写在开头：
微前端似乎是最近一个很火的话题，我们也即将使用在生产环境中，接下来会更新一系列微前端源码分析、手写微前端文章
废话不多说，直接参考目前的微前端框架注册子应用模块代码
- 下面代码，我指定的entry,就是子应用的访问入口地址
registerMicroApps(
[
{
name: 'rental-web',
entry: isDev ? '//rental-dev.mysoft.com.cn:8809' : `//${url}:8809`,
container: '#rental-web',
render,
activeRule: '/static',
props: {
value,
setValue
}
},
{
name: 'fed-rental-web',
entry: isDev ? '//rental-dev.mysoft.com.cn:8006' : `//${url}:8006`,
container: '#fed-rental-web',
render,
activeRule: '/fed',
props: {
value,
setValue
}
},]- 微前端到底是怎么回事呢？ 我画了一张图
我们今天不谈其他的实现技术细节，坑点，就谈整体架构，这张图就能完全解释清楚
那么registerMicroApps,到底做了什么呢？
源码解析下，只看重要部分今天：
代码语言：javascript复制export function registerMicroApps(apps, lifeCycles) {
var _this = this; // Each app only needs to be registered once
var unregisteredApps = apps.filter(function (app) {
return !microApps.some(function (registeredApp) {
return registeredApp.name === app.name;
});
});
microApps = __spread(microApps, unregisteredApps);
unregisteredApps.forEach(function (app) {
var name = app.name,
activeRule = app.activeRule,
props = app.props,
appConfig = __rest(app, ["name", "activeRule", "props"]);
registerApplication({
name: name,
app: function app() {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
return [4
/*yield*/
, frameworkStartedDefer.promise];
case 1:
_a.sent();
return [2
/*return*/
, loadApp(__assign({
name: name,
props: props
}, appConfig), frameworkConfiguration, lifeCycles)];
}
});
});
},
activeWhen: activeRule,
customProps: props
});
});
}lifeCycles是我们自己传入的生命周期函数（这里先不解释），跟react这种框架一样，微前端针对每个子应用，也封装了一些生命周期，如果你是小白，那我就用最简单的话告诉你，生命周期钩子，其实在框架源码就是一个函数编写调用顺序而已（有的分异步和同步）
- apps就是我们传入的数组，子应用集合
- 代码里做了一些防重复注册、数据处理等
- 看源码，不要全部都看，那样很费时间，而且你也得不到利益最大化，只看最精髓、重要部分
- 无论上面做了上面子应用去重、数据处理，我只要盯着每个子应用，即app这个对象即可
- 看到了loadApp这个方法，我们可以大概猜测到，是通过这个方法加载
下面__rest是对数据进行处理
代码语言：javascript复制export function __rest(s, e) {
var t = {};
for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
t[p] = s[p];
if (s != null && typeof Object.getOwnPropertySymbols === "function")
for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i ) {
if (e.indexOf(p[i]) < 0 && Object.prototype.propertyIsEnumerable.call(s, p[i]))
t[p[i]] = s[p[i]];
}
return t;
}- loadApp这个函数有大概300行，挑最重点地方看
export function loadApp(app, configuration, lifeCycles) {
if (configuration === void 0) {
configuration = {};
}
var _a;
return __awaiter(this, void 0, void 0, function () {
var entry, appName, _b, singular, _c, sandbox, importEntryOpts, _d, template, execScripts, assetPublicPath, appInstanceId, strictStyleIsolation, appContent, element, container, legacyRender, render, containerGetter, global, mountSandbox, unmountSandbox, sandboxInstance, _e, _f, beforeUnmount, _g, afterUnmount, _h, afterMount, _j, beforeMount, _k, beforeLoad, scriptExports, bootstrap, mount, unmount, globalVariableExports, _l, onGlobalStateChange, setGlobalState, offGlobalStateChange;
var _this = this;
return __generator(this, function (_m) {
switch (_m.label) {
case 0:
entry = app.entry, appName = app.name;
_b = configuration.singular, singular = _b === void 0 ? false : _b, _c = configuration.sandbox, sandbox = _c === void 0 ? true : _c, importEntryOpts = __rest(configuration, ["singular", "sandbox"]);
return [4
/*yield*/
, importEntry(entry, importEntryOpts)];
case 1:
_d = _m.sent(), template = _d.template, execScripts = _d.execScripts, assetPublicPath = _d.assetPublicPath;
return [4
/*yield*/
, validateSingularMode(singular, app)];
case 2:
if (!_m.sent()) return [3
/*break*/
, 4];
return [4
/*yield*/
, prevAppUnmountedDeferred && prevAppUnmountedDeferred.promise];
case 3:
_m.sent();
_m.label = 4;
case 4:
appInstanceId = appName "_" (appInstanceCounts.hasOwnProperty(appName) ? ((_a = appInstanceCounts[appName]) !== null && _a !== void 0 ? _a : 0) 1 : 0);
strictStyleIsolation = _typeof(sandbox) === 'object' && !!sandbox.strictStyleIsolation;
appContent = getDefaultTplWrapper(appInstanceId)(template);
element = createElement(appContent, strictStyleIsolation);
container = 'container' in app ? app.container : undefined;
legacyRender = 'render' in app ? app.render : undefined;
render = getRender(appContent, container, legacyRender); // 第一次加载设置应用可见区域 dom 结构
// 确保每次应用加载前容器 dom 结构已经设置完毕
render({
element: element,
loading: true
});
containerGetter = getAppWrapperGetter(appInstanceId, !!legacyRender, strictStyleIsolation, function () {
return element;
});
global = window;
mountSandbox = function mountSandbox() {
return Promise.resolve();
};
unmountSandbox = function unmountSandbox() {
return Promise.resolve();
};
if (sandbox) {
sandboxInstance = createSandbox(appName, containerGetter, Boolean(singular)); // 用沙箱的代理对象作为接下来使用的全局对象
global = sandboxInstance.proxy;
mountSandbox = sandboxInstance.mount;
unmountSandbox = sandboxInstance.unmount;
}
_e = _mergeWith({}, getAddOns(global, assetPublicPath), lifeCycles, function (v1, v2) {
return _concat(v1 !== null && v1 !== void 0 ? v1 : [], v2 !== null && v2 !== void 0 ? v2 : []);
}), _f = _e.beforeUnmount, beforeUnmount = _f === void 0 ? [] : _f, _g = _e.afterUnmount, afterUnmount = _g === void 0 ? [] : _g, _h = _e.afterMount, afterMount = _h === void 0 ? [] : _h, _j = _e.beforeMount, beforeMount = _j === void 0 ? [] : _j, _k = _e.beforeLoad, beforeLoad = _k === void 0 ? [] : _k;
return [4
/*yield*/
, execHooksChain(toArray(beforeLoad), app)];
case 5:
_m.sent(); // cache the execScripts returned promise
if (!appExportPromiseCaches[appName]) {
appExportPromiseCaches[appName] = execScripts(global, !singular);
}
return [4
/*yield*/
, appExportPromiseCaches[appName]];
case 6:
scriptExports = _m.sent();
if (validateExportLifecycle(scriptExports)) {
// eslint-disable-next-line prefer-destructuring
bootstrap = scriptExports.bootstrap; // eslint-disable-next-line prefer-destructuring
mount = scriptExports.mount; // eslint-disable-next-line prefer-destructuring
unmount = scriptExports.unmount;
} else {
if (process.env.NODE_ENV === 'development') {
console.warn("[qiankun] lifecycle not found from " appName " entry exports, fallback to get from window['" appName "']");
}
globalVariableExports = global[appName];
if (validateExportLifecycle(globalVariableExports)) {
// eslint-disable-next-line prefer-destructuring
bootstrap = globalVariableExports.bootstrap; // eslint-disable-next-line prefer-destructuring
mount = globalVariableExports.mount; // eslint-disable-next-line prefer-destructuring
unmount = globalVariableExports.unmount;
} else {
delete appExportPromiseCaches[appName];
throw new Error("[qiankun] You need to export lifecycle functions in " appName " entry");
}
}
_l = getMicroAppStateActions(appInstanceId), onGlobalStateChange = _l.onGlobalStateChange, setGlobalState = _l.setGlobalState, offGlobalStateChange = _l.offGlobalStateChange;
return [2
/*return*/
, {
name: appInstanceId,
bootstrap: [bootstrap],
mount: [function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
return [4
/*yield*/
, validateSingularMode(singular, app)];
case 1:
if (_a.sent() && prevAppUnmountedDeferred) {
return [2
/*return*/
, prevAppUnmountedDeferred.promise];
}
return [2
/*return*/
, undefined];
}
});
});
}, // 添加 mount hook, 确保每次应用加载前容器 dom 结构已经设置完毕
function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
// element would be destroyed after unmounted, we need to recreate it if it not exist
element = element || createElement(appContent, strictStyleIsolation);
render({
element: element,
loading: true
});
return [2
/*return*/
];
});
});
}, // exec the chain after rendering to keep the behavior with beforeLoad
function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, execHooksChain(toArray(beforeMount), app)];
});
});
}, mountSandbox, function (props) {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, mount(__assign(__assign({}, props), {
container: containerGetter(),
setGlobalState: setGlobalState,
onGlobalStateChange: onGlobalStateChange
}))];
});
});
}, // 应用 mount 完成后结束 loading
function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, render({
element: element,
loading: false
})];
});
});
}, function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, execHooksChain(toArray(afterMount), app)];
});
});
}, // initialize the unmount defer after app mounted and resolve the defer after it unmounted
function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
return [4
/*yield*/
, validateSingularMode(singular, app)];
case 1:
if (_a.sent()) {
prevAppUnmountedDeferred = new Deferred();
}
return [2
/*return*/
];
}
});
});
}],
unmount: [function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, execHooksChain(toArray(beforeUnmount), app)];
});
});
}, function (props) {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, unmount(__assign(__assign({}, props), {
container: containerGetter()
}))];
});
});
}, unmountSandbox, function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
return [2
/*return*/
, execHooksChain(toArray(afterUnmount), app)];
});
});
}, function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
render({
element: null,
loading: false
});
offGlobalStateChange(appInstanceId); // for gc
element = null;
return [2
/*return*/
];
});
});
}, function () {
return __awaiter(_this, void 0, void 0, function () {
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
return [4
/*yield*/
, validateSingularMode(singular, app)];
case 1:
if (_a.sent() && prevAppUnmountedDeferred) {
prevAppUnmountedDeferred.resolve();
}
return [2
/*return*/
];
}
});
});
}]
}];
}
});
});
}- registerApplication是single-spa的方法，我们这里通过loadApp这个方法，对数据进行处理
function registerApplication(appNameOrConfig, appOrLoadApp, activeWhen, customProps) {
const registration = sanitizeArguments(appNameOrConfig, appOrLoadApp, activeWhen, customProps);
if (getAppNames().indexOf(registration.name) !== -1) throw Error(formatErrorMessage(21, `There is already an app registered with name ${registration.name}`, registration.name));
apps.push(assign({
loadErrorTime: null,
status: NOT_LOADED,
parcels: {},
devtools: {
overlays: {
options: {},
selectors: []
}
}
}, registration));
if (isInBrowser) {
ensureJQuerySupport();
reroute();
}
}- 上面这个函数，应该是整个微前端框架最复杂的地方，它最终会返回一个函数，当成函数传递给single-spa这个库的registerApplication方法使用
- 它的内部是switch case逻辑，然后返回一个数组
- 这是一个逻辑判断
case 0:
entry = app.entry, appName = app.name;
_b = configuration.singular, singular = _b === void 0 ? false : _b, _c = configuration.sandbox, sandbox = _c === void 0 ? true : _c, importEntryOpts = __rest(configuration, ["singular", "sandbox"]);
return [4
/*yield*/
, importEntry(entry, importEntryOpts)];重点来了
- 会通过
importEntry去加载entry（子应用地址）
function importEntry(entry) {
var opts = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
var _opts$fetch3 = opts.fetch,
fetch = _opts$fetch3 === void 0 ? defaultFetch : _opts$fetch3,
_opts$getTemplate = opts.getTemplate,
getTemplate = _opts$getTemplate === void 0 ? defaultGetTemplate : _opts$getTemplate;
var getPublicPath = opts.getPublicPath || opts.getDomain || _utils.defaultGetPublicPath;
if (!entry) {
throw new SyntaxError('entry should not be empty!');
} // html entry
if (typeof entry === 'string') {
return importHTML(entry, {
fetch: fetch,
getPublicPath: getPublicPath,
getTemplate: getTemplate
});
} // config entry
if (Array.isArray(entry.scripts) || Array.isArray(entry.styles)) {
var _entry$scripts = entry.scripts,
scripts = _entry$scripts === void 0 ? [] : _entry$scripts,
_entry$styles = entry.styles,
styles = _entry$styles === void 0 ? [] : _entry$styles,
_entry$html = entry.html,
html = _entry$html === void 0 ? '' : _entry$html;
return getEmbedHTML(getTemplate(html), styles, {
fetch: fetch
}).then(function (embedHTML) {
return {
template: embedHTML,
assetPublicPath: getPublicPath('/'),
getExternalScripts: function getExternalScripts() {
return _getExternalScripts(scripts, fetch);
},
getExternalStyleSheets: function getExternalStyleSheets() {
return _getExternalStyleSheets(styles, fetch);
},
execScripts: function execScripts(proxy, strictGlobal) {
if (!scripts.length) {
return Promise.resolve();
}
return _execScripts(scripts[scripts.length - 1], scripts, proxy, {
fetch: fetch,
strictGlobal: strictGlobal
});
}
};
});
} else {
throw new SyntaxError('entry scripts or styles should be array!');
}
}- 上面代码里最重要的，如果我们entry传入字符串，那么就会使用这个函数去加载HTML内容（其实微前端的所有子应用加载，都是把dom节点加载渲染到基座的index.html文件中的一个div标签内）
if (typeof entry === 'string') {
return importHTML(entry, {
fetch: fetch,
getPublicPath: getPublicPath,
getTemplate: getTemplate
});
} // config entry- importHTML这个函数，就是我们今晚最重要的一个点
- 传入url地址，发起fetch请求（此时由于域名或者端口不一样，会出现跨域，所有子应用的热更新开发模式下，webpack配置要做以下处理，部署也要考虑这个问题）
devServer: {
contentBase: path.resolve(__dirname, '../'),
port: CONFIG.serverPort,
host: 'rental-dev.mysoft.com.cn',
historyApiFallback: true,
disableHostCheck: true,
headers: {
'Access-Control-Allow-Origin': '*',
},
stats: {
timings: true,
assets: false,
entrypoints: false,
modules: false
},
proxy: {
'/api/*': {
target: CONFIG.proxyServer,
changeOrigin: true,
secure: false,
pathRewrite: {
'^/api': ''
},
headers: {
// Cookie: 'RENTALCENTER=5fc10ee067fa5d15a9a7840bd4a75dc98dc7f47a'
}
}
},
before(app) {
app.get('/cookie/set', (req, res) => {
const cookies = req.query
console.log('resolve cookie')
for (const cookie in cookies) {
if (Object.prototype.hasOwnProperty.call(cookies, cookie)) {
res.cookie(cookie, cookies[cookie], {
httpOnly: true
})
}
}
res.redirect(
`${req.protocol}://${req.host}:${CONFIG.serverPort}${
CONFIG.baseAlias
}`
)
})
},
inline: true,
hot: true // 新增
},整个importHTML函数好像很长很长，但是我们就看最重要的地方，一个框架（库），流程线很长 版本迭代原因，需要兼容老的版本，所以很多源码对于我们其实是无用的
代码语言：javascript复制function importHTML(url) {
var opts = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
var fetch = defaultFetch;
var getPublicPath = _utils.defaultGetPublicPath;
var getTemplate = defaultGetTemplate; // compatible with the legacy importHTML api
if (typeof opts === 'function') {
fetch = opts;
} else {
fetch = opts.fetch || defaultFetch;
getPublicPath = opts.getPublicPath || opts.getDomain || _utils.defaultGetPublicPath;
getTemplate = opts.getTemplate || defaultGetTemplate;
}
return embedHTMLCache[url] || (embedHTMLCache[url] = fetch(url).then(function (response) {
return response.text();
}).then(function (html) {
var assetPublicPath = getPublicPath(url);
var _processTpl = (0, _processTpl2["default"])(getTemplate(html), assetPublicPath),
template = _processTpl.template,
scripts = _processTpl.scripts,
entry = _processTpl.entry,
styles = _processTpl.styles;
return getEmbedHTML(template, styles, {
fetch: fetch
}).then(function (embedHTML) {
return {
template: embedHTML,
assetPublicPath: assetPublicPath,
getExternalScripts: function getExternalScripts() {
return _getExternalScripts(scripts, fetch);
},
getExternalStyleSheets: function getExternalStyleSheets() {
return _getExternalStyleSheets(styles, fetch);
},
execScripts: function execScripts(proxy, strictGlobal) {
if (!scripts.length) {
return Promise.resolve();
}
return _execScripts(entry, scripts, proxy, {
fetch: fetch,
strictGlobal: strictGlobal
});
}
};
});
}));
}- 整个函数，最后返回了一个对象，这里很明显，通过fetch请求，获取了对应子应用entry入口的资源文件后，转换成了字符串
- 这里processTpl其实就是对这个子应用的dom模版（字符串格式）进行一个数据拼装，其实也不是很复杂，由于时间关系，可以自己看看过程，重点看结果
- 这里的思想，是redux的中间件源码思想，将数据进行了一层包装，高可用使用
function processTpl(tpl, baseURI) {
var scripts = [];
var styles = [];
var entry = null;
var template = tpl
/*
remove html comment first
*/
.replace(HTML_COMMENT_REGEX, '').replace(LINK_TAG_REGEX, function (match) {
/*
change the css link
*/
var styleType = !!match.match(STYLE_TYPE_REGEX);
if (styleType) {
var styleHref = match.match(STYLE_HREF_REGEX);
var styleIgnore = match.match(LINK_IGNORE_REGEX);
if (styleHref) {
var href = styleHref && styleHref[2];
var newHref = href;
if (href && !hasProtocol(href)) {
newHref = getEntirePath(href, baseURI);
}
if (styleIgnore) {
return genIgnoreAssetReplaceSymbol(newHref);
}
styles.push(newHref);
return genLinkReplaceSymbol(newHref);
}
}
var preloadOrPrefetchType = match.match(LINK_PRELOAD_OR_PREFETCH_REGEX) && match.match(LINK_HREF_REGEX);
if (preloadOrPrefetchType) {
var _match$match = match.match(LINK_HREF_REGEX),
_match$match2 = (0, _slicedToArray2["default"])(_match$match, 3),
linkHref = _match$match2[2];
return genLinkReplaceSymbol(linkHref, true);
}
return match;
}).replace(STYLE_TAG_REGEX, function (match) {
if (STYLE_IGNORE_REGEX.test(match)) {
return genIgnoreAssetReplaceSymbol('style file');
}
return match;
}).replace(ALL_SCRIPT_REGEX, function (match) {
var scriptIgnore = match.match(SCRIPT_IGNORE_REGEX); // in order to keep the exec order of all javascripts
// if it is a external script
if (SCRIPT_TAG_REGEX.test(match) && match.match(SCRIPT_SRC_REGEX)) {
/*
collect scripts and replace the ref
*/
var matchedScriptEntry = match.match(SCRIPT_ENTRY_REGEX);
var matchedScriptSrcMatch = match.match(SCRIPT_SRC_REGEX);
var matchedScriptSrc = matchedScriptSrcMatch && matchedScriptSrcMatch[2];
if (entry && matchedScriptEntry) {
throw new SyntaxError('You should not set multiply entry script!');
} else {
// append the domain while the script not have an protocol prefix
if (matchedScriptSrc && !hasProtocol(matchedScriptSrc)) {
matchedScriptSrc = getEntirePath(matchedScriptSrc, baseURI);
}
entry = entry || matchedScriptEntry && matchedScriptSrc;
}
if (scriptIgnore) {
return genIgnoreAssetReplaceSymbol(matchedScriptSrc || 'js file');
}
if (matchedScriptSrc) {
var asyncScript = !!match.match(SCRIPT_ASYNC_REGEX);
scripts.push(asyncScript ? {
async: true,
src: matchedScriptSrc
} : matchedScriptSrc);
return genScriptReplaceSymbol(matchedScriptSrc, asyncScript);
}
return match;
} else {
if (scriptIgnore) {
return genIgnoreAssetReplaceSymbol('js file');
} // if it is an inline script
var code = (0, _utils.getInlineCode)(match); // remove script blocks when all of these lines are comments.
var isPureCommentBlock = code.split(/[rn] /).every(function (line) {
return !line.trim() || line.trim().startsWith('//');
});
if (!isPureCommentBlock) {
scripts.push(match);
}
return inlineScriptReplaceSymbol;
}
});
scripts = scripts.filter(function (script) {
// filter empty script
return !!script;
});
return {
template: template,
scripts: scripts,
styles: styles,
// set the last script as entry if have not set
entry: entry || scripts[scripts.length - 1]
};
}- 最终返回了一个对象，此时已经不是一个纯html的字符串了，而是一个对象，而且脚本样式都分离了
return {
template: template,
scripts: scripts,
styles: styles,
// set the last script as entry if have not set
entry: entry || scripts[scripts.length - 1]
};- 这个是框架帮我们处理的，必须要设置一个入口js文件
// set the last script as entry if have not set- 下面是真正的single-spa源码，注册子应用，用apps这个数组去收集所有的子应用（数组每一项已经拥有了脚本、html、css样式的内容）
此时我们只要根据我们之前编写的activeRule和监听前端路由变化去控制展示子应用即可，原理如下:(今天不做过多讲解这块)
代码语言：javascript复制window.addEventListener('hashchange', reroute);
window.addEventListener('popstate', reroute);
// 拦截所有注册的事件，以便确保这里的事件总是第一个执行
const originalAddEventListener = window.addEventListener;
const originalRemoveEventListener = window.removeEventListener;
window.addEventListener = function (eventName, handler, args) {
if (eventName && HIJACK_EVENTS_NAME.test(eventName) && typeof handler === 'function') {
EVENTS_POOL[eventName].indexOf(handler) === -1 && EVENTS_POOL[eventName].push(handler);
}
return originalAddEventListener.apply(this, arguments);
};
window.removeEventListener = function (eventName, handler) {
if (eventName && HIJACK_EVENTS_NAME.test(eventName) && typeof handler === 'function') {
let eventList = EVENTS_POOL[eventName];
eventList.indexOf(handler) > -1 && (EVENTS_POOL[eventName] = eventList.filter(fn => fn !== handler));
}
return originalRemoveEventListener.apply(this, arguments);
};也是redux的中间件思想，劫持了事件，然后进行派发，优先调用微前端框架的路由事件，然后进行过滤展示子应用：
代码语言：javascript复制export function getAppsToLoad() {
return APPS.filter(notSkipped).filter(withoutLoadError).filter(isntLoaded).filter(shouldBeActive);
}整个微前端的触发流程图
相信通过此文，你能真正了解微前端的使用原理，后期我会出一个手写微前端框架的文章
最后
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