Define the APIs

Main > Using Liquid for building your application > Define the APIs

A microservice must expose its functionalities as public accessible endpoints.

Currently Liquid makes it easier for a microservice to receive synchronous calls via REST endpoints as well as asynchronous ones via messages sent to topics and queues of a message bus.

Take a look at related key concepts of Liquid
Encapsulated Domain Logic
Microservice Sizing
Business Error Handling

#Synchronous calls (via REST)

Liquid provides a LightController base class with many high level primitives so as to respond to REST calls in a much easier and standardized way.

[ApiVersion("1.0")]
public class MyController : LightController
{
    [HttpGet("/All")]
    public IActionResult GetAll()
    { 
        var response = Factory<MyService>().GetAsync();
        return Result(response);
    }
}

See how this is done in Liquid Hotel360 sample application.

##Activate Swagger/Open API Specification Liquid also abstracts the basic and common Swagger decoration of a Controller (with Attributes), thus freeing developers of doing repetitive work.

[HttpGet("/All")] //This will be automatically documented with Swagger
public IActionResult GetAll()
{ 
    ...
}

Additionally, Liquid encapsulates the activation of Swagger based on configuration files.

public void ConfigureServices(IServiceCollection services)
{
   ...

   services.AddWorkBench(Configuration); //This activates Swagger automatically
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
   ...

   app.UseWorkBench(Configuration); //This activates Swagger automatically
}

See how this is done in Liquid Hotel360 sample application.

#Asynchronous messages (via Message Bus)

Messages a microservice respond to are also considered one of its public exposed APIs - an asynchronous one.

Therefore, Liquid allows receiving and processing messages from a specific Message Bus cartridge that was previously configured:

[MessageBus("FOO")]
public class FooWorker: LightWorker
{
    [Queue("my_queue", 1)]
    public void ProcessMessage(QueuedMessage1 msg)
    {             
        ValidateInput(msg);

        //Calls domain (business) logic
        var response = Factory<FooService>().AddAsync(msg.MapTo<fooVM>());

        //Terminates the message according to domain response
        Terminate(response.Result);
    }
}

    [Topic("my_topic", "AllNotification")] 
    public void ProcessNotification(SubscribedMessage1 msg)
    {
        ...
    }

See how this is done in Liquid Hotel360 sample application.