How to recrawl initial page for new links without purging to keep track of duplicates?

Thank you for releasing Crawlee as an open source project.

I have setup a very simple CheerioCrawler that crawls the home page of a news website for starters.
I am then scraping certain articles and saving some information to an external database. I aim to run the crawler at a regular interval (every few hours) to check for new links/articles.
I want to keep track of what I've crawled in previous runs as to not re-visit those pages and waste resources (mine and the hosts), so I set CRAWLEE_PURGE_ON_START to false to keep track of what's been crawled.

Current State:
- Once I run the crawler once, the home page is marked as "handled" and never visited again on subsequent runs to look for new links within it.
Desired State:
- On each new run, crawl the same home page, and enqueue any and only new links found for handling/scaping.

Is there a way to make my starting home page (example.com) re-crawlable on each run without purging? I believe it's something I can add within the default handler, I'm just not sure what exactly it is.

// .env
CRAWLEE_PURGE_ON_START=false

// main.ts
const startUrls = ["example.com"]
const crawler = new CheerioCrawler({
  requestHandler: router,
  maxRequestsPerCrawl: 5,
  maxConcurrency: 1,
  // maxRequestsPerMinute: 30,
});
const main = async () => {
  await crawler.addRequests(startUrls);
  await crawler.run();
};
main();

// router.ts
router.addDefaultHandler(async ({ enqueueLinks, log }) => {
  log.info(`enqueueing new URLs`);
  await enqueueLinks({
    strategy: EnqueueStrategy.SameHostname,
    globs: [
      "https://example.com/news/*",
    ],
    label: "detail"
  })
});

router.addHandler("detail", async ({ request: req, $, log }) => {
  const title = await page.title();
  log.info(`Title of ${request.loadedUrl} is '${title}'`);

  // Save to DB Code here
});

// .env
CRAWLEE_PURGE_ON_START=false

// main.ts
const startUrls = ["example.com"]
const crawler = new CheerioCrawler({
  requestHandler: router,
  maxRequestsPerCrawl: 5,
  maxConcurrency: 1,
  // maxRequestsPerMinute: 30,
});
const main = async () => {
  await crawler.addRequests(startUrls);
  await crawler.run();
};
main();

// router.ts
router.addDefaultHandler(async ({ enqueueLinks, log }) => {
  log.info(`enqueueing new URLs`);
  await enqueueLinks({
    strategy: EnqueueStrategy.SameHostname,
    globs: [
      "https://example.com/news/*",
    ],
    label: "detail"
  })
});

router.addHandler("detail", async ({ request: req, $, log }) => {
  const title = await page.title();
  log.info(`Title of ${request.loadedUrl} is '${title}'`);

  // Save to DB Code here
});

Thank you.

Apify & Crawlee•4y ago•

12 replies

spotty-amber

How to recrawl initial page for new links without purging to keep track of duplicates?

// .env
CRAWLEE_PURGE_ON_START=false

// main.ts
const startUrls = ["example.com"]
const crawler = new CheerioCrawler({
  requestHandler: router,
  maxRequestsPerCrawl: 5,
  maxConcurrency: 1,
  // maxRequestsPerMinute: 30,
});
const main = async () => {
  await crawler.addRequests(startUrls);
  await crawler.run();
};
main();

// router.ts
router.addDefaultHandler(async ({ enqueueLinks, log }) => {
  log.info(`enqueueing new URLs`);
  await enqueueLinks({
    strategy: EnqueueStrategy.SameHostname,
    globs: [
      "https://example.com/news/*",
    ],
    label: "detail"
  })
});

router.addHandler("detail", async ({ request: req, $, log }) => {
  const title = await page.title();
  log.info(`Title of ${request.loadedUrl} is '${title}'`);

  // Save to DB Code here
});

// .env
CRAWLEE_PURGE_ON_START=false

// main.ts
const startUrls = ["example.com"]
const crawler = new CheerioCrawler({
  requestHandler: router,
  maxRequestsPerCrawl: 5,
  maxConcurrency: 1,
  // maxRequestsPerMinute: 30,
});
const main = async () => {
  await crawler.addRequests(startUrls);
  await crawler.run();
};
main();

// router.ts
router.addDefaultHandler(async ({ enqueueLinks, log }) => {
  log.info(`enqueueing new URLs`);
  await enqueueLinks({
    strategy: EnqueueStrategy.SameHostname,
    globs: [
      "https://example.com/news/*",
    ],
    label: "detail"
  })
});

router.addHandler("detail", async ({ request: req, $, log }) => {
  const title = await page.title();
  log.info(`Title of ${request.loadedUrl} is '${title}'`);

  // Save to DB Code here
});

Thank you.

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How to recrawl initial page for new links without purging to keep track of duplicates?

How to recrawl initial page for new links without purging to keep track of duplicates?

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