Re: How to publish SPARQL endpoint limits/metadata?

Hello,

If it has really been established that there is no standardized way to 
make these things like service limitations known I think it would be a 
nice idea to try to initiate a community project.

Below are some things that I think would benefit communication between 
SPARQL endpoints and user agents. Please know that I am a novice in 
Linked Data, so perhaps some of these are already covered by existing 
standards or best practices, or do not make sense.

 1. The maximum number of results per request (hard limit)
 2. The amount of remaining requests (This could be used for a
    throttling mechanism that allows only a certain amount of request
    per unit of time and IP address. I remember having talked to a data
    service on the web where this information was put in the HTTP
    response headers)
 3. The time period of the next scheduled downtime
 4. The version(s) of the protocol that are supported
 5. (the URI of) a document that contains a human readable SLA or fair
    use policy for the service
 6. URIs of mirrors

Regards,
Frans


On 8-10-2013 17:45, Leigh Dodds wrote:
> Hi,
>
> As others have suggested, extending service descriptions would be the
> best way to do this. This might make a nice little community project.
>
> It would be useful to itemise a list of the type of limits that might
> be faced, then look at how best to model them.
>
> Perhaps something we could do on the list?
>
> Cheers,
>
> L.
>
>
>
> On Tue, Oct 8, 2013 at 10:46 AM, Frans Knibbe | Geodan
> <frans.knibbe@geodan.nl> wrote:
>> Hello,
>>
>> I am experimenting with running SPARQL endpoints and I notice the need to
>> impose some limits to prevent overloading/abuse. The easiest and I believe
>> fairly common way to do that is to LIMIT the number of results that the
>> endpoint will return for a single query.
>>
>> I now wonder how I can publish the fact that my SPARQL endpoint has a LIMIT
>> and that is has a certain value.
>>
>> I have read the thread Public SPARQL endpoints:managing (mis)-use and
>> communicating limits to users, but that seemed to be about how to
>> communicate limits during querying. I would like to know if there is a way
>> to communicate limits before querying is started.
>>
>> It seems to me that a logical place to publish a limit would be in the
>> metadata of the SPARQL endpoint. Those metadata could contain all limits
>> imposed on the endpoint, and perhaps other things like a SLA or a
>> maintenance schedule... data that could help in the proper use of the
>> endpoint by both software agents and human users.
>>
>> So perhaps my enquiry really is about a standard for publishing SPARQL
>> endpoint metadata, and how to access them.
>>
>> Greetings,
>> Frans
>>
>>
>> --------------------------------------
>> Geodan
>> President Kennedylaan 1
>> 1079 MB Amsterdam (NL)
>>
>> T +31 (0)20 - 5711 347
>> E frans.knibbe@geodan.nl
>> www.geodan.nl | disclaimer
>> --------------------------------------
>
>


-- 
--------------------------------------
*Geodan*
President Kennedylaan 1
1079 MB Amsterdam (NL)

T +31 (0)20 - 5711 347
E frans.knibbe@geodan.nl
www.geodan.nl <http://www.geodan.nl> | disclaimer 
<http://www.geodan.nl/disclaimer>
--------------------------------------