Re: Cool URIs (was: Re: Java Framework for Content Negotiation)
On 1 Jun 2010, at 19:37, Bernhard Schandl wrote: I want to throw in another question, are there currently arguments for or against the two alternatives: http://www.example.org/doc/alice.html vs http://www.example.org/doc/html/alice and the same for .rdf vs rdf/ In terms of web architecture both options are the same. But the first one has several “soft” advantages: - more idiomatic and hence easier to remember and use - more compatible with the Hierarchical URIs pattern [1] - yields an obvious URI for the generic, format-independent version of the resource (chop off the extension) Best, Richard [1] http://patterns.dataincubator.org/book/hierarchical-uris.html Best Bernhard
Re: Cool URIs (was: Re: Java Framework for Content Negotiation)
Hi Angelo, On 31 May 2010, at 10:32, Angelo Veltens wrote: DBpedia has copied the approach from D2R Server. The person who came up with it and designed and implemented it for D2R Server is me. This was back in 2006, before the term Linked Data was even coined, so I didn't exactly have a lot of experience to rely on. With what I know today, I would never, ever again choose that approach. Use 303s if you must; but please do me a favour and add that generic document, and please do me a favour and name the different variants foo.html and foo.rdf rather than page/foo and data/foo. Thanks a lot for sharing your experience with me. I will follow your advice. So if i'm going to implement what is described in section 4.2. i have to - serve html at http://www.example.org/doc/alice if text/html wins content negotiation and set content-location header to http://www.example.org/doc/alice.html - serve rdf/xml at http://www.example.org/doc/alice if application/ rdf+xml wins content negotiation and set content-location header to http://www.example.org/doc/alice.rdf - serve html at http://www.example.org/doc/alice.html always - serve rdf/xml at http://www.example.org/doc/alice.rdf always Right? Correct! By the way: Is there any defined behavior for the client, what to do with the content-location information? Do Browsers take account of it? Not really. It's generally recommended to put the format-specific URIs into the Content-Location header, but I don't think that clients really use that information much (neither in Linked Data nor in other contexts where content negotiation is used). So I'd still recommend using the header, but more important is perhaps to have the format- specific URIs linked from the HTML and RDF representations, so that users of the data -- both in the RDF form and in the HTML form -- can discover a URI where they can reliably retrieve a representation in a specific format. The DBpedia guys are probably stuck with my stupid design forever because changing it now would break all sorts of links. But the thing that really kills me is how lots of newbies copy that design just because they saw it on DBpedia and therefore think that it must be good. I think the problem is not only, that dbpedia uses that design, but that it is described in many examples as a possible or even cool solution, e.g. http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/ (one of the first documents i stumbled upon) If we want to prevent people from using that design it should be clarified that and why it is a bad choice. Yes, that's a good point. Best, Richard Kind regards and thanks for your patience, Angelo
Re: Cool URIs (was: Re: Java Framework for Content Negotiation)
Hi, - serve html at http://www.example.org/doc/alice.html always - serve rdf/xml at http://www.example.org/doc/alice.rdf always Right? Correct! I want to throw in another question, are there currently arguments for or against the two alternatives: http://www.example.org/doc/alice.html vs http://www.example.org/doc/html/alice and the same for .rdf vs rdf/ Best Bernhard
Cool URIs (was: Re: Java Framework for Content Negotiation)
On 27.05.2010 15:51, Richard Cyganiak wrote: On 27 May 2010, at 10:47, Angelo Veltens wrote: What I am going to implement is this: http://www.w3.org/TR/cooluris/#r303uri I think, this is the way dbpedia works and it seems a good solution for me. It's the way DBpedia works, but it's by far the worst solution of the three presented in the document. DBpedia has copied the approach from D2R Server. The person who came up with it and designed and implemented it for D2R Server is me. This was back in 2006, before the term Linked Data was even coined, so I didn't exactly have a lot of experience to rely on. With what I know today, I would never, ever again choose that approach. Use 303s if you must; but please do me a favour and add that generic document, and please do me a favour and name the different variants foo.html and foo.rdf rather than page/foo and data/foo. Thanks a lot for sharing your experience with me. I will follow your advice. So if i'm going to implement what is described in section 4.2. i have to - serve html at http://www.example.org/doc/alice if text/html wins content negotiation and set content-location header to http://www.example.org/doc/alice.html - serve rdf/xml at http://www.example.org/doc/alice if application/rdf+xml wins content negotiation and set content-location header to http://www.example.org/doc/alice.rdf - serve html at http://www.example.org/doc/alice.html always - serve rdf/xml at http://www.example.org/doc/alice.rdf always Right? By the way: Is there any defined behavior for the client, what to do with the content-location information? Do Browsers take account of it? The DBpedia guys are probably stuck with my stupid design forever because changing it now would break all sorts of links. But the thing that really kills me is how lots of newbies copy that design just because they saw it on DBpedia and therefore think that it must be good. I think the problem is not only, that dbpedia uses that design, but that it is described in many examples as a possible or even cool solution, e.g. http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/ (one of the first documents i stumbled upon) If we want to prevent people from using that design it should be clarified that and why it is a bad choice. Kind regards and thanks for your patience, Angelo
Re: Java Framework for Content Negotiation
On 27 May 2010, at 10:47, Angelo Veltens wrote:
What I am going to implement is this: http://www.w3.org/TR/cooluris/#r303uri
I think, this is the way dbpedia works and it seems a good solution
for me.
It's the way DBpedia works, but it's by far the worst solution of the
three presented in the document.
DBpedia has copied the approach from D2R Server. The person who came
up with it and designed and implemented it for D2R Server is me. This
was back in 2006, before the term Linked Data was even coined, so I
didn't exactly have a lot of experience to rely on. With what I know
today, I would never, ever again choose that approach. Use 303s if you
must; but please do me a favour and add that generic document, and
please do me a favour and name the different variants foo.html and
foo.rdf rather than page/foo and data/foo.
The DBpedia guys are probably stuck with my stupid design forever
because changing it now would break all sorts of links. But the thing
that really kills me is how lots of newbies copy that design just
because they saw it on DBpedia and therefore think that it must be good.
Richard
My question is, if there is a java solution / framework for what is
shown in the picture in this section.
I imagine something like this:
I can configure URI-patterns for (non-)information resources, e.g.
Non-Information-Resources: http:/example.com/id/{.*}
RDF-Representation: http:/example.com/data/{.*}
HTML-Representation: http:/example.com/page/{.*}
The conneg and 303-redirection stuff should be handled automatically
so that i only have to implement what my application serves at these
uris.
I have played arround with REST-Webservices as recommended. This is
what i do at the moment:
I have a service at http:/example.com/id/person/0815 with methods
that are annotated to produce html respectively rdf/xml. But
instead of serving the representations immediately I use
Response.seeOther to do a 303-redirect to http:/example.com/page/
person/0815 respectivly http:/example.com/data/person/0815. This
works fine, but perhaps there is a more automated solution, that
does conneg as well as 303-redirect.
But also:
http://www.w3.org/TR/cooluris/#hashuri
http://www.w3.org/TR/cooluris/#choosing
If you can build your site with hash URIs rather than 303
redirects, I highly recommend doing so.
Thanks, i have thought about it, but hash-uris don't fit my needs.
Kind Regards,
Angelo
Java Framework for Content Negotiation
Hello, I am just looking for a framework to do content negotiation in java. Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. Thanks in advance, Angelo
Re: Java Framework for Content Negotiation
There is the RESTlet framework http://www.restlet.org/ Henry On 20 May 2010, at 10:49, Angelo Veltens wrote: Hello, I am just looking for a framework to do content negotiation in java. Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. Thanks in advance, Angelo
Re: Java Framework for Content Negotiation
Hi Angelo, On Thu, May 20, 2010 at 11:49 AM, Angelo Veltens angelo.velt...@online.de wrote: Hello, I am just looking for a framework to do content negotiation in java. Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. I suggest taking a look at Restlet [1], which has support for both the client and server side of conneg (and a lot more). Best regards, Niklas [1]: http://www.restlet.org/
Re: Java Framework for Content Negotiation
On 20/05/2010 11:03, Story Henry wrote: There is the RESTlet framework http://www.restlet.org/ There's also Jersey [1] and, for a minimalist solution to just the content matching piece see Mimeparse [2]. Dave [1] https://jersey.dev.java.net/ [2] http://code.google.com/p/mimeparse/ On 20 May 2010, at 10:49, Angelo Veltens wrote: Hello, I am just looking for a framework to do content negotiation in java. Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. Thanks in advance, Angelo
Re: Java Framework for Content Negotiation
There's also Jersey [1] ... +1 to Jersey - had overall very good experience with it. If you want to have a quick look (not saying it's beautiful/exciting, but might helps to kick-start things) see [1] for my hacking with it. Cheers, Michael [1] http://bitbucket.org/mhausenblas/sparestfulql/ -- Dr. Michael Hausenblas LiDRC - Linked Data Research Centre DERI - Digital Enterprise Research Institute NUIG - National University of Ireland, Galway Ireland, Europe Tel. +353 91 495730 http://linkeddata.deri.ie/ http://sw-app.org/about.html From: Dave Reynolds dave.e.reyno...@googlemail.com Date: Thu, 20 May 2010 11:08:03 +0100 To: Angelo Veltens angelo.velt...@online.de Cc: Linked Data community public-lod@w3.org Subject: Re: Java Framework for Content Negotiation Resent-From: Linked Data community public-lod@w3.org Resent-Date: Thu, 20 May 2010 10:08:45 + On 20/05/2010 11:03, Story Henry wrote: There is the RESTlet framework http://www.restlet.org/ There's also Jersey [1] and, for a minimalist solution to just the content matching piece see Mimeparse [2]. Dave [1] https://jersey.dev.java.net/ [2] http://code.google.com/p/mimeparse/ On 20 May 2010, at 10:49, Angelo Veltens wrote: Hello, I am just looking for a framework to do content negotiation in java. Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. Thanks in advance, Angelo
Re: Java Framework for Content Negotiation
On 20 May 2010, at 11:18, Michael Hausenblas wrote: There's also Jersey [1] ... +1 to Jersey - had overall very good experience with it. If you want to have a quick look (not saying it's beautiful/exciting, but might helps to kick-start things) see [1] for my hacking with it. Since this is an RDF list, I wrote a blog post on how one could use Jersey to create linked data using annotations on objects http://blogs.sun.com/bblfish/entry/serialising_java_objects_to_rdf Something that could be looked into in more detail I have not had time to pursue it since then, but others are welcome to continue from there Henry Cheers, Michael [1] http://bitbucket.org/mhausenblas/sparestfulql/ -- Dr. Michael Hausenblas LiDRC - Linked Data Research Centre DERI - Digital Enterprise Research Institute NUIG - National University of Ireland, Galway Ireland, Europe Tel. +353 91 495730 http://linkeddata.deri.ie/ http://sw-app.org/about.html From: Dave Reynolds dave.e.reyno...@googlemail.com Date: Thu, 20 May 2010 11:08:03 +0100 To: Angelo Veltens angelo.velt...@online.de Cc: Linked Data community public-lod@w3.org Subject: Re: Java Framework for Content Negotiation Resent-From: Linked Data community public-lod@w3.org Resent-Date: Thu, 20 May 2010 10:08:45 + On 20/05/2010 11:03, Story Henry wrote: There is the RESTlet framework http://www.restlet.org/ There's also Jersey [1] and, for a minimalist solution to just the content matching piece see Mimeparse [2]. Dave [1] https://jersey.dev.java.net/ [2] http://code.google.com/p/mimeparse/ On 20 May 2010, at 10:49, Angelo Veltens wrote: Hello, I am just looking for a framework to do content negotiation in java. Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. Thanks in advance, Angelo
Re: Java Framework for Content Negotiation
On 20.05.2010 12:18, Michael Hausenblas wrote: There's also Jersey [1] ... +1 to Jersey - had overall very good experience with it. If you want to have a quick look (not saying it's beautiful/exciting, but might helps to kick-start things) see [1] for my hacking with it. Cheers, Michael [1] http://bitbucket.org/mhausenblas/sparestfulql/ Mmh, i have been thinking about using REST-Webservice already, but there is one thing i'm quite unsteady with: I might have a non-information resource http://example.org/resource/foo I could place a REST-Webservice there and do content negotiation with @GET / @Produces Annotations. But this seems not correct to me, because it is a non-information resource and not a html or rdf/xml document. So it should never return html or rdf/xml but do a 303 redirect to an information resource instead, doesn't it? Kind regards, Angelo
Re: Java Framework for Content Negotiation
Angelo, I might have a non-information resource http://example.org/resource/foo I could place a REST-Webservice there and do content negotiation with @GET / @Produces Annotations. But this seems not correct to me, because it is a non-information resource and not a html or rdf/xml document. So it should never return html or rdf/xml but do a 303 redirect to an information resource instead, doesn't it? This is a recurring pattern and people tend to confuse things (conneg and 303), in my experience. I assume you've read [1], already ? ;) Without more detailed knowledge about what you want to achieve it is hard for me to tell you anything beyond what has been discussed in various forums. Can you give me a more concrete description of your setup and goals? How does your data look like? What's the task you try to solve? Etc. Cheers, Michael [1] http://www.w3.org/TR/cooluris/ -- Dr. Michael Hausenblas LiDRC - Linked Data Research Centre DERI - Digital Enterprise Research Institute NUIG - National University of Ireland, Galway Ireland, Europe Tel. +353 91 495730 http://linkeddata.deri.ie/ http://sw-app.org/about.html From: Angelo Veltens angelo.velt...@online.de Date: Thu, 20 May 2010 14:38:53 +0200 To: Linked Data community public-lod@w3.org Subject: Re: Java Framework for Content Negotiation Resent-From: Linked Data community public-lod@w3.org Resent-Date: Thu, 20 May 2010 12:39:34 + On 20.05.2010 12:18, Michael Hausenblas wrote: There's also Jersey [1] ... +1 to Jersey - had overall very good experience with it. If you want to have a quick look (not saying it's beautiful/exciting, but might helps to kick-start things) see [1] for my hacking with it. Cheers, Michael [1] http://bitbucket.org/mhausenblas/sparestfulql/ Mmh, i have been thinking about using REST-Webservice already, but there is one thing i'm quite unsteady with: I might have a non-information resource http://example.org/resource/foo I could place a REST-Webservice there and do content negotiation with @GET / @Produces Annotations. But this seems not correct to me, because it is a non-information resource and not a html or rdf/xml document. So it should never return html or rdf/xml but do a 303 redirect to an information resource instead, doesn't it? Kind regards, Angelo
Re: Java Framework for Content Negotiation
On 20 May 2010, at 10:49, Angelo Veltens wrote: I am just looking for a framework to do content negotiation in java. There's a reasonably stable and well-tested implementation that is used both in the Pubby and D2R Server codebases. See here: http://d2rq-map.cvs.sourceforge.net/viewvc/d2rq-map/d2r-server/src/de/fuberlin/wiwiss/pubby/negotiation/ This just does the negotiation part (that is, matching an HTTP Accept header against a list of media types that the server supports, including support for q values). It only supports media type negotiation, there's nothing for language negotiation or encoding negotiation in there. The package works like this: You configure a ContentTypeNegotiator with the media types supported by your app. Then you use its getBestMatch(...) method to determine the best response for a given request. The PubbyNegotiator class has a pre-configured negotiator for a server that supports HTML and various RDF syntaxes. Best, Richard Currently I am checking the HttpServletRequest myself quickdirty. Perhaps someone can recommend a framework/library that has solved this already. Thanks in advance, Angelo
Re: Java Framework for Content Negotiation
On 20 May 2010, at 13:38, Angelo Veltens wrote: I might have a non-information resource http://example.org/resource/ foo I could place a REST-Webservice there and do content negotiation with @GET / @Produces Annotations. But this seems not correct to me, because it is a non-information resource and not a html or rdf/xml document. So it should never return html or rdf/xml but do a 303 redirect to an information resource instead, doesn't it? I second Michael's recommendation to have a look at the Cool URIs for SemWeb document, in particular this section: http://www.w3.org/TR/cooluris/#r303gendocument But also: http://www.w3.org/TR/cooluris/#hashuri http://www.w3.org/TR/cooluris/#choosing If you can build your site with hash URIs rather than 303 redirects, I highly recommend doing so. Best, Richard Kind regards, Angelo
