[oslc-core] Provided guidance for adding relationship labels

[Arthur Ryman]

Jim,

Your suggestion is for the client to actually have a cache, i.e. the value 
of the link label would not be part of subject resource. The client would 
check the cache at display time.

The approach I was thinking of was that the link label would be part of 
the subject resource, and the subject resource would also include the ETag 
of the object resource that it obtained the label from. At display time, 
the client would send a HEAD request to the object resource, and if it got 
a different ETag, then it would request the new link label via GET and 
update the subject resource with the new label and ETag. This could also 
be done in a single request using a conditional GET with If-Match.

Regards, 
___________________________________________________________________________ 

Arthur Ryman, PhD, DE


Chief Architect, Project and Portfolio Management

IBM Software, Rational

Markham, ON, Canada | Office: 905-413-3077, Cell: 416-939-5063
Twitter | Facebook | YouTube







From:
James Conallen/Philadelphia/IBM at IBMUS
To:
Arthur Ryman <ryman at ca.ibm.com>
Cc:
oslc-cm at open-services.net, oslc-core at open-services.net, 
oslc-core-bounces at open-services.net, Steve K Speicher/Raleigh/IBM at IBMUS
Date:
09/01/2010 09:54 AM
Subject:
Re: [oslc-core] Provided guidance for adding relationship labels


Good point.

I wonder if it is then appropriate to provide some guidance on the use 
HTTP cache control - i don't think etags will help here. 

So, if a provider wants to cache some information about the object 
resource, like the title (using Steve's example), that server should also 
look for an Cache-Control header and then decide if it can cache the 
information, and if it can, how long it can cache it.  (this information 
can also be stored in the reified statement).

while all this can be done, and presumably to address expected performance 
issues, i still think the guidance should be to refrain from using link 
annotations to describe information about the target (object), and instead 
only use it to describe the link itself.

<jim/>

jim conallen
CAM Lead Architect
jconallen at us.ibm.com
Rational Software, IBM Software Group






From:   Arthur Ryman <ryman at ca.ibm.com>
To:     James Conallen/Philadelphia/IBM at IBMUS
Cc:     oslc-cm at open-services.net, oslc-core at open-services.net, 
oslc-core-bounces at open-services.net, Steve K Speicher/Raleigh/IBM at IBMUS
Date:   08/31/2010 04:19 PM
Subject:        Re: [oslc-core] Provided guidance for adding relationship 
labels



Steve/James,

There are standard HTTP practices that describe how to safely cache 
resources, and well-behaved clients (e.g. Web browsers) should use those. 
OSLC clients should be well-behaved HTTP clients. This includes the use of 

ETags, expiry dates, and HEAD requests.

Regards, 
___________________________________________________________________________ 


Arthur Ryman, PhD, DE


Chief Architect, Project and Portfolio Management

IBM Software, Rational

Markham, ON, Canada | Office: 905-413-3077, Cell: 416-939-5063
Twitter | Facebook | YouTube







From:
James Conallen <jconallen at us.ibm.com>
To:
Steve K Speicher <sspeiche at us.ibm.com>
Cc:
oslc-cm at open-services.net, oslc-core at open-services.net
Date:
08/31/2010 03:29 PM
Subject:
Re: [oslc-core] Provided guidance for adding relationship labels
Sent by:
oslc-core-bounces at open-services.net



my 2c,

I worry about guidance that that suggests that it is ok to essentially 
cache information about a resource that is being referenced (and managed 
by) on another server. If this is to be a practice, what are the 
recommendations for ensuring that this information remains in sync. 
Looking at the referenced example, what happens if the owner of the 
resource 123 changes its title to "Enhancement 123: Enable multi-root 
installs"? Will this have to be manually updated? If not, does the system 
automatically update properties of links whenever it detects them.

While I do recognize this may be a way to save a GET call. I don't think 
it represents a best practice.

<jim/>

jim conallen
CAM Lead Architect
jconallen at us.ibm.com
Rational Software, IBM Software Group



Steve K Speicher---08/31/2010 02:47:42 PM---I wanted to call out some 
specification updates that was created for handling of relationship label

From: Steve K Speicher/Raleigh/IBM at IBMUS
To: oslc-cm at open-services.net
Cc: oslc-core at open-services.net
Date: 08/31/2010 02:47 PM
Subject: [oslc-core] Provided guidance for adding relationship labels
Sent by: oslc-core-bounces at open-services.net



I wanted to call out some specification updates that was created for 
handling of relationship labels on URI relationship properties.  Note the 
support for this is optional but wanted to make sure this was done in a 
uniform way across implementations.  Let me know if there are any issues 
with this.

http://open-services.net/bin/view/Main/CmSpecificationV2#Labels_for_Relationships



Thanks,
Steve Speicher | IBM Rational Software | (919) 254-0645


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