使用react-router-v4验证异步

Question

我有这个PrivateRoute组件(来自文档):

const PrivateRoute = ({ component: Component, ...rest }) => (
  <Route {...rest} render={props => (
    isAuthenticated ? (
      <Component {...props}/>
    ) : (
      <Redirect to={{
        pathname: '/login',
        state: { from: props.location }
      }}/>
    )
  )}/>
)

我想改成isAuthenticatedaysnc请求isAuthenticated().但是,在响应返回之前,页面重定向.

为了澄清,该isAuthenticated功能已经建立.

在决定显示什么之前,我该如何等待异步调用完成？

Answer 1

如果您不使用Redux或任何其他类型的状态管理模式,则可以使用Redirect组件和组件状态来确定页面是否应呈现.这将包括将状态设置为加载状态,进行异步调用,请求完成后保存用户,或者缺少用户说明和呈现Redirect组件,如果不满足条件,组件将重定向.

class PrivateRoute extends React.Component {
  state = {
    loading: true,
    isAuthenticated: false,
  }
  componentDidMount() {
    asyncCall().then((isAuthenticated) => {
      this.setState({
        loading: false,
        isAuthenticated,
      });
    });
  }
  render() {
    const { component: Component, ...rest } = this.props;
    if (this.state.loading) {
      return <div>LOADING</div>;
    } else {
      return (
        <Route {...rest} render={props => (
          <div>
            {!this.state.isAuthenticated && <Redirect to={{ pathname: '/login', state: { from: this.props.location } }} />}
            <Component {...this.props} />
          </div>
          )}
        />
      )
    }
  }
}

Answer 2

如果有人对使用钩子而不是类组件的@CraigMyles 实现感兴趣：

export const PrivateRoute = (props) => {
    const [loading, setLoading] = useState(true);
    const [isAuthenticated, setIsAuthenticated] = useState(false);

    const { component: Component, ...rest } = props;

    useEffect(() => {
        const fetchData = async () => {
            const result = await asynCall();

            setIsAuthenticated(result);
            setLoading(false);
        };
        fetchData();
    }, []);

    return (
        <Route
            {...rest}
            render={() =>
                isAuthenticated ? (
                    <Component {...props} />
                ) : loading ? (
                    <div>LOADING...</div>
                ) : (
                    <Redirect
                        to={{
                            pathname: "/login",
                            state: { from: props.location },
                        }}
                    />
                )
            }
        />
    );
};

使用以下方法调用时效果很好：

<PrivateRoute path="/routeA" component={ComponentA} />
<PrivateRoute path="/routeB" component={ComponentB} />

Answer 3

@pizza-r0b 的解决方案对我来说非常有效。但是，我不得不稍微修改解决方案，以防止加载 div 被多次显示（对于应用程序中定义的每个 PrivateRoute 一次），通过在 Route 内部而不是外部渲染加载 div（类似于React Router 的 auth 示例） ：

class PrivateRoute extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
      loading: true,
      isAuthenticated: false
    }
  }

  componentDidMount() {
    asyncCall().then((isAuthenticated) => {
      this.setState({
        loading: false,
        isAuthenticated
      })
    })
  }

  render() {
    const { component: Component, ...rest } = this.props
    return (
      <Route
        {...rest}
        render={props =>
          this.state.isAuthenticated ? (
            <Component {...props} />
          ) : (
              this.state.loading ? (
                <div>LOADING</div>
              ) : (
                  <Redirect to={{ pathname: '/login', state: { from: this.props.location } }} />
                )
            )
        }
      />
    )
  }
}

为了完整起见，从我的 App.js 中摘录：

<DashboardLayout>
  <PrivateRoute exact path="/status" component={Status} />
  <PrivateRoute exact path="/account" component={Account} />
</DashboardLayout>