Kate

This article was originally published as a blog entry at http://alweb.dk/blog/anders/kate_named_sessions and is now donated to this website.

The biggest change in Kate (http://kate.kde.org, http://www.kate-editor.org) in the KDE 3.5 series is definitely the introduction of named sessions. Instead of defaulting to one instance, Kate now as a standard allows you to run many instances. And not even that, it will allow you to keep those sessions, with the list of open files as well as the instance specific GUI configuration. This is a big change in behavior, but once you get used to it, you will hopefully appreciate the benefits.

If not, it is still possible to restore the old-style kate behavior by utilizing the various related commandline and configuration options. You will of course loose at least some of the advantages of named settings, but if you desire keeping things as they were, you probably do not care a lot.

Because this is new, there are of course problems and unforeseen issues. Due to busyness with real life, I have not had a chance to get much into named sessions prior to the KDE 3.5/Kate 2.5 release, but I have been working hard on enhancing the named sessions experience for KDE 3.5.1/Kate 2.5.1 and upwards.

Read on for more about how it works, what have been fixed so far and some ideas for future improvements.

Kate Session Basics

Basically, a Kate session is a instance of the application with its own set of open documents and its own window setup (toolbars, toolviews, editor frame[s]). The session can be named and saved with the file list and optional the window setup, so that it can easily be restored again.

If you edit a lot of text files for different purposes, such sessions can make your life much easier. I for example have sessions for various websites I maintain and for my various KDE related projects. When I want to work on a project, I open the session and have the setup as I left it last time I used it. For one thing, the named sessions feature will obsolete the filelist loader plug-in that some of you may have used.

You can create a new session in many ways:

• Use the Sessions->Save As menu item to save the current session under a new name
• Use the Sessions->Save menu item to save an anonymous session.
• Start kate with --start <New session name>. If the session with the specified name does not exist, it is created.
• Use the Kate Session Menu kicker applet made available by yours sincerely (http://alweb.dk/projects/kate_session_menu)

There are equally easy ways to open a session once you have some:

• The default behavior for Kate is to ask which session you want to open if you don’t specify one on the command line. But you can change that to always start a new (anonymous) session, or to allways load the last used session.
• You can specify a session on the command line. (if you want desktop icons, you can create a kate icon with kate --start YourSession in the exec property)
• You can use the Sessions->Quick Open menu item to load it into your Kate instance (the current session will be closed, and you will optionally be asked if you want to save it if it is named and has changes).
• You can use the Kate Session Menu kicker applet (see above)

If I want to open one or more files and forget about them again, I can just open then in an anonymous session which will not be saved.

If I want to add files to a running session from outside, I can use command line options to do so. In Kate 2.5 that means any running instance (—use) or an instance selected by its process ID (PID) (—use —pid PID).

Kate saves your sessions pr. default, but you can have it ask you or not save sessions if that suits your work flow better (I’m personally happy with this default, although i sometimes forgets to close some files that I’m done with).

Session related command line options

As indicated above, Kate has tree new command line options to support named sessions:

-s, --start <name>

Start Kate with a given session. From Kate 2.5.1 (KDE 3.5.1) this will also work with --use so that when both is specified only the specified session will be reused, if it is not running it will be started or created.

-u, --use

Use a already running kate instance (if possible). If no instance is specified using --pid <PID> (or, in the future, --start >name<) the first instance found by DCOP (the one with the lowest PID) will be used.

-p, --pid <pid>

Only try to reuse kate instance with this pid

Session Configuration Options

Sessions have gotten their own panel in Kate’s configuration dialog, with so far tree options allowing you to tweak the behavior.

Elements of Sessions

This is really a promise, since a group box with one option is an indication that more will follow ;). Include window configuration is enabled pr default. When enabled, the entire configuration of the application window is saved with your session, including toolbar setup, toolviews, and the editor area.

Behavior on Application Startup

contains tree options, namely

• Start new session
• Start last used session
• Manually choose a session (default)

Choose the one that suits your work flow best. For me that is the first one (start a new session) since I tend to start the session I want by using my kicker applet, and when I want to dig into something and open one or more source file I prefer Kate — with a new session — for the syntax highlight and the ability to open more files. I can then save the session for later use if I find those files very interesting…

Behavior on Application Exit or Session Switch

This again contains tree options, namely save (default), not save or ask.

Restoring the Old Style Kate Behavior

Many users have grown accustomed to the old style behavior, where Kate would run only one instance and all files would be forwarded to that instance. We know from the bugs database (http://bugs.kde.org) and mailling list (http://lists.kde.org/?l=kwrite-devel) that many users got a bit confused when kate didn’t behave as usual, and given the lack of warning and documentation of the new behavior that is not suprising.

To restore the old style behavior, you can follow this strategy:

• Configure Kate to load the last used session on startup and save sessions on exit, and enable the window configuration session element.
• in the KDE menu editor, edit the exec line of kate to to kate --use %U
• Use an alias in your shell to add --use automatically. If you use bash as your shell, add something like alias kate="kate --use" to your ~/.bashrc file.

Be warned though that until KDE 3.5.1 is released (soon!) you will experience some problems with this: when opening files from the KDE environment with --use, you get a KIO error about not being able to launch kate. As indicated, this has been fixed in the 3.5 branch of KDE and if you compile KDE yourself, get this version of the kdebase module to fix those problems.

Improvements and Fixes in Kate 2.5.1

I have tried to do a few improvements in Kate 2.5.1 because there is quite some time until we get to KDE 4. Most are really bug fixes, although mostly for unreported issues. Many but not all are related to named sessions.

Improvements include

• Kate will show the name of a named session in the window title.
• --start <name> will work with --use.
• when a session is specified using the application startup behavior option, it will allways be loaded, no matter if there are files on the command line.
• The error about kdeinit not being able to launch kate is history.
• Kate can now handle temporary files correctly, so the warning about the file being deleted when using kate to view Konqueror sources has gone.

Future Development with Named Sessions

A very obvious step is to include more configurations in the session data. This could include

• Plug-in configuration
• Filesystem browser configuration and history
• Recent files

In Kate 2.5.1 the pid is exported to the environment variable KATE_PID so that you can alias kate with kate -up $KATE_PID if that is set, in Kate 2.5.2 this will not be nessecary anymore, Kate will automatically select the current instance if the KATE_PID variable is set.

One thing that has lead to quite a few complaints is the removal of the project support in Kate. This came as a suprise to us developers, as we all found the project support very poor, but it appears that it has been used and appreciated by quite a few users. Adding project support on the top of named sessions would be good, and I am considering how it can be done in a nice and flexible way. My own demands are that any file can be a member of a project, and I would like to see some sort of project type that would support various commands such as building software, synchronizing directories etc.