我是ServiceWorkers的新手，正在尝试弄清楚如何在create-react-app中手动检查应用程序更新。我们创建了一个自定义类来替代[{基于] registerServiceWorker.js文件。我们有一个测试按钮，它将运行registration.update()。
此类被添加到mobx提供程序中，并注入到home组件中，该按钮是我用来手动运行updateServiceWorker()方法的按钮。
在已打开的选项卡上-部署后-单击运行updateServiceWorker的按钮。我在该函数中看到了三个控制台日志，但是handleOnUpdateFound函数没有运行。然后，如果我单击Chrome>开发工具>应用程序> Service Workers中的Update链接，则会执行handleOnUpdateFound回调，并且我们观察到布尔值的消息将按预期显示。
与我们在本课程中所做的更新和Chrome正在做什么有什么不同？
这是课程：
import { observable, action } from 'mobx';
export interface IAppStateService {
isLocalhost: boolean;
registerServiceWorker();
unregisterServiceWorker();
updateServiceWorker();
}
export class AppStateService implements IAppStateService {
@observable installingUpdate: boolean = false;
@observable updateInstalled: boolean = false;
@observable isOfflineMode: boolean = false;
public get isLocalhost(): boolean {
return Boolean(
window.location.hostname === 'localhost' ||
// [::1] is the IPv6 localhost address.
window.location.hostname === '[::1]' ||
// 127.0.0.1/8 is considered localhost for IPv4.
window.location.hostname.match(
/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
)
);
}
public registerServiceWorker() {
console.log('registerServiceWorker', process.env);
// if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
// The URL constructor is available in all browsers that support SW.
const publicUrl = new URL(
process.env.PUBLIC_URL!,
window.location.toString()
);
if (publicUrl.origin !== window.location.origin) {
// Our service worker won't work if PUBLIC_URL is on a different origin
// from what our page is served on. This might happen if a CDN is used to
// serve assets; see https://github.com/facebookincubator/create-react-app/issues/2374
return;
}
window.addEventListener('load', () => {
const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;
if (this.isLocalhost) {
// This is running on localhost. Lets check if a service worker still exists or not.
this.checkValidServiceWorker(swUrl);
// Add some additional logging to localhost, pointing developers to the
// service worker/PWA documentation.
navigator.serviceWorker.ready.then(registration => {
console.log(
'This web app is being...'
);
});
} else {
// Is not local host. Just register service worker
this.registerValidSW(swUrl);
}
});
// }
}
public unregisterServiceWorker(): void {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.ready.then(registration => {
registration.unregister();
});
}
}
public updateServiceWorker(): void {
console.log('updateServiceWorker', navigator.serviceWorker);
if ('serviceWorker' in navigator) {
navigator.serviceWorker.ready.then(registration => {
console.log('checking for an update...');
registration.update().then(() => {
console.log('...done checking for an update');
});
});
}
}
private checkValidServiceWorker(swUrl: string) {
this.isOfflineMode = false;
// Check if the service worker can be found. If it can't reload the page.
fetch(swUrl)
.then(response => {
// console.log('checkValidServiceWorker', response);
// Ensure service worker exists, and that we really are getting a JS file.
if (
response.status === 404 ||
response.headers.get('content-type')!.indexOf('javascript') === -1
) {
// No service worker found. Probably a different app. Reload the page.
navigator.serviceWorker.ready.then(registration => {
registration.unregister().then(() => {
window.location.reload();
});
});
} else {
// Service worker found. Proceed as normal.
this.registerValidSW(swUrl);
}
})
.catch(() => {
console.log('No internet connection found. App is running in offline mode.');
this.isOfflineMode = true;
});
}
private registerValidSW(swUrl: string) {
return navigator.serviceWorker
.register(swUrl)
.then(registration => {
registration.onupdatefound = this.handleOnUpdateFound;
})
.catch(error => {
console.error('Error during service worker registration:', error);
});
}
@action private handleOnUpdateFound = (): void => {
console.log('handleOnUpdateFound');
navigator.serviceWorker.ready.then(registration => {
console.log('handleOnUpdateFound 2', registration);
const installingWorker = registration.installing;
if (installingWorker) {
this.installingUpdate = true;
installingWorker.onstatechange = () => {
if (installingWorker.state === 'installed') {
// console.log('navigator', navigator);
if (navigator.serviceWorker.controller) {
// At this point, the old content will have been purged and
// the fresh content will have been added to the cache.
// It's the perfect time to display a 'New content is
// available; please refresh.' message in your web app.
// console.log('New content is available; please refresh.');
setTimeout(() => {
window.location.reload();
// tslint:disable-next-line:align
}, 7000);
} else {
// At this point, everything has been precached.
// It's the perfect time to display a
// 'Content is cached for offline use.' message.
// console.log('Content is cached for offline use.');
}
this.updateInstalled = true;
this.installingUpdate = false;
}
};
}
});
}
}
答案 0 :(得分：0)
是否进行了更多的故障排除，而该故障排除不起作用的主要原因是需要设置Cache-Control: public,max-age=0（以前不是零）。 Chrome的DevTools必须在做一些事情来绕过它。