mempool/unfurler/src/index.ts
2023-04-04 07:55:55 +09:00

224 lines
7.8 KiB
TypeScript

import express from "express";
import { Application, Request, Response, NextFunction } from 'express';
import * as http from 'http';
import * as https from 'https';
import config from './config';
import { Cluster } from 'puppeteer-cluster';
import ReusablePage from './concurrency/ReusablePage';
import { parseLanguageUrl } from './language/lang';
import { matchRoute } from './routes';
import logger from './logger';
const puppeteerConfig = require('../puppeteer.config.json');
if (config.PUPPETEER.EXEC_PATH) {
puppeteerConfig.executablePath = config.PUPPETEER.EXEC_PATH;
}
const puppeteerEnabled = config.PUPPETEER.ENABLED && (config.PUPPETEER.CLUSTER_SIZE > 0);
class Server {
private server: http.Server | undefined;
private app: Application;
cluster?: Cluster;
mempoolHost: string;
network: string;
secureHost = true;
constructor() {
this.app = express();
this.mempoolHost = config.MEMPOOL.HTTP_HOST + (config.MEMPOOL.HTTP_PORT ? ':' + config.MEMPOOL.HTTP_PORT : '');
this.secureHost = config.SERVER.HOST.startsWith('https');
this.network = config.MEMPOOL.NETWORK || 'bitcoin';
this.startServer();
}
async startServer() {
this.app
.use((req: Request, res: Response, next: NextFunction) => {
res.setHeader('Access-Control-Allow-Origin', '*');
next();
})
.use(express.urlencoded({ extended: true }))
.use(express.text())
;
if (puppeteerEnabled) {
this.cluster = await Cluster.launch({
concurrency: ReusablePage,
maxConcurrency: config.PUPPETEER.CLUSTER_SIZE,
puppeteerOptions: puppeteerConfig,
});
await this.cluster?.task(async (args) => { return this.clusterTask(args) });
}
this.setUpRoutes();
this.server = http.createServer(this.app);
this.server.listen(config.SERVER.HTTP_PORT, () => {
logger.info(`Mempool Unfurl Server is running on port ${config.SERVER.HTTP_PORT}`);
});
}
async stopServer() {
if (this.cluster) {
await this.cluster.idle();
await this.cluster.close();
}
if (this.server) {
await this.server.close();
}
}
setUpRoutes() {
if (puppeteerEnabled) {
this.app.get('/render*', async (req, res) => { return this.renderPreview(req, res) })
} else {
this.app.get('/render*', async (req, res) => { return this.renderDisabled(req, res) })
}
this.app.get('*', (req, res) => { return this.renderHTML(req, res) })
}
async clusterTask({ page, data: { url, path, action } }) {
try {
const urlParts = parseLanguageUrl(path);
if (page.language !== urlParts.lang) {
// switch language
page.language = urlParts.lang;
const localizedUrl = urlParts.lang ? `${this.mempoolHost}/${urlParts.lang}${urlParts.path}` : `${this.mempoolHost}${urlParts.path}` ;
await page.goto(localizedUrl, { waitUntil: "load" });
} else {
const loaded = await page.evaluate(async (path) => {
if (window['ogService']) {
window['ogService'].loadPage(path);
return true;
} else {
return false;
}
}, urlParts.path);
if (!loaded) {
throw new Error('failed to access open graph service');
}
}
// wait for preview component to initialize
await page.waitForSelector('meta[property="og:preview:loading"]', { timeout: config.PUPPETEER.RENDER_TIMEOUT || 3000 })
let success;
success = await Promise.race([
page.waitForSelector('meta[property="og:preview:ready"]', { timeout: config.PUPPETEER.RENDER_TIMEOUT || 3000 }).then(() => true),
page.waitForSelector('meta[property="og:preview:fail"]', { timeout: config.PUPPETEER.RENDER_TIMEOUT || 3000 }).then(() => false)
])
if (success === true) {
const screenshot = await page.screenshot({
captureBeyondViewport: false,
clip: { width: 1200, height: 600, x: 0, y: 0, scale: 1 },
});
return screenshot;
} else if (success === false) {
logger.warn(`failed to render ${path} for ${action} due to client-side error, e.g. requested an invalid txid`);
page.repairRequested = true;
} else {
logger.warn(`failed to render ${path} for ${action} due to puppeteer timeout`);
page.repairRequested = true;
}
} catch (e) {
logger.err(`failed to render ${path} for ${action}: ` + (e instanceof Error ? e.message : `${e}`));
page.repairRequested = true;
}
}
async renderDisabled(req, res) {
res.status(500).send("preview rendering disabled");
}
async renderPreview(req, res) {
try {
const rawPath = req.params[0];
let img = null;
const { lang, path } = parseLanguageUrl(rawPath);
const matchedRoute = matchRoute(this.network, path);
// don't bother unless the route is definitely renderable
if (rawPath.includes('/preview/') && matchedRoute.render) {
img = await this.cluster?.execute({ url: this.mempoolHost + rawPath, path: rawPath, action: 'screenshot' });
}
if (!img) {
// proxy fallback image from the frontend
if (this.secureHost) {
https.get(config.SERVER.HOST + matchedRoute.fallbackImg, (got) => got.pipe(res));
} else {
http.get(config.SERVER.HOST + matchedRoute.fallbackImg, (got) => got.pipe(res));
}
} else {
res.contentType('image/png');
res.send(img);
}
} catch (e) {
logger.err(e instanceof Error ? e.message : `${e} ${req.params[0]}`);
res.status(500).send(e instanceof Error ? e.message : e);
}
}
async renderHTML(req, res) {
// drop requests for static files
const rawPath = req.params[0];
const match = rawPath.match(/\.[\w]+$/);
if (match?.length && match[0] !== '.html') {
res.status(404).send();
return;
}
const { lang, path } = parseLanguageUrl(rawPath);
const matchedRoute = matchRoute(this.network, path);
let ogImageUrl = config.SERVER.HOST + (matchedRoute.staticImg || matchedRoute.fallbackImg);
let ogTitle = 'The Mempool Open Source Project™';
if (matchedRoute.render) {
ogImageUrl = `${config.SERVER.HOST}/render/${lang || 'en'}/preview${path}`;
ogTitle = `${this.network ? capitalize(this.network) + ' ' : ''}${matchedRoute.networkMode !== 'mainnet' ? capitalize(matchedRoute.networkMode) + ' ' : ''}${matchedRoute.title}`;
}
res.send(`
<!doctype html>
<html lang="en-US" dir="ltr">
<head>
<meta charset="utf-8">
<title>${ogTitle}</title>
<meta name="description" content="The Mempool Open Source Project™ - Explore the full Bitcoin ecosystem with mempool.space™"/>
<meta property="og:image" content="${ogImageUrl}"/>
<meta property="og:image:type" content="image/png"/>
<meta property="og:image:width" content="${matchedRoute.render ? 1200 : 1000}"/>
<meta property="og:image:height" content="${matchedRoute.render ? 600 : 500}"/>
<meta property="og:title" content="${ogTitle}">
<meta property="twitter:card" content="summary_large_image">
<meta property="twitter:site" content="@mempool">
<meta property="twitter:creator" content="@mempool">
<meta property="twitter:title" content="${ogTitle}">
<meta property="twitter:description" content="Explore the full Bitcoin ecosystem with mempool.space"/>
<meta property="twitter:image:src" content="${ogImageUrl}"/>
<meta property="twitter:domain" content="mempool.space">
<body></body>
</html>
`);
}
}
const server = new Server();
process.on('SIGTERM', async () => {
logger.info('Shutting down Mempool Unfurl Server');
await server.stopServer();
process.exit(0);
});
function capitalize(str) {
if (str && str.length) {
return str[0].toUpperCase() + str.slice(1);
} else {
return str;
}
}