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Re: representing file pathnames



Chuck Lever wrote:
> The downside of using a binary XDR blob is that it's not observable or
> editable via typical LDAP tools.

Some tools allow implementing plugins for certain attributes.
But of course it's rather cumbersome.

> It's been suggested that we use a file URL to represent export pathnames.
> A file URL is expressed in US-ASCII with escaping, 
> [..]
> Can we represent the full range of the UTF-8 code set with a US-ASCII file
> URL?

Yes, of course just like HTTP URLs can contain non-ASCII chars in an
URL-quoted form. You first encode to UTF-8 and then URL-quote. Decoding means
URL-unquote and the decode UTF-8 to Unicode char entities.

> We could also use an NFS URL, which would allow us to express the server
> hostname, a port number, and the pathname in a single string.  But both the
> hostname and pathname are enocded in US-ASCII, not UTF-8, and the NFS URL
> format employs a fixed pathname separator character.

That's what I would prefer. Think of file browsers which can open the NFS
mount point just by clicking on it. Same encoding steps as with file URLs.

> An alternative we have considered would store the pathname in a
> single-valued UTF-8 string attribute, including pathname separators, but
> also store the pathname separator character in a separate attribute.  A
> simple escaping mechanism would be used to represent a separator character
> embedded in a component.

I would not do this.

Ciao, Michael.

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