hoakley Macs, Technology, xattr

xattr: org.openmetainfo: and org.openmetainfo.time: families, third-party metadata

Type: org.openmetainfo and org.openmetainfo.time families
Subtypes: many
Serialisation: none
Data type: binary property list normally containing text metadata
Example: org.openmetainfo:kMDItemCopyright <62706c69 73743030 5f103268 74747073 3a2f2f63 72656174 69766563 6f6d6d6f 6e732e6f 72672f70 75626c69 63646f6d 61696e2f 7a65726f 2f312e30 2f080000 00000000 01010000 00000000 00010000 00000000 00000000 00000000 003d> «bplist00_ 2https://creativecommons.org/publicdomain/zero/1.0/ =»
macOS: El Capitan, Sierra, High Sierra
System use: none
App use: rare
Document use: widespread
Other usage: rare.

Purpose: contains metadata, the equivalent of com.apple.metadata subtypes.
Information:
These two families of xattr types originated in the effort by Tom Andersen of Ironic Software to implement an open source system of metadata tags using extended attributes. First released in January 2009 in Ironic’s apps Deep and Tagit, they are now also supported by apps Yep and Leap, and others, and in command line tools available from Goggle Code (see below).

Among the more widely-used xattr types in these families are:

  • org.openmetainfo.time:kMDItemCity
  • org.openmetainfo.time:kMDItemCopyright
  • org.openmetainfo.time:kMDItemCountry
  • org.openmetainfo.time:kMDItemCreator
  • org.openmetainfo.time:kMDItemDescription
  • org.openmetainfo.time:kMDItemHeadline
  • org.openmetainfo.time:kMDItemInstruction
  • org.openmetainfo.time:kMDItemKeywords
  • org.openmetainfo.time:kMDItemNamedLocation
  • org.openmetainfo.time:kMDItemStarRating
  • org.openmetainfo:kMDItemCity
  • org.openmetainfo:kMDItemCopyright
  • org.openmetainfo:kMDItemCountry
  • org.openmetainfo:kMDItemCreator
  • org.openmetainfo:kMDItemDescription
  • org.openmetainfo:kMDItemHeadline
  • org.openmetainfo:kMDItemInstruction
  • org.openmetainfo:kMDItemKeywords
  • org.openmetainfo:kMDItemNamedLocation
  • org.openmetainfo:kMDItemStarRating

In most cases, there are now direct equivalents defined in the com.apple.metadata family. However, Apple’s current documentation of those refers to com.apple.metadata:kMDItemInstructions in the plural despite the singular version being in general use, and com.apple.metadata:kMDItemNamedLocation is not documented by Apple but widely used.

Apple also defines corresponding NSMetadataItem Attribute Keys, such as NSMetadataItemCityKey, etc., which are intended for use with Spotlight search.

There are three significant disadvantages to using these over their com.apple.metadata equivalents:

  • They are likely to be stripped when files are passed through iCloud Drive between computers, whereas many com.apple.metadata types are preserved.
  • Accessing org.openmetainfo metadata using Spotlight is considerably more difficult, if it remains possible at all.
  • Spotlight indexing doesn’t appear to work with org.openmetainfo metadata, but does with that in com.apple.metadata types.

It is hard to think of any good reason now for using the org.openmetainfo and org.openmetainfo.time families now, except for compatibility with Ironic apps.

Tools: xattred, xattr, Deep, Tagit, Yep, Leap, various tools on OpenMeta site

Links:
OpenMeta on Google Code
Ironic Software

Original page: 2018-02-04
Last modified: 2018-02-04