Webmasters Stack Exchange is a question and answer site for pro webmasters. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a link to PDF document on a public web-page. How do I prevent search engines from indexing this link and PDF document?

The only idea I thought of is to use CAPTCHA. However, I wonder if there are any magic words that tell a search engine to not index the link and PDF document? Options using PHP or JavaScript are also fine.

Just to make it clear. I do not want to encrypt PDF and protect it with password. I just want to make it invisible for search engines, but not for users.

share|improve this question

migrated from stackoverflow.com May 28 '11 at 16:22

This question came from our site for professional and enthusiast programmers.

To prevent your PDF file (or any non HTML file) from being listed in search results, the only way is to use the HTTP X-Robots-Tag response header, e.g.:

X-Robots-Tag: noindex

You can do this by adding the following snippet to the site's root .htaccess file or httpd.conf file:

<Files ~ "\.pdf$">
  Header set X-Robots-Tag "noindex, nofollow"
</Files>

Note that for the above to work, you must be able to modify the HTTP headers of the file in question. Thus you may not be able to do this, for example, on GitHub Pages.

Also note that robots.txt does not prevent your page from being listed in search results.

What it does is stop the bot from crawling your page, but if a third party links to your PDF file from their website, your page will still be listed.

If you stop the bot from crawling your page using robots.txt, it will not have the chance to see the X-Robots-Tag: noindex response tag. Therefore, never ever ever disallow a page in robots.txt if you employ the X-Robots-Tag header. More info can be found on Google Developers: Robots Meta Tag.

share|improve this answer

There are multiple ways to do this (combining them is obviously a sure way to accomplish this):

1) Use robots.txt to block the files from search engines crawlers:

User-agent: *
Disallow: /pdfs/ # Block the /pdfs/directory.
Disallow: *.pdf  # Block pdf files. Non-standard but works for major search engines.

2) Use rel="nofollow" on links to those PDFs

<a href="something.pdf" rel="nofollow">Download PDF</a>

3) Use the x-robots-tag: noindex HTTP header to prevent crawlers from indexing them. Place this code in your .htaccess file:

<FilesMatch "\.pdf$">
  header set x-robots-tag: noindex
</FilesMatch>
share|improve this answer

You can use robots.txt file. You can read more here.

share|improve this answer
3  
Using robots.txt does not prevent indexing. It only prevents crawling. See Pacerier's answer for correct solution. – toxalot Nov 25 '13 at 15:48

You can use a robots.txt file. Search engines that honour that file will not index the PDF. Just use the command for disallowing the indexing of a file and designate which folder or PDF file you don't want the search engines to index.

share|improve this answer
4  
Using robots.txt does not prevent indexing. It only prevents crawling. See Pacerier's answer for correct solution. I did read recently about using a noindex directive (rather than disallow) inside the robots.txt file, but it's undocumented and non-standard. And now I can't find where I read it. – toxalot Nov 25 '13 at 15:57
    
We have a question about it: How does “Noindex:” in robots.txt work? – Stephen Ostermiller Mar 24 at 11:38

Maybe use robots.txt to disallow index?

share|improve this answer
4  
Using robots.txt does not prevent indexing. It only prevents crawling. See Pacerier's answer for correct solution. – toxalot Nov 25 '13 at 15:58
    
Typically Google will not index files that are blocked by robots.txt unless there are several external links to them. Unless the PDF files are externally linked, robots.txt would be a reasonable solution. – Stephen Ostermiller Nov 30 '13 at 22:32

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.