接收 HTTP 端點的事件
本文說明如何驗證 HTTP 端點以從事件訂閱接收事件，然後接收和還原序列化事件。 本文針對示範用途使用 Azure Function，但是不論應用程式裝載的位置都適用相同概念。
注意
建議您在使用事件方格觸發 Azure 函數時使用事件方格觸發程序。 其提供事件方格與 Azure Functions 之間更簡單且更快速的整合。 不過請注意，Azure Functions 事件方格觸發程序不支援以下情節：裝載的程式碼需要控制傳回事件方格的 HTTP 狀態碼。 例如，基於這項限制，您在 Azure 函數上執行的程式碼將無法傳回 5XX 錯誤，以起始事件方格的事件傳遞重試。
必要條件
您需要具有 HTTP 觸發函式的函數應用程式。
新增相依性
若您正以 .NET 進行開發，請為 Azure.Messaging.EventGridNuget 套件將相依性新增到函數。
其他語言的 SDK 可以透過發行 SDK 參考取得。 這些套件包含原生事件類型的模型，例如 EventGridEvent、StorageBlobCreatedEventData 和 EventHubCaptureFileCreatedEventData。
端點驗證
首先您應該做的是處理 Microsoft.EventGrid.SubscriptionValidationEvent 事件。 每次有人訂閱事件時，事件方格即會將驗證事件傳送至在資料承載中具有 validationCode 的端點。 需要端點才能在回應主體中回應以證明端點有效且為您所擁有。 若您是使用事件方格觸發程序而非 WebHook 觸發的函式，系統會為您處理端點的驗證。 如果您使用第三方 API 服務 (例如 Zapier 或 IFTTT)，可能就無法以程式設計方式回應驗證程式碼。 針對那些服務，您可以使用要在訂用帳戶驗證事件中傳送的驗證 URL，以手動方式驗證訂用帳戶。 在 validationUrl 屬性中複製該 URL，並透過 REST 用戶端或您的網頁瀏覽器傳送 GET 要求。
在 C# 中，ParseMany() 方法可用來將包含一個或多個事件的 BinaryData 執行個體還原序列化為 EventGridEvent 陣列。 如果您事先知道您要還原序列化的只有單一事件，則可以改用 Parse 方法。
若要以程式設計方式回應驗證程式碼，請使用下列程式碼。
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using System;
using Azure.Messaging.EventGrid;
using Azure.Messaging.EventGrid.SystemEvents;
namespace Function1
{
public static class Function1
{
[FunctionName("Function1")]
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
string response = string.Empty;
BinaryData events = await BinaryData.FromStreamAsync(req.Body);
log.LogInformation($"Received events: {events}");
EventGridEvent[] eventGridEvents = EventGridEvent.ParseMany(events);
foreach (EventGridEvent eventGridEvent in eventGridEvents)
{
// Handle system events
if (eventGridEvent.TryGetSystemEventData(out object eventData))
{
// Handle the subscription validation event
if (eventData is SubscriptionValidationEventData subscriptionValidationEventData)
{
log.LogInformation($"Got SubscriptionValidation event data, validation code: {subscriptionValidationEventData.ValidationCode}, topic: {eventGridEvent.Topic}");
// Do any additional validation (as required) and then return back the below response
var responseData = new
{
ValidationResponse = subscriptionValidationEventData.ValidationCode
};
return new OkObjectResult(responseData);
}
}
}
return new OkObjectResult(response);
}
}
}
module.exports = function (context, req) {
context.log('JavaScript HTTP trigger function begun');
var validationEventType = "Microsoft.EventGrid.SubscriptionValidationEvent";
for (var events in req.body) {
var body = req.body[events];
// Deserialize the event data into the appropriate type based on event type
if (body.data && body.eventType == validationEventType) {
context.log("Got SubscriptionValidation event data, validation code: " + body.data.validationCode + " topic: " + body.topic);
// Do any additional validation (as required) and then return back the below response
var code = body.data.validationCode;
context.res = { status: 200, body: { "ValidationResponse": code } };
}
}
context.done();
};
測試驗證回應
藉由將範例事件貼至函式的測試欄位來測試驗證回應函式：
[{
"id": "2d1781af-3a4c-4d7c-bd0c-e34b19da4e66",
"topic": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
"subject": "",
"data": {
"validationCode": "512d38b6-c7b8-40c8-89fe-f46f9e9622b6"
},
"eventType": "Microsoft.EventGrid.SubscriptionValidationEvent",
"eventTime": "2018-01-25T22:12:19.4556811Z",
"metadataVersion": "1",
"dataVersion": "1"
}]
當您選取 [執行] 時，在主體中輸出應該是「200 OK」和 {"validationResponse":"512d38b6-c7b8-40c8-89fe-f46f9e9622b6"}：
處理 Blob 儲存體事件
現在，我們要擴充函數以處理 Microsoft.Storage.BlobCreated 系統事件：
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using System;
using Azure.Messaging.EventGrid;
using Azure.Messaging.EventGrid.SystemEvents;
namespace Function1
{
public static class Function1
{
[FunctionName("Function1")]
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
string response = string.Empty;
BinaryData events = await BinaryData.FromStreamAsync(req.Body);
log.LogInformation($"Received events: {events}");
EventGridEvent[] eventGridEvents = EventGridEvent.ParseMany(events);
foreach (EventGridEvent eventGridEvent in eventGridEvents)
{
// Handle system events
if (eventGridEvent.TryGetSystemEventData(out object eventData))
{
// Handle the subscription validation event
if (eventData is SubscriptionValidationEventData subscriptionValidationEventData)
{
log.LogInformation($"Got SubscriptionValidation event data, validation code: {subscriptionValidationEventData.ValidationCode}, topic: {eventGridEvent.Topic}");
// Do any additional validation (as required) and then return back the below response
var responseData = new
{
ValidationResponse = subscriptionValidationEventData.ValidationCode
};
return new OkObjectResult(responseData);
}
// Handle the storage blob created event
else if (eventData is StorageBlobCreatedEventData storageBlobCreatedEventData)
{
log.LogInformation($"Got BlobCreated event data, blob URI {storageBlobCreatedEventData.Url}");
}
}
}
return new OkObjectResult(response);
}
}
}
module.exports = function (context, req) {
context.log('JavaScript HTTP trigger function begun');
var validationEventType = "Microsoft.EventGrid.SubscriptionValidationEvent";
var storageBlobCreatedEvent = "Microsoft.Storage.BlobCreated";
for (var events in req.body) {
var body = req.body[events];
// Deserialize the event data into the appropriate type based on event type
if (body.data && body.eventType == validationEventType) {
context.log("Got SubscriptionValidation event data, validation code: " + body.data.validationCode + " topic: " + body.topic);
// Do any additional validation (as required) and then return back the below response
var code = body.data.validationCode;
context.res = { status: 200, body: { "ValidationResponse": code } };
}
else if (body.data && body.eventType == storageBlobCreatedEvent) {
var blobCreatedEventData = body.data;
context.log("Relaying received blob created event payload:" + JSON.stringify(blobCreatedEventData));
}
}
context.done();
};
測試 Blob 建立事件處理
測試函式的新功能，方法是將 Blob 儲存體事件放入測試欄位並執行：
[{
"topic": "/subscriptions/{subscription-id}/resourceGroups/Storage/providers/Microsoft.Storage/storageAccounts/xstoretestaccount",
"subject": "/blobServices/default/containers/testcontainer/blobs/testfile.txt",
"eventType": "Microsoft.Storage.BlobCreated",
"eventTime": "2017-06-26T18:41:00.9584103Z",
"id": "831e1650-001e-001b-66ab-eeb76e069631",
"data": {
"api": "PutBlockList",
"clientRequestId": "6d79dbfb-0e37-4fc4-981f-442c9ca65760",
"requestId": "831e1650-001e-001b-66ab-eeb76e000000",
"eTag": "0x8D4BCC2E4835CD0",
"contentType": "text/plain",
"contentLength": 524288,
"blobType": "BlockBlob",
"url": "https://example.blob.core.windows.net/testcontainer/testfile.txt",
"sequencer": "00000000000004420000000000028963",
"storageDiagnostics": {
"batchId": "b68529f3-68cd-4744-baa4-3c0498ec19f0"
}
},
"dataVersion": "",
"metadataVersion": "1"
}]
您應該會在函式記錄中看到 Blob URL 輸出：
2022-11-14T22:40:45.978 [Information] Executing 'Function1' (Reason='This function was programmatically called via the host APIs.', Id=8429137d-9245-438c-8206-f9e85ef5dd61)
2022-11-14T22:40:46.012 [Information] C# HTTP trigger function processed a request.
2022-11-14T22:40:46.017 [Information] Received events: [{"topic": "/subscriptions/{subscription-id}/resourceGroups/Storage/providers/Microsoft.Storage/storageAccounts/xstoretestaccount","subject": "/blobServices/default/containers/testcontainer/blobs/testfile.txt","eventType": "Microsoft.Storage.BlobCreated","eventTime": "2017-06-26T18:41:00.9584103Z","id": "831e1650-001e-001b-66ab-eeb76e069631","data": {"api": "PutBlockList","clientRequestId": "6d79dbfb-0e37-4fc4-981f-442c9ca65760","requestId": "831e1650-001e-001b-66ab-eeb76e000000","eTag": "0x8D4BCC2E4835CD0","contentType": "text/plain","contentLength": 524288,"blobType": "BlockBlob","url": "https://example.blob.core.windows.net/testcontainer/testfile.txt","sequencer": "00000000000004420000000000028963","storageDiagnostics": {"batchId": "b68529f3-68cd-4744-baa4-3c0498ec19f0"}},"dataVersion": "","metadataVersion": "1"}]
2022-11-14T22:40:46.335 [Information] Got BlobCreated event data, blob URI https://example.blob.core.windows.net/testcontainer/testfile.txt
2022-11-14T22:40:46.346 [Information] Executed 'Function1' (Succeeded, Id=8429137d-9245-438c-8206-f9e85ef5dd61, Duration=387ms)
您也可以進行測試，方法是建立 Blob 儲存體帳戶或一般用途 V2 儲存體帳戶、新增事件訂閱，以及將端點設為函數 URL：
處理自訂事件
最後，讓我們再次擴充函式，讓它也可以處理自訂事件。
為您的事件 Contoso.Items.ItemReceived 新增檢查。 最終的程式碼應該會如下所示：
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using System;
using Azure.Messaging.EventGrid;
using Azure.Messaging.EventGrid.SystemEvents;
namespace Function1
{
public static class Function1
{
[FunctionName("Function1")]
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
string response = string.Empty;
BinaryData events = await BinaryData.FromStreamAsync(req.Body);
log.LogInformation($"Received events: {events}");
EventGridEvent[] eventGridEvents = EventGridEvent.ParseMany(events);
foreach (EventGridEvent eventGridEvent in eventGridEvents)
{
// Handle system events
if (eventGridEvent.TryGetSystemEventData(out object eventData))
{
// Handle the subscription validation event
if (eventData is SubscriptionValidationEventData subscriptionValidationEventData)
{
log.LogInformation($"Got SubscriptionValidation event data, validation code: {subscriptionValidationEventData.ValidationCode}, topic: {eventGridEvent.Topic}");
// Do any additional validation (as required) and then return back the below response
var responseData = new
{
ValidationResponse = subscriptionValidationEventData.ValidationCode
};
return new OkObjectResult(responseData);
}
// Handle the storage blob created event
else if (eventData is StorageBlobCreatedEventData storageBlobCreatedEventData)
{
log.LogInformation($"Got BlobCreated event data, blob URI {storageBlobCreatedEventData.Url}");
}
}
// Handle the custom contoso event
else if (eventGridEvent.EventType == "Contoso.Items.ItemReceived")
{
var contosoEventData = eventGridEvent.Data.ToObjectFromJson<ContosoItemReceivedEventData>();
log.LogInformation($"Got ContosoItemReceived event data, item SKU {contosoEventData.ItemSku}");
}
}
return new OkObjectResult(response);
}
}
}
module.exports = function (context, req) {
context.log('JavaScript HTTP trigger function begun');
var validationEventType = "Microsoft.EventGrid.SubscriptionValidationEvent";
var storageBlobCreatedEvent = "Microsoft.Storage.BlobCreated";
var customEventType = "Contoso.Items.ItemReceived";
for (var events in req.body) {
var body = req.body[events];
// Deserialize the event data into the appropriate type based on event type
if (body.data && body.eventType == validationEventType) {
context.log("Got SubscriptionValidation event data, validation code: " + body.data.validationCode + " topic: " + body.topic);
// Do any additional validation (as required) and then return back the below response
var code = body.data.validationCode;
context.res = { status: 200, body: { "ValidationResponse": code } };
}
else if (body.data && body.eventType == storageBlobCreatedEvent) {
var blobCreatedEventData = body.data;
context.log("Relaying received blob created event payload:" + JSON.stringify(blobCreatedEventData));
}
else if (body.data && body.eventType == customEventType) {
var payload = body.data;
context.log("Relaying received custom payload:" + JSON.stringify(payload));
}
}
context.done();
};
測試自訂事件處理
最後，測試您的函式現在是否可以處理您的自訂事件類型：
[{
"subject": "Contoso/foo/bar/items",
"eventType": "Contoso.Items.ItemReceived",
"eventTime": "2017-08-16T01:57:26.005121Z",
"id": "602a88ef-0001-00e6-1233-1646070610ea",
"data": {
"itemSku": "Standard"
},
"dataVersion": "",
"metadataVersion": "1"
}]
您也可以即時測試此功能，方法是從入口網站傳送自訂事件與 CURL，或使用可以張貼到端點的任何服務或應用程式 (例如 Postman) 張貼到自訂主題。 在端點設為函式 URL 時建立自訂主題和事件訂閱。
訊息標頭
以下是您在訊息標頭中收到的屬性：
| 屬性名稱 | 描述 |
|---|---|
| aeg-subscription-name | 事件訂閱的名稱。 |
| aeg-delivery-count | 對事件進行的嘗試次數。 |
| aeg-event-type | 事件的類型。 它可能是下列其中一個值：
|
| aeg-metadata-version | 事件的中繼資料版本。 針對事件方格事件結構描述，此屬性代表中繼資料版本；而針對雲端事件結構描述，其代表規格版本。 |
| aeg-data-version | 事件的資料版本。 針對事件方格事件結構描述，此屬性代表資料版本；而針對雲端事件結構描述，則不會套用。 |
| aeg-output-event-id | 事件方格事件的識別碼。 |
下一步
- 探索 Azure 事件方格管理和發行 SDK
- 深入了解如何張貼到自訂主題
- 嘗試其中一個深入的事件格線和函式教學課程，例如調整上傳至 Blob 儲存體的映像大小