There is an active branch that converts all these samples to ASP.NET Core 3.1 and ASP.NET Core 5.
If you are studying ASP.NET Core, I am lurking on this Gitter Channel.
Hi Nuget visitors, if you have problem finding the sample you are looking for, please use the github search functionality or otherwise file a case. I will be happy to point you to the right direction.
The goal of this project is to enable .NET programmers to learn the new ASP.NET Core stack from the ground up directly from code. There is so much power in the underlying ASP.NET Core stack. Don't miss them!
I highly recommend using Visual Studio Code to play around with these samples but it is not required. You can use Visual Studio 2019 as well.
Note: If you encounter problem with downloading packages or Nuget, try the following command nuget.exe locals -clear all.
ASP.NET Core API Browser is also very handy.
To run these samples, simply open your command line console, go to each folder and execute dotnet watch run.
Most of the examples here uses Microsoft.AspNetCore package which is a package consisted of
Microsoft.AspNetCore.Diagnostics
Microsoft.AspNetCore.HostFiltering
Microsoft.AspNetCore.Hosting
Microsoft.AspNetCore.Routing
Microsoft.AspNetCore.Server.IISIntegration
Microsoft.AspNetCore.Server.Kestrel
Microsoft.AspNetCore.Server.Kestrel.Https
Microsoft.Extensions.Configuration.CommandLine
Microsoft.Extensions.Configuration.EnvironmentVariables
Microsoft.Extensions.Configuration.FileExtensions
Microsoft.Extensions.Configuration.Json
Microsoft.Extensions.Configuration.UserSecrets
Microsoft.Extensions.Logging
Microsoft.Extensions.Logging.Configuration
Microsoft.Extensions.Logging.Console
Microsoft.Extensions.Logging.Debug
When an example requires packages that are not listed here, it will be added to the project file.
Foundation ASP.NET Core 2.1 SamplesAll these projects require the following dependencies
"Microsoft.AspNetCore" : "2.1.0"
Hello World (22)
Setup your most basic web app and enable the change+refresh development experience.
We are using IApplicationBuilder Run, an extension method for adding terminal middleware.
Startup class
Hello World with startup basic
This project contains all the available services available in Startup class constructor, ConfigureServices and Configure methods.
Hello World with custom startup class name
You don't have to call your startup class Startup. Any valid C# class will do.
Hello World with responding to multiple urls
Configure so that your web app responds to multiple urls.
Hello World with multiple startups
This project highlights the fact that you can create multiple Startup classes and choose them at start depending on your needs.
Hello World with multiple startups using environment
This project highlights the fact that you can create multiple startup classes and choose them at start depending on your needs depending on your environment (You do have to name the startup class with Startup).
Hello World with multiple Configure methods based on environment
This project demonstrates the ability to pick Configure method in a single Startup class based on environment.
Hello World with multiple ConfigureServices methods based on environment
This project demonstrates the ability to pick ConfigureServices method in a single Startup class based on environment.
Hello World with an implementation of IStartup interface
We are really getting into the weed of startup right now. This is an example on how to implement IStartup directly.
Hello World without a startup class
Why? just because we can.
Hello world with IStartupFilter
Use IStartupFilter to configure your middleware. This is an advanced topic. This article tries at explaining IStartupFilter. I will add more samples so IStartupFilter can be clearer.
Show a detailed report on exceptions that happen during the startup phase of your web app. It is very useful during development.
Enumerate the connection information of a HTTP request.
Set your application environment to Development or Production or other mode directly from code.
Setup a basic logging in your app and show it to console.
We add the following dependencies "Microsoft.Extensions.Logging": "1.1.0" and "Microsoft.Extensions.Logging.Console": "1.1.0"
We are using IApplicationBuilder Run, an extension method for adding terminal middleware.
Console logging - without framework log
Filter out frameworking logging from your log output. Without filtering, logging can get very annoying because the framework produces a lot of messages.
ASPNetCore is built on top of pipelines of functions called middleware.
We are using IApplicationBuilder Use, an extension method for adding middleware and IApplicationBuilder Run.
Respond to application startup and shutdown.
We are using IApplicationLifetime that trigger events during application startup and shutdown.
IHostingEnvironment is available at Startup constuctor and Startup.Configure. This sample shows all the properties available in this interface.
IHostingEnvironment at ConfigureServices
This sample shows how to access IHostingEnvironment from ConfigureServices.
This sample shows how to obtain application environment information (target framework, etc).
Demonstrate on how to add a response header and where is allowed place to do it.
Request(9)
This section shows all the different ways you capture input and examine request to your web application.
HTTP Verb (1)
Detect the verb/method of the current request.
Headers (3)
Enumerate all the available headers in a request.
Access Request Headers using common HTTP header names contained in HeaderNames
This sample shows all the common HTTP header names contained in HeaderNames class. So instead of using string to obtain a HTTP Header, you can just use a convenient constant such as HeaderNames.ContentType.
Type Safe Access to Request Headers
Instead of using string to access HTTP headers, use type safe object properties to access common HTTP headers.
Query String (1)
Access single value query string.
Access multiples values query string.
List all query string values. Also shows the implicat conversion from StringValues to string.
Form (2)
Handles the values submitted via a form.
Upload a single file and save it to the current directory (check out the usage of .UseContentRoot(Directory.GetCurrentDirectory()))
Cookies (2)
Read and write cookies.
Simply demonstrates on how to remove cookies.
Routing (9)
We go deep into Microsoft.AspNetCore.Routing library that provides routing facilities in your aspnetcore apps. There are several samples to illuminate this powerful library.
A single route handler that handles every path request.
Two route handler, one for home page (/) and the other takes the rest of the request using asterisk (*) in the url template.
We are exploring default handler - this is the entry point to create your own framework.
We are mixing optional route parameter, route parameter with default value and default handler.
[Router 5]
This is still broken. I am trying to figure out how to do nested routing. Wish me luck!
We are building a template route segment by segment and parts by parts, oldskool. We are using TemplateMatcher, TemplateSegment and TemplatePart.
Hold your mask, we are going deep.
We are creating a routing template with two segments, one with Literal part and the other Parameter part, e.g, "/page/{*title}"
We are creating a routing template with one segment consisted of two parts, one Literal and one Parameter, e.g. "/page{*title}". Note the difference between this example and Router 7.
I am still trying to determine whether TemplateMatcher uses the InlineConstraint information.
Update: No, TemplateMatcher does not run constraints. #362
We have been building a RouteTemplate manually using TemplateSegment and TemplatePart. In this example we are using TemplateParser to build the RouteTemplate using string.
Middleware (12)
We will explore all aspect of middleware building in this section.
This example shows how to pass information from one middleware to another using HttpContext.Items.
As a general rule, only one of your Middleware should write to Response in an execution path. This sample shows how to work around this by buffering the Response.
e.g.
If path / involves the execution of Middleware 1, Middleware 2 and Middleware 3, only one of these should write to Response.
This is the simplest middleware class you can create.
Use app.Map (MapMiddleware) to configure your middleware pipeline to respond only on specific url path.
Nested app.Map (show Request.Path and Request.PathBase).
Use app.MapWhen(MapWhenMiddleware) and Nested app.Map (show Request.Path and Request.PathBase).
Use MapMiddleware and MapWhenMiddleware directly without using extensions (show Request.Path and Request.PathBase).
Demonstrate the various ways you can inject dependency to your middleware class manually.
Demonstrate how to ASP.NET Core built in DI (Dependency Injection) mechanism to provide dependency for your middleware.
Demonstrate that a middleware is a singleton.
This sample is similar to Middleware 10 except that this one implement IMiddleware to create Factory-based middleware activation. This means that you can create a middleware that is not a singleton (either Transient or Scoped).
Contrast the usage of MapWhen (which branch execution) and UseWhen (which doesn't branch execution) in configuring your Middleware.
Features (9)
Features are collection of objects you can obtain from the framework at runtime that serve different purposes.
Use this Feature to obtain a list of urls that your app is responding to.
Use IServer interface to access server addressess when you don't have access to IApplicationBuilder.
Obtain details of a current request. It has some similarity to HttpContext.Request. They are not equal. HttpContext.Request has more properties.
Use IHttpConnectionFeature interface to obtain local ip/port and remote ip/port.
Create your own custom Feature and pass it along from a middleware.
Shows how you can replace an implementation of a Feature with another within the request pipeline.
Use this feature to detect the culture of a web request through IRequestCultureFeature. It needs the following dependency "Microsoft.AspNetCore.Localization": "2.1.0".
Use session within your middlewares. This sample shows a basic usage of in memory session. It needs the following dependency '"Microsoft.AspNetCore.Session" : "1.1.0-"and"Microsoft.Extensions.Caching.Memory" : "2.1.0-"`.
Maximum Request Body Size Feature
Use this feature to read and set maximum HTTP Request body size.
Dependency Injection (2)
ASP.NET Corenetcore lives and die by DI. It relies on Microsoft.Extensions.DependencyInjection library.
Dependency Injection 1 - The basic
Demonstrate the three lifetime registrations for the out of the box DI functionality: singleton (one and only forever), scoped (one in every request) and transient (new everytime).
Dependency Injection 3 - Easy registration
Register all objects configured by classes that implements a specific interface (IBootstrap in this example). This is useful when you have large amount of classes in your project that needs registration. You can register them near where they are (usually in the same folder) instead of registering them somewhere in a giant registration function.
Note: example 2 is forthcoming. The inspiration has not arrived yet.
File Provider (2)
We will deal with various types of file providers supported by ASP.NET Core
Physical File Provider - Content and Web roots
Access the file information on your Web and Content roots.
Implement a simple and largely nonsense file provider. It is a good starting point to implement your own proper File Provider.
In Memory Caching (a.k.a local cache) (4)
These samples depends on Microsoft.Extensions.Caching.Memory library.
Caching - Absolute/Sliding expiration
This is the most basic caching you can use either by setting absolute or sliding expiration for your cache. Absolute expiration will remove your cache at a certain point in the future. Sliding expiration will remove your cache after period of inactivity.
Add file dependency to your caching so when the file changes, your cache expires. Make sure to set cache-file.txt to copy over to bin.
Caching 3 - Cache removal event
Register callback when a cached value is removed.
Caching 4 - CancellationChangeToken dependency
Bind several cache entries to a single dependency that you can reset manually.
Configuration (7)
This section is all about configuration, from memory configuration to INI, JSON and XML.
This is the 'hello world' of configuration. Just use a memory based configuration and read/write values to/from it.
Use IOptions at the most basic.
Configuration - Environment variables
Load environment variables and display all of them.
Read from INI file. It requires taking a new dependency, "Microsoft.Extensions.Configuration.INI" : "2.1.0".
Configuration - INI file - Options
Read from INI file (with nested keys) and IOptions. It requires taking two new dependencies, "Microsoft.Extensions.Configuration.INI" : "2.1.0" and "Microsoft.Extensions.Options.ConfigurationExtensions" : "2.1.0".
Read from XML file. It requires taking a new dependency, "Microsoft.Extensions.Configuration.Xml" : "2.1.0".
Note: This Xml Configuration provider does not support repeated element.
The following configuration settings will break:
<appSettings>
<add key="webpages:Version" value="3.0.0.0" />
<add key="webpages:Enabled" value="false" />
</appSettings>
On the other hand you can get unlimited nested elements and also attributes.
Configuration - XML file - Options
Read from XML file and use IOptions. It requires taking two new dependencies, "Microsoft.Extensions.Configuration.Xml" : "2.1.0" and "Microsoft.Extensions.Options.ConfigurationExtensions" : "2.1.0".
Localization and Globalization (6)
This section is all about languages, culture, etc.
Shows the most basic use of localization using a resource file. This sample only supports French language (because we are fancy). It needs the following dependency "Microsoft.AspNetCore.Localization": "2.1.0" and "Microsoft.Extensions.Localization": "2.1.0".
We build upon the previous sample and demonstrate how to switch request culture via query string using the built in QueryStringRequestCultureProvider. This sample supports English and French.
Demonstrate the difference between Culture and UI Culture.
Demonstrate how to switch request culture via cookie using the built in CookieRequestCultureProvider. This sample supports English and French.
Demonstrate using Portable Object (PO) files to support localization instead of the cumbersome resx file. This sample requires OrchardCore.Localization.Core package. This sample requires ASPNET Core 2.
This is a continuation of previous sample but with context, which allows the same translation key to return different strings.
URL Redirect/Rewriting (6)
This section explore the dark arts of URL Rewriting
Shows the most basic of URL rewriting which will redirect (returns HTTP 302) anything to the home page "/". It requires an additional "Microsoft.AspNetCore.Rewrite" : "2.1.0-*" dependency.
If you have used routing yet, I recommend of checking out the routing examples.
Redirect (returns HTTP 302) anything with an extension e.g. about-us.html or welcome.aspx to home page (/). It also shows how to capture the matched regex values.
Rewrite anything with an extension e.g. about-us.html or welcome.aspx to home page (/). It also shows how to capture the matched regex values.
Permanent Redirect (returns HTTP 301) anything with an extension e.g. about-us.html or welcome.aspx to home page (/). It also shows how to capture the matched regex values.
Implement a custom redirect logic based on IRule implementation. Require additional dependency of "Microsoft.AspNetCore.StaticFiles": "1.1.0" to serve images.
This custom redirection logic allows us to simply specify the image file names without worrying about their exact path e.g.'xx.jpg' and 'yy.png'.
Implement a custom redirect logic using lambda (similar functionality to Rewrite - 5). Require additional dependency of "Microsoft.AspNetCore.StaticFiles": "1.1.0" to serve images.
This custom redirection logic allows us to simply specify the image file names without worrying about their exact path e.g.'xx.jpg' and 'yy.png'.
Compression (1)
Enable the ability to compress ASP.NET Core responses. These samples takes a dependency of Microsoft.AspNetCore.ResponseCompression": "2.1.0.
Default Gzip Output Compression
Compress everything using the default Gzip compression.
Everything means the following MIME output
Diagnostics(6)
These samples take a dependency of "Microsoft.AspNetCore.Diagnostics":"1.1.1".
Simply show a welcome page to indicate that the app is working properly. This sample does not use a startup class simply because it's just a one line code.
Show any unhandled exception in a nicely formatted page with error details. Only use this in development environment!
Use IExceptionHandlerFeature feature provided by Microsoft.AspNetCore.Diagnostics.Abstractions to create custom global exception page.
Custom Global Exception Page - 2
Similar to the previous one except that that we use the custom error page defined in separate path.
Use UseStatusCodePagesWithRedirects. Beware: This extension method handles your 5xx return status code by redirecting it to a specific url. It will not handle your application exception in general (for this use UseExceptionHandler - check previous samples).
Here we go into the weeds of analysing middlewares in your request pipeline. This is a bit complicated. It requires the following packages:
Microsoft.AspNetCore.MiddlewareAnalysisMicrosoft.Extensions.DiagnosticAdapterMicrosoft.Extensions.Logging.ConsoleStatic Files(6)
This additional dependency is required to enable the functionality "Microsoft.AspNetCore.StaticFiles": "1.1.0".
Simply serve static files (html, css, images, etc).
There are two static files being served in this project, index.html and hello.css. They are stored under wwwroot folder, which is the default folder location for this library.
To access them you have to refer them directly e.g. localhost:5000/index.html and localhost:5000/hello.css.
Allow listing and browsing of your wwwroot folder.
Combines the functionality of UseStaticFiles, UseDefaultFiles, and UseDirectoryBrowser.
Customize the way Directory Browsing is displayed. In this sample the custom view only handles flat directory. We will deal with more complex scenario in the next sample.
Custom Directory Formatter - 2
Show custom Directory Browsing and handle directory listing as well as files.
Use Directory Browsing on a certain path using DirectoryBrowserOptions.RequestPath, e.g. /browse.
Web Sockets (5)
We are going to explore websocket functionality provided by ASP.NET Core. All the samples here require Microsoft.AspNetCore.WebSockets.
Warning: These samples are low level websocket code. For production, use SignalR. Yes I will work on SignalR samples soon.
This is the simplest web socket code you can write. It simply returns what you sent. It does not handle the closing of the connection. It does not handle data that is larger than buffer. It only handles text payload.
We improve upon the previous sample by adding console logging (requiring Microsoft.Extensions.Logging.Console package) and handling data larger than the buffer. I set the buffer to be very small (4 bytes) so you can see how it works.
We improve upon the previous sample by enabling broadcast. What you see here is a very crude chat functionality.
We improve upon the previous sample by handling closing event intiated by the web client.
Implement a rudimentary single channel chat server.
Server-Sent Events (1)
This server will send a 'hello world' greeting forever.
Syndications (2)
We are using the brand new Microsoft.SyndicationFeed.ReaderWriter package to read RSS and ATOM feeds.
This is the shortest amount of code to read an RSS feed. This example read the feed from the inventor of RSS, Dave Winer at http://scripting.com/rss.xml.
Syndication - Read RSS with extensions
This sample process RSS Outline Extension.
Utils(3)
Here we contrast between the usage of Microsoft.AspNetCore.Http.StatusCodes and System.Net.HttpStatusCode.
This class provides convenient constants for some common MIME types. It's not extensive by any means however MediaTypeNames.Text.Html and MediaTypeNames.Application.Json come handy.
Using FileExtensionContentTypeProvider to obtain the correct MIME type of a filename extension.
Misc (3)
Serve markdown file as html file. You will see how you can create useful app using a few basic facilities in aspnetcore.
We take "Markdig" : "0.15.1" as dependency.
Markdown server - implemented as middleware component
Serve markdown file as html file. It has the same exact functionality as Markdown server but implemented using middleware component.
We take "Markdig" : "0.15.1" as dependency.
Check out the documentation on how to write your own middleware.
Give it a string and it will generate a secure hash for you, e.g. localhost:5000?password=mypassword.
We add dependency "Microsoft.AspNetCore.Identity": "2.1.0" to enable this functionality.
Web Utilities(3)
This section shows various functions avaiable at Microsoft.AspNetCore.WebUtilities.
This utility helps you generate query string for your url safely (ht Rehan Saeed).
QueryHelpers.ParseQuery allows you to parse a raw query string and access its individual key and values.
This utility returns HTTP response phrases given a status code number.
Uri Helper(5)
This section shows various methods available at Microsoft.AspNetCore.Http.Extensions.UriHelper.
Request.GetDisplayUrl() shows complete url with host, path and query string of the current request. It's to be used for display purposes only.
Request.GetEncodedUrl() returns the combined components of the request URL in a fully escaped form suitable for use in HTTP headers and other HTTP operations.
UriHelper.GetEncodedPathAndQuery returns the relative URL of a request.
UriHelper.FromAbsolute separates the given absolute URI string into components.
UriHelper.BuildAbsolute combines the given URI components into a string that is properly encoded for use in HTTP headers. This sample shows 9 ways on how to use it.
Trimming (1)
This section shows the various way on how to trim the size of your application by using Microsoft.Packagin.Tools.Trimming
Trimming Microsoft.AspNetCore.All hello world application
Run dotnet publish or dotnet build and read the output in your terminal. It will read something similar to Trimmed 115 out of 168 files for a savings of 18.93 MB Final app size is 3.07 MB. You can turn off the trimming by setting <TrimUnusedDependencies>true</TrimUnusedDependencies> to false at the project file.
Email (1)
This section shows samples of using MailKit, which is essentially the library to use for sending and receiving email in ASP.NET Core.
This shows an example on how to send an email using SMTP.
Thanks to @Kinani95.
Keeping track of anonymous users
Keep track of anonymous user in your ASP.NET Core (useful in scenario such as keeping track of shopping cart) using ReturnTrue.AspNetCore.Identity.Anonymous library.
Middleware (1)
Use Microsoft.AspNetCore.Buffering 0.2.2 middleware to implement response buffering facility. This will allow you to change your response after you write them.
Device Detection (1)
The samples in this section rely on Wangkanai.Detection library.
This is the most basic device detection. You will be able to detect whether the client is a desktop or a mobile client.
Owin (1)
All these samples require Microsoft.AspNetCore.Owin package. These are low level samples and in most cases are not relevant to your day to day ASP.NET Core development.
Hello world the hard way.
Image Sharp (1)
All these samples require SixLabors.ImageSharp.Web middleware package. This middleware is an excelent tool to process your day to day image processing need.
This example shows how to enable image resizing functionality to your site. It's super easy and the middleware takes care of caching, etc.
Generic Host is an awesome way to host all sort of long running tasks and applications, e.g. messaging, background tasks, etc.
This section is dedicated to all the nitty gritty of Generic Host. All the examples in this section rely on Microsoft.AspNetCore.App package.
This is the hello world equivalent of a Generic Host service.
Hello World using Console Lifetime
Use UseConsoleLifetime implicitly.
Demonstrates the startup and shutdown order of hosted services.
Demonstrates starting and stopping the host programmatically.
A service with timed execution
Demonstrate processing a task on a regular interval using Task.Delay.
Configure Host using Dictionary
Demonstrate the way to inject configuration values to the host using Dictionary.
Set your environment using EnvironmentName.Development or EnvironmentName.Production or EnvironmentName.Staging.
Configure logging for your Generic Host.
Listen to IApplicationLifetime events
Inject IApplicationLifetime and listen to ApplicationStarted, ApplicationStopping and ApplicationStopped events. This is important to allow services to be shutdown gracefully. The shutdown process blocks until ApplicatinStopping and ApplicationStopped events complete.
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