diff --git a/docs/en/API/Dynamic-CSharp-API-Clients.md b/docs/en/API/Dynamic-CSharp-API-Clients.md index d92846f5e8..b1d71e0bb1 100644 --- a/docs/en/API/Dynamic-CSharp-API-Clients.md +++ b/docs/en/API/Dynamic-CSharp-API-Clients.md @@ -1,10 +1,23 @@ # Dynamic C# API Client Proxies -ABP can dynamically create C# API client proxies to call remote HTTP services (REST APIs). In this way, you don't need to deal with `HttpClient` and other low level HTTP features to call remote services and get results. +ABP can dynamically create C# API client proxies to call your remote HTTP services (REST APIs). In this way, you don't need to deal with `HttpClient` and other low level details to call remote services and get results. + +Dynamic C# proxies automatically handles the following stuff for you; + +* Maps C# **method calls** to remote server **HTTP calls** by considering the HTTP method, route, query string parameters, request payload and other details. +* **Authenticates** the HTTP Client by adding access token to the HTTP header. +* **Serializes** to and deserialize from JSON. +* Handles HTTP API **versioning**. +* Add **correlation id**, current **tenant** id and the current **culture** to the request. +* Properly **handles the error messages** sent by the server and throws proper exceptions. + +This system can be used by any type of .NET client to consume your HTTP APIs. ## Service Interface -Your service/controller should implement an interface that is shared between the server and the client. So, first define a service interface in a shared library project. Example: +Your service/controller should implement an interface that is shared between the server and the client. So, first define a service interface in a shared library project, typically in the `Application.Contracts` project if you've created your solution using the startup templates. + +Example: ````csharp public interface IBookAppService : IApplicationService @@ -13,7 +26,7 @@ public interface IBookAppService : IApplicationService } ```` -Your interface should implement the `IRemoteService` interface to be automatically discovered. Since the `IApplicationService` inherits the `IRemoteService` interface, the `IBookAppService` above satisfies this condition. +> Your interface should implement the `IRemoteService` interface to be automatically discovered. Since the `IApplicationService` inherits the `IRemoteService` interface, the `IBookAppService` above satisfies this condition. Implement this class in your service application. You can use [auto API controller system](Auto-API-Controllers.md) to expose the service as a REST API endpoint. @@ -55,6 +68,8 @@ public class MyClientAppModule : AbpModule `AddHttpClientProxies` method gets an assembly, finds all service interfaces in the given assembly, creates and registers proxy classes. +> The startup templates already comes pre-configured for the client proxy generation, in the `HttpApi.Client` project. + ### Endpoint Configuration `RemoteServices` section in the `appsettings.json` file is used to get remote service address by default. Simplest configuration is shown below: @@ -106,7 +121,7 @@ While you can inject `IBookAppService` like above to use the client proxy, you c ### AbpRemoteServiceOptions -`AbpRemoteServiceOptions` is automatically set from the `appsettings.json` by default. Alternatively, you can use `Configure` method to set or override it. Example: +`AbpRemoteServiceOptions` is automatically set from the `appsettings.json` by default. Alternatively, you can configure it in the `ConfigureServices` method of your [module](../Module-Development-Basics.md) to set or override it. Example: ````csharp public override void ConfigureServices(ServiceConfigurationContext context) @@ -162,4 +177,30 @@ context.Services.AddHttpClientProxies( Using `asDefaultServices: false` may only be needed if your application has already an implementation of the service and you do not want to override/replace the other implementation by your client proxy. -> If you disable `asDefaultServices`, you can only use `IHttpClientProxy` interface to use the client proxies. See the *IHttpClientProxy Interface* section above. \ No newline at end of file +> If you disable `asDefaultServices`, you can only use `IHttpClientProxy` interface to use the client proxies. See the *IHttpClientProxy Interface* section above. + +### Retry/Failure Logic & Polly Integration + +If you want to add retry logic for the failing remote HTTP calls for the client proxies, you can configure the `AbpHttpClientBuilderOptions` in the `PreConfigureServices` method of your module class. + +**Example: Use the [Polly](https://github.com/App-vNext/Polly) library to re-try 3 times on a failure** + +````csharp +public override void PreConfigureServices(ServiceConfigurationContext context) +{ + PreConfigure(options => + { + options.ProxyClientBuildActions.Add((remoteServiceName, clientBuilder) => + { + clientBuilder.AddTransientHttpErrorPolicy(policyBuilder => + policyBuilder.WaitAndRetryAsync( + 3, + i => TimeSpan.FromSeconds(Math.Pow(2, i)) + ) + ); + }); + }); +} +```` + +This example uses the [Microsoft.Extensions.Http.Polly](https://www.nuget.org/packages/Microsoft.Extensions.Http.Polly) package. You also need to import the `Polly` namespace (`using Polly;`) to be able to use the `WaitAndRetryAsync` method. \ No newline at end of file