While reorganizing my images, in anticipation of OSX Mavericks I am writing a script to insert tags into the xattr
fields of my image files, so I can search them with Spotlight. (I am also editing the EXIF just to be safe.)
My questions are:
Which attribute is the best to use?
_kMDItemUserTags
seems to be the OSX version, butkMDItemOMUserTags
is already in use by OpenMeta. I would ideally like something that will be Linux and OSX forward compatible.How do I set multiple tags? Are the comma- or space-delimited or something else?
As an example, using the python xattr
module, I am issuing these commands:
xattr.setxattr(FileName, "_kMDItemUserTags", "Name - Sample")
xattr.setxattr(FileName, "kMDItemOMUserTags", "Name,Institution,Sample")
I have also seen mention of these tags: kOMUserTags
and kMDItemkeywords
but don't know if they are likely to be implemented...
EDIT: Further investigation has shown that for things to be searchable in 10.8,
- You need to preface the kMD with com.apple.metadata:
- You have to either hex-encode or wrap in a plist.
This python code will generate the tag for kMDItemFinderComment which is searchable in spotlight...
def writexattrs(F,TagList):
""" writexattrs(F,TagList):
writes the list of tags to three xattr field:
'kMDItemFinderComment','_kMDItemUserTags','kMDItemOMUserTags'
This version uses the xattr library """
plistFront = '<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0"><array>'
plistEnd = '</array></plist>'
plistTagString = ''
for Tag in TagList:
plistTagString = plistTagString + '<string>{}</string>'.format(Tag)
TagText = plistFront + plistTagString + plistEnd
OptionalTag = "com.apple.metadata:"
XattrList = ["kMDItemFinderComment","_kMDItemUserTags","kMDItemOMUserTags"]
for Field in XattrList:
xattr.setxattr (F,OptionalTag+Field,TagText.encode('utf8'))
# Equivalent shell command is xattr -w com.apple.metadata:kMDItemFinderComment [PLIST value] [File name]
I could not get it to work recursively on a folder with reliable results.
If you are worried about compatibility you have to set both of the attributes
_kMDItemUserTags
andkMDItemOMUserTags
. I don't think there's a different solution since all the new OS X apps will use the former attribute, while the old apps still use the latter. This is just my speculation, but I guess OpenMeta will eventually be discontinued in favor of the new native API. Looking to the future you can use the_kMDItemUserTags
attribute for your new apps/scripts even in Linux environment.The tags are set as a property list-encoded array of strings as you have figured out. I don't know if it is a requirement but the OS X encodes the property list in the binary format and not in XML as you did.
I adapted your code to use binary property list as attribute values and everything worked. Here's my code. I am using biplist library which you can get with easy_install biplist
.
import xattr
import biplist
def write_xattr_tags(file_path, tags):
bpl_tags = biplist.writePlistToString(tags)
optional_tag = "com.apple.metadata:"
map(lambda a: xattr.setxattr(file_path, optional_tag + a, bpl_tags),
["kMDItemFinderComment", "_kMDItemUserTags", "kMDItemOMUserTags"])
Tested with files and directories using tag:<some_tag>
in Spotlight.
Hope this helps.
- Note: I am using OS X Lion in this answer but it should work on Mavericks without any problems.
- Edit: If you want to apply the tags to the contents of a directory it has to be done individually for every file since the xattr python module doesn't have the recursive option.
来源:https://stackoverflow.com/questions/18009101/using-multiple-keywords-in-xattr-via-kmditemusertags-or-kmditemomusertags