使用webpack dev server中间件无法加载图片

Question

所以我花了过去24小时来调整我的代码并尝试让它工作，搜遍了SO和Google，但没有运气 - 或许有人可以帮忙！我的React应用程序正在Express上运行，但使用webpack-dev-server中间件。当我加载页面时，图片显示为空白，就好像它们不存在一样。我在控制台中没有收到任何错误消息（例如没有404错误），但图像元素只显示“alt”文本，而不是应该存在的实际“png”或“svg”。顺便说一句，不仅是React组件无法呈现图像 - 我尝试将一个图像文件硬编码到我的index.html文件中进行测试，结果也是一样的。以下是我的代码：server.js（截断以排除数据库设置和其他express路由）

const express = require('express');
const webpack = require('webpack');
const webpackDevMiddleware = require('webpack-dev-middleware');
const webpackHotMiddleware = require('webpack-hot-middleware');
const path = require('path');
const mongoose = require('mongoose');
const config = require('./webpack.dev.config');

// SERVER SETUP

const app = express();
const router = express.Router();

var publicPath = path.resolve(__dirname, 'public');

compiler=webpack(config);

app.use(webpackDevMiddleware(compiler, {
    publicPath: config.output.publicPath,
    stats: {colors: true}
}));

app.use(webpackHotMiddleware(compiler, {
    log: console.log
}));

//Routes

// ...additional routes

app.get('*', function(req, res){
    res.sendFile(path.resolve(publicPath, 'index.html'));
})

app.use(express.static(publicPath));

app.listen(3000, function(){
    console.log('Server running on port 3000');
});

webpack.dev.config.js

var webpack = require('webpack');
var path = require('path');
var nodeModulesPath = path.resolve(__dirname, 'node_modules');
var buildPath = path.resolve(__dirname, 'public', 'build');
var mainPath = path.resolve(__dirname, 'app', 'main.js');

var config = {

    devtool: 'eval-source-map',
    devServer: {
      historyApiFallback: true
    },
    entry: [

        'webpack/hot/dev-server',
        'webpack-hot-middleware/client',
        'whatwg-fetch',
        //Our application
        mainPath
    ],
    output: {
        path: '/',
        publicPath: 'http://localhost:3000/build/',
        assetsPublicPath: 'http://localhost:3000/',
        filename: 'bundle.js'
    },
    module: {
        loaders: [
            {
                test: /\.js?$/,
                loader: 'babel',
                exclude: nodeModulesPath
            },
            {
                test: /\.css$/,
                loader: 'style!css?modules!postcss'
            },
            {
                test: /\.(jpe?g|png|gif|svg)$/i,
                loader: 'url-loader'
            }
        ]
    },
    postcss: [
        require('autoprefixer'),
        require('precss')
    ],
    plugins: [
        new webpack.HotModuleReplacementPlugin()
    ],
    target: 'web'
};

module.exports = config;

下面是一个例子React组件，应该可以访问图像：

import React, {Component, PropTypes} from 'react';
import TopMenu from "./TopMenu";
import styles from '../cssPartials/TopBar.css';

const logo = './images/svg/xenonLogo.svg';

const TopBar = () => {

    return (
        <div className={styles.topBar}>
            <div className={styles.logoHolder}>
                <img src={logo} alt="Xenon Logo" />
            </div>
            <TopMenu />
        </div>
    )

}

export default TopBar

以下是应用程序的文件结构：

root
  |-app
     |-admin
        |-components //React components
     |-users
        |-components //React components
  |-data //contains database and redux files
  |-node_modules
  |-public //This is the public folder specified in server.js and webpack.dev.config.js
     |-images
        |-svg //contains the svg files
     |-index.html
     |-bundle.js
  |-.babelrc // babel config file
  |-nodemon.json //nodemon config file
  |-package.json
  |-server.js
  |-webpack.dev.config.js

我觉得这就是全部了，如果需要更多的代码，请告诉我。谢谢大家！

- Chris

Answer 1

你需要检查webpack配置中的几个要点。

首先，请确保你已经安装了url-loader和file-loader npm包。

尝试将输出配置更改为以下内容 -

  output: {
    path: path.join(__dirname, 'public'),
    publicPath: 'http://localhost:8080/public/',
    filename: 'bundle.js'
  }

图片加载器

 {
    test: /\.(jpe?g|png|gif|svg)$/i,
    include : path.join(__dirname, 'images'),
    loader  : 'url-loader?limit=30000&name=images/[name].[ext]'
 }, // inline base64 URLs for <=30k images, direct URLs for the rest

同时，在你的React组件中，你需要导入SVG文件。

import React, {Component, PropTypes} from 'react';
import TopMenu from "./TopMenu";
import styles from '../cssPartials/TopBar.css';

import logo from './images/svg/xenonLogo.svg';

const TopBar = () => {

    return (
        <div className={styles.topBar}>
            <div className={styles.logoHolder}>
                <img src={logo} alt="Xenon Logo" />
            </div>
            <TopMenu />
        </div>
    )

}

- WitVault

---

使用 file-loader 和 import 语法对我很有效。 - JJJ

我曾经遇到过同样的问题，添加正确的 publicPath 解决了这个问题。 - tomtomssi