ds_store - Manipulate Finder .DS_Store files from Python

This document refers to version 1.2.0

What is this?

Historically the Mac OS Finder stored additional per-file information in a special Finder Info field in the HFS/HFS+ filesystem. It also held other information in a single file known as the Desktop Database.

Filesystems other than HFS obviously do not have the Finder Info structure, and until recently support for extended attributes was rare. As a result, the Mac OS X Finder was written to store the necessary information in hidden files named .DS_Store, which it places into every directory where it needs to store information.

The format of these files is, sadly, not documented by Apple. This is a pain for software developers, who often distribute their software in Apple Disk Image (or .dmg) files. Typically developers set an attractive background on their disk images, increase the icon size and font size and often include a link to the /Applications folder. Unfortunately, the only supported way to set many of these things is via Finder itself. You might think that you could drive Finder with AppleScript for this purpose, but this turns out to be unreliable (Finder may not save the changes to the .DS_Store file immediately), and worse still Apple has made changes to the information Finder uses between versions of Mac OS X, such that setting some of these things on newer versions of the OS X Finder will not set them for users of older versions.

This module allows programmatic access to and construction of .DS_Store files directly from Python, with no Mac OS X specific code involved.

Usage

Typical usage looks like this:

from ds_store import DSStore

with DSStore.open('/Users/alastair/.DS_Store', 'r+') as d:
  # Position the icon for "foo.txt" at (128, 128)
  d['foo.txt']['Iloc'] = (128, 128)

  # Display the plists for this folder
  print d['.']['bwsp']
  print d['.']['icvp']

Importantly, deleting the DSStore object is not sufficient to flush changes to disk. If you use the with syntax above, changes you make to the .DS_Store file will automatically be persisted. Otherwise, you will need to call flush() or close() to flush your changes to disk.

Note that Finder generally places information about folders in the containing folder. The exception is that if it cannot write to the containing folder, or the folder in question is at the root of a volume, Finder will put the information in a record for “.” inside the folder to which it applies.

ds_store currently knows how to decode the following items

Supported item codes
Code Type Python representation
Iloc blob (x, y) tuple
bwsp blob Property list (dict)
lsvp blob Property list (dict)
lsvP blob Property list (dict)
icvp blob Property list (dict)

Items not in the list above will be returned as (type, value) tuples. Supported type values are

Suported type codes
Type Python representation
bool Boolean (True or False)
long Integer
shor Integer
ustr Unicode string
type 4-character byte string
comp Integer
dutc Integer
blob Byte string

If ds_store happens across any other type code, it will raise ValueError. This is unavoidable because the .DS_Store file format does not include length information, so if we find a type code we do not support, we cannot read the file.

Code Documentation

Indices and tables