webpack-dev-server、historyApiFallback 不工作(webpack-4、react-router-4)

Question

我正在用 webpack4 测试 react-router4，但我无法获得 webpack-dev-server 的设置:

{historyApiFallback: true}

工作。这在 webpack3 中使用得很好，所以我不确定哪里出了问题...这是我的 webpack.config.js:

const HtmlWebpackPlugin = require('html-webpack-plugin');

module.exports = () => {
  return {
    mode: 'development',
    devtool: 'source-map',
    devServer: {
      port: 8888,
      historyApiFallback: true,
      stats: 'minimal'
    },
    resolve: {
      extensions: ['*', '.mjs', '.js', '.jsx']
    },
    module: {
      rules: [
        {
          test: /\.m?jsx?$/,
          exclude: /(node_modules)/,
          use: {
            loader: 'babel-loader'
          }
        }
      ]
    },
    plugins: [
      new HtmlWebpackPlugin({
        title:'React Lab',
        template: 'src/index.html'
      })
    ]
  }
}

这是我使用 react-router4 的简单 React 应用程序:

import React from 'react';
import ReactDOM  from 'react-dom';
import {
  BrowserRouter as Router,
  Route,
  Link,
  Switch
} from 'react-router-dom';

const mountNode = document.getElementById('app');

const App = () => (
  <Router>
    <div>

      <ul>
        <li><Link to="/">Link to: /</Link></li>
        <li><Link to="/page1">Link to: /page1</Link></li>
        <li><Link to="/page2">Link to: /page2</Link></li>
        <li><Link to="/does/not/exist">Link to: /does/not/exist</Link></li>
      </ul>
      <button onClick={()=>{location.reload();}}>reload page</button>

      <Switch>
        <Route exact path="/"      component={()=>(<h2>home</h2>)} />
        <Route exact path="/page1" component={()=>(<h2>page1</h2>)} />
        <Route exact path="/page2" component={()=>(<h2>page2</h2>)} />
        <Route                     component={()=>(<h2>no match</h2>)} />
      </Switch>

      <Route path="/" component={(props) =><div>{`props.location.pathname: ${props.location.pathname}`}</div>} />

    </div>
  </Router>
);

ReactDOM.render( <App/>, mountNode

导航到之后:

<Link to="/does/not/exist" /> 

然后点击

<button>reload page</button>

webpack 开发服务器无法重定向到 main.js

完整代码在github: https://github.com/ApolloTang/webpack-dev-server-history-api-fall-back-not-working .

如有任何帮助或评论，我们将不胜感激。

Answer 1

原来我在webpack.config.js中缺少output.publicPath:

output: {
  //  must specified output.publicPath otherwise
  //  devServer.historyApiFallback will not work
  publicPath: '/'
},

使用上面指定的 output.publicPath，historyApiFallback 工作。

我不记得我在哪里读到过 output.publicPath 在 webpack4 的配置中是可选的，但它确实需要与 webpack-dev-server 一起工作。

文档位于 https://webpack.js.org/configuration/output/#output-publicpath说:

The webpack-dev-server also takes a hint from publicPath, using it to determine where to serve the output files from.

但我不明白这与 historyApiFallback 有什么关系。