38 lines
1.3 KiB
TypeScript
38 lines
1.3 KiB
TypeScript
import ApplicationComponent from "../ApplicationComponent";
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import {NextFunction, Request, Response, Router} from "express";
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import {ServiceUnavailableHttpError} from "../HttpError";
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import Application from "../Application";
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import config from "config";
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export default class MaintenanceComponent extends ApplicationComponent {
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private readonly application: Application;
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private readonly canServe: () => boolean;
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public constructor(application: Application, canServe: () => boolean) {
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super();
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this.application = application;
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this.canServe = canServe;
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}
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public async handle(router: Router): Promise<void> {
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router.use((req: Request, res: Response, next: NextFunction) => {
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if (res.headersSent) {
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return next();
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}
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if (!this.application.isReady()) {
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res.header({'Retry-After': 60});
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res.locals.refresh_after = 5;
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throw new ServiceUnavailableHttpError(`${config.get('app.name')} is readying up. Please wait a few seconds...`);
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}
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if (!this.canServe()) {
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res.locals.refresh_after = 30;
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throw new ServiceUnavailableHttpError(`${config.get('app.name')} is unavailable due to failure of dependent services.`);
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}
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next();
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});
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}
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}
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