Metadata

In order to provide a description to each ZIM file that can be easily extracted we defined a special namespace M and a standardized set of keywords that should be used.

Every key is defined like an article, the key name is used as the article name, the key value is put into the article text. This way also metadata is compressed, but extendable. Further keys could be used in a ZIM file without breaking the standard but please be aware that maybe the openZIM project will define additional keys in the future. Any ZIM library reading this metadata should ignore missing keys / values and just return NULL values in such cases.

Keys

Key	Mandatory	Description	Example
Name	yes	A human readable identifier for the resource. It's the same across versions (should be stable across time).	wikipedia_fr_football
Title	yes	title of zim file. 30 graphemes maximum recommended.	English Wikipedia
Creator	yes	creator(s) of the ZIM file content	English speaking Wikipedia contributors
Publisher	yes	creator of the ZIM file itself	Wikipedia user Foobar
Date	yes	ZIM creation date (ISO - YYYY-MM-DD)	2009-11-21
Description	yes	description of content (one short sentence). 80 graphemes maximum recommended.	All articles (without images) from the english Wikipedia
LongDescription	no	extended description of content. It should not copy the Description or be shorter than it. Carriage return allowed. 4,000 graphemes maximum recommended.	This ZIM file contains all articles (without images) from the english Wikipedia by 2009-11-10. The topics are ...
Language	yes	ISO639-3 language identifier. If many, comma separated, and ordered by "importance" (which should be the number of entries, but in a edge case it can be ordered on an other criteria).	eng
License	No	License code of the content.	CC-BY
Tags	no	A list of tags	wikipedia;_category:wikipedia;_pictures:no;_videos:no;_details:yes;_ftindex:yes
Relation	no	URI of external related ressources
Flavour	no	A human readable string describing the way how the content has been scraped. It's the same across versions (should be stable across time).	nopic
Source	no	URI of the original source	https://en.wikipedia.org/
Counter	no	Number of non-redirect entries per mime-type in the C namespace	image/jpeg=5;image/gif=3;image/png=2;...
Scraper	no	Details about the software used to scrape the content, with its version	mwoffliner 1.2.3
Illustration_[height]x[width]@[scale]	yes	A png image (resolution [height] by [width]) to illustrate the zim file. This must be a binary content (png) with mimeytpe `image/png`. We follow the same specification than freedesktop https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html for the size and scale of the icon. height, width, scale describe the target size (where the icon is intended to be displayed) : - Illustration_48x48@1 is a 48x48 pixels image to be displayed as a 48x48 icon on a scale 1 screen. - Illustration_48x48@2 is a 96x96 pixels image to be displayed as a 48x48 icon on a scale 2 screen. - Illustration_96x96@1 is a 96x96 pixels image to be displayes as a 96x96 icon on a scale 1 screen. Illustration_48x48@1 is mandatory. Others are optional.

Favicon (Old zim file)

Old zim file may have a illustration in -/favicon (it can be a redirection to the real content).

Reader must be able to read the illustration using this path.

Writer must not set a -/favicon

See also

• Dublin Core
• ZIM Naming Convention