Support for asynchronous autopagination

stripe · Mar 7, 2020 · 0bfe8b4 · 0bfe8b4
1 parent 8c1141a
commit 0bfe8b4
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Showing 6 changed files with 495 additions and 8 deletions.
diff --git a/src/Stripe.net/Services/Coupons/CouponService.cs b/src/Stripe.net/Services/Coupons/CouponService.cs
@@ -68,6 +68,13 @@ public virtual IEnumerable<Coupon> ListAutoPaging(CouponListOptions options = nu
             return this.ListEntitiesAutoPaging(options, requestOptions);
         }
 
+#if !NET45
+        public virtual IAsyncEnumerable<Coupon> ListAutoPagingAsync(CouponListOptions options = null, RequestOptions requestOptions = null, CancellationToken cancellationToken = default)
+        {
+            return this.ListEntitiesAutoPagingAsync(options, requestOptions, cancellationToken);
+        }
+#endif
+
         public virtual Coupon Update(string couponId, CouponUpdateOptions options, RequestOptions requestOptions = null)
         {
             return this.UpdateEntity(couponId, options, requestOptions);

diff --git a/src/Stripe.net/Services/_base/Service.cs b/src/Stripe.net/Services/_base/Service.cs
@@ -6,9 +6,11 @@ namespace Stripe
     using System.Net;
     using System.Net.Http;
     using System.Reflection;
+#if !NET45
+    using System.Runtime.CompilerServices;
+#endif
     using System.Threading;
     using System.Threading.Tasks;
-    using Stripe.Infrastructure;
 
     /// <summary>Abstract base class for all services.</summary>
     /// <typeparam name="TEntityReturned">
@@ -163,6 +165,20 @@ protected TEntityReturned CreateEntity(BaseOptions options, RequestOptions reque
                 requestOptions);
         }
 
+#if !NET45
+        protected IAsyncEnumerable<TEntityReturned> ListEntitiesAutoPagingAsync(
+            ListOptions options,
+            RequestOptions requestOptions,
+            CancellationToken cancellationToken)
+        {
+            return this.ListRequestAutoPagingAsync<TEntityReturned>(
+                this.ClassUrl(),
+                options,
+                requestOptions,
+                cancellationToken);
+        }
+#endif
+
         protected TEntityReturned UpdateEntity(
             string id,
             BaseOptions options,
@@ -245,6 +261,91 @@ protected TEntityReturned CreateEntity(BaseOptions options, RequestOptions reque
                 cancellationToken).ConfigureAwait(false);
         }
 
+#if !NET45
+        protected IEnumerable<T> ListRequestAutoPaging<T>(
+            string url,
+            ListOptions options,
+            RequestOptions requestOptions)
+            where T : IStripeEntity
+        {
+            return this.ListRequestAutoPagingAsync<T>(url, options, requestOptions)
+                .ToEnumerable();
+        }
+
+        protected async IAsyncEnumerable<T> ListRequestAutoPagingAsync<T>(
+            string url,
+            ListOptions options,
+            RequestOptions requestOptions,
+            [EnumeratorCancellation] CancellationToken cancellationToken = default)
+            where T : IStripeEntity
+        {
+            var page = await this.RequestAsync<StripeList<T>>(
+                HttpMethod.Get,
+                url,
+                options,
+                requestOptions,
+                cancellationToken);
+
+            options = options ?? new ListOptions();
+            bool iterateBackward = false;
+
+            // Backward iterating activates if we have an `EndingBefore`
+            // constraint and not a `StartingAfter` constraint
+            if (!string.IsNullOrEmpty(options.EndingBefore) && string.IsNullOrEmpty(options.StartingAfter))
+            {
+                iterateBackward = true;
+            }
+
+            while (true)
+            {
+                cancellationToken.ThrowIfCancellationRequested();
+
+                if (iterateBackward)
+                {
+                    page.Reverse();
+                }
+
+                string itemId = null;
+                foreach (var item in page)
+                {
+                    cancellationToken.ThrowIfCancellationRequested();
+
+                    // Elements in `StripeList` instances are decoded by `StripeObjectConverter`,
+                    // which returns `null` for objects it doesn't know how to decode.
+                    // When auto-paginating, we simply ignore these null elements but still return
+                    // other elements.
+                    if (item == null)
+                    {
+                        continue;
+                    }
+
+                    itemId = ((IHasId)item).Id;
+                    yield return item;
+                }
+
+                if (!page.HasMore || string.IsNullOrEmpty(itemId))
+                {
+                    break;
+                }
+
+                if (iterateBackward)
+                {
+                    options.EndingBefore = itemId;
+                }
+                else
+                {
+                    options.StartingAfter = itemId;
+                }
+
+                page = await this.RequestAsync<StripeList<T>>(
+                    HttpMethod.Get,
+                    url,
+                    options,
+                    requestOptions,
+                    cancellationToken);
+            }
+        }
+#else
         protected IEnumerable<T> ListRequestAutoPaging<T>(
             string url,
             ListOptions options,
@@ -311,6 +412,7 @@ protected TEntityReturned CreateEntity(BaseOptions options, RequestOptions reque
                     requestOptions);
             }
         }
+#endif
 
         protected RequestOptions SetupRequestOptions(RequestOptions requestOptions)
         {

diff --git a/src/Stripe.net/Stripe.net.csproj b/src/Stripe.net/Stripe.net.csproj
@@ -4,6 +4,7 @@
   <PropertyGroup>
     <Description>Stripe.net is a sync/async .NET 4.5+ client, and a portable class library for the Stripe API.  (Official Library)</Description>
     <AssemblyTitle>Stripe.net</AssemblyTitle>
+    <LangVersion>8</LangVersion>
     <VersionPrefix>35.3.0</VersionPrefix>
     <Version>35.3.0</Version>
     <Authors>Stripe, Jayme Davis</Authors>
@@ -38,6 +39,12 @@
     <CodeAnalysisRuleSet>..\_stylecop\StyleCopRules.ruleset</CodeAnalysisRuleSet>
   </PropertyGroup>
 
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+    <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="1.1.0" />
+    <PackageReference Include="System.Configuration.ConfigurationManager" Version="4.5.0" />
+    <PackageReference Include="System.Linq.Async" Version="4.0.0" />
+  </ItemGroup>
+
   <ItemGroup Condition=" '$(TargetFramework)' == 'net45' ">
     <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" />
     <Reference Include="Microsoft.CSharp" />
@@ -53,9 +60,4 @@
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
-
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <PackageReference Include="System.Configuration.ConfigurationManager" Version="4.5.0" />
-  </ItemGroup>
-
 </Project>