# ASP.NET Core routing example This sample shows using Dapr with ASP.NET Core routing. This application is a simple and not-so-secure banking application. The application uses the Dapr state-store for its data storage. It exposes the following endpoints over HTTP: - GET `/{id}`: Get the balance for the account specified by `id` - POST `/deposit`: Accepts a JSON payload to deposit money to an account - POST `/withdraw`: Accepts a JSON payload to withdraw money from an account The application also registers for pub/sub with the `deposit` and `withdraw` topics. ## Prerequisites - [.NET Core 3.1 or .NET 5+](https://dotnet.microsoft.com/download) installed - [Dapr CLI](https://docs.dapr.io/getting-started/install-dapr-cli/) - [Initialized Dapr environment](https://docs.dapr.io/getting-started/install-dapr-selfhost/) - [Dapr .NET SDK](https://docs.dapr.io/developing-applications/sdks/dotnet/) ## Running the Sample To run the sample locally run this command in this project root directory: ```sh dapr run --app-id routing --app-port 5000 -- dotnet run ``` The application will listen on port 5000 for HTTP. *Note: For Running the sample in ISS express, change the launchsettings.json to use 127.0.0.1 instead of localhost.* ### Examples **Deposit Money** On Linux, MacOS: ```sh curl -X POST http://127.0.0.1:5000/deposit \ -H 'Content-Type: application/json' \ -d '{ "id": "17", "amount": 12 }' ``` On Windows: ```sh curl -X POST http://127.0.0.1:5000/deposit -H "Content-Type: application/json" -d "{ \"id\": \"17\", \"amount\": 12 }" ``` Or, we can also do this using the Visual Studio Code [Rest Client Plugin](https://marketplace.visualstudio.com/items?itemName=humao.rest-client) [sample.http](sample.http) ```http POST http://127.0.0.1:5000/deposit Content-Type: application/json { "id": "17", "amount": 12 } ``` Output: ```txt {"id":"17","balance":12} ``` --- **Withdraw Money** On Linux, MacOS: ```sh curl -X POST http://127.0.0.1:5000/withdraw \ -H 'Content-Type: application/json' \ -d '{ "id": "17", "amount": 10 }' ``` On Windows: ```sh curl -X POST http://127.0.0.1:5000/withdraw -H "Content-Type: application/json" -d "{ \"id\": \"17\", \"amount\": 10 }" ``` or using the Visual Studio Code [Rest Client Plugin](https://marketplace.visualstudio.com/items?itemName=humao.rest-client) [sample.http](sample.http) ```http POST http://127.0.0.1:5000/withdraw Content-Type: application/json { "id": "17", "amount": 5 } ``` Output: ```txt {"id":"17","balance":2} ``` --- **Get Balance** ```sh curl http://127.0.0.1:5000/17 ``` or using the Visual Studio Code [Rest Client Plugin](https://marketplace.visualstudio.com/items?itemName=humao.rest-client) [sample.http](sample.http) ```http GET http://127.0.0.1:5000/17 ``` Output: ```txt {"id":"17","balance":2} ``` --- **Withdraw Money (pubsub)** Publish events using Dapr cli: On Linux, MacOS: ```sh dapr publish --pubsub pubsub --publish-app-id routing -t withdraw -d '{"id": "17", "amount": 15 }' ``` On Windows: ```sh dapr publish --pubsub pubsub --publish-app-id routing -t withdraw -d "{\"id\": \"17\", \"amount\": 15 }" ``` --- **Deposit Money (pubsub)** Publish events using Dapr cli: On Linux, MacOS: ```sh dapr publish --pubsub pubsub --publish-app-id routing -t deposit -d '{"id": "17", "amount": 15 }' ``` On Windows: ```sh dapr publish --pubsub pubsub --publish-app-id routing -t deposit -d "{\"id\": \"17\", \"amount\": 15 }" ``` --- ## Code Samples *All of the interesting code in this sample is in Startup.cs* ```C# public void ConfigureServices(IServiceCollection services) { services.AddDaprClient(builder => builder.UseJsonSerializationOptions( new JsonSerializerOptions() { PropertyNamingPolicy = JsonNamingPolicy.CamelCase, PropertyNameCaseInsensitive = true, })); ... } ``` `AddDaprClient()` registers the `DaprClient` service with the dependency injection container (using the sepcified `DaprClientBuilder` for settings options). This service can be used to interact with the dapr runtime (e.g. invoke services, publish messages, interact with a state-store, ...). --- ```C# app.UseCloudEvents(); ``` `UseCloudEvents()` registers the Cloud Events middleware in the request processing pipeline. This middleware will unwrap requests with Content-Type `application/cloudevents+json` so that application code can access the event payload in the request body directly. This is recommended when using pub/sub unless you have a need to process the event metadata yourself. --- ```C# app.UseEndpoints(endpoints => { endpoints.MapSubscribeHandler(); endpoints.MapGet("{id}", Balance); endpoints.MapPost("deposit", Deposit).WithTopic(PubsubName, "deposit"); endpoints.MapPost("withdraw", Withdraw).WithTopic(PubsubName, "withdraw"); }); ``` `MapSubscribeHandler()` registers an endpoint that will be called by the Dapr runtime to register for pub/sub topics. This is is not needed unless using pub/sub. `MapGet(...)` and `MapPost(...)` are provided by ASP.NET Core routing - these are used to setup endpoints to handle HTTP requests. `WithTopic(...)` associates an endpoint with a pub/sub topic. --- ```C# async Task Balance(HttpContext context) { var client = context.RequestServices.GetRequiredService(); var id = (string)context.Request.RouteValues["id"]; var account = await client.GetStateAsync(id); if (account == null) { context.Response.StatusCode = 404; return; } context.Response.ContentType = "application/json"; await JsonSerializer.SerializeAsync(context.Response.Body, account, serializerOptions); } ``` Here `GetRequiredService()` is used to retrieve the `StateClient` from the service provider. `client.GetStateAsync(id)` is used to retrieve an `Account` object from that state-store using the key in the variable `id`. The `Account` object stored in the state-store as JSON. If no entry is found for the specified key, then `null` will be returned. --- ```C# await client.SaveStateAsync(transaction.Id, account); ``` `SaveStateAsync(...)` is used to save data to the state-store.