| Packages | Version | Downloads |
|---|---|---|
| AspNetCore.ApiGateway |  |
 |
| AspNetCore.ApiGateway.Client |  |
 |
| ts-aspnetcore-apigateway-client |  |
 |
+ This project has been on-boarded by the .NET Foundation, in the Seed category.Read more. Social Media: LinkedIn post.
| More of my open-source projects | ||
|---|---|---|
| Live Health Checks | Real-Time Api Health Check Monitoring system | Browse |
The microservices architecture uses an Api Gateway as shown below.
The package:
- Makes creating an Api Gateway a breeze!!
- Swagger
- Authorization
- Filters
- Action
- Exception
- Result
- Load balancing
- Response caching
- Web sockets
- Event sourcing
- Request aggregation
- Middleware service
- Logging
- Clients available in
- .NET
- Typescript
Your Gateway API is a microservice which exposes endpoints that are a facade over your backend API endpoints.
- GET
- HEAD
- POST
- PUT
- PATCH
- DELETE
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.
Let us say you have a GET endpoint like this.
- HTTP GET - /weatherforecast/forecast
You add a Route for the backend GET call in the Api Orchrestrator.
You create a backend API with ApiKey called weatherservice for eg. And, a Route with RouteKey called forecast for eg.
So, the call to the Gateway would become:
- HTTP GET - /weatherservice/forecast
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("forecast-custom", GatewayVerb.GET, weatherService.GetForecast)
//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.
If you want, you can keep the ApiKey, RouteKey, backend API base urls and Route path,
in the appsettings.json, read it using a Config Service,
and pass it to the Api Orchestrator in the Create method.
Read more.
As with any Web API, when there is any code change, the API Gateway too is published and deployed using Blue/Green deployment.
This is available in Azure & AWS.
In Azure App Service, you use deployment slots etc.
Azure Kubernetes Service (AKS) also supports Blue/Green deployment. Read more.
In AWS, you use Elastic Beanstalk. Read more.
So, there is no down time.
You can check out how the Api Gateway supported Verbs are used & Routing below.
Just like a Web API's Authorization Filter, the framework provides a Gateway Authorization Filter.
Here you can perform any kind of Authorization you like. There is no prescribed Authorization.
- Create a new or customize the default HttpClient used by all the routes, to hit the backend Api.
- Create a new or customize the default HttpClient which each route uses to hit the backend Api.
- Use your own custom implementation to hit the backend Api.
For Request aggregation, see this section.
Your Gateway's Api Orchestration is published by GET /api/Gateway/orchestration endpoint.
The Api Gateway uses ILogger<ApiGatewayLog> to create logs.
In your Gateway API project, this can be used to tap into these logs.
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: