详解webpack-dev-server的简单使用
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:"bundle.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-dev-server/index.html.
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
- 在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.
- 将<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);
在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:
- 在webpack.config.js的entry选项中添加:webpack/hot/dev-server
- 在webpack.config.js的plugins选项中添加:new webpack.hotmodulereplacementplugin()
- 在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:
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