[CalendarServer-dev] Re: twisted dav : xattrprops on linux

[Wilfredo Sánchez Vega]

   Thanks, Guido.  I've committed this on the Twisted branch we're  
using and closed the bug.

   The question remains as to how "correct" this is really.  Is the  
"user." prefix a Linux system-wide restriction, or is it a per- 
filesystem thing?  If it's the latter, that means we'd have to check  
the filesystem type (which I don't know how to do from Python,  
offhand) every time we want to write a property.  That may be a  
downer, performance, wise.

   Something to keep an eye on.

	-wsv


On Sep 12, 2006, at 12:11 AM, Guido Guenther wrote:

> Hi Wilfredo,
> On Mon, Sep 11, 2006 at 03:12:51PM -0700, Wilfredo Sánchez Vega wrote:
>>   (Let's chat on the mailing list; I don't always respond to direct
>> mail, get too much and all that.)
>>
>>   That's a weird rule...
>>
>>   Does it make sense for this to be hidden in the xattr library?
>> Perhaps not...  I kinda hate to so this on OS X just because Linux is
>> weird.
> I'm using this in twisted to fix this:
>
> --- twisted/web2/dav/xattrprops.py.orig	2006-09-05  
> 22:09:03.000000000 +0200
> +++ twisted/web2/dav/xattrprops.py	2006-09-05 23:12:17.000000000 +0200
> @@ -32,6 +32,7 @@
>  __all__ = ["xattrPropertyStore"]
>
>  import urllib
> +import sys
>
>  import xattr
>
> @@ -58,8 +59,11 @@
>      #
>      # Dead properties are stored as extended attributes on disk.   
> In order to
>      # avoid conflicts with other attributes, prefix dead property  
> names.
> -    #
> -    deadPropertyXattrPrefix = "WebDAV:"
> +    # Linux additionally needs everything in the user namespace
> +    if sys.platform == 'linux2':
> +        deadPropertyXattrPrefix = "user.WebDav:"
> +    else:
> +        deadPropertyXattrPrefix = "WebDAV:"
>
>      def _encode(clazz, name):
>          #
>
> This looks clean and hardcodes the namespace at exactly one place.
> Addingt this to xattr doesn't seem reasonable since there are other
> namespaces.
> Cheers,
>  -- Guido