What is meta? ×
Meta Stack Exchange is where users like you discuss bugs, features, and support issues that affect the software powering all 131 Stack Exchange communities.

You can access questions with tags by link construction:

http://stackoverflow.com/questions/tagged/[tag1] or [tag2] or [tag3]

But when I combine a lot of tags I get an error 400 (invalid URL). In my case the URL length was 755 characters.

But when I use the link

http://stackoverflow.com/feeds/tag?tagnames=[tag1] or [tag2] or [tag3]&sort=newest

then the page is loaded, even though I used the same big set of tags (and this time we have 768 characters).

When I pass the link to my RSS reader (with %20 instead of a space)

http://stackoverflow.com/feeds/tag?tagnames=[tag1]%20or%20[tag2]%20or%20[tag3]

all data was properly loaded with no errors (908 characters this time).

Is there some bug/limitation to the length of the first link construction (http://stackoverflow.com/questions/tagged/%5Btags%5D) that does not apply to second method (http://stackoverflow.com/feeds/tag?tagnames=%5Btags%5D)?

share|improve this question
    
It's very likely that the URL mapper (which redirects you to the second format "under the hood") has a max limit somehow. Either it has a fail-safe that is enabled above a certain URL length (for performance reasons or whatnot), or the regular expression engine simply doesn't match more than a certain number of characters, resulting in a failed match. –  Blixt Nov 6 '09 at 14:28

1 Answer 1

up vote 2 down vote accepted

URLs of the form

http://example.com/tagged/foo+bar+baz

have a "path length limit" of about ~260 characters

URLs of the form

http://example.com/?tags=foo+bar+baz

do not.

edit: we can now change this, as we've switched to .NET 4.0 which supports the HttpRuntimeSection.MaxUrlLength property -- for now I am relaxing it to 512 characters, from the default of 260.

see related SO question about general practical length of URLs at:
http://stackoverflow.com/questions/417142/what-is-the-maximum-length-of-an-url

share|improve this answer
    
Re-he-he-heally! I wonder what is so special about 260 chars. I mean, shouldn't it be 255 chars? MAX_PATH in windows is also 260 chars. I wonder if this is different on linux-based systems. –  bobobobo Apr 29 '10 at 0:39

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .