Blazor tutorial for beginners - part 3

Blazor Server App 入門教學為主。Authentication.

How to add Authentication in Server-side Blazor | Blazor Tutorial 8

一般來說在 Blazor 都是使用 ideneity 做為登入認證。之前常用的表單驗證 FormsAuthentication 似乎已不再支援。

且會搭配 Microsoft.AspNetCore.Identity.UI包含適用于 ASP.NET Core 上之身分識別的 Razor Pages 內建 UI 類型。俱體上就是 Blazor 框架把登入認證與授權的UI都做好了，且半強迫的強制應用。

支援的指令有

Microsoft.AspNetCore.Components.Authorization 命名空間MicrosoftLearn

• AuthenticationStateProvider

• <CascadingAuthenticationState />

• @attribute [Authorize]

• <AuthorizeRouteView />

• <AuthorizeView Policy="..." Roles="..." />

• <Authorized />

• <Authorizing />

• <NotAuthorized />

一些範例碼

若登入認證機制完成，我們可以這樣下指令

Showcase.razor

@page
@attribute [Authorize]

<AuthorizeView>
    <Authorized>
        <p>@authState.User.Identit.Name</p>
        <p>Page Content<p>
    <Authorized>
    <NotAuthorized>
        <p>Sorry you cannot see this page.</p>
    <NotAuthorized>
</AuthorizeView>

@code{
    [CascadingParameter]
    private AuthenticationState authState {get; set;}
    
}

App.razor

<CascadingAuthenticationState>
    <Router AppAssembly="@typeof(Program).Assembly" PreferExactMatches="@true">
        <Found Context="routeData">
            <AuthorizeRouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)">
                <Authorizing>
                    <h1>Just a second</h1>
                    <p>You are bging authorized</p>
                <Authorizing>
                <NotAuthorized>
                    <h1>Sorry</h1>
                    <p>You cannot see this bye bye</p>
                </NOtAuthorized>
            </AuthorizeRouteView>            
        </Found>
        <NotFound>
            <LayoutView Layout="@typeof(MainLayout)">
                <p>Sorry, there's nothing at this address.</p>
            </LayoutView>
        </NotFound>
    </Router>
</CascadingAuthenticationState>

Authorization in Server-Side Blazor | Blazor Tutorial 9

• Authentication = Who you are

• Authorization = What you can do

1. Default Authentication

2. User is in role

3. User has claim

4. Police is satisfied

練習比較重要。下面為 Roles, Policy 的範例部份截錄

Showcase.razor

@page

<AuthorizeView Policy="IsAdmin">
    <Authorized>
        ...
    </Authorized>
</AuthorizeView>

<AuthorizeView Roles="SecretRole">
    <Authorized>
        ...
    </Authorized>
</AuthorizeView>

Blazor identity 登入認證的資料很多。不過方法都一樣，開專案時直接加入identity認證機制後再改寫。

How to use HTML5 Web Storage in Blazor | Blazor Tutorial 10

請直接參考下面附件。

https://docs.microsoft.com/zh-tw/aspnet/core/blazor/state-management?view=aspnetcore-5.0&pivots=serverdocs.microsoft.com

ASP.NET Core Blazor狀態管理

下面二個模組：Blazored/SessionStorage, Blazored/LocalStorage 可用於 Blazor WASM App，但不適合用於 Blazor Server App。Blazor Server App 直接使用預設的 ProtectedSessionStorage、ProtectedLocalStorage會更好。

GitHub - Blazored/SessionStorage: A library to provide access to session storage in Blazor applicationsGitHub

GitHub - Blazored/LocalStorage: A library to provide access to local storage in Blazor applicationsGitHub

Managing Blazor state using Redux | Blazor Tutorial 11

疑問？Redux 應該只適用於 Blazor WASM App 模式才對吧？經測試在二種模式下皆可運作，不過在 Blazer Server App 模式下並不需要 Redux。 應該用 C#9 record type 記錄類型 實作 State，因為前端的狀態是 immutable。

在 Blazor Server App 模式下並不需要 Flux/Redux 。在 Blazor WASM App 模式下若前端資料很多的話就可以考慮加入 Flue/Redux 。

個人見解 以C#的解法來說，開發成泛型狀態物件再配合Event應該是更輕量的解。也就是說：不必採用 Redux/Flux。

一個推薦方案：Fluxor

Install-Package Fluxor
Install-Package Fluxor.Blazor.Web
Install-Package Fluxor.Blazor.Web.ReduxDevTools

GitHub - mrpmorris/Fluxor: Fluxor is a zero boilerplate Flux/Redux library for Microsoft .NET and Blazor.GitHub

GitHub - BerserkerDotNet/BlazorState: Yet Another Blazor Redux implementationGitHub

補充：一些進階文章整理

ASP.NET Core Blazor 樣板化元件MicrosoftLearn

ASP.NET Core Blazor樣板化元件

ASP.NET Core Blazor 表單總覽MicrosoftLearn

ASP.NET Core Blazor表單和驗證

Building Custom Input Components for Blazor using InputBaseChris Sainty - Building with Blazor

Building Custom Input Components for Blazor using InputBase

Building Custom Input Components for Blazor using InputBaseChris Sainty - Building with Blazor

Understanding Cascading Values & Cascading Parameters

Creating a Custom Validation Message Component for Blazor FormsChris Sainty - Building with Blazor

Creating a Custom Validation Message Component for Blazor Forms

Blazor University - Writing custom validationBlazor University

Writing custom validation