我是React Hooks的新手,尝试着玩了玩它们+实验性的React Router 6版本库,这样我就不用在未来的某一天把我的代码从5版本升级到6版本了。
注注意:第6版与第5版不能兼容,所以没有。Switch
不是答案;)
想法: 创建一个简单的管理应用程序,你可以通过按钮点击登录退出。管理页面通过访问锁保护,所以没有人可以通过直接的URL访问它。
遇到的问题: 点击登录按钮后,URL改为 /admin
但我没有看到管理页面(只有在页面刷新或通过强制刷新页面后才会看到 windows.location.reload()
).
这是React Router v6中的问题还是我用错了API?源代码 (https:/codesandbox.iosquirky-black-rsdy0):
import React, {useEffect, useState} from "react";
import {BrowserRouter, Route, Routes, useNavigate} from "react-router-dom";
async function isLoggedIn() {
// In real life this function is calling a REST endpoint and awaiting the result
return localStorage.getItem("loggedin") !== null;
}
async function setLoginStatus(status) {
// In real life this function is calling a REST endpoint and awaiting the result
if (status === true) {
localStorage.setItem("loggedin", true);
} else {
localStorage.removeItem("loggedin");
}
}
function LoginPage() {
const navigate = useNavigate();
async function handleLogin(event) {
event.preventDefault();
await setLoginStatus(true);
navigate("/admin"); // --> The user is logged in and the URL changes to /admin, but he doesn't see the admin page (Only after a page refresh)
//window.location.reload(); // Hack to reload the page to see the admin page
}
return (
<form onSubmit={handleLogin}>
<button type="submit">Login</button>
</form>
);
}
function LogoutPage() {
const navigate = useNavigate();
useEffect(() => {
const logoutAccount = async () => {
await setLoginStatus(false);
navigate("/login");
};
logoutAccount();
});
return <p>Logging out</p>;
}
function AdminPage() {
return (
<div>
<p>The secured admin page</p>
<a href="/logout">Logout</a>
</div>
);
}
function AuthenticationLock(props) {
if (props.isLoggedIn === true) {
return <div>{props.children}</div>;
} else {
return <LoginPage/>;
}
}
export default function App() {
const [loginStatus, setAppLoginStatus] = useState(false);
useEffect(() => {
const login = async () => {
const value = await isLoggedIn();
setAppLoginStatus(value);
};
login();
});
return (
<BrowserRouter>
<AuthenticationLock isLoggedIn={loginStatus}>
<Routes>
<Route path="/" element={<AdminPage/>}/>
<Route path="/admin" element={<AdminPage/>}/>
<Route path="/login" element={<LoginPage/>}/>
<Route path="/logout" element={<LogoutPage/>}/>
<Route path="/*" element={<AdminPage/>}/>
</Routes>
</AuthenticationLock>
</BrowserRouter>
);
}
把你所有的路由都包起来 <Switch></Switch>
并设置道具 exact={true}
除了最后一条之外,所有的路线都是如此。
import {BrowserRouter, Route, Routes, Switch, useNavigate} from "react-router-dom";
[...]
return (
<BrowserRouter>
<AuthenticationLock isLoggedIn={loginStatus}>
<Routes>
<Switch>
<Route path="/" exact={true} element={<AdminPage/>}/>
<Route path="/admin" exact={true} element={<AdminPage/>}/>
<Route path="/login" exact={true} element={<LoginPage/>}/>
<Route path="/logout" exact={true} element={<LogoutPage/>}/>
<Route path="/*" element={<AdminPage/>}/>
</Switch>
</Routes>
</AuthenticationLock>
</BrowserRouter>
);
所以在这种情况下,我们需要在所有路由上使用 <Switch> </Switch>
组件,它需要将所有的 <Route />
因此,它将一次只渲染一条路径。
对于所有的组件,我们总是需要设置 exact
bool,这样就不会弄错 route='/'
与 route='/about'
它们都具有 /
角色,或者说如果我们有这样的路线。/about
和 /about/blabla
. 因此,开关将知道什么 <Route />
来渲染。
如果你想有一个 <NotFoundPage />
组件的链接不存在。你只需要为一个不存在的链接分配 component prop
至 <Route />
组件,如
<Switch>
<Route exact path='/' />
<Route exact path='/about' />
<Route component={NotFoundPage} />
</Switch>
不知为何,我的 AuthenticationLock
是这个问题的责任。我换了一个不同的设计,现在它的工作。
import React, { useEffect } from "react";
import {
BrowserRouter,
Route,
Routes,
Link,
useNavigate
} from "react-router-dom";
function isLoggedIn() {
// In real life this function is calling a REST endpoint and awaiting the result
return localStorage.getItem("loggedin") !== null;
}
async function setLoginStatus(status) {
// In real life this function is calling a REST endpoint and awaiting the result
if (status) {
localStorage.setItem("loggedin", "1");
} else {
localStorage.removeItem("loggedin");
}
}
function DashboardPage() {
return (
<div>
<h1>Dashboard page</h1>
<p>This is the dashboard page</p>
<Link to={"/accounts"}>Accounts</Link>
<br />
<Link to={"/logout"}>Logout</Link>
</div>
);
}
function AccountsPage() {
return (
<div>
<h1>Accounts page</h1>
<p>This is the accounts page</p>
<Link to={"/dashboard"}>Dashboard</Link>
<br />
<Link to={"/logout"}>Logout</Link>
</div>
);
}
function LoginPage() {
const navigate = useNavigate();
async function handleLogin(event) {
event.preventDefault();
await setLoginStatus(true);
navigate("/dashboard");
}
return (
<div>
<h1>Login</h1>
<form onSubmit={handleLogin}>
<button type="submit">Login</button>
</form>
</div>
);
}
function LogoutPage() {
const navigate = useNavigate();
useEffect(() => {
const logoutAccount = async () => {
await setLoginStatus(false);
navigate("/login");
};
logoutAccount();
});
return <p>Logging out</p>;
}
const PrivateRoute = ({ component, ...rest }) => {
if (isLoggedIn()) {
const routeComponent = props => React.createElement(component, props);
return <Route {...rest} render={routeComponent} />;
} else {
return <LoginPage />;
}
};
function App() {
return (
<BrowserRouter>
<Routes>
<PrivateRoute path="/" element={<DashboardPage />} />
<PrivateRoute path="/dashboard" element={<DashboardPage />} />
<PrivateRoute path="/accounts" element={<AccountsPage />} />
<Route path="/login" element={<LoginPage />} />
<PrivateRoute path="/logout" element={<LogoutPage />} />
<PrivateRoute path="/*" element={<DashboardPage />} />
</Routes>
</BrowserRouter>
);
}
export default App;