On Thu, Sep 4, 2014 at 12:26 PM, Jonas Öberg <jonas(a)commonsmachinery.se>
wrote:
But in order to do so, we need information from
Commons, and we want to
make this as easy on the WMF servers as possible, so we'd appreciate some
help and pointers. What we're looking at retrieving is information about
(1) title, (2) author, (3) license, and (4) thumbnails of medium size.
Not sure what you mean by title (the filename might be the closest thing -
files have a description but that's long and can contain arbitrary HTML),
but for author/license you can use the imageinfo/extmetadata API. [1][2]
(The author name might also contain HTML, and in many cases complex
structure like a listing of multiple authors.)
The ongoing structured data project [3] will hopefully make it easier to
process image attribution metadata.
From what we can understand, you can request any size
thumbnail on an image
simply by prefixing it with the size you want (like 123x-Filename.jpg). But
it seems really silly to always request 640x for instance, since that would
mean the WMF servers would need to generate that for us specifically if the
resolution doesn't exist.
What we'd find much more appealing is to be able to determine before
making the call what sizes already exist and which can be retrieved without
the WMF servers needing to rescale them for us. And while the viewer on
Commons do seem to offer thumbnails in various sizes, we can't seem to get
that information from any API.
There is no way to know whether a size exists already (other than trying).
Standardizing some common sizes is an ongoing effort, so the result is not
set in stone yet, but we will probably end up with the standard screen
widths, such as 640 and 800 pixel; various tools use tools use those
already.
[1]
https://www.mediawiki.org/wiki/API:Properties#imageinfo_.2F_ii
[2]
https://en.wikipedia.org/w/api.php?format=jsonfm&action=query&title…les=File:
30C3_Commons_Machinery_2.jpg
&prop=imageinfo&iiprop=extmetadata&iiextmetadatafilter=ObjectName|Artist|LicenseShortName
[3]
https://commons.wikimedia.org/wiki/Commons:Structured_data