Erweiterung:CommonsMetadata

The extension in its current form is intended to be a temporary solution, eventually replaced by Wikidata on Commons.

The assumptions of this extension are the following.

• At some point in the future, Wikidata will take over handling metadata at Commons. To avoid disruptive changes, which will soon need to be changed again, the extension should work with common metadata as it currently is (so not introducing new parser functions). Hence, screen scraping.

• The content of many of the fields on a commons description page includes rich formatting (In particular: Links, italics, bold. In some cases, more complex things like embedded images)

• • As a result, the extension outputs parsed html (wikitext sucks, plain text doesn't capture the data)

• • Furthermore, the data tends to be formatted for human display rather than (for example) machine-formatted dates. When the date field says something like "circa 1600s", it's hard to convert that to a precise date (many examples can be).

• • To carry that forward, also apply formatting to EXIF metadata, which is controlled on the wiki (For example, commons links the camera name to a Wikipedia article)

• If we can't extract info from the description page, but the file has the author tagged in EXIF/XMP/iptc metadata, we should use that as a fallback.

• Ideally, such a system would be as commons-specific as possible, with the commons and non-commons parts separated.

• Commons description pages have multilingual descriptions. Lots of users probably want one language.

• • This implementation applies per language conventions to dates and things. Additionally, for explicitly multi-lingual fields (description), there is an option to return all or just a single language. Even in single language mode, some things are still language-specific (like the thousands separator on numbers)

When testing with remote images (e.g. Commons images if you have enabled $wgUseInstantCommons ), you can set $wgCommonsMetadataForceRecalculate = true; to force CommonsMetadata to parse the description page of the image and extract the metadata (normally, if the remote repository had CommonsMetadata installed as well, it would just copy the API output from there).

Use the imageinfo API, and include extmetadata as an image info property specified via iiprop.

View this example in the API sandbox:

The extension currently provides the following items in the extmetadata field of the response (the field names were chosen, where possible, to follow the IPTC-IIM format used in EXIF headers):

Data based on machine-readable data in the Information template:

• ImageDescription - image description

• Artist - author name (might contain complex HTML, multiple authors, etc)

• Credit - source

• DateTimeOriginal - time of creation (space-separated ISO 8601 timestamp whenever possible, but can be any other textual description of a date, possibly with HTML mixed in)

• ObjectName - title (for a book/painting; otherwise just the file name)

• Permission - contents of the Permission field of the template. It can be a lot of things (license template, OTRS ID, details on how to attribute...)

• AuthorCount - the number of templates with authors (e.g., Book, Photograph...). The number of actual authors might be higher if a template describes multiple authors in a single string.

Data based on machine-readable data in the Location template:

• GPSLatitude - latitude
• GPSLongitude - longitude
• GPSMapDatum - coordinate type (only WGS-84 supported for now)

Data based on machine-readable data in the license template:

• LicenseShortName - short human-readable license name
• LicenseUrl
• UsageTerms
• Copyrighted - True or False (for public domain images)

For multi-licensed images, these values are currently unreliable.

• Attribution - custom attribution that should replace Artist + Credit (can also originate from the Information template)

• AttributionRequired - booleanish (phab:T86726), tells whether there is a legal requirement to attribute

• NonFree - booleanish, true means the image is not under a free license. (Used for non-Commons images only.)

Other data:

• CommonsMedadataExtension - contains the metadata parser version number; mostly for internal use
• License - a best guess at the license of the image (mostly for internal use by MediaViewer, might change; LicenseShortName is probably more reliable)
• Categories - a |-separated list of the categories of the image.

• Assessments - a |-separated list of the assessments of the image (currently five values are supported: poty, potd, featured, quality, valued).

• Restrictions - reuse restrictions such as trademarks or personality rights; an array of keywords (the class names from this table, without the restriction- prefix). See also the restrict-* icons in MediaViewer.
• DeletionReason - if set, the template is being considered for deletion.

• How to add metadata

• Template detection on local wikis with locally uploaded files – Describes how to prepare the templates for fetching metadata and thus displaying them when using the MultimediaViewer extension.