dirnotes/README.md

Dirnotes

Table of Contents

• SYNOPSIS
• USAGE
• INSTALLATION
  • CONFIG FILE
• LIMITATIONS
• PROGRAMMER NOTES
  • MacOS
• DEVELOPMENT STATUS
• QUESTIONS

SYNOPSIS

The dirnotes family of apps allows you to add a descriptive comment to a file. The descriptions are stored in two places:

• in the xattr properties of the file
• in a database located in the user's home directory

[The MacOS stores its comments in a similar way.]

The dirnotes app is a GUI app, using the Qt5 framework. At startup, it displays the contents of the current directory, and the comments associated with any of the files or directories. Simple mouse clicks allow you to add or edit comments, tunnel down into directories, or rise up the file system. You can copy or move files (with comments), and choose whether the xattr or database version of the comments have display priority.

The dirnotes-tui is a very similar app, but uses the curses framework to display its activity in a terminal window. This can be handy if you have to work across a network, or if terminal apps are your preference.

The dirnotes-cli is a command line tool, which may be handy for scripting. This all can also do maintenance on the database.

USAGE

The dirnotes program displays usage and keystoke info when you press F1. The dirnotes-tui program display onscreen usage when you press the 'h' key, or F1. The dirnotes-cli program has a man page.

In short, you navigate dirnotes and dirnotes-tui by using the up/down arrow keys, <enter> to enter into a directory. The -tui version accepts e for edit, s for sort, M to change between xattr/database priority.

The dirnotes-cli has options for -l list and -c create a comment. See also dirnotes-cli.1 man page.

All three apps in the dirnotes family have the ability to copy/move files from the current directory, keeping the comments intact. All three apps have the -h option which shows command line usage.

INSTALLATION

Each of the 3 apps in the family is self contained. The dirnotes app requires Python3 and the Qt5 framework. The dirnotes-tui and dirnotes-cli apps simply require Python3.

Simply mark the 3 python files as executable copy them into your path, to ~/.local/bin/ or /usr/local/bin/.

    chmod a+x dirnotes dirnotes-tui dirnotes-cli
    cp dirnotes dirnotes-tui dirnotes-cli \~/.local/bin/

For a better GUI experience, copy dirnotes.desktop to ~/.local/share/applications and dirnotes.xpm to ~/.local/share/icons/

If you are using the command-line tool dirnotes-cli, you can generate a man page using

    pandoc -s -t man -o dirnotes-cli.1 dirnotes-cli.md

and copy that to ~/.local/share/man/man1

CONFIG FILE

By default, the file ~/.config/dirnotes/dirnotes.conf will be used to load the user's config. This is a JSON file, with three attributes that are important:

• xattr_tag (default: user.xdg.comment)
• database (default: ~/.local/share/dirnotes/dirnotes.db, sensible alt: /var/lib/dirnotes.db)
• start_mode (xattr or db display priority)

The _configfile should be auto-generated the first time one of the dirnotes apps is run.

LIMITATIONS

The file comments are located in two locations: a database, and in the xattr properties of the file. Each of these storage locations has its own benefits and limitations. These can be summed up: xattr comments follow the iNode, database comments follow the file name.

xattr

Comments stored in the xattr properties can be copied/moved with the file, if you use the correct options: cp -p src dest. The mv utility automatically preserves xattr. Other programs can also be coerced into perserving xattr properties:

• rsync
• tar
• mksquashfs

Not all file systems support xattr properties (vfat/exfat does not).

xattr comments may only be applied to files for which the user has write permission.

The current implementation of sshfs and scp do not support copying of xattr properties. Dropbox type mounts are unlikely to support xattr comments. If you want to copy files to a remote machine and include the xattr comments, use rsync with the -X option. Or tar.

Some editing apps (like vim) will create a new file when saving the data, which orphans the xattr comments. For these apps, use the database system.

Removable disk devices (usb sticks) which are formatted with a Linux-based filesystem (ext2/3/4, btrfs, xfs, zfs) will carry the xattr comments embedded in the filesystem metadata, and are portable to anther computer.

database

Comments stored in the database work for all filesystem types (including vfat/exfat/sshfs)

The database comments that are stored in ~/.local/share/dirnotes/dirnotes.db are inherently associated with a single user. If the database is located in /var/lib/dirnotes.db, it can be shared by all the users in the system.

Files are indexed by their complete path name. Removable filesystems should be mounted in a consistent way, so that the complete path name is reproducable. Symlinks are not dereferenced, so they may have comments bound to them.

Comments stored in the database do not travel with the files when they are moved or copied, unless using the dirnotes family of tools.

Database comments may be applied to any visible file, even if they are readonly. For exmple, comments may be attached to the files in /usr/bin/* even though they are probably owned by root.

PROGRAMMER NOTES

Instead of an API, here is how you can get directly at the underlying comment data. If you intend to use the dirnotes apps, try to keep the two versions of the comments in sync.

• xattr

Use the commands

    xattr -l [filename]  

to display the comments/author/date on a file. For example:

    $ xattr -l /etc/fstab
    user.xdg.comment: controls the default mount bindings
    user.xdg.comment.author: patb
    user.xdg.comment.date: 2022-09-29 08:07:42

The other options on the xattr command line tool allow you to write (xattr -w) or delete (xattr -d) the comments.

• database

The comments are stored in an Sqlite3 database, usually located at "~/.local/share/dirnotes/dirnotes.db". The database itself is contained within that file, and its schema is this:

    CREATE TABLE dirnotes (name TEXT, date DATETIME, size INTEGER, comment TEXT, comment_date DATETIME, author TEXT)

field	usage	example
name	the long filename, using python's os.path.abspath()	/home/patb/projects/dirnotes/README.md
date	the file's modified date	2020-01-13 09:25:40
size	the byte count of the file	145
comment	a utf-8 string	the readme for the GIT page
comment_date	the date of the comment itself	2020-10-03 22:30:19
author	the system name of the user who created the comment	patb

The date and size fields reflect the file's modification date and size at the time of the last edit of the file comment, which is stored in _commentdate.

As comments are editted or appended, new records are added to the database. Older records are are not purged. This gives you a history of the comments, but it means that fetching the most recent comment involves something like

    SELECT * FROM dirnotes WHERE name=? ORDER BY comment_date DESC

and just fetch the first record.

The database is created the first time one of the dirnotes apps is run.

• misc

The dirnotes gui app has a desktop icon built into the code. There is not need for an external .icon file, but there is an .xpm file included in the project, which can be copied to ~/.local/share/icons/

The 3 apps share a big block of common code. At this point, the code is embedded in each executable, but perhaps in the future it will be brought out as a library. I just like apps to be a single file I can copy to my various devices and servers, but it does create a problem of keepint the 3 apps in sync.

comment date & author

The copy()/move() methods that are built into the dirnotes library will ask the operating system to copy/move the file with xattr intact. The entry in the database is created at the time of invocation. Therefore, the xattrs will reflect the original author+date on the comments, whereas the database version is updated on each copy/move; the dirnotes-comments details will therefor diverge over time.

There was no consideration given for language translation. Email me if you want this, or can help.

All these apps only accomadate a single line comment. An embedded newline will cause unpredictable behaviour.

MacOS

The MacOS inherently supports file comments. The Finder app manages most of the user activity. It handles file comments in a similar manner to Dirnotes. Comments are stored in two places:

• in the xattr properties of the file
  
  • using a different xattr-tag (com.apple.metadata:kMDItemFinderComment)
  • the comment string is wrapped in a pList
• in a database located in each directory
  
  • in the .DS-Store file

The user can examine the file comments by opening the GetInfo dialog, and scrolling down to "Comment"

If the Finder is used to copy/move files, the comments are moved properly to both destinations. If you use the os to copy/move the files, you can ask that the xattr properties get moved, but the .DS-Store file will not be updated. That means the Finder will not see file comments on the destination file.

MacOS has AppleScript, by which you can ask the Finder to perform the file copy/move. In this case, the comments are moved properly.

DEVELOPMENT STATUS

Each app is a standalone file. That means there is a lot of redundancy between the three apps. And there may be some inconsistency.

2022-10-04 : All three apps are functioning and usable.
The _configfile is fully implemented.
Themes are not implemented.
Comments are intended to be utf-8, but are strings in some places.
MacOS code is not written yet.
The help dialogs in dirnotes-tui are meagre.
The qt-gui app is working pretty well.

QUESTIONS:

There are several open-ended questions that need to be answered. Does anyone have an opinion?

1. How important is multi-line comments?

2. Is it ok to put the config file and database file buried in ~/.config and ~/.local?

   These directories exist on computers with a gui/windowing system installed, but don't neccessarily exist on headless servers. Perhaps the default locations should be in the user directory? (~/.dirnotes.conf and ~/.dirnotes.db)

3. Who needs translations?

4. Does anybody have a better edit-window for CURSES?

5. What about storing the database per directory. That's what MacOS does (the .DS_Store file)

   • PRO

     • copy of an entire directory will transport the database with it
       
     • database stored on a remote directory (sshfs, nfs, etc) will work properly
       
     • the database only needs to store the basename, not the entire path name
     • if a removable drive is remounted on a different mount point, it'll still work

   • CON

     • won't work on directories where the user doesn't have write permission
       
     • so, for example, the user can't add comments to /usr/bin/*

6. Is anyone interested in the MacOS version?