AspNetCore.ApiGateway
Asp Net Core Api Gateway package.
| Packages | Version & Downloads |
|---|---|
| AspNetCore.ApiGateway | |
| AspNetCore.ApiGateway.Client |
The microservices architecture uses an Api Gateway as shown below.
The package:
- Makes creating an Api Gateway a breeze!!
Features
- Swagger
- Authorization
- Filters
- Action
- Exception
- Result
- Load balancing
- Response caching
- Web sockets
- Event sourcing
- Request aggregation
- Middleware service
- Logging
Gateway as a Microservice Facade
Your Gateway API is a microservice which exposes endpoints that are a facade over your backend API endpoints.
- GET
- HEAD
- POST
- PUT
- PATCH
- DELETE
Implementation
In the solution, there are 2 back end APIs : Weather API and Stock API.
For eg. To make a GET call to the backend API, you would set up an Api and a GET Route in your Gateway API's Api Orchestrator.
Then, the client app would make a GET call to the Gateway API which would make a GET call to the backend API using HttpClient.
In your Backend API project
Let us say you have a GET endpoint like this.
- HTTP GET - /weatherforecast/forecast
In your Gateway API project
You add a Route for the backend GET call in the Api Orchrestrator.
Add a reference to the package and...
-
Create an Api Orchestration.
You create an Api (weatherservice) and add a Route (forecast).
public static class ApiOrchestration
{
public static void Create(IApiOrchestrator orchestrator, IApplicationBuilder app)
{
var serviceProvider = app.ApplicationServices;
var weatherService = serviceProvider.GetService<IWeatherService>();
var weatherApiClientConfig = weatherService.GetClientConfig();
orchestrator.StartGatewayHub = true;
orchestrator.GatewayHubUrl = "https://localhost:44360/GatewayHub";
orchestrator.AddApi("weatherservice", "http://localhost:63969/")
//Get
.AddRoute("forecast", GatewayVerb.GET, new RouteInfo { Path = "weatherforecast/forecast", ResponseType = typeof(IEnumerable<WeatherForecast>) })
//Head
.AddRoute("forecasthead", GatewayVerb.HEAD, new RouteInfo { Path = "weatherforecast/forecast" })
//Get with params
.AddRoute("typewithparams", GatewayVerb.GET, new RouteInfo { Path = "weatherforecast/types/{index}"})
//Get using custom HttpClient
.AddRoute("types", GatewayVerb.GET, new RouteInfo { Path = "weatherforecast/types", ResponseType = typeof(string[]), HttpClientConfig = weatherApiClientConfig })
//Get with param using custom HttpClient
.AddRoute("type", GatewayVerb.GET, new RouteInfo { Path = "weatherforecast/types/", ResponseType = typeof(WeatherTypeResponse), HttpClientConfig = weatherApiClientConfig })
//Get using custom implementation
.AddRoute("typescustom", GatewayVerb.GET, weatherService.GetTypes)
//Post
.AddRoute("add", GatewayVerb.POST, new RouteInfo { Path = "weatherforecast/types/add", RequestType = typeof(AddWeatherTypeRequest), ResponseType = typeof(string[])})
//Put
.AddRoute("update", GatewayVerb.PUT, new RouteInfo { Path = "weatherforecast/types/update", RequestType = typeof(UpdateWeatherTypeRequest), ResponseType = typeof(string[]) })
//Patch
.AddRoute("patch", GatewayVerb.PATCH, new RouteInfo { Path = "weatherforecast/forecast/patch", ResponseType = typeof(WeatherForecast) })
//Delete
.AddRoute("remove", GatewayVerb.DELETE, new RouteInfo { Path = "weatherforecast/types/remove/", ResponseType = typeof(string[]) })
.AddApi("stockservice", "http://localhost:63967/")
.AddRoute("stocks", GatewayVerb.GET, new RouteInfo { Path = "stock", ResponseType = typeof(IEnumerable<StockQuote>) })
.AddRoute("stock", GatewayVerb.GET, new RouteInfo { Path = "stock/", ResponseType = typeof(StockQuote) })
.AddHub("chatservice", ConnectionHelpers.BuildHubConnection, "2f85e3c6-66d2-48a3-8ff7-31a65073558b")
.AddRoute("room", new HubRouteInfo { InvokeMethod = "SendMessage", ReceiveMethod = "ReceiveMessage", ReceiveParameterTypes = new Type[] { typeof(string), typeof(string) } })
.AddEventSource("eventsourceservice", ConnectionHelpers.BuildEventSourceConnection, "281802b8-6f19-4b9d-820c-9ed29ee127f3")
.AddRoute("mystream", new EventSourceRouteInfo { ReceiveMethod = "ReceiveMyStreamEvent", Type = EventSourcingType.EventStore, OperationType = EventSourcingOperationType.PublishSubscribe, StreamName = "my-stream", GroupName = "my-group" });
}
}- Hook up in Startup.cs
public void ConfigureServices(IServiceCollection services)
{
services.AddTransient<IWeatherService, WeatherService>();
//Api gateway
services.AddApiGateway();
services.AddControllers();
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo { Title = "My Api Gateway", Version = "v1" });
});
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseSwagger();
app.UseSwaggerUI(c =>
{
c.SwaggerEndpoint("/swagger/v1/swagger.json", "My Api Gateway");
});
//Api gateway
app.UseApiGateway(orchestrator => ApiOrchestration.Create(orchestrator, app));
app.UseHttpsRedirection();
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
//GatewayHub endpoint
endpoints.MapHub<GatewayHub>("/gatewayhub");
endpoints.MapControllers();
});
}The Gateway Swagger appears as shown below:
To call the forecast Route on the weather service Api,
you can enter the Api key and Route key into Swagger as below:
This will hit the weatherforecast/forecast endpoint on the backend Weather API.
You can check out how the Api Gateway supported Verbs are used below.
Verbs Usage
You can check out how the Api Gateway's endpoint Authorization support below.
Authorization
Customizations
- You can customize the default HttpClient which the endpoints use to hit the backend api.
- You can use your own HttpClient to hit the backend Api.
- You can create your own implementation to hit the backend Api.
For Request aggregation, see this section.
Customizations
Load Balancing
Load Balancing
Response Caching
Response Caching
Web Sockets
Web Sockets
Event Sourcing
Event Sourcing
Filters
Middleware Service
Middleware Service
Viewing your Gateway's Api Orchestration
Your Gateway's Api Orchestration is published by GET /api/Gateway/orchestration endpoint.
Viewing Api Orchestration
Logging
The Api Gateway uses ILogger<ApiGatewayLog> to create logs.
In your Gateway API project, this can be used to tap into these logs.
Clients
The Api Gateway supports a fixed set of endpoints.
All routes go through these endpoints.
The Client application has to talk to these endpoints of the Api Gateway.
A Client library is provided for: