Tore.Service.ActionShell 5.0.0

Tore.Service.ActionShell

Language: C#.

Nuget package: Tore.Service.ActionShell

Dependencies: <br/>

ActionShell v5.0.0 for net5 .<br/>   .net5<br/>   Microsoft.AspNetCore.Mvc.NewtonsoftJson (5.0.10) [Please refer to note 2 below]<br/> <br/> ActionShell v6.0.0+ for net6 .<br/>   .net6<br/>   Microsoft.AspNetCore.Mvc.NewtonsoftJson (>= 6) [Please refer to note 2 below]<br/>

ActionShell :

A standard action filter attribute class for .Net web API <br/>

Why?<br/>

• Bored of writing the same thing every time for services.

• This code contains the common behaviour of an action filter attribute.

• Having project dependent request scope data is so good.

• I can gather any data requied and process it and/or check sessions, access caches, databases, get the IP's etc. <br/> In the multi tenant server mode (Kestrel default) each request arriving is processed in its own thread,<br/> The request context is built, then the target controller instance is created.<br/> If there are action filters:<br/> Filter OnActionExecuting methods are called before the endpoint is invoked and,<br/> Filter OnActionExecuted methods are called after the endpoint is left.<br/> <br/> ActionShell class as a filter attribute:<br/>

• Constructs a developer defined object descendant of RequestScopeBase class gathering request scope data.

• Stores the scope in HttpContext.

• Before endpoint invocation, calls ActionShell.enter delegate if bound, with scope.

• After endpoint completion, calls ActionShell.leave delegate if bound, with scope.

For using it, modifications must be done before service kicks in, e.g.: in startup.cs:

// Add this to your startup.cs usings.

using Tore.Service;

Add bindings at service configure method:

  public void Configure(IApplicationBuilder app, IWebHostEnvironment env) {
      ...
      ActionShell.requestScopeType = typeof(DeveloperDefinedClassDescendingFromRequestScopeBase);
      ActionShell.enter = SomeClass.aStaticMethodToCallBeforeEnteringEndpoint;
      ActionShell.leave = SomeClass.aStaticMethodToCallAfterLeavingEndpoint;
      ...
      
      app.UseRouting();
 
      app.UseAuthorization();

      app.UseEndpoints(endpoints => {endpoints.MapControllers();});
  }

The enter and leave methods are not mandatory.<br/> They receive scope object which is RequestScopeBase descendant as parameter.<br/> So if defined they should be a delegate of type:

public delegate void ActionShellDelegate(RequestScopeBase scope);

The methods should be bound as:

    ActionShell.enter = SomeClass.aStaticMethodToCallBeforeEnteringEndpoint;
    ActionShell.leave = SomeClass.aStaticMethodToCallAfterLeavingEndpoint;

Binding to controllers:

using Tore.Service; // <-- Needed.

namespace WorldDomination.Secret.Project.Controllers {

    [ApiController]
    [ActionShell] // <-- Easy.
    public class TheSuperDuperController: ControllerBase {
        // The super duper controller things here.
    }
}

RequestScopeBase :

To generate project oriented request information, developers must extend the RequestScopeBase class. <br/> It is already populated as follows : <br/>

    routerPath = context.HttpContext.Request.Path;
    actionName = context.ActionDescriptor.RouteValues["Action"];
    modelValid = context.ModelState.IsValid;
    controller = (ControllerBase)context.Controller;
    leftAction = false;   // this is set to true at OnActionExecuted.

Here is an example, additionally collecting the IP address of the client:

public class ExampleRequestScope : RequestScopeBase {
    public string ipAddress {get; private set;} = null // We will store IP address of requester here.
    // other things needed...
    
    public ExampleRequestScope(ActionExecutingContext context):base(context){
        ipAddress = context.HttpContext.Connection.RemoteIpAddress?.ToString();
        /// collect other data needed.
    }
}

For the extended class to take control it has to be assigned like this: <br/>

    ActionShell.requestScopeType = typeof(ExampleRequestScope);

Wherever HttpContext object is accessible then scope is accessible via:

    var ctx = Somewhere.to.obtain.HttpContext;
    var scope = (ExampleRequestScope)ActionShell.fetchScope(ctx);

Notes:<br/> <br/> 1] ActionShell assignments should be done at configuration.<br/>   After service starts, since system goes multithreading, do not change assignments.<br/>   Turkish proverb :While crossing the river, one does not switch horses...<br/> <br/> 2] Why Microsoft.AspNetCore.Mvc.NewtonsoftJson? <br/>   Weirdly enough default http abstractions miss some methods.<br/>   So it saves me from a lot of class chasings and abstractions and I use it in my API's anyway.