你当前正在访问 Microsoft Azure Global Edition 技术文档网站。 如果需要访问由世纪互联运营的 Microsoft Azure 中国技术文档网站，请访问 https://docs.azure.cn。

如何在呼叫之间传递上下文数据

通话自动化允许开发人员在路由呼叫时传递自定义上下文信息。 开发人员可以传递有关呼叫、被叫方或任何其他与应用程序或业务逻辑相关的信息的元数据。 这样，企业就可以跨网络管理和路由呼叫，而无需担心丢失上下文。

传递上下文是通过指定自定义标头来支持的。 这些是可包含在 AddParticipant 或 Transfer 操作中的键值对的可选列表。 上下文稍后可以作为 IncomingCall 事件有效负载的一部分进行检索。

自定义呼叫上下文也会转发到 SIP 协议，其中包括自由格式的自定义标头以及标准的用户到用户信息 (UUI) SIP 标头。 从电话网络路由入站呼叫时，自定义标头和 UUI 中 SBC 的数据集同样包含在 IncomingCall 事件有效负载中。

所有自定义上下文数据对于通话自动化或 SIP 协议都是不透明的，并且其内容与任何基本功能都无关。

下面是有关如何开始在通话自动化中使用自定义上下文标头的示例。

作为先决条件，我们建议阅读以下文章以充分理解本指南：

• 介绍操作事件编程模型和事件回调的通话自动化概念指南。
• 了解本指南中使用的用户标识符，例如 CommunicationUserIdentifier 和 PhoneNumberIdentifier。

对于所有代码示例，client 是可以按示例所示创建的 CallAutomationClient 对象，callConnection 是从 Answer 或 CreateCall 响应中获取的 CallConnection 对象。 也可以从应用程序收到的回调事件中获取该对象。

技术参数

通话自动化最多支持 5 个自定义 SIP 标头和 1000 个自定义 VOIP 标头。 此外，开发人员还可以将专用的用户到用户标头作为 SIP 标头列表的一部分。

自定义 SIP 标头键必须以必需的 ‘X-MS-Custom-’ 前缀开头。 SIP 标头键的最大长度为 64 个字符，包括 X-MS-Custom 前缀。 SIP 标头键可由字母数字字符和一些选定的符号组成，包括 .、!、%、*、_、+、~、-。 SIP 标头值的最大长度为 256 个字符。 在 SBC 上配置 SIP 标头时，同样的限制适用。 SIP 标头值可由字母数字字符和一些选定的符号组成，包括 =、;、.、!、%、*、_、+、~、-。

VOIP 标头键的最大长度为 64 个字符。 可以在不带 ‘x-MS-Custom’ 前缀的情况下发送这些标头。 VOIP 标头值的最大长度为 1024 个字符。

邀请参与者时添加自定义上下文

csharp

// Invite a communication services user and include one VOIP header
var addThisPerson = new CallInvite(new CommunicationUserIdentifier("<user_id>"));
addThisPerson.CustomCallingContext.AddVoip("myHeader", "myValue");
AddParticipantsResult result = await callConnection.AddParticipantAsync(addThisPerson);
// Invite a PSTN user and set UUI and custom SIP headers
var callerIdNumber = new PhoneNumberIdentifier("+16044561234"); 
var addThisPerson = new CallInvite(new PhoneNumberIdentifier("+16041234567"), callerIdNumber);

// Set custom UUI header. This key is sent on SIP protocol as User-to-User
addThisPerson.CustomCallingContext.AddSipUui("value");

// This provided key will be automatically prefixed with X-MS-Custom on SIP protocol, such as 'X-MS-Custom-{key}'
addThisPerson.CustomCallingContext.AddSipX("header1", "customSipHeaderValue1");
AddParticipantsResult result = await callConnection.AddParticipantAsync(addThisPerson);

Java

// Invite a communication services user and include one VOIP header
CallInvite callInvite = new CallInvite(new CommunicationUserIdentifier("<user_id>"));
callInvite.getCustomCallingContext().addVoip("voipHeaderName", "voipHeaderValue");
AddParticipantOptions addParticipantOptions = new AddParticipantOptions(callInvite);
Response<AddParticipantResult> addParticipantResultResponse = callConnectionAsync.addParticipantWithResponse(addParticipantOptions).block();

// Invite a PSTN user and set UUI and custom SIP headers
PhoneNumberIdentifier callerIdNumber = new PhoneNumberIdentifier("+16044561234");
CallInvite callInvite = new CallInvite(new PhoneNumberIdentifier("+16041234567"), callerIdNumber);
callInvite.getCustomCallingContext().addSipUui("value");
callInvite.getCustomCallingContext().addSipX("header1", "customSipHeaderValue1");
AddParticipantOptions addParticipantOptions = new AddParticipantOptions(callInvite);
Response<AddParticipantResult> addParticipantResultResponse = callConnectionAsync.addParticipantWithResponse(addParticipantOptions).block();

JavaScript

// Invite a communication services user and include one VOIP header
const customCallingContext: CustomCallingContext = [];
customCallingContext.push({ kind: "voip", key: "voipHeaderName", value: "voipHeaderValue" })
const addThisPerson = {
    targetParticipant: { communicationUserId: "<acs_user_id>" },
    customCallingContext: customCallingContext,
};
const addParticipantResult = await callConnection.addParticipant(addThisPerson);

// Invite a PSTN user and set UUI and custom SIP headers
const callerIdNumber = { phoneNumber: "+16044561234" };
const customCallingContext: CustomCallingContext = [];
customCallingContext.push({ kind: "sipuui", key: "", value: "value" });
customCallingContext.push({ kind: "sipx", key: "headerName", value: "headerValue" })
const addThisPerson = {
    targetParticipant: { phoneNumber: "+16041234567" }, 
    sourceCallIdNumber: callerIdNumber,
    customCallingContext: customCallingContext,
};
const addParticipantResult = await callConnection.addParticipant(addThisPerson);

Python

#Invite a communication services user and include one VOIP header
voip_headers = {"voipHeaderName", "voipHeaderValue"}
target = CommunicationUserIdentifier("<acs_user_id>")
result = call_connection_client.add_participant(
    target,
    voip_headers=voip_headers
)

#Invite a PSTN user and set UUI and custom SIP headers
caller_id_number = PhoneNumberIdentifier("+16044561234")
sip_headers = {}
sip_headers["User-To-User"] = "value"
sip_headers["X-MS-Custom-headerName"] = "headerValue"
target = PhoneNumberIdentifier("+16041234567")
result = call_connection_client.add_participant(
    target,
    sip_headers=sip_headers,
    source_caller_id_number=caller_id_number
)

在呼叫转移期间添加自定义上下文

csharp

//Transfer to communication services user and include one VOIP header
var transferDestination = new CommunicationUserIdentifier("<user_id>"); 
var transferOption = new TransferToParticipantOptions(transferDestination);   
var transferOption = new TransferToParticipantOptions(transferDestination) {
    OperationContext = "<Your_context>",
    OperationCallbackUri = new Uri("<uri_endpoint>") // Sending event to a non-default endpoint.
};
transferOption.CustomCallingContext.AddVoip("customVoipHeader1", "customVoipHeaderValue1");
TransferCallToParticipantResult result = await callConnection.TransferCallToParticipantAsync(transferOption);

//Transfer a PSTN call to phone number and set UUI and custom SIP headers
var transferDestination = new PhoneNumberIdentifier("<target_phoneNumber>");
var transferOption = new TransferToParticipantOptions(transferDestination);
transferOption.CustomCallingContext.AddSipUui("uuivalue");
transferOption.CustomCallingContext.AddSipX("header1", "headerValue");
TransferCallToParticipantResult result = await callConnection.TransferCallToParticipantAsync(transferOption)

Java

//Transfer to communication services user and include one VOIP header
CommunicationIdentifier transferDestination = new CommunicationUserIdentifier("<user_id>");
TransferCallToParticipantOptions options = new TransferCallToParticipantOptions(transferDestination);
options.getCustomCallingContext().addVoip("voipHeaderName", "voipHeaderValue");
Response<TransferCallResult> transferResponse = callConnectionAsync.transferToParticipantCallWithResponse(options).block();

//Transfer a PSTN call to phone number and set UUI and custom SIP headers
CommunicationIdentifier transferDestination = new PhoneNumberIdentifier("<taget_phoneNumber>");
TransferCallToParticipantOptions options = new TransferCallToParticipantOptions(transferDestination);
options.getCustomCallingContext().addSipUui("UUIvalue");
options.getCustomCallingContext().addSipX("sipHeaderName", "value");
Response<TransferCallResult> transferResponse = callConnectionAsync.transferToParticipantCallWithResponse(options).block();

JavaScript

//Transfer to communication services user and include one VOIP header
const transferDestination = { communicationUserId: "<user_id>" };
const transferee = { communicationUserId: "<transferee_user_id>" };
const options = { transferee: transferee, operationContext: "<Your_context>", operationCallbackUrl: "<url_endpoint>" };
const customCallingContext: CustomCallingContext = [];
customCallingContext.push({ kind: "voip", key: "customVoipHeader1", value: "customVoipHeaderValue1" })
options.customCallingContext = customCallingContext;
const result = await callConnection.transferCallToParticipant(transferDestination, options);

//Transfer a PSTN call to phone number and set UUI and custom SIP headers
const transferDestination = { phoneNumber: "<taget_phoneNumber>" };
const transferee = { phoneNumber: "<transferee_phoneNumber>" };
const options = { transferee: transferee, operationContext: "<Your_context>", operationCallbackUrl: "<url_endpoint>" };
const customCallingContext: CustomCallingContext = [];
customCallingContext.push({ kind: "sipuui", key: "", value: "uuivalue" });
customCallingContext.push({ kind: "sipx", key: "headerName", value: "headerValue" })
options.customCallingContext = customCallingContext;
const result = await callConnection.transferCallToParticipant(transferDestination, options);

Python

#Transfer to communication services user and include one VOIP header
transfer_destination = CommunicationUserIdentifier("<user_id>")
transferee = CommnunicationUserIdentifer("transferee_user_id")
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 a PSTN call to phone number and set UUI and custom SIP headers
transfer_destination = PhoneNumberIdentifer("<target_phoneNumber>")
transferee = PhoneNumberIdentifer("transferee_phoneNumber")
sip_headers={}
sip_headers["X-MS-Custom-headerName"] = "headerValue"
sip_headers["User-To-User"] = "uuivalue"
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>"
)

目前不支持将 VoIP 呼叫转移到某个电话号码。

从传入呼叫事件读取自定义上下文

csharp

AcsIncomingCallEventData incomingEvent = <incoming call event from Event Grid>;
// Retrieve incoming call custom context
AcsIncomingCallCustomContext callCustomContext = incomingEvent.CustomContext;

// Inspect dictionary with key/value pairs
var voipHeaders = callCustomContext.VoipHeaders;
var sipHeaders = callCustomContext.SipHeaders;

// Get SIP UUI header value
var userToUser = sipHeaders["user-To-User"]

// Proceed to answer or reject call as usual

Java

AcsIncomingCallEventData incomingEvent = <incoming call event from Event Grid>;
// Retrieve incoming call custom context
AcsIncomingCallCustomContext callCustomContext = incomingEvent.getCustomContext();

// Inspect dictionary with key/value pairs
Map<String, String> voipHeaders = callCustomContext.getVoipHeaders();
Map<String, String> sipHeaders = callCustomContext.getSipHeaders();

// Get SIP UUI header value
String userToUser = sipHeaders.get("user-To-User");

// Proceed to answer or reject call as usual

JavaScript

// Retrieve incoming call custom context
const callCustomContext = incomingEvent.customContext;

// Inspect dictionary with key/value pairs
const voipHeaders = callCustomContext.voipHeaders;
const sipHeaders = callCustomContext.sipHeaders;

// Get SIP UUI header value
const userToUser = sipHeaders["user-To-User"];

// Proceed to answer or reject call as usual

Python

# Retrieve incoming call custom context
callCustomContext = incomingEvent.customContext

# Inspect dictionary with key/value pairs
voipHeaders = callCustomContext.voipHeaders
sipHeaders = callCustomContext.sipHeaders

# Get SIP UUI header value
userToUser = sipHeaders["user-To-User"]

# Proceed to answer or reject call as usual

其他资源

• 有关传入呼叫的示例有效负载，请参阅此指南。

• 详细了解直接路由的 SIP 协议详细信息。