ASP.NET Core

https://learn.microsoft.com/en-us/aspnet/core
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### Complete short-circuit configuration example

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/routing

A full WebApplication setup demonstrating both individual and bulk short-circuiting.

```C#
var app = WebApplication.Create();

app.UseHttpLogging();

app.MapGet("/", () => "No short-circuiting!");
app.MapGet("/short-circuit", () => "Short circuiting!").ShortCircuit();
app.MapShortCircuit(404, "robots.txt", "favicon.ico");

app.Run();
```

--------------------------------

### Application Execution Output

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/aot/native-aot-tutorial

Example output showing the application starting and listening on a local port.

```text
info: Microsoft.Hosting.Lifetime[14]
      Now listening on: http://localhost:5000
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Production
info: Microsoft.Hosting.Lifetime[0]
      Content root path: C:\Code\Demos\MyFirstAotWebApi
```

--------------------------------

### Example .csproj Configuration

Source: https://learn.microsoft.com/en-us/aspnet/core/client-side/dotnet-interop/wasm-browser-app

Complete project file examples showing the required configuration for WebAssembly browser applications.

```xml
<Project Sdk="Microsoft.NET.Sdk.WebAssembly">

  <PropertyGroup>
    <TargetFramework>{TARGET FRAMEWORK}</TargetFramework>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
  </PropertyGroup>

</Project>
```

```xml
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <RuntimeIdentifier>browser-wasm</RuntimeIdentifier>
    <OutputType>Exe</OutputType>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
    <WasmMainJSPath>main.js</WasmMainJSPath>
    <Nullable>enable</Nullable>
  </PropertyGroup>

</Project>
```

--------------------------------

### Add examples to documentation

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/openapi/openapi-comments

Use the <example> tag for types or the example attribute for parameters to include sample data in the generated documentation.

```csharp
/// <example>{"name":"Sample","value":42}</example>
/// <param name="id" example="42">The unique identifier</param>
```

--------------------------------

### Example JSON response for GET requests

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Sample JSON output returned by the API when querying all items or a single item by ID.

```json
[
  {
    "id": 1,
    "name": "walk dog",
    "isComplete": true
  }
]
```

```json
{
  "id": 1,
  "name": "walk dog",
  "isComplete": true
}
```

--------------------------------

### Complete Minimal API Implementation with TypedResults

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

A full example demonstrating the setup of a minimal API using Entity Framework Core and the TypedResults API for all CRUD operations.

```C#
using Microsoft.EntityFrameworkCore;
using Scalar.AspNetCore;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDbContext<TodoDb>(opt => opt.UseInMemoryDatabase("TodoList"));
builder.Services.AddOpenApi();
var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
    app.MapScalarApiReference();
}

var todoItems = app.MapGroup("/todoitems");

todoItems.MapGet("/", GetAllTodos);
todoItems.MapGet("/complete", GetCompleteTodos);
todoItems.MapGet("/{id}", GetTodo);
todoItems.MapPost("/", CreateTodo);
todoItems.MapPut("/{id}", UpdateTodo);
todoItems.MapPatch("/{id}", PatchTodo);
todoItems.MapDelete("/{id}", DeleteTodo);

app.Run();

static async Task<IResult> GetAllTodos(TodoDb db)
{
    return TypedResults.Ok(await db.Todos.ToArrayAsync());
}

static async Task<IResult> GetCompleteTodos(TodoDb db)
{
    return TypedResults.Ok(await db.Todos.Where(t => t.IsComplete).ToListAsync());
}

static async Task<IResult> GetTodo(int id, TodoDb db)
{
    return await db.Todos.FindAsync(id)
        is Todo todo
            ? TypedResults.Ok(todo)
            : TypedResults.NotFound();
}

static async Task<IResult> CreateTodo(Todo todo, TodoDb db)
{
    db.Todos.Add(todo);
    await db.SaveChangesAsync();

    return TypedResults.Created($"/todoitems/{todo.Id}", todo);
}

static async Task<IResult> UpdateTodo(int id, Todo inputTodo, TodoDb db)
{
    var todo = await db.Todos.FindAsync(id);

    if (todo is null) return TypedResults.NotFound();

    todo.Name = inputTodo.Name;
    todo.IsComplete = inputTodo.IsComplete;

    await db.SaveChangesAsync();

    return TypedResults.NoContent();
}

static async Task<IResult> PatchTodo(int id, TodoPatchDto inputTodo, TodoDb db)
{
    var todo = await db.Todos.FindAsync(id);

    if (todo is null) return TypedResults.NotFound();

    if (inputTodo.Name is not null) todo.Name = inputTodo.Name;
    if (inputTodo.IsComplete is not null) todo.IsComplete = inputTodo.IsComplete.Value;

    await db.SaveChangesAsync();

    return TypedResults.NoContent();
}

static async Task<IResult> DeleteTodo(int id, TodoDb db)
{
    if (await db.Todos.FindAsync(id) is Todo todo)
    {
        db.Todos.Remove(todo);
        await db.SaveChangesAsync();
        return TypedResults.NoContent();
    }

    return TypedResults.NotFound();
}
```

--------------------------------

### ResponseHeader Example Output

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/servers/yarp/transforms-response

Example of the resulting header format.

```text
HeaderName: value
```

--------------------------------

### Install SignalR client via npm

Source: https://learn.microsoft.com/en-us/aspnet/core/signalr/javascript-client

Initializes npm and installs the Microsoft SignalR client library package.

```bash
npm init -y
npm install @microsoft/signalr

```

```bash
npm init -y
npm install @microsoft/signalr

```

--------------------------------

### Issue an HTTP GET request

Source: https://learn.microsoft.com/en-us/aspnet/core/web-api/http-repl

Example of running the get command on an endpoint.

```console
https://localhost:5001/people> get
```

--------------------------------

### Using Startup with Minimal Hosting

Source: https://learn.microsoft.com/en-us/aspnet/core/migration/50-to-60

Demonstrates how to integrate an existing Startup class into the .NET 6 minimal hosting model.

```C#
using Microsoft.AspNetCore.Builder;

var builder = WebApplication.CreateBuilder(args);

var startup = new Startup(builder.Configuration);

startup.ConfigureServices(builder.Services);

var app = builder.Build();

startup.Configure(app, app.Environment);

app.Run();
```

--------------------------------

### Example Project File Configuration

Source: https://learn.microsoft.com/en-us/aspnet/core/security/authentication/scaffold-identity

Shows a sample .csproj file structure with the required PackageReference entries for Identity and Entity Framework.

```xml
<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore" Version="3.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.UI" Version="3.1.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="3.1.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="3.1.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.0" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.0" />
  </ItemGroup>

</Project>
```

--------------------------------

### Cross-Origin GET Request Headers

Source: https://learn.microsoft.com/en-us/aspnet/core/security/cors

Example of HTTP headers observed during a standard cross-origin GET request.

```http
Request URL: https://cors1.azurewebsites.net/api/values
Request Method: GET
Status Code: 200 OK
```

```http
Content-Encoding: gzip
Content-Type: text/plain; charset=utf-8
Server: Microsoft-IIS/10.0
Set-Cookie: ARRAffinity=8f...;Path=/;HttpOnly;Domain=cors1.azurewebsites.net
Transfer-Encoding: chunked
Vary: Accept-Encoding
X-Powered-By: ASP.NET
```

```http
Accept: */*
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9
Connection: keep-alive
Host: cors1.azurewebsites.net
Origin: https://cors3.azurewebsites.net
Referer: https://cors3.azurewebsites.net/
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: cross-site
User-Agent: Mozilla/5.0 ...
```

--------------------------------

### View LibMan installation output

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr

Shows example terminal output after running the LibMan client library installation command.

```shell
Downloading file https://unpkg.com/@microsoft/signalr@latest/dist/browser/signalr.js...
wwwroot/js/signalr/dist/browser/signalr.js written to disk
Installed library "@microsoft/signalr@latest" to "wwwroot/js/signalr"

```

--------------------------------

### Verify GET action collection response in JSON

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mongo-app

Example JSON output returned when testing the parameterless Get action method on the books controller.

```JSON
[
  {
    "id": "61a6058e6c43f32854e51f51",
    "bookName": "Design Patterns",
    "price": 54.93,
    "category": "Computers",
    "author": "Ralph Johnson"
  },
  {
    "id": "61a6058e6c43f32854e51f52",
    "bookName": "Clean Code",
    "price": 43.15,
    "category": "Computers",
    "author": "Robert C. Martin"
  }
]

```

--------------------------------

### WebHost.Start(string url, RequestDelegate app)

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/web-host

Initializes and starts a new host with preconfigured defaults using a specified URL and RequestDelegate handler.

```APIDOC
## WebHost.Start(string url, RequestDelegate app)

### Description
Initializes and starts a new host with preconfigured defaults bound to the specified URL using a RequestDelegate handler.

### Syntax
```csharp
public static IWebHost Start(string url, RequestDelegate app)
```

### Parameters
- **url** (`string`) - Required - The URL the server should listen on.
- **app** (`RequestDelegate`) - Required - The delegate used to handle incoming HTTP requests.

### Example
```csharp
using (var host = WebHost.Start("http://localhost:8080", app => app.Response.WriteAsync("Hello, World!")))
{
    Console.WriteLine("Use Ctrl-C to shutdown the host...");
    host.WaitForShutdown();
}
```
```

--------------------------------

### Initialize and Configure Web API Project

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-web-api

Creates a new Web API project, navigates to the directory, installs the In-Memory Entity Framework provider, and opens the project in VS Code.

```bash
dotnet new webapi --use-controllers -o TodoApi
cd TodoApi
dotnet add package Microsoft.EntityFrameworkCore.InMemory
code -r .
```

--------------------------------

### Example GET search query URL structure

Source: https://learn.microsoft.com/en-us/aspnet/core/data/ef-rp/sort-filter-page

Represents the resulting URL with query parameters generated upon submitting the GET search form.

```plaintext
https://localhost:5001/Students?SearchString=an

```

--------------------------------

### Application listening output

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Example of the console output indicating the port the application is listening on.

```text
info: Microsoft.Hosting.Lifetime[14]
      Now listening on: http://localhost:5090
```

--------------------------------

### WebHost.Start(RequestDelegate app)

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/web-host

Initializes and starts a new host with preconfigured defaults using a RequestDelegate. Listens on default URL http://localhost:5000 without console output.

```APIDOC
## WebHost.Start(RequestDelegate app)

### Description
Initializes and starts a new host with the preconfigured defaults of CreateDefaultBuilder using a RequestDelegate handler.

### Syntax
```csharp
public static IWebHost Start(RequestDelegate app)
```

### Parameters
- **app** (`RequestDelegate`) - Required - The delegate used to handle incoming HTTP requests.

### Example
```csharp
using (var host = WebHost.Start(app => app.Response.WriteAsync("Hello, World!")))
{
    Console.WriteLine("Use Ctrl-C to shutdown the host...");
    host.WaitForShutdown();
}
```
```

--------------------------------

### Verify GET action single item response in JSON

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mongo-app

Example JSON output returned when requesting a specific book ID from the overloaded Get action method.

```JSON
{
  "id": "61a6058e6c43f32854e51f52",
  "bookName": "Clean Code",
  "price": 43.15,
  "category": "Computers",
  "author": "Robert C. Martin"
}

```

--------------------------------

### Start Nginx service via Bash

Source: https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/linux-nginx

Explicitly start the Nginx daemon after initial installation on Linux. Verify that the server displays the default Nginx landing page in a browser.

```Bash
sudo service nginx start

```

--------------------------------

### Set up a Web Host in C#

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/web-host

Defines the entry point and configures an IWebHostBuilder instance with default settings and a Startup class. Separating CreateWebHostBuilder from Main is required for Entity Framework Core design-time tooling.

```C#
public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>();
}
```

--------------------------------

### Install Entity Framework Core In-Memory Package

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Use the .NET CLI to add the required in-memory database provider package to the project.

```bash
  dotnet add package Microsoft.EntityFrameworkCore.InMemory
```

--------------------------------

### Install Scalar NuGet package

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Use the .NET CLI to add the Scalar.AspNetCore package to your project.

```bash
dotnet add package Scalar.AspNetCore
```

--------------------------------

### Retrieve a specific record

Source: https://learn.microsoft.com/en-us/aspnet/core/web-api/http-repl

Example of passing a parameter to the get command to filter results.

```console
https://localhost:5001/people> get 2
```

--------------------------------

### Initialize Project and Install JWT Package

Source: https://learn.microsoft.com/en-us/aspnet/core/security/authentication/jwt-authn

Commands to create a new web project and add the necessary authentication package.

```bash
dotnet new web -o MyJWT
cd MyJWT
dotnet add package Microsoft.AspNetCore.Authentication.JwtBearer
```

--------------------------------

### HTTP request for todoitems

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Example HTTP request format for the todoitems endpoint.

```HTTP
  GET {{TodoApi_HostAddress}}/todoitems

  ###
```

--------------------------------

### WebHost.Start(Action<IRouteBuilder> routeBuilder)

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/web-host

Initializes and starts a new host with preconfigured defaults using routing middleware and IRouteBuilder. Listens on default URL http://localhost:5000.

```APIDOC
## WebHost.Start(Action<IRouteBuilder> routeBuilder)

### Description
Runs the host by configuring an instance of IRouteBuilder for endpoint routing.

### Syntax
```csharp
public static IWebHost Start(Action<IRouteBuilder> routeBuilder)
```

### Parameters
- **routeBuilder** (`Action<IRouteBuilder>`) - Required - A callback to configure route endpoints.

### Example
```csharp
using (var host = WebHost.Start(router => router
    .MapGet("hello/{name}", (req, res, data) => 
        res.WriteAsync($"Hello, {data.Values["name"]}!"))
    .MapGet("buenosdias/{name}", (req, res, data) => 
        res.WriteAsync($"Buenos dias, {data.Values["name"]}!"))
    .MapGet("throw/{message?}", (req, res, data) => 
        throw new Exception((string)data.Values["message"] ?? "Uh oh!"))
    .MapGet("{greeting}/{name}", (req, res, data) => 
        res.WriteAsync($"{data.Values["greeting"]}, {data.Values["name"]}!"))
    .MapGet("", (req, res, data) => res.WriteAsync("Hello, World!"))))
{
    Console.WriteLine("Use Ctrl-C to shutdown the host...");
    host.WaitForShutdown();
}
```
```

--------------------------------

### Define GET endpoints in Program.cs

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Uses MapGet to define routes for retrieving all items, completed items, and specific items by ID.

```C#
app.MapGet("/todoitems", async (TodoDb db) =>
    await db.Todos.ToListAsync());

app.MapGet("/todoitems/complete", async (TodoDb db) =>
    await db.Todos.Where(t => t.IsComplete).ToListAsync());

app.MapGet("/todoitems/{id}", async (int id, TodoDb db) =>
    await db.Todos.FindAsync(id)
        is Todo todo
            ? Results.Ok(todo)
            : Results.NotFound());
```

--------------------------------

### Initialize a new React project

Source: https://learn.microsoft.com/en-us/aspnet/core/client-side/spa/react

Use the .NET CLI to scaffold a new React application and navigate into the project directory.

```bash
dotnet new react -o my-new-app
cd my-new-app
```

--------------------------------

### JSON request body

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Example JSON payload for creating a new to-do item.

```json
  {
    "name":"walk dog",
    "isComplete":true
  }
```

--------------------------------

### WebHost.Start(string url, Action<IRouteBuilder> routeBuilder)

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/web-host

Initializes and starts a new host bound to a specified URL using routing middleware and IRouteBuilder.

```APIDOC
## WebHost.Start(string url, Action<IRouteBuilder> routeBuilder)

### Description
Runs the host with a specified URL by configuring an instance of IRouteBuilder for routing.

### Syntax
```csharp
public static IWebHost Start(string url, Action<IRouteBuilder> routeBuilder)
```

### Parameters
- **url** (`string`) - Required - The URL the server should listen on.
- **routeBuilder** (`Action<IRouteBuilder>`) - Required - A callback to configure route endpoints.

### Example
```csharp
using (var host = WebHost.Start("http://localhost:8080", router => router
    .MapGet("hello/{name}", (req, res, data) => 
        res.WriteAsync($"Hello, {data.Values["name"]}!"))
    .MapGet("buenosdias/{name}", (req, res, data) => 
        res.WriteAsync($"Buenos dias, {data.Values["name"]}!"))
    .MapGet("throw/{message?}", (req, res, data) => 
        throw new Exception((string)data.Values["message"] ?? "Uh oh!"))
    .MapGet("{greeting}/{name}", (req, res, data) => 
        res.WriteAsync($"{data.Values["greeting"]}, {data.Values["name"]}!"))
    .MapGet("", (req, res, data) => res.WriteAsync("Hello, World!"))))
{
    Console.WriteLine("Use Ctrl-C to shut down the host...");
    host.WaitForShutdown();
}
```
```

--------------------------------

### Example response containing book collection

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mongo-app

Displays the JSON payload returned by the GET /books endpoint.

```json
[
  {
    "Id": "61a6058e6c43f32854e51f51",
    "Name": "Design Patterns",
    "Price": 54.93,
    "Category": "Computers",
    "Author": "Ralph Johnson"
  },
  {
    "Id": "61a6058e6c43f32854e51f52",
    "Name": "Clean Code",
    "Price": 43.15,
    "Category": "Computers",
    "Author": "Robert C. Martin"
  }
]

```

--------------------------------

### Define HTTP request in .http file

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Examples of defining host addresses, request headers, and JSON bodies for testing API endpoints.

```http
  @TodoApi_HostAddress = https://localhost:7031

  POST {{TodoApi_HostAddress}}/todoitems

  ###
```

```http
  Content-Type: application/json

  {
    "name":"walk dog",
    "isComplete":true
  }
```

```http
  @TodoApi_HostAddress = https://localhost:7057

  POST {{TodoApi_HostAddress}}/todoitems
  Content-Type: application/json

  {
    "name":"walk dog",
    "isComplete":true
  }

  ###
```

--------------------------------

### Example Filtered URL

Source: https://learn.microsoft.com/en-us/aspnet/core/data/ef-mvc/sort-filter-page

Shows the resulting URL structure when using the GET method for search filtering.

```text
http://localhost:5813/Students?SearchString=an
```

--------------------------------

### Implement API endpoints with DTOs

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Full implementation of a Minimal API using DTOs for GET, POST, PUT, and DELETE operations.

```C#
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDatabaseDeveloperPageExceptionFilter();
builder.Services.AddDbContext<TodoDb>(opt => opt.UseInMemoryDatabase("TodoList"));
var app = builder.Build();

app.MapGet("/todoitems", async (TodoDb db) =>
    await db.Todos.Select(x => new TodoItemDTO(x)).ToListAsync());

app.MapGet("/todoitems/{id}", async (int id, TodoDb db) =>
    await db.Todos.FindAsync(id)
        is Todo todo
            ? Results.Ok(new TodoItemDTO(todo))
            : Results.NotFound());

app.MapPost("/todoitems", async (TodoItemDTO todoItemDTO, TodoDb db) =>
{
    var todoItem = new Todo
    {
        IsComplete = todoItemDTO.IsComplete,
        Name = todoItemDTO.Name
    };

    db.Todos.Add(todoItem);
    await db.SaveChangesAsync();

    return Results.Created($"/todoitems/{todoItem.Id}", new TodoItemDTO(todoItem));
});

app.MapPut("/todoitems/{id}", async (int id, TodoItemDTO todoItemDTO, TodoDb db) =>
{
    var todo = await db.Todos.FindAsync(id);

    if (todo is null) return Results.NotFound();

    todo.Name = todoItemDTO.Name;
    todo.IsComplete = todoItemDTO.IsComplete;

    await db.SaveChangesAsync();

    return Results.NoContent();
});

app.MapDelete("/todoitems/{id}", async (int id, TodoDb db) =>
{
    if (await db.Todos.FindAsync(id) is Todo todo)
    {
        db.Todos.Remove(todo);
        await db.SaveChangesAsync();
        return Results.NoContent();
    }

    return Results.NotFound();
});

app.Run();

public class Todo
{
    public int Id { get; set; }
    public string? Name { get; set; }
    public bool IsComplete { get; set; }
    public string? Secret { get; set; }
}

public class TodoItemDTO
{
    public int Id { get; set; }
    public string? Name { get; set; }
    public bool IsComplete { get; set; }

    public TodoItemDTO() { }
    public TodoItemDTO(Todo todoItem) =>
    (Id, Name, IsComplete) = (todoItem.Id, todoItem.Name, todoItem.IsComplete);
}


class TodoDb : DbContext
{
    public TodoDb(DbContextOptions<TodoDb> options)
        : base(options) { }

    public DbSet<Todo> Todos => Set<Todo>();
}
```

--------------------------------

### Configure and Run a Web Host with Startup Class in C#

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/generic-host

Configures web host defaults and registers a Startup class to handle HTTP workloads asynchronously.

```C#
await Host.CreateDefaultBuilder(args)
    .ConfigureWebHostDefaults(webBuilder =>
    {
        webBuilder.UseStartup<Startup>();
    })
    .Build()
    .RunAsync();

```

--------------------------------

### Parent Component Setup for ElementReference

Source: https://learn.microsoft.com/en-us/aspnet/core/blazor/javascript-interoperability/call-javascript-from-dotnet

Examples of parent component structures used to pass references to child components.

```razor
@page "/call-js-7"

<PageTitle>Call JS 7</PageTitle>

<h1>Call JS Example 7</h1>

<h2 @ref="title">Hello, world!</h2>

Welcome to your new app.

<SurveyPrompt Parent="this" Title="How is Blazor working for you?" />
```

```razor
@page "/call-js-example-7"

<h1>Call JS Example 7</h1>

<h2 @ref="title">Hello, world!</h2>

Welcome to your new app.

<SurveyPrompt Parent="this" Title="How is Blazor working for you?" />
```

--------------------------------

### Test DELETE request in HTTP file

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Example of a DELETE request formatted for an .http file.

```HTTP
  DELETE {{TodoApi_HostAddress}}/todoitems/1

  ###
```

--------------------------------

### Individual Key Revocation XML

Source: https://learn.microsoft.com/en-us/aspnet/core/security/data-protection/implementation/key-storage-format

Example of an XML file used to revoke a specific key identified by its GUID.

```xml
<?xml version="1.0" encoding="utf-8"?>
<revocation version="1">
  <revocationDate>2015-03-20T22:45:30.2616742Z</revocationDate>
  <key id="bbbbbbbb-1c1c-2d2d-3e3e-444444444444" />
  <reason>human-readable reason</reason>
</revocation>
```

--------------------------------

### Create and run a new web app with authentication

Source: https://learn.microsoft.com/en-us/aspnet/core/security/authentication/accconfirm

Initializes a new ASP.NET Core web application with individual user accounts and starts the development server.

```bash
dotnet new webapp -au Individual -o WebPWrecover
cd WebPWrecover
dotnet run
```

--------------------------------

### Configure project file for hosting startup in XML

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/platform-specific-configuration

Sets up a console application project targeting .NET Core and referencing Microsoft.AspNetCore.Hosting.Abstractions. Used to generate the required dependencies file upon publishing.

```xml
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" 
                      Version="3.0.0" />
  </ItemGroup>

</Project>
```

--------------------------------

### Configure package.json with private setting

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr-typescript-webpack

Setting private to true prevents npm package installation warnings during dependency setup.

```json
{
  "name": "SignalRWebpack",
  "version": "1.0.0",
  "private": true,
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

```

--------------------------------

### Unit Test TypedResults Handlers

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Examples showing how to isolate and verify the return types of minimal API handlers in unit tests.

```csharp
static async Task<IResult> GetAllTodos(TodoDb db)
{
    return TypedResults.Ok(await db.Todos.ToArrayAsync());
}
```

```csharp
public async Task GetAllTodos_ReturnsOkOfTodosResult()
{
    // Arrange
    var db = CreateDbContext();

    // Act
    var result = await TodosApi.GetAllTodos(db);

    // Assert: Check for the correct returned type
    Assert.IsType<Ok<Todo[]>>(result);
}
```

--------------------------------

### Run the API sample using .NET CLI

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/openapi/openapi-comments

Navigate to the API directory and execute the application.

```bash
cd api
dotnet run
```

--------------------------------

### Define PUT request JSON body

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Example JSON payload for updating a to-do item entity.

```json
{
  "name": "feed fish",
  "isComplete": false
}
```

--------------------------------

### View HTTP logging middleware log output

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/http-logging

Example log output generated for a GET request when using an interceptor with redacted headers and request/response enrichment.

```text
info: Microsoft.AspNetCore.HttpLogging.HttpLoggingMiddleware[1]
      Request:
      Path: RedactedPath
      Accept: RedactedHeader
      Host: RedactedHeader
      User-Agent: RedactedHeader
      Accept-Encoding: RedactedHeader
      Accept-Language: RedactedHeader
      Upgrade-Insecure-Requests: RedactedHeader
      sec-ch-ua: RedactedHeader
      sec-ch-ua-mobile: RedactedHeader
      sec-ch-ua-platform: RedactedHeader
      sec-fetch-site: RedactedHeader
      sec-fetch-mode: RedactedHeader
      sec-fetch-user: RedactedHeader
      sec-fetch-dest: RedactedHeader
      RequestEnrichment: Stuff
      Protocol: HTTP/2
      Method: GET
      Scheme: https
info: Microsoft.AspNetCore.HttpLogging.HttpLoggingMiddleware[2]
      Response:
      Content-Type: RedactedHeader
      MyResponseHeader: RedactedHeader
      ResponseEnrichment: Stuff
      StatusCode: 200
info: Microsoft.AspNetCore.HttpLogging.HttpLoggingMiddleware[4]
      ResponseBody: Hello World!
info: Microsoft.AspNetCore.HttpLogging.HttpLoggingMiddleware[8]
      Duration: 2.2778ms

```

--------------------------------

### Build Web Host with Startup Configuration in C#

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/generic-host

Configures startup error capture and registers a Startup class within the host builder initialization.

```C#
public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.CaptureStartupErrors(true);
            webBuilder.UseStartup<Startup>();
        });
```

--------------------------------

### Unit Testing TypedResults Methods

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/min-web-api

Example of a handler method isolated for unit testing purposes.

```C#
static async Task<IResult> GetAllTodos(TodoDb db)
{
    return TypedResults.Ok(await db.Todos.ToArrayAsync());
}
```

--------------------------------

### Application Startup Output

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-web-api

Example console output indicating the application is listening for requests.

```text
...
info: Microsoft.Hosting.Lifetime[14]
      Now listening on: https://localhost:{port}
...
```

--------------------------------

### Troubleshoot Missing Database Migration Exceptions

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mvc-app/adding-model

Occurs when starting the application if the database migration command was omitted during setup. Ensure you execute database update commands before running the app.

```Console
SqlException: Cannot open database "MvcMovieContext-1" requested by the login. The login failed.

```

```Console
SqliteException: SQLite Error 1: 'no such table: Movie'.

```

--------------------------------

### Initial Minimal API Setup

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/minimal-apis/parameter-binding

Basic configuration and endpoint definitions for a Todo API.

```C#
using Microsoft.EntityFrameworkCore;
using TodoApi.Models;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddDatabaseDeveloperPageExceptionFilter();
builder.Services.AddDbContext<TodoDb>(opt => opt.UseInMemoryDatabase("TodoList"));
var app = builder.Build();

app.MapGet("/todoitems", async (TodoDb db) =>
    await db.Todos.Select(x => new TodoItemDTO(x)).ToListAsync());

app.MapGet("/todoitems/{id}",
                             async (int Id, TodoDb Db) =>
    await Db.Todos.FindAsync(Id)
        is Todo todo
            ? Results.Ok(new TodoItemDTO(todo))
            : Results.NotFound());
// Remaining code removed for brevity.
```

--------------------------------

### Restart IIS Services

Source: https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/iis

Commands to stop the Windows Process Activation Service and start the World Wide Web Publishing Service, used after installing the Hosting Bundle or updating the shared framework.

```console
net stop was /y
net start w3svc
```

--------------------------------

### Initialize Web API Project with .NET CLI

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-web-api

Creates a new Web API project, installs the required in-memory database package, and opens the project in Visual Studio Code.

```bash
dotnet new webapi --use-controllers -o TodoApi
cd TodoApi
dotnet add package Microsoft.EntityFrameworkCore.InMemory
code -r ../TodoApi
```

--------------------------------

### libman install

Source: https://learn.microsoft.com/en-us/aspnet/core/client-side/libman/libman-cli

The libman install command downloads and installs library files into the project and updates the libman.json configuration file.

```APIDOC
## libman install

### Description
Downloads and installs library files into the project. A libman.json file is created or updated to store configuration details.

### Arguments
- **LIBRARY** (string) - Required - The name of the library to install, optionally including version notation (e.g., @1.2.0).

### Options
- **-d, --destination** (string) - Optional - The location to install the library. Required if no defaultDestination is set in libman.json.
- **--files** (string) - Optional - The name of a specific file to install. Can be provided multiple times for multiple files.
- **-p, --provider** (string) - Optional - The provider to use (cdnjs, filesystem, jsdelivr, unpkg). Required if no defaultProvider is set in libman.json.
- **--verbosity** (string) - Optional - Sets output verbosity (quiet, normal, detailed).
- **-h, --help** - Optional - Shows help information.

### Example
libman install jquery@3.2.1 --provider cdnjs --destination wwwroot/scripts/jquery --files jquery.min.js
```

--------------------------------

### Configure Startup for Authentication

Source: https://learn.microsoft.com/en-us/aspnet/core/security/authentication/scaffold-identity

Example of updating the Startup class to include authentication and authorization middleware in the request pipeline.

```csharp
public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddRazorPages();
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseDatabaseErrorPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseAuthentication();
        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapRazorPages();
        });
    }
}
```

--------------------------------

### Create a new ASP.NET Core project

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/servers/yarp/getting-started

Initializes an empty ASP.NET Core web project using the .NET CLI.

```bash
dotnet new web -n MyProxy
```

--------------------------------

### ResponseHeaderRemove Example Input

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/servers/yarp/transforms-response

Example of headers before removal.

```text
HeaderName: value
AnotherHeader: another-value
```

--------------------------------

### Install LibMan CLI tool using .NET CLI

Source: https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr

Uninstalls any existing global installation before installing the latest Microsoft.Web.LibraryManager.Cli global tool.

```.NET CLI
dotnet tool uninstall -g Microsoft.Web.LibraryManager.Cli
dotnet tool install -g Microsoft.Web.LibraryManager.Cli

```

```.NET CLI
dotnet tool uninstall -g Microsoft.Web.LibraryManager.Cli
dotnet tool install -g Microsoft.Web.LibraryManager.Cli

```

--------------------------------

### Create and publish a new MVC app

Source: https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/visual-studio-publish-profiles

Initialize a new MVC project and publish it using default settings.

```bash
dotnet new mvc
dotnet publish
```

--------------------------------

### Create a new project with Windows Authentication via .NET CLI

Source: https://learn.microsoft.com/en-us/aspnet/core/security/authentication/windowsauth

Initializes a new ASP.NET Core web application with Windows Authentication enabled.

```bash
dotnet new webapp --auth Windows
```

--------------------------------

### Configure hosting startup assemblies in C#

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/platform-specific-configuration

Set hosting startup assemblies programmatically using WebHostDefaults.HostingStartupAssembliesKey. Assemblies execute their Configure methods in the order they are listed.

```C#
public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseSetting(
                    WebHostDefaults.HostingStartupAssembliesKey, 
                    "{ASSEMBLY1;ASSEMBLY2; ...}")
                .UseStartup<Startup>();
        });

```

--------------------------------

### Install Homebrew

Source: https://learn.microsoft.com/en-us/aspnet/core/mobile/native-mobile-backend

Command to install Homebrew on macOS via terminal.

```Bash
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
```

--------------------------------

### Clone the sample repository

Source: https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/scaling-aspnet-apps/scaling-aspnet-apps

Use this command to download the sample project from GitHub.

```bash
git clone "https://github.com/dotnet/AspNetCore.Docs.Samples.git"
```

--------------------------------

### Updated libman.json after jQuery installation

Source: https://learn.microsoft.com/en-us/aspnet/core/client-side/libman/libman-cli

The state of libman.json after installing the jQuery library.

```JSON
{
  "version": "1.0",
  "defaultProvider": "cdnjs",
  "libraries": [
    {
      "library": "jquery@3.2.1",
      "destination": "wwwroot/scripts/jquery",
      "files": [
        "jquery.min.js"
      ]
    }
  ]
}
```

--------------------------------

### Inject configuration from a class library hosting startup in C#

Source: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/platform-specific-configuration

Requires decorating the assembly with HostingStartupAttribute pointing to the IHostingStartup implementation. Applies in-memory configuration keys to the web host builder.

```C#
[assembly: HostingStartup(typeof(HostingStartupLibrary.ServiceKeyInjection))]

namespace HostingStartupLibrary
{
    public class ServiceKeyInjection : IHostingStartup
    {
        public void Configure(IWebHostBuilder builder)
        {
            builder.ConfigureAppConfiguration(config =>
            {
                var dict = new Dictionary<string, string>
                {
                    {"DevAccount_FromLibrary", "DEV_1111111-1111"},
                    {"ProdAccount_FromLibrary", "PROD_2222222-2222"}
                };

                config.AddInMemoryCollection(dict);
            });
        }
    }
}
```
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