robots.txt 中的美元符号是什么意思 [英] What does the dollar sign mean in robots.txt

问题描述

我对一个网站很好奇，想在 /s 路径上做一些网络爬虫.它的robots.txt:

I am curious about a website and want to do some web crawling at the /s path. Its robots.txt:

User-Agent: *
Allow: /$
Allow: /debug/
Allow: /qa/
Allow: /wiki/
Allow: /cgi-bin/loginpage
Disallow: /

我的问题是:

• 美元符号在这种情况下是什么意思?

• What does the dollar-sign mean in this case?

爬取 URL /s 是否合适?关于 robots.txt 文件?

And is it appropriate to crawl the URL /s? with respect to the robots.txt file?

推荐答案

如果你按照 原版 robots.txt规范，$没有特殊含义，也没有定义Allow字段.符合要求的机器人必须忽略它不知道的字段，因此这样的机器人实际上会看到此记录:

If you follow the original robots.txt specification, $ has no special meaning, and there is no Allow field defined. A conforming bot would have to ignore fields it does not know, therefore such a bot would actually see this record:

User-Agent: *
Disallow: /

然而，原始的robots.txt规范已经被各方扩展.但由于有问题的 robots.txt 的作者没有针对特定的机器人，我们不知道他们想到的是哪个扩展".

However, the original robots.txt specification has been extended by various parties. But as the authors of the robots.txt in question did not target a specific bot, we don’t know which "extension" they had in mind.

通常(但不是必然，因为它没有正式指定)，Allow 覆盖 Disallow 中指定的规则，$ 代表 URL 路径的结尾.

Typically (but not necessarily, as it’s not formally specified), Allow overwrites rules specified in Disallow, and $ represents the end of the URL path.

遵循此解释(例如，Google 使用), Allow:/$ 表示:您可以抓取 /，但不能抓取 /a, /b等.

Following this interpretation (it’s, for example, used by Google), Allow: /$ would mean: You may crawl /, but you may not crawl /a, /b and so on.

因此不允许抓取路径以 /s 开头的 URL(无论是根据原始规范，感谢 Disallow:/，也不是根据 Google 的扩展).

So crawling of URLs whose path starts with /s would not be allowed (neither according to the original spec, thanks to Disallow: /, nor according to Google’s extension).

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