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A comment on How to crawl a quarter billion webpages in 40 hours (2012). Parent comment

Re:How to crawl a quarter billion webpages in 40 hours (2012) by merb on Thursday July 05, 2018 @09:54AM (#17463248)
so you will actually respect:

    User-agent: google
    Allow: /
    
    User-agent: *
    Disallow: /
well, yes it's good behavior to actually respect it, but well I've seen such robots.txt already which makes it really painful to create a competing search engine.
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Re:How to crawl a quarter billion webpages in 40 hours (2012) by taeric on Thursday July 05, 2018 @12:32PM (#17464593)
This has me ridiculously curious now. Is that common? Other than a random sampling of sites I go to, there a good way to get numbers on how often this is used?

Edit: In my scanning, I have to confess that wikipedia's robot file is the best. Fairly heavily commented on why the rules are there. https://en.wikipedia.org/robots.txt

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Re:How to crawl a quarter billion webpages in 40 hours (2012) by benfrederickson on Thursday July 05, 2018 @01:45PM (#17465226)
I analyzed the top 1 million robots.txt files looking for sites that allow google and block everyone else here: https://www.benfrederickson.com/robots-txt-analysis/ - it's a relatively common pattern for major websites
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Re:How to crawl a quarter billion webpages in 40 hours (2012) by _trampeltier on Thursday July 05, 2018 @01:03PM (#17464867)
I did run a Yacy web crawler (P2P websearch https://yacy.net) a while ago. As far I remember I just saw Yandex for a few times disallowed in the robots.txt when I had trouble with crawling a site. Mostly I just got an empty website for my Yacy crawler instead the "real" Website.
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Re:How to crawl a quarter billion webpages in 40 hours (2012) by gcb0 on Thursday July 05, 2018 @03:03PM (#17465861)
just do like browsers did with user agent strings. call your bot "botx (google crawler compatible)" and crawl everything that allows Google bot without any weight on your conscience.
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