My two cents: In my experience of writing a HTTP connector for Dydra for dotNetRDF it proved to be a pretty awful implementation of HTTP conneg and SPARQL protocols in general compared to other similar systems like Sesame, Stardog, Fuseki etc. and I had to put an awful lot of implementation specific hacks in place to get things working.
For example I have a still open bug related to something very similar to this (https://getsatisfaction.com/dydra/topics/basic_digest_http_authentication_ is_not_supported) which relates to them doing dumb stuff with conneg and not just using HTTP authentication nicely. In essence if you are not logged in and the Accept header does not ask for machine readable formats they automatically redirect to a HTML login form instead of doing HTTP auth. This is particularly problematic because their processing of the Accept header is poor, if you so much as mention HTML in there it will think you are a browser even if machine readable formats are ahead of HTML in the Accept header. I agree with Andy that maybe there is some room for improvement in Jena to allow this to be configured in general but I wouldn't want to turn this on in general just to work with Dydra which I'm still expecting to die a death. I know for a fact that one of their core developers has long since parted ways with the company and I haven't seen any activity on any of my various open bugs in a long time. Rob On 12/6/12 3:14 AM, "Andy Seaborne" <[email protected]> wrote: >Hi Simon, > >What a nuisance. It's not, as far as I know, illegal, but it is a >rather odd interpretation of HTTP POST for remote operations. > >Not sending "Accept" is because it's a POST which does not need to >return anything. conneg for an HTML page is find but it's not conneg if >it returns it without being asked for! I'm a bit worried that changing >in the general casefor Dydra means it will be inconvenient elsewhere. >(And don't some (old) browsers send */* always?) > >So it's will need some sort of configuration mechanism to make it >endpoint specific. > >Good news - every UpdateProcessor has a Context object that is >associated with the request. It's currently null for a remote request >but the mechanism is at least there. > >Remote query (either QueryExecutionFactory.sparelService or SERVICE in a >query) has a mechanism for setting the request with custom headers. > >See ARQ.serviceParams and class Service. > >Do you want to raise a JIRA for this? And (ideally) contribute a patch? > > Andy > >On 05/12/12 21:43, Simon Gábor wrote: >> Hi Andy, >> >> I am trying to use Dydra (http://dydra.com/). It requires to send Accept >> header, otherwise it returns with a full HTML webpage (with Dydra's >>online >> query tool on it). For update commands it is happy with just an Accept: >>*/* >> then returns 200 and a simple boolean SPARQL XML result. >> >> Example: >> POST http://dydra.com/orkszoft/test01/sparql HTTP/1.1 >> Accept: */* >> Content-Length: 364 >> Content-Type: application/sparql-update >> Host: dydra.com >> Connection: Keep-Alive >> User-Agent: Apache-HttpClient/4.2.2 (java 1.5) >> Authorization: Basic *** >> >> PREFIX dc: <http://purl.org/dc/elements/1.1/> >> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> >> PREFIX owl: <http://www.w3.org/2002/07/owl#> >> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> >> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> >> >> DELETE DATA { >> <http://dbpedia.org/resource/San_Francisco> rdfs:label "My San >>Francisco" >> . >> } >> >> Response: >> HTTP/1.1 200 OK >> Content-Type: */* >> Connection: keep-alive >> Status: 200 >> X-Powered-By: Phusion Passenger (mod_rails/mod_rack) 3.0.9 >> Cache-Control: no-cache >> X-UA-Compatible: IE=Edge,chrome=1 >> Set-Cookie: _dydra_session=****; path=/; HttpOnly >> X-Runtime: 0.849964 >> Server: nginx/1.0.8 + Phusion Passenger 3.0.9 (mod_rails/mod_rack) >> Access-Control-Allow-Origin: * >> Access-Control-Allow-Credentials: * >> Content-Length: 123 >> >> <?xml version='1.0'?> >> <sparql xmlns='http://www.w3.org/2005/sparql-results#'> >> <head/> >> <boolean>true</boolean> >> </sparql> >> >> >> I'm having trouble to decide whether Dydra has a faulty design (it's not >> conform with the protocol recommendation) or Jena has no support for the >> optional content negotiation (or both)? >> It's for sure that Dydra's method is somewhat weird because for a wrong >> SPARQL it returns code 400 - so it seems that the response body holds no >> new info. >> >> >> Gabor Simon >> >> >> >> >> 2012/12/5 Andy Seaborne <[email protected]> >> >>> On 03/12/12 12:44, Simon Gábor wrote: >>> >>>> Hi All, >>>> >>>> According to the SPARQL Update protocol recommendation: >>>> "The response body of a successful update request is implementation >>>> defined. Implementations *may* use HTTP content negotiation to provide >>>> both >>>> >>>> human-readable and machine-processable information about the completed >>>> update request." >>>> >>>> How can i specify accept header in the SPARQL Update request? I cannot >>>> find >>>> a way in UpdateProcessor (UpdateProcessRemote) or in UpdateRequest. >>>> >>> >>> Simon, >>> >>> There currently isn't a way to do that and also the .execute() >>>operation >>> does not return anything. Errors appear as exceptions driven from the >>>HTTP >>> response code. >>> >>> What had you in mind? >>> >>> I don't know of any systems currently that return different entity >>>bodies >>> based on conneg. Are there any? >>> >>> The reason in the spec for "MAY" is that there is no standard format >>>for a >>> reply. RDFa, RDF, JSON [1] (why have an RDF processor when you send a >>> string?) all make sense in different scenarios. >>> >>> Andy >>> >>> [1] >>>http://tools.ietf.org/html/**draft-nottingham-http-problem-**01<http://t >>>ools.ietf.org/html/draft-nottingham-http-problem-01> >>> >> >
