Re: Public SPARQL endpoints:managing (mis)-use and communicating limits to users.

On Fri, Apr 19, 2013 at 9:25 AM, Rob Warren <warren@muninn-project.org> wrote:
>> Hi Rob,
>>
>> There is a fundamental problem with HTTP status codes.
>> Lets say a user submits a complex but small sparql request.
>>
>> My server sees the syntax is good and starts to reply in good faith.
>> This means the server starts the http response and sends an 200 OK
>> Some results are being send....
>> However, during the evaluation the server gets an exception.
>> What to do? I can't change the status code anymore...
>
>
> Is this really so? Failures in large transfers are common and there are a
> few ways to detect it from the client's end (wrong format, wrong
> Content-Length and dropped connection).

Yes, this is a well known (to HTTP geeks) problem with HTTP framing.
Trailers were introduced to solve similar problems, but because the
response status code isn't a header, there's no standard way to
communicate "this is the new status code". And even if they're were,
it can't easily be communicated through existing HTTP client libraries
without an interface change which makes it prohibitively expensive to
deploy.

IIRC, HTTP 2.0 framing will address this.

Mark.

Received on Friday, 19 April 2013 19:13:37 UTC