saPaul's blog

[Update] CF FetchCodes v25.12.7: Smart Retries, Lazy Loading & Instant Caching!
By saPaul, history, 11 months ago, In English

Hello Codeforces!

You're stuck on a problem during practice, and you see that your friend accepted it. You just want to see how they did it.

Previously, using this tool felt a bit... heavy. It would try to fetch everyone's code at once. If you had many friends, you hit rate limits, waited forever, and ended up with a massive list of codes you didn't even need. And if it failed? You just got a sad "Failed to Load" message. :(

v25.12.7 changes the game. Here is how we made your upsolving smoother:

[The Problem] "Too Much, Too Slow" Before, we fetched everything instantly. This wasted bandwidth and often triggered API warnings. Plus, if your session expired mid-way, everything broke.

[The Fix] Lazy Loading & You Choose! Now, we show you a clean list of friends who solved the problem first.

  • You Click, We Fetch: The code only loads when you actually click on a specific friend's name. No more wasting data on solutions you don't want to see.
  • Smart Progress Bar: A blue line fills up as we scan your friends list, turning Green when done. You always know exactly how many friends have been checked.

[+] Zero Waiting with Caching Ever opened a friend's code, closed it, and then realized you missed something? Previously, you had to wait for it to fetch again. Not anymore. We've added smart caching. Once you fetch a solution, it stays in memory. Open it a second time? It appears instantly. Zero network wait.

[+] Login & Retry in Place If the extension fails to fetch code (maybe your session timed out?), we don't just give up.

  1. We show a clear "Session Expired" alert.
  2. You click Login (new tab) -> Come back -> Click Retry.
  3. It retries just that code instantly without reloading the page!

[+] The "View Original" Safety Net And if all else fails (maybe Codeforces is just having a bad day), we replaced the generic error with a direct "View Original Submission" button. You can always jump straight to their submission page to see the full details and test cases.

Try it out now:

If you face any issues or have a cool idea, drop a PR or Issue on GitHub.

Happy Upsolving!

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11 months ago, hide # |
 
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Auto comment: topic has been updated by saPaul (previous revision, new revision, compare).

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11 months ago, hide # |
 
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YAUMAUEFU

(Yet Another User Making A Useless Extension For Upvotes)

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11 months ago, hide # |
 
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When using it, it gives this error :
Screenshot 2025 12 14 144109

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11 months ago, hide # |
 
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I have a very similar extension CodeForces Friends Tracker

Also thanks for the extension!

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10 months ago, hide # |
 
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  • I view the friend submissions, no one (it caches)
  • Friend A solves the problem
  • I fetch the submissions, still empty (because for the old cache)

Fix this issue!

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    10 months ago, hide # ^ |
     
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    Hi @potatoArmy Thanks for reporting. A quick page refresh will solve this instantly as it clears the internal cache and forces a fresh search for all your friend's latest submissions.

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