Saturday, April 28, 2012

Nepomuk Semantic desktop in Ubuntu

If you want to read about what Nepomuk is, go here.


  1. Install Dolphin, Nepomuk and KDE System Settings (Dolphin already has all needed dependencies, including Nepomuk, so no need to specify explicitly):
    sudo apt-get install dolphin systemsettings gtk2-engines-qtcurve


  2. Try to call "nepomukserver" from terminal, just to make sure it is installed and works. It should give many outputs, which mean that it started indexing files.

  3. Add "nepomukserver" command to Startup Applications

  4. Restart Gnome session - Nepomuk will start automatically and run Strigi indexer


The indexing takes quite some time, depending on the number of files and folders under indexer. For my computer it took several hours, because I had large collection of music, films and books. There should appear and icon in the tray, which indicates the indexing process. You may open a menu on this icon, select "Configure File Indexer" and watch the current process of indexing. You can also choose, which folders Strigi must index, in the same dialog window. Another way to open this window is from KDE System Settings -> Desktop Search, which can be issued from terminal with "systemsettings" command. You may find useful to leave Desktop Search window open to watch the indexing process until it is finished.

In the meantime, run Dolphin, select some file (e.g. MP3) and press F11 - it will show a side panel with all meta-information about selected file. Until the indexing process is finished you may see strange incorrect information in Dolphin for imported file properties. For example, ID3 tags may contain something like ":aksdfh". This should change to normal when the indexing is over. You can control the indexing process from Desktop Search dialog described above.

The indexer also still contains some bugs. It may fail on some files. You can see, which file is problematic, by watching the indexing process in Desktop Search dialog. If you find that some folder with files cannot be indexed and Strigi fails on this folder, then you can exclude this folder from indexing from the same dialog, then click Apply and indexing process will start again (no worries, it will quickly skip all already indexed files and concentrate on not yet indexed ones).

Gnomifying Dolphin

While the search is going on, you can make Dolphin look more like a GNOME native GTK-based application (similar to how Nautilus looks like).


  1. Run in terminal: kbuildsycoca4 --noincremental
    Don't pay attention to warnings it will give you.

  2. Run systemsettings command from Terminal or from Alt-F2.

  3. Open Application Appearance.

  4. In section Style change Widget style to GTK+

  5. In section Icons select something related to the current Ubuntu theme in Gnome. For example, I chose "Ubuntu-Mono-Dark"

  6. Apply changes

  7. Open Dolphin and make sure it looks like other applications in Gnome


Making Dolphin A Default File Manager

Since we now use Dolphin, you can make it a default file manager in your Ubuntu desktop.

  1. Right click on Applications / Places / System menu, select "Edit Menus"

  2. In the section Other change commands in both "File Manager" and "Open Folder" items from what they currently have to just "dolphin"

  3. That's all. Open Places -> Home Folder to make sure it is now opened in Dolphin


After Indexing Is Finished

When the Desktop Search dialog shows that indexing finished, you may try Nepomuk in action.

  1. Open Dolphin, choose some file (e.g. MP3) and remember its properties. Then type the value of one property in the "Search..." box and see if the file appears in the list

  2. Assign several tags to a group of different files and search for the tags

  3. Search for text content in one of your PDF or office documents


Now you can organize your media collections using existing properties and custom tags, group files by their meaning, assign comment to files, rate them and so on. Potentially its possible to integrate different applications, not only Dolphin, with Nepomuk, but this is a topic for another post.

THANKS: Nuclear Passion

 


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