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详解webpack-dev-server的使用

2016-11-19 10:31 931 查看


webpack-dev-server

webpack-dev-server是一个小型的
Node.js Express
服务器,它使用
webpack-dev-middleware
来服务于webpack的包,除此自外,它还有一个通过Sock.js来连接到服务器的微型运行时.

我们来看一下下面的配置文件(
webpack.config.js
)
var path = require("path");
module.exports = {
entry:{
app:["./app/main.js"]
},
output:{
path:path.resolve(__dirname,"build"),
publicPath:"/assets/",
filename:"bundles.js"
}
}


这里你将你的源文件放在
app
文件夹下,并通过
webpack
将其打包到
build
文件夹下的
bundle.js
中.

注意:
webpack-dev-server
是一个独立的NPM包,你可以通过
npm
install webpack-dev-server
来安装它.


基本目录

webpack-dev-server默认会以当前目录为基本目录,除非你制定它.
webpack-dev-server --content-base build/


上述命令是在命令行中执行的,它将
build
目录作为根目录.有一点需要注意的是:webpack-dev-server生成的包并没有放在你的真实目录中,而是放在了内存中.

我们在基本目录下新建一个
index.html
文件,然后在浏览器中输入
http://localhost:8080
访问.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script src="assets/bundle.js"></script>
</body>
</html>


自动刷新

webpack-dev-server支持两种模式来自动刷新页面.

iframe模式(页面放在iframe中,当发生改变时重载)

inline模式(将webpack-dev-sever的客户端入口添加到包(bundle)中)

两种模式都支持热模块替换(Hot Module Replacement).热模块替换的好处是只替换更新的部分,而不是页面重载.


iframe模式

使用这种模式不需要额外的配置,只需要以下面这种URL格式访问即可
http://«host»:«port»/webpack-dev-server/«path»


例如:http://localhost:8080/webpack...


inline模式

inline模式下我们访问的URL不用发生变化,启用这种模式分两种情况:

1 当以命令行启动webpack-dev-server时,需要做两点:

在命令行中添加
--inline
命令

webpack.config.js
中添加
devServer:{inline:true}


2 当以Node.js API启动
webpack-dev-server
时,我们也需要做两点:

由于
webpack-dev-server
的配置中无
inline
选项,我们需要添加
webpack-dev-server/client?http://«path»:«port»/
到webpack配置的entry入口点中.

<script src="http://localhost:8080/webpack-dev-server.js"></script>
添加到html文件中

var config = require("./webpack.config.js");
var webpack = require('webpack');
var WebpackDevServer = require('webpack-dev-server');

config.entry.app.unshift("webpack-dev-server/client?http://localhost:8080/");

var compiler = webpack(config);
var server = new WebpackDevServer(compiler, {
contentBase:'build/',
publicPath: "/assets/"
});
server.listen(8080);


Node
中运行上面的代码即可。

注意:webpack配置中的
devSever
配置项只对在命令行模式有效。


(Hot Module Replacement)热模块替换


在命令行中运行inline模式,并启用热模块替换

这里只需要多增加 
--hot
指令就OK了.如下所示.
webpack-dev-server --content-base build --inline --hot


注意:命令行模式下,
webpack.config.js
中一定要配置
output.publicPath
来指定编译后的包(bundle)的访问位置.


在Nodejs API中运行inline模式,并启用热模块替换

这里需要做以下三点:

webpack.config.js
entry
选项中添加:webpack/hot/dev-server

webpack.config.js
plugins
选项中添加:
new
webpack.HotModuleReplacementPlugin()


webpack-dev-server
的配置中添加:
hot:true



webpack-dev-server中的配置选项

var WebpackDevServer = require("webpack-dev-server");
var webpack = require("webpack");

var compiler = webpack({
// configuration
});
var server = new WebpackDevServer(compiler, {
// webpack-dev-server options

contentBase: "/path/to/directory",
// Can also be an array, or: contentBase: "http://localhost/",

hot: true,
// Enable special support for Hot Module Replacement
// Page is no longer updated, but a "webpackHotUpdate" message is send to the content
// Use "webpack/hot/dev-server" as additional module in your entry point
// Note: this does _not_ add the `HotModuleReplacementPlugin` like the CLI option does.

// Set this as true if you want to access dev server from arbitrary url.
// This is handy if you are using a html5 router.
historyApiFallback: false,

// Set this if you want to enable gzip compression for assets
compress: true,

// Set this if you want webpack-dev-server to delegate a single path to an arbitrary server.
// Use "**" to proxy all paths to the specified server.
// This is useful if you want to get rid of 'http://localhost:8080/' in script[src],
// and has many other use cases (see https://github.com/webpack/webpack-dev-server/pull/127 ).
proxy: {
"**": "http://localhost:9090"
},

setup: function(app) {
// Here you can access the Express app object and add your own custom middleware to it.
// For example, to define custom handlers for some paths:
// app.get('/some/path', function(req, res) {
//   res.json({ custom: 'response' });
// });
},

// pass [static options](http://expressjs.com/en/4x/api.html#express.static) to inner express server
staticOptions: {
},

// webpack-dev-middleware options
quiet: false,
noInfo: false,
lazy: true,
filename: "bundle.js",
watchOptions: {
aggregateTimeout: 300,
poll: 1000
},
// It's a required option.
publicPath: "/assets/",
headers: { "X-Custom-Header": "yes" },
stats: { colors: true }
});
server.listen(8080, "localhost", function() {});
// server.close();


参考:http://webpack.github.io/docs...

转载:https://segmentfault.com/a/1190000006964335
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