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European ASP.NET Core Hosting :: AutoWrapper Version 2.1.0 Released

clock November 12, 2019 10:42 by author Peter

AutoWrapper 2.1.0 has been released with newly features added based on community feedback. Here are the newly features added:

  • Added [AutoWrapIgnore] action filter attribute.
  • Added support to override non-success message when using IActionResult return types.
  • Added EnableResponseLogging and EnableExceptionLogging options to turn off auto logging.
  • Added UnAuthorize and BadRequest message for HandleNotSucessAsync() method response.

Using IActionResult Return Types
AutoWrapper now supports IActionResult return types that allows you to return non successful requests such as BadRequest, NotFound, UnAuthorize and etc.
For example:
[Route("{id:long}")] 
[HttpGet] 
public async Task<IActionResult> Get(long id)   

    var person = await _personManager.GetByIdAsync(id); 
    if (person != null) 
    { 
        return Ok(person); 
    } 
    else 
        return NotFound($"Record with id: { id } does not exist."); 


Another example such as:
return Unauthorized("Access token is invalid.");   
return BadRequest("SomeField is null.");   


AutoWrapIgnore Attribute
You can now use the [AutoWrapIgnore] filter attribute for enpoints that you don't want to be wrapped.
For example:
[HttpGet] 
[AutoWrapIgnore] 
public async Task<IActionResult> Get()   

    var data = await _personManager.GetAllAsync(); 
    return Ok(data); 


or
[HttpGet] 
[AutoWrapIgnore] 
public async Task<IEnumerable<Person>> Get()   

    return await _personManager.GetAllAsync(); 


Turn-off Default Logging
You can now turn off Logging by setting EnableResponseLogging and EnableExceptionLogging options to false in AutoWrapper options.
For example:
app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions {   
              EnableResponseLogging = false,  
              EnableExceptionLogging = false  
}); 


That's it. Feel free to request an issue on github if you find bugs or request a new feature. Your valuable feedback is much appreciated to better improve this project. If you find this useful, please give it a star to show your support for this project.



European ASP.NET Core Hosting :: All About Sessions In ASP.NET Core

clock November 5, 2019 10:53 by author Peter

HTTP is a stateless protocol, so we need some mechanism to maintain our App State. Server Side Session has been a way to maintain our state on the server side. In this article we'll see what differences ASP.NET Core has introduced regarding SESSION.

We'll quickly discuss how we used to use Sessions before ASP.NET Core and then we'll see how to access Sessions in ASP.NET Core.

Session In Pre-ASP.NET Core era
You get Session functionality by default (without adding any package)
Previously, you would have accessed Session by -

    Session variable in your Controllers/Forms
    System.Web.HttpContext.Current.Session in places where you don't have direct access to the Session variable.

Anything you store in session is stored as Object. You store values in Key/Value format.

    Session["mydata"] = 10;  

Or to access on those places where Session is not available (e.g. Non-Controller classes)

    System.Web.HttpContext.Current.Session["mydata"] = 10;  

Quite difficult to mock Session Object for Unit Testing

Session in ASP.NET Core 2.2
Now, Session is not available by default.
You need to add the following package. Meta package by default provides you this.

    <PackageReference Include="Microsoft.AspNetCore.Session" Version="2.2.0" /> 
In Startup.ConfigureServices, you need to add the following to register services with DI Container.
    services.AddDistributedMemoryCache();//To Store session in Memory, This is default implementation of IDistributedCache   
    services.AddSession(); 

In Startup.Configure, you need to add the following (before UseMVC) to add Session Middleware.

    app.UseCookiePolicy();     
    app.UseSession();     
    app.UseMvc(routes =>   

Make sure the following is also there (It is added by default when you use ASP.NET Core MVC Template).

    app.UseCookiePolicy();  

ASP.NET Core 2.2 onwards adds Cookie Consent (true) in the Startup file. When an application runs, the user needs to accept Cookie Consent on screen. When the user accepts the policy on the page, it creates a consent cookie. It is to follow GDPR and to give control to the user if the user wants to store cookies from a site or not. If the user doesn't accept that, Session does not work because Session requires a cookie to send/receive session Id. You may face this issue while working with ASP.NET Core MVC default template.

How to access Session in Controller?

You will notice that you don't have "Session" variable available now. Controller now has a property "HttpContext" which has "Session" variable. So, you can access session in controller by using the following code.

var a = this.HttpContext.Session.GetString("login");   
HttpContext.Session.SetString("login", dto.Login); 


How to access Session in Non-Controller class?

Now, you don't have System.Web.HttpContext.Current.Session in ASP.NET Core. To access session in non-controller class -

First, register the following service in Startup.ConfigureServices;

    services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>(); 

Now, register a class (example - TestManager) where you want to access the Session in Startup.ConfigureServices;
    services.AddScoped<TestManager>(); 
Note
You may use AddTransient or AddSingleton according to your logic.

Now, in TestManager class, add the following code.
    private readonly IHttpContextAccessor _httpContextAccessor;   
    private readonly ISession _session;   
    public TestManager(IHttpContextAccessor httpContextAccessor)   
       {   
            _httpContextAccessor = httpContextAccessor;   
            _session = _httpContextAccessor.HttpContext.Session;   
        } 


The above code is receiving IHttpContextAccessor object through dependency injection and then, it is storing Sessions in a local variable.

How to access Session in View file?

Add the following at the top of your View file.
@using Microsoft.AspNetCore.Http   
@inject IHttpContextAccessor httpContextAccessor  


Then, you may access the Session variable in your View like following.
@httpContextAccessor.HttpContext.Session.GetString("login")  

What else is changed regarding Session?

Session is non-locking now.
A session is not created until you have at least one value in it
You need to use functions to get & set data. Array syntax is not supported now.
Now, ISession only provides Get & Set method which takes & returns data in Byte Array format.
If you want to store data in the String format, you may add the following in your file and use extension methods.
    using Microsoft.AspNetCore.Http;  
It exposes the new extension methods.
    SetInt32   
    GetInt32   
    SetString   
    GetString   
Under the hood, these covert the data into bytes.

You may also write your own extension methods. For example, the following Extension Methods help you store & retrieve any complex type.
    public static class SessionExtensions       
        {       
            public static void Set<T>(this ISession session, string key, T value)       
            {       
                session.Set<(key, JsonConvert.SerializeObject(value));       
            }       
           
            public static T GetObject<T>(this ISession session, string key)       
            {       
                var value = session.GetString(key);       
                return value == null ? default(T) : JsonConvert.DeserializeObject<T>(value);       
            }       
        }  


In the next article, we'll learn about SESSION Wrapper Design Pattern.

Summary

Session concepts are similar to what we've seen in earlier .NET Frameworks. The real difference is that now, it is cleaner & more flexible to use.

 



European ASP.NET Core Hosting :: Error When Published ASP.NET Core? See Below Tips!

clock November 5, 2019 05:38 by author Scott

At the past few years, we have discussed about common error that you can find when published .NET Core, the most common error is 502.5 – process failure error.

Startup errors with ASP.NET Core don’t provide much information either, at least not in a production environment. Here are 7 tips for understanding and fixing those errors.

1. There are two types of startup errors.

There are unhandled exceptions originating outside of the Startup class, and exceptions from inside of Startup. These two error types can produce different behavior and may require different troubleshooting techniques.

2. ASP.NET Core will handle exceptions from inside the Startup class.

If code in the ConfigureServices or Configure methods throw an exception, the framework will catch the exception and continue execution.

Although the process continues to run after the exception, every incoming request will generate a 500 response with the message “An error occurred while starting the application”.

Two additional pieces of information about this behavior:

- If you want the process to fail in this scenario, call CaptureStartupErrors on the web host builder and pass the value false.

- In a production environment, the “error occurred” message is all the information you’ll see in a web browser. The framework follows the practice of not giving away error details in a response because error details might give an attacker too much information. You can change the environment setting using the environment variable ASPNETCORE_ENVIRONMENT, but see the next two tips first. You don’t have to change the entire environment to see more error details.

3. Set detailedErrors in code to see a stack trace.

The following bit of code allows for detailed error message, even in production, so use with caution.

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
           .CaptureStartupErrors(true) // the default
           .UseSetting("detailedErrors", "true")
           .UseStartup<Startup>();

4. Alternatively, set the ASPNETCORE_DETAILEDERRORS environment variable.

Set the value to true and you’ll also see a stack trace, even in production, so use with caution.

5. Unhandled exceptions outside of the Startup class will kill the process.

Perhaps you have code inside of Program.cs to run schema migrations or perform other initialization tasks which fail, or perhaps the application cannot bind to the desired ports. If you are running behind IIS, this is the scenario where you’ll see a generic 502.5 Process Failure error message.

These types of errors can be a bit more difficult to track down, but the following two tips should help.

6. For IIS, turn on standard output logging in web.config.

If you are carefully logging using other tools, you might be able to capture output there, too, but if all else fails, ASP.NET will write exception information to stdout by default. By turning the log flag to true, and creating the output directory, you’ll have a file with exception information and a stack trace inside to help track down the problem.

The following shows the web.config file created by dotnet publish and is typically the config file in use when hosting .NET Core in IIS. The attribute to change is the stdoutLogEnabled flag.

<system.webServer>
  <handlers>
    <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModule" resourceType="Unspecified" />

  </handlers>
  <aspNetCore processPath="dotnet" arguments=".\codes.dll"
              stdoutLogEnabled="true" stdoutLogFile=".\logs\stdout" />
</system.webServer>

Important: Make sure to create the logging output directory.

Important: Make sure to turn logging off after troubleshooting is complete.

7. Use the dotnet CLI to run the application on your server.

If you have access to the server, it is sometimes easier to go directly to the server and use dotnet to witness the exception in real time. There’s no need to turn on logging or set and unset environment variables.

Summary

Debugging startup errors in ASP.NET Core is a simple case of finding the exception. In many cases, #7 is the simplest approach that doesn’t require code or environment changes. FYI, we also have support latest ASP.NET Core on our hosting environment. Feel free to visit our site at https://www.hostforlife.eu.



About HostForLIFE.eu

HostForLIFE.eu is European Windows Hosting Provider which focuses on Windows Platform only. We deliver on-demand hosting solutions including Shared hosting, Reseller Hosting, Cloud Hosting, Dedicated Servers, and IT as a Service for companies of all sizes.

We have offered the latest Windows 2016 Hosting, ASP.NET Core 2.2.1 Hosting, ASP.NET MVC 6 Hosting and SQL 2017 Hosting.


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