I use the following basic setup for running Puppeteer:
const puppeteer = require("puppeteer");
let browser;
(async () => {
browser = await puppeteer.launch();
const [page] = await browser.pages();
/* use the page */
})()
.catch(err => console.error(err))
.finally(() => browser?.close());
Here, the finally block guarantees the browser will close correctly regardless of whether an error was thrown. Errors are logged (if desired). I like .catch and .finally as chained calls because the mainline Puppeteer code is one level flatter, but this accomplishes the same thing:
const puppeteer = require("puppeteer");
(async () => {
let browser;
try {
browser = await puppeteer.launch();
const [page] = await browser.pages();
/* use the page */
}
catch (err) {
console.error(err);
}
finally {
await browser?.close();
}
})();
There's no reason to call newPage because Puppeteer starts with a page open.
As for Express, you need only place the entire code above, including let browser; and excluding require("puppeteer"), into your route, and you're good to go, although you might want to use an async middleware error handler.
You ask:
Is there a better way to get the same result other than puppeteer and headless chrome?
That depends on what you're doing and what you mean by "better". If your goal is to get document.body.innerHTML and the page content you're interested in is baked into the static HTML, you can dump Puppeteer entirely and just make a request to get the resource, then use Cheerio to extract the desired information.
Another consideration is that you may not need to load and close a whole browser per request. If you can use one new page per request, consider the following strategy:
const express = require("express");
const puppeteer = require("puppeteer");
const asyncHandler = fn => (req, res, next) =>
Promise.resolve(fn(req, res, next)).catch(next);
const browserReady = puppeteer.launch({
args: ["--no-sandbox", "--disable-setuid-sandbox"]
});
const app = express();
app
.set("port", process.env.PORT || 5000)
.get("/", asyncHandler(async (req, res) => {
const browser = await browserReady;
const page = await browser.newPage();
try {
await page.goto(req.query.url || "http://www.example.com");
return res.send(await page.content());
}
catch (err) {
return res.status(400).send(err.message);
}
finally {
await page.close();
}
}))
.use((err, req, res, next) => res.sendStatus(500))
.listen(app.get("port"), () =>
console.log("listening on port", app.get("port"))
);
Finally, make sure to never set any timeouts to 0 (for example, page.setDefaultNavigationTimeout(0);), which introduces the potential for the script to hang forever. If you need a generous timeout, at most set it to a few minutes--long enough not to trigger false positives.
See also:
