Found something odd with documented SharePoint Foundation URL limits

I haven't had time to post much, as everything I am writing about SharePoint Foundation is going into the Mastering book, but I've discovered something that can't go in the book that I've just got to get off my chest.

It's about Microsoft's published limits for URLs (http://technet.microsoft.com/en-us/library/ff919562.aspx). I've seen the info all over the web-- "SharePoint can only support 260 character URLs."

It's supposed to include the protocol, server name, path (with folders and file name), and parameters (stuff added after a question mark to the end of the path).

Well, just messing around with subfolders, file names, and views, I've discovered something.

If I just open a file (with a long file name) deep in a nested subfolder structure, the URL fails to open the file after 340 characters. I am using IE 8 on Server 2008 R2. I am sure that, instead of folders, I had a long path of subsites, or a combo of both in the path, it would amount to the same thing. The point, I think, is maxing out the characters.

If I have a URL with parameters appended to it, like opening the create view page on a library in a subsite with a long name, it can exceed 1600 characters and be fine.

So I think SharePoint's limit for URLs without parameters is actually 340 characters to see a file, and with parameters it depends on the browser you are using-- IE supports more than 1660 (actually more than 2000 characters for IE 7 & 8).

This is just my experience using SharePoint Foundation 2010 RTM, on a Server 2008 R2 VM, using the built in IE 8 32 bit.

If anyone could check this, I'd like to know if you got similar results.

EDITED TO ADD: Just got a chance to test the URL limit on a Windows 7 Ultimate client (IE 8), and found something interesting that didn't happen on the 2008 R2 server using IE 8. I can browse to a file that is well past 260 characters. I got to the file that was at a 340 character URL (with filename), and tried to open it.

This time I got an error of sorts. It warned me that the URL to the file had too many characters, that it could cache it to the local computer and then I could save it under a different name.

Interesting. When I clicked OK, it opened the file in the browser as it was supposed to. No problems. So my 2008 R2 server was opening the file without the error, Windows 7 showed the error, but opened the file- albeit after caching.

When I took the characters out of the file name to get its URL back down to 260, the same thing happened. However, at 259 characters, there was no error on the Windows 7 box using IE8, and the file opened as it is supposed to.

So now you know. The bottom line, the server doesn't seem to mind going over 260 characters for a URL. The Windows client however, wants URLs just under 260 characters.

Something else to keep in mind (that I did put in the book), if you are going to use Send To for libraries or the Links list, or any other list or library field that contains URLs-- the single line text field limit for characters is 255. Making that the practical character limit for URLs on your site. Regardless of whether you're opening something on the server or client. 255 is all a single line of text field can take (like the Links URL field or the Send To Destination field).

This may not be a show stopper, but I just had to say it somewhere. Thanks for listening.

(and yes, this is what I do with my time. Click every button and challenge everything I can. It's my job. ; P)