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nickevansuknickevansuk
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feat: Implement idempotency for B/P requests (#207)
1 parent f8a4150 commit c909ec7

6 files changed

Lines changed: 109 additions & 13 deletions

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‎Examples/BookingSystem.AspNetCore/BookingSystem.AspNetCore.csproj‎

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@@ -7,6 +7,7 @@
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<ItemGroup>
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<PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="2.1.2" />
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<PackageReference Include="System.Runtime.Caching" Version="7.0.0" />
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</ItemGroup>
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<ItemGroup>

‎Examples/BookingSystem.AspNetCore/Settings/EngineConfig.cs‎

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@@ -166,6 +166,9 @@ public static StoreBookingEngine CreateStoreBookingEngine(AppSettings appSetting
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),
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HasSingleSeller = appSettings.FeatureFlags.SingleSeller,
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// IdempotencyStore used for storing the response to Order Creation B/P requests
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IdempotencyStore = new AcmeIdempotencyStore(),
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OpenDataFeeds = new Dictionary<OpportunityType, IOpportunityDataRpdeFeedGenerator> {
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{
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OpportunityType.ScheduledSession, new AcmeScheduledSessionRpdeGenerator(fakeBookingSystem)

‎Examples/BookingSystem.AspNetCore/Stores/IdempotencyStore.cs‎

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using OpenActive.Server.NET.OpenBookingHelper;
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using System;
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using System.Threading.Tasks;
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using System.Runtime.Caching;
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namespace BookingSystem
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{
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public class AcmeIdempotencyStore : IdempotencyStore
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{
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private readonly ObjectCache _cache = MemoryCache.Default;
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protected override ValueTask<string> GetSuccessfulOrderCreationResponse(string idempotencyKey)
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{
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return new ValueTask<string>((string)_cache.Get(idempotencyKey));
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}
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protected override ValueTask SetSuccessfulOrderCreationResponse(string idempotencyKey, string responseJson)
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{
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var policy = new CacheItemPolicy();
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policy.AbsoluteExpiration = DateTimeOffset.Now.AddMinutes(5);
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_cache.Set(idempotencyKey, responseJson, policy);
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return new ValueTask();
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}
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}
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}

‎OpenActive.Server.NET/CustomBookingEngine/CustomBookingEngine.cs‎

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Original file line numberDiff line numberDiff line change
@@ -414,9 +414,6 @@ private async Task<ResponseContent> ProcessCheckpoint(string clientId, Uri selle
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}
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public async Task<ResponseContent> ProcessOrderCreationB(string clientId, Uri sellerId, string uuidString, string orderJson, Uri customerAccountId = null)
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{
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// Note B will never contain OrderItem level errors, and any issues that occur will be thrown as exceptions.
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// If C1 and C2 are used correctly, B should not fail except in very exceptional cases.
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Order order = OpenActiveSerializer.Deserialize<Order>(orderJson);
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if (order == null || order.GetType() != typeof(Order))
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{
@@ -425,21 +422,23 @@ public async Task<ResponseContent> ProcessOrderCreationB(string clientId, Uri se
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var (orderId, sellerIdComponents, seller, customerAccountIdComponents) = await ConstructIdsFromRequest(clientId, sellerId, customerAccountId, uuidString, OrderType.Order);
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using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
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{
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// Attempt to use idempotency cache if it exists
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var cachedResponse = await GetResponseFromIdempotencyStoreIfExists(settings, orderId, orderJson);
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if (cachedResponse != null)
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{
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return cachedResponse;
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}
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var response = order.OrderProposalVersion != null ?
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await ProcessOrderCreationFromOrderProposal(orderId, settings.OrderIdTemplate, seller, sellerIdComponents, customerAccountIdComponents, order) :
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await ProcessFlowRequest(ValidateFlowRequest<Order>(orderId, sellerIdComponents, seller, customerAccountIdComponents, FlowStage.B, order), order);
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// Return a 409 status code if any OrderItem level errors exist
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return ResponseContent.OpenBookingResponse(OpenActiveSerializer.Serialize(response),
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response.OrderedItem.Exists(x => x.Error?.Count > 0) ? HttpStatusCode.Conflict : HttpStatusCode.Created);
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return await CreateResponseViaIdempotencyStoreIfExists(settings, orderId, orderJson, response);
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}
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}
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public async Task<ResponseContent> ProcessOrderProposalCreationP(string clientId, Uri sellerId, string uuidString, string orderJson, Uri customerAccountId = null)
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{
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// Note B will never contain OrderItem level errors, and any issues that occur will be thrown as exceptions.
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// If C1 and C2 are used correctly, P should not fail except in very exceptional cases.
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OrderProposal order = OpenActiveSerializer.Deserialize<OrderProposal>(orderJson);
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if (order == null || order.GetType() != typeof(OrderProposal))
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{
@@ -448,14 +447,47 @@ public async Task<ResponseContent> ProcessOrderProposalCreationP(string clientId
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var (orderId, sellerIdComponents, seller, customerAccountIdComponents) = await ConstructIdsFromRequest(clientId, sellerId, customerAccountId, uuidString, OrderType.OrderProposal);
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using (await asyncDuplicateLock.LockAsync(GetParallelLockKey(orderId)))
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{
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// Attempt to use idempotency cache if it exists
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var cachedResponse = await GetResponseFromIdempotencyStoreIfExists(settings, orderId, orderJson);
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if (cachedResponse != null)
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{
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return cachedResponse;
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}
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var response = await ProcessFlowRequest(ValidateFlowRequest<OrderProposal>(orderId, sellerIdComponents, seller, customerAccountIdComponents, FlowStage.P, order), order);
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// Return a 409 status code if any OrderItem level errors exist
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return ResponseContent.OpenBookingResponse(OpenActiveSerializer.Serialize(response),
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response.OrderedItem.Exists(x => x.Error?.Count > 0) ? HttpStatusCode.Conflict : HttpStatusCode.Created);
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return await CreateResponseViaIdempotencyStoreIfExists(settings, orderId, orderJson, response);
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}
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}
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463+
private async Task<ResponseContent> GetResponseFromIdempotencyStoreIfExists(BookingEngineSettings settings, OrderIdComponents orderId, string orderJson)
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{
465+
// Attempt to use idempotency cache if it exists
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if (settings.IdempotencyStore != null)
467+
{
468+
var cachedResponse = await settings.IdempotencyStore.GetSuccessfulOrderCreationResponse(orderId, orderJson);
469+
if (cachedResponse != null)
470+
{
471+
return ResponseContent.OpenBookingResponse(cachedResponse, HttpStatusCode.Created);
472+
}
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}
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return null;
475+
}
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private async Task<ResponseContent> CreateResponseViaIdempotencyStoreIfExists(BookingEngineSettings settings, OrderIdComponents orderId, string orderJson, Order response) {
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// Return a 409 status code if any OrderItem level errors exist
479+
var httpStatusCode = response.OrderedItem.Exists(x => x.Error?.Count > 0) ? HttpStatusCode.Conflict : HttpStatusCode.Created;
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var responseJson = OpenActiveSerializer.Serialize(response);
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// Store response in idempotency cache if it exists, and if the response is successful
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if (settings.IdempotencyStore != null && httpStatusCode == HttpStatusCode.Created)
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{
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await settings.IdempotencyStore.SetSuccessfulOrderCreationResponse(orderId, orderJson, responseJson);
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}
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return ResponseContent.OpenBookingResponse(responseJson, httpStatusCode);
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}
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private SimpleIdComponents GetSimpleIdComponentsFromApiKey(Uri sellerId)
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{
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// Return empty SimpleIdComponents in Single Seller mode, as it is not required in the API Key

‎OpenActive.Server.NET/OpenBookingHelper/Settings/BookingEngineSettings.cs‎

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@@ -28,6 +28,7 @@ public class BookingEngineSettings
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public OrdersRPDEFeedGenerator OrdersFeedGenerator { get; set; }
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public OrdersRPDEFeedGenerator OrderProposalsFeedGenerator { get; set; }
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public SellerStore SellerStore { get; set; }
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public IdempotencyStore IdempotencyStore { get; set; }
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public bool HasSingleSeller { get; set; } = false;
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/// <summary>
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/// TTL in the Cache-Control header for all RPDE pages that contain greater than zero items
@@ -44,5 +45,5 @@ public class BookingEngineSettings
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/// See https://developer.openactive.io/publishing-data/data-feeds/scaling-feeds for CDN configuration instructions
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/// </summary>
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public TimeSpan DatasetSiteCacheDuration { get; set; } = TimeSpan.FromMinutes(15);
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}
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}
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}

‎OpenActive.Server.NET/OpenBookingHelper/Stores/IdempotencyStore.cs‎

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using OpenActive.NET;
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using System;
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using System.Threading.Tasks;
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using System.Security.Cryptography;
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using System.Text;
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namespace OpenActive.Server.NET.OpenBookingHelper
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{
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public abstract class IdempotencyStore
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{
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protected abstract ValueTask<string> GetSuccessfulOrderCreationResponse(string idempotencyKey);
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protected abstract ValueTask SetSuccessfulOrderCreationResponse(string idempotencyKey, string responseJson);
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internal ValueTask<string> GetSuccessfulOrderCreationResponse(OrderIdComponents orderId, string orderJson) {
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return GetSuccessfulOrderCreationResponse(CalculateIdempotencyKey(orderId, orderJson));
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}
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18+
internal ValueTask SetSuccessfulOrderCreationResponse(OrderIdComponents orderId, string orderJson, string responseJson) {
19+
return SetSuccessfulOrderCreationResponse(CalculateIdempotencyKey(orderId, orderJson), responseJson);
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}
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protected string CalculateIdempotencyKey(OrderIdComponents orderId, string orderJson) {
23+
return $"{orderId.ClientId}|{orderId.uuid}|{orderId.OrderType.ToString()}|{ComputeSHA256Hash(orderJson)}";
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}
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protected static string ComputeSHA256Hash(string text)
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{
28+
using (var sha256 = SHA256.Create())
29+
{
30+
return BitConverter.ToString(sha256.ComputeHash(Encoding.UTF8.GetBytes(text))).Replace("-", "");
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}
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}
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}
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}

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