperties = callConnection.getCallProperties().block(); 

JavaScript

const callConnectionProperties = await callConnection.getCallConnectionProperties();

Python

call_connection_properties = call_connection_client.get_call_properties()