十三、实现登出
至此关于Blazor的内容，先写到这里， 我们基本上完成了登入、增加、删除、查询、修改等功能，应对一般的应用，已经足够。今天实现登录功能。有登入，必然要有登出，本文我们来介绍一下如何登出。
1. 在Visual Studio 2022的解决方案资源管理器中，鼠标左键选中“Pages”文件夹，右键单击，在弹出菜单中选择“添加—>Razor组件…”，并将组件命名为“Logout.razor”。登出组件的功能是用于退出登入，返回首面。其代码如下：
@page "/Logout"
@using BlazorAppDemo.Auth;
@inject IAuthService authService
@inject NavigationManager navigation
@code {
protected override async Task OnInitializedAsync()
{
await authService.LogoutAsync();
navigation.NavigateTo("/");
}
}
2. 在Visual Studio 2022的解决方案管理器中，使用鼠标左键，双击TokenManager.cs文件，对代码进行修改。具体代码如下：
using BlazorAppDemo.Models;
using System.Collections.Concurrent;
namespace BlazorAppDemo.Utils
{
public class TokenManager
{
private const string TOKEN = "authToken";
private static readonly ConcurrentDictionary<string, UserToken> tokenManager;
static TokenManager()
{
tokenManager=new ConcurrentDictionary<string, UserToken>();
}
public static ConcurrentDictionary<string, UserToken> Instance { get { return tokenManager; } }
public static string Token { get { return TOKEN; } }
public static bool RemoveToken(string token)
{
if (tokenManager.TryRemove(token,out UserToken delUserToken))
{
Console.WriteLine($"delete token {delUserToken.Token}");
return true;
}
else
{
Console.WriteLine($"unable delete token {delUserToken.Token}");
return false;
}
}
}
}
3.在Visual Studio 2022的解决方案资源管理器中，鼠标左键双击“Api”文件夹中的 “AuthController.cs”文件，将此文件中的Logout方法的代码补全。代码如下：
using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.IdentityModel.Tokens;
using Newtonsoft.Json.Linq;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
namespace BlazorAppDemo.Api
{
[Route("api/[controller]")]
[ApiController]
public class AuthController : ControllerBase
{
private readonly IJWTHelper jwtHelper;
public AuthController(IJWTHelper _IJWTHelper)
{
this.jwtHelper = _IJWTHelper;
}
[HttpPost("Login")]
public async Task> Login(UserInfo userInfo)
{
//Demo用
if (userInfo.UserName == "admin" && userInfo.Password == "111111")
{
return BuildToken(userInfo);
}
else
{
UserToken userToken = new UserToken()
{
StatusCode = System.Net.HttpStatusCode.Unauthorized,
IsSuccess = false
};
return userToken;
}
}
/// (userInfo);
//建立UserToken，回传客户端
UserToken userToken = new UserToken()
{
StatusCode = System.Net.HttpStatusCode.OK,
Token = jwtToken,
ExpireTime = DateTime.Now.AddMinutes(30),
IsSuccess= true
};
return userToken;
}
[HttpGet("Logout")]
public async Task> Logout()
{
bool flag= TokenManager.RemoveToken(TokenManager.Token);
var response = new UserToken();
response.IsSuccess = !flag;
return response;
}
}
}
4.在Visual Studio 2022的解决方案资源管理器中，鼠标左键选中“Auth”文件夹中的 “AuthService.cs”文件，将此文件中的LogoutAsync方法中添加如下代码：
using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.AspNetCore.Identity;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Collections.Concurrent;
using System.Net.Http;
using System.Text;
namespace BlazorAppDemo.Auth
{
public class AuthService : IAuthService
{
private readonly HttpClient httpClient;
private readonly AuthenticationStateProvider authenticationStateProvider;
private readonly IConfiguration configuration;
private readonly Api.AuthController authController;
private readonly string currentUserUrl, loginUrl, logoutUrl;
public AuthService( HttpClient httpClient, AuthenticationStateProvider authenticationStateProvider,
IConfiguration configuration,Api.AuthController authController)
{
this.authController = authController;
this.httpClient = httpClient;
this.authenticationStateProvider = authenticationStateProvider;
this.configuration = configuration;
currentUserUrl = configuration["AuthUrl:Current"] ?? "Auth/Current/";
loginUrl = configuration["AuthUrl:Login"] ?? "api/Auth/Login";
logoutUrl = configuration["AuthUrl:Logout"] ?? "/api/Auth/Logout/";
}
public async Task LoginAsync(UserInfo userInfo)
{
response.Content.ReadFromJsonAsync();
var result = authController.Login(userInfo);
var loginResponse = result.Result.Value;
if (loginResponse != null && loginResponse.IsSuccess)
{
TokenManager.Instance.TryAdd(TokenManager.Token, loginResponse);
((ImitateAuthStateProvider)authenticationStateProvider).NotifyUserAuthentication(loginResponse.Token);
httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("bearer",
loginResponse.Token);
return loginResponse;
}
return new UserToken() { IsSuccess = false };
}
public async Task LogoutAsync()
{
var result = authController.Logout();
var logoutResponse = result.Result.Value;
((ImitateAuthStateProvider)authenticationStateProvider).NotifyUserLogOut();
httpClient.DefaultRequestHeaders.Authorization = null;
return logoutResponse;
}
}
}
LogoutAsync方法：
- 将token从TokenManger实例中移除
- 通知前面页面更新登录状态
- 将request中的header参数bearer token移除。
5. 在Visual Studio 2022的解决方案管理器中，使用鼠标左键，双击ImitateAuthStateProvider.cs文件，对代码进行修改。具体代码如下：
using BlazorAppDemo.Models;
using BlazorAppDemo.Utils;
using Microsoft.AspNetCore.Components.Authorization;
using System.Net.Http;
using System.Security.Claims;
namespace BlazorAppDemo.Auth
{
public class ImitateAuthStateProvider : AuthenticationStateProvider
{
private readonly IJWTHelper jwt;
private AuthenticationState anonymous;
private readonly HttpClient httpClient;
public ImitateAuthStateProvider(IJWTHelper _jwt, HttpClient httpClient)
{
anonymous = new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
jwt = _jwt;
this.httpClient = httpClient;
}
bool isLogin = false;
string token = string.Empty;
public override Task GetAuthenticationStateAsync()
{
//确认是否已经登录
UserToken userToken;
TokenManager.Instance.TryGetValue(TokenManager.Token,out userToken);
string tokenInLocalStorage=string.Empty;
if (userToken != null)
{
tokenInLocalStorage = userToken.Token;
}
if (string.IsNullOrEmpty(tokenInLocalStorage))
{
//沒有登录，则返回匿名登录者
return Task.FromResult(anonymous);
}
//將token取出转换为claim
var claims = jwt.ParseToken(tokenInLocalStorage);
//在每次request的header中都将加入bearer token
httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("bearer",
tokenInLocalStorage);
//回传带有user claim的AuthenticationState
return Task.FromResult(new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt"))));
}
public void Login(UserInfo request)
{
//1.验证用户账号密码是否正确
if (request == null)
{
isLogin=false;
}
if (request.UserName == "user" && request.Password == "111111")
{
isLogin = true;
token= jwt.CreateJwtToken(request);
Console.WriteLine($"JWT Token={token}");
}
NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
}
public void NotifyUserAuthentication(string token)
{
var claims = jwt.ParseToken(token);
var authenticatedUser = new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt"));
var authState = Task.FromResult(new AuthenticationState(authenticatedUser));
NotifyAuthenticationStateChanged(authState);
}
public void NotifyUserLogOut()
{
var authState = Task.FromResult(anonymous);
NotifyAuthenticationStateChanged(authState);
}
}
}
6. 在Visual Studio 2022的解决方案管理器中，使用鼠标左键，双击MainLayout.razor文件，对代码进行修改。具体代码如下：
@using BlazorAppDemo.Pages
@inherits LayoutComponentBase
<PageTitle>BlazorAppDemoPageTitle>
<div class="page">
<div class="sidebar">
<NavMenu />
div>
<main>
<AuthorizeView>
<Authorized>
<div class="top-row px-4">
<a href="https://docs.microsoft.com/aspnet/" target="_blank">Abouta>
<div class ="col-3 oi-align-right">
你好, @context.User.Identity.Name!<a href="/Logout">Logouta>
div>
div>
<article class="content px-4">
@Body
article>
Authorized>
<NotAuthorized>
<div style="margin: 120px 0; width:100%; text-align: center; color: red;">
<span style="font-size:20px">检测到登录超时，请重新<a href="/login" style="text-decoration:underline">登录a>！
span>
div>
<RedirectToLogin>RedirectToLogin>
NotAuthorized>
AuthorizeView>
main>
div>
7. 在Visual Studio 2022的菜单栏上，找到“调试-->开始调试”或是按F5键，Visual Studio 2022会生成BlazorAppDemo应用程序。浏览器会打开登录页面。我们在登录页面的用户名输入框中输入用户名，在密码输入框中输入密码，点击“登录”按钮，进行登录。我们进入了系统，在页面的右上角处，会出现登录用户的用户名，与一个“Logout”按钮。如下图。
