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From Andrew Gaul <g...@apache.org>
Subject Re: directoryExists vs blobExists
Date Tue, 19 Sep 2017 08:17:31 GMT
Prefix allows clients to filter results which only match a prefix.  For
example, prefix a/ with a/1, a/2 and b/3 keys would only match a/1 and
a/2.  Delimiter filters results based on a partial suffix.  For example,
delimiter / with the previous keys would return a and b.

Prefix and delimiter have more utility and match how blobstores actually
work.  File systems have an actual hierarchy such that creating a/b will
create two entries and must prohibit operations like removing a before
removing a/b.  Object stores remove these invariants to increase
scalability.  jclouds previously mapped directory operations onto
pseudo-file system operations, inconsistently and poorly.

On Tue, Sep 19, 2017 at 08:37:26AM +0200, GARDAIS Ionel wrote:
> Thanks Andrew.
> 
> Do I understand correctly that "prefix and delimiter" is "path ending with a /" (like
in "folder/") ?
> 
> Regards,
> -- 
> Ionel GARDAIS
> Tech'Advantage CIO - IT Team manager
> 
> ----- Mail original -----
> De: "Andrew Gaul" <gaul@apache.org>
> À: "user" <user@jclouds.apache.org>
> Envoyé: Lundi 18 Septembre 2017 19:53:08
> Objet: Re: directoryExists vs blobExists
> 
> jclouds deprecated and will remove support for directories from the
> portable abstraction since most object stores do not not support them.
> Directories should still work through the provider level but I recommend
> using the prefix and delimiter options instead.  Tracking issue:
> 
> https://issues.apache.org/jira/browse/JCLOUDS-1066
> 
> On Mon, Sep 18, 2017 at 05:26:31PM +0200, GARDAIS Ionel wrote:
> > Hi, 
> > 
> > Got a question about using the filesystem API. 
> > As a blob wrote using putBlob(« container », "folder/file.t xt »); 
> > 
> > directoryExists(« container », « folder") returns true 
> > 
> > blobExists(« container », « folder") returns false 
> > blobExists(« container », « folder/") returns false 
> > 
> > As directoryExists() is deprecated, what should be used ? 
> > 
> > Thanks, 
> > Ionel 
> > 
> > --
> > 
> > 232 avenue Napoleon BONAPARTE 92500 RUEIL MALMAISON
> > 
> > Capital EUR 219 300,00 - RCS Nanterre B 408 832 301 - TVA FR 09 408 832 301
> > 
> 
> > BEGIN:VCARD
> > VERSION:3.0
> > FN:GARDAIS\, Ionel
> > N:GARDAIS;Ionel;;;
> > ADR;TYPE=work,postal,parcel:;;1 Rue Isabey;RUEIL MALMAISON;IdF;92500;FRANCE
> > TEL;TYPE=work,voice:0147088131
> > EMAIL;TYPE=internet:ionel.gardais@tech-advantage.com
> > URL;TYPE=work:http://www.techad.fr
> > ORG:TECH advantage
> > TITLE:CIO
> > REV:2016-12-16T11:52:22Z
> > UID:5a4525af-5d0c-4a32-a77b-c565580b116e:114277
> > END:VCARD
> 
> 
> -- 
> Andrew Gaul
> http://gaul.org/
> --
> 232 avenue Napoleon BONAPARTE 92500 RUEIL MALMAISON
> Capital EUR 219 300,00 - RCS Nanterre B 408 832 301 - TVA FR 09 408 832 301
> 

-- 
Andrew Gaul
http://gaul.org/

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