LISTSERV mailing list manager LISTSERV 16.5

Help for CODE4LIB Archives


CODE4LIB Archives

CODE4LIB Archives


CODE4LIB@LISTS.CLIR.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Monospaced Font

LISTSERV Archives

LISTSERV Archives

CODE4LIB Home

CODE4LIB Home

CODE4LIB  November 2013

CODE4LIB November 2013

Subject:

Re: The lie of the API

From:

Péter Király <[log in to unmask]>

Reply-To:

Code for Libraries <[log in to unmask]>

Date:

Fri, 29 Nov 2013 21:39:16 +0100

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (136 lines)

Hi,

I was happy to read this blog post, because it contain lots of very
important statements, but as one of the developers of Europeana API I
would like to mention some points.

The idea of content negotiation is nice, but it also adds some
additional burden for the API users. In some tools and programming
languages it is easy to modify HTTP headers, in others it is not that
trivial. For non tech people it is a burden. In an environment such as
Europeana not only tech people would like to see and check the non
HTML output, but it also has a meaning for metadata experts, marketing
people, ingestion team members and so on.

Europeana has a history, and even the API and the metadata model
behind has its own history. When we released the new API which
reflects the new metadata structure, it was evident, that we did not
want to break existing client side applications. So we had to
introduce versioning. With versioning we had the same choces as with
content type: we can make it transparent in the URL or use hypermedia
versioning via HTTP headers. This lead to the same problem as we had,
so we choosed URL approach.

Finally, when creating an API there are lots of different aspect we
should consider. Beside technological, scientific or aesthetic aspects
there are lots of other ones as well. We follow a way, which has good
and bad points, but as I see the same is true for Ruben's suggestions.
It is not true, that our way is driven by simle ignorance. We never
claimed, that we created RESTFul and pedantic API. We did a practical
one, and we keep improving it gradually, considering such a feedbacks
as this post.

Regards,
Péter


2013/11/29 Robert Sanderson <[log in to unmask]>:
> (posted in the comments on the blog and reposted here for further
> discussion, if interest)
>
>
> While I couldn't agree more with the post's starting point -- URIs identify
> (concepts) and use HTTP as your API -- I couldn't disagree more with the
> "use content negotiation" conclusion.
>
> I'm with Dan Cohen in his comment regarding using different URIs for
> different representations for several reasons below.
>
> It's harder to implement Content Negotiation than your own API, because you
> get to define your own API whereas you have to follow someone else's rules
> when you implement conneg. You can't get your own API wrong. I agree with
> Ruben that HTTP is better than rolling your own proprietary API, we
> disagree that conneg is the correct solution. The choice is between conneg
> or regular HTTP, not conneg or a proprietary API.
>
> Secondly, you need to look at the HTTP headers and parse quite a complex
> structure to determine what is being requested. You can't just put a file
> in the file system, unlike with separate URIs for distinct representations
> where it just works, instead you need server side processing. This also
> makes it much harder to cache the responses, as the cache needs to
> determine whether or not the representation has changed -- the cache also
> needs to parse the headers rather than just comparing URI and content. For
> large scale systems like DPLA and Europeana, caching is essential for
> quality of service.
>
> How do you find our which formats are supported by conneg? By reading the
> documentation. Which could just say "add .json on the end". The Vary header
> tells you that negotiation in the format dimension is possible, just not
> what to do to actually get anything back. There isn't a way to find this
> out from HTTP automatically,so now you need to read both the site's docs
> AND the HTTP docs. APIs can, on the other hand, do this. Consider
> OAI-PMH's ListMetadataFormats and SRU's Explain response.
>
> Instead you can have a separate URI for each representation and link them
> with Link headers, or just a simple rule like add '.json' on the end. No
> need for complicated content negotiation at all. Link headers can be added
> with a simple apache configuration rule, and as they're static are easy to
> cache. So the server side is easy, and the client side is trivial.
> Compared to being difficult at both ends with content negotiation.
>
> It can be useful to make statements about the different representations,
> and especially if you need to annotate the structure or content. Or share
> it -- you can't email someone a link that includes the right Accept headers
> to send -- as in the post, you need to send them a command line like curl
> with -H.
>
> An experiment for fans of content negotiation: Have both .json and 302
> style conneg from your original URI to that .json file. Advertise both. See
> how many people do the conneg. If it's non-zero, I'll be extremely
> surprised.
>
> And a challenge: Even with libraries there's still complexity to figuring
> out how and what to serve. Find me sites that correctly implement * based
> fallbacks. Or even process q values. I'll bet I can find 10 that do content
> negotiation wrong, for every 1 that does it correctly. I'll start:
> dx.doi.org touts its content negotiation for metadata, yet doesn't
> implement q values or *s. You have to go to the documentation to figure out
> what Accept headers it will do string equality tests against.
>
> Rob
>
>
>
> On Fri, Nov 29, 2013 at 6:24 AM, Seth van Hooland <[log in to unmask]>
> wrote:
>>
>> Dear all,
>>
>> I guess some of you will be interested in the blogpost of my colleague
> and co-author Ruben regarding the misunderstandings on the use and abuse of
> APIs in a digital libraries context, including a description of both good
> and bad practices from Europeana, DPLA and the Cooper Hewitt museum:
>>
>> http://ruben.verborgh.org/blog/2013/11/29/the-lie-of-the-api/
>>
>> Kind regards,
>>
>> Seth van Hooland
>> Président du Master en Sciences et Technologies de l'Information et de la
> Communication (MaSTIC)
>> Université Libre de Bruxelles
>> Av. F.D. Roosevelt, 50 CP 123 | 1050 Bruxelles
>> http://homepages.ulb.ac.be/~svhoolan/
>> http://twitter.com/#!/sethvanhooland
>> http://mastic.ulb.ac.be
>> 0032 2 650 4765
>> Office: DC11.102



--
Péter Király
software developer

Europeana - http://europeana.eu
eXtensible Catalog - http://eXtensibleCatalog.org

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

October 2024
September 2024
August 2024
July 2024
June 2024
May 2024
April 2024
March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003

ATOM RSS1 RSS2



LISTS.CLIR.ORG

CataList Email List Search Powered by the LISTSERV Email List Manager