Ceci est une ancienne révision du document !
This is the final episode of this series since we don’t need to browse the full code of the application, but I will stop only where there is something noteworthy. Last time, the main window was up and running – ready to accept user events. The code that handles them starts from line 157, and at line 189 we see another use of threading, in this case to load the DB. I didn’t do it in the non-GUI app, the reason here is that if it is a big file, we still want the UI to be responsive (i.e. updating a progress bar). Same usage of threading goes at line 218 when we update the view of data. Here, note that the toggle is to display only tracks that are missing sort information. This way, the user can choose between seeing the whole DB, or just the songs that need sort information. I used only the latter option but I thought the former can be useful to others. When the user right-clicks a track, we want to provide a quick way of entering sort information; this is accomplished through the function at line 270. At 295 there is code to automatically handle “The” in front of a band name. Here, there could be more ideas in place. The other automatic option is looking for the first space to try offer: “Bruce Springsteen” or “Springsteen, Bruce”. This may work well if you have a single track, but it’s not handy with many of them. Also because I wasn’t able to correctly handle the right-click on a multiple selection to update a group of tracks. To solve this issue, I came up with the “filling” icons on the toolbar. There’s three of them: automatically, asking and manual. The automatic one is implemented from line 536 and this is similar to the right-click on the track, but with no user input. Since this was written originally for me, I want “Houston, Whitney” and “Smiths, The”, with the year, as album sort information. If you want something different you can use the other ones or change the code. Note also that here “Green Day” will become “Day, Green” which of course is unwanted. Automatic, but not very clever.
Voici le dernier épisode de cette série, puisque nous n'avons pas besoin d'examiner le code complet de l'application ; je m'arrêterai uniquement quand il y a quelque chose à remarquer. La dernière fois, la fenêtre principale était en état de marche et prêt à accepter les événements de l'utilisateur. Le code qui les traite démarre à partir de la ligne 157 et, à la ligne 189, on voit une autre utilisation de filetage : dans ce cas pour charger la base de données. Je ne l'ai pas fait dans l'appli sans interface graphique, car, même si le fichier est gros, nous voulons que l'interface soit réactive (c-à-d avec une barre de progression qui se met à jour). Le même usage de filetage se trouve à la ligne 218 quand nous mettons à jour l'affichage des données. Ici, remarquez que le commutateur sert à n'afficher que les pistes où il n'y a pas des informations de tri. De cette façon, l'utilisateur peut choisir de voir toute la base de données ou seulement les chansons qui ont besoin d'informations de tri. Je me suis servi uniquement de la dernière option, but je pensais que la première peut être utile à d'autres.
Quand l'utilisateur fait un clic droit sur une piste, nous voulons fournir la possibilité d'entrer des informations de tri rapidement ; cela se fait avec la fonction à la ligne 270. À la ligne 295, il y a le code pour le traitement automatique de l'article « The » au début du nom d'un groupe. Ici, on pourrait insérer plus d'idées. L'autre option automatique est la recherche du premier espace pour essayer l'ordre : « Bruce Springsteen » ou « Springsteen, Bruce ». Ceci peut bien fonctionner si vous n'avez qu'une seule piste, mais ce n'est pas utile quand il y en a beaucoup. En fait, je n'arrivais pas à gérer correctement le clic droit sur une sélection multiple pour mettre à jour un ensemble de pistes. Pour résoudre ce problème, j'ai eu l'idée de mettre des icônes de remplissage sur la barre d'outils. Il y en a trois : automatiquement, en demandant et manuel. Celui qui est automatique est implémenté à partir de la ligne 536 et est similaire au clic droit sur la piste, mais sans instructions de l'utilisateur. Étant donné que je l'avais écrit au départ pour mon usage, je veux « Houston, Whitney » et « Smiths, The », accompagnés de l'année comme informations de tri des albums. Si vous voulez quelques chose de différent, vous pouvez vous servir des autres ou modifier le code. Remarquez aussi que « Green Day » deviendra « Day, Green » ici, ce qui, bien entendu, n'est pas ce que l'on veut. Automatique, mais pas très futé.
The second mode (line 569 and on) asks for user input, so you can avoid the Green Day issue amongst other things. Still the year is hard-coded. When the user is asked to choose, we don’t want him to play around with the other windows of the application, it doesn’t add any value to the user and it could cause issues (closing the DB in the middle of this function, or reloading an older version….). Hence at line 596:
selection_dialog.set_modal(True)
This locks the user on the dialog window until a choice is made.
Since this process can take some time, and stops when the user has to make a choice, we have the following lines of code:
while Gtk.events_pending():
Gtk.main_iteration()
This allows the UI to react in between user inputs (and while cycling through tracks). One reason is to update the treeview on the go.
The subsequent lines try to add a bit of cleverness to the program. If the user has already said that “Scouting for Girls” should stay as it is, there’s no point in asking it for every track. So every time we have some user input, this is saved in a temporary array:
already_found.append(selected_artist)
already_chosen.append(proposed_sort_artist)
This is checked at the beginning of the loop where user action is required, only if it is a “new” artist encountered:
if selected_artist not in already_found:
This information is lost at the end of the function, I’ll come back to this.
The third option allows the user to enter any sort information including the album sort field. The code begins at line 637. All of these functions use the update_record to change the DB (in memory, not on the file yet!). This function (line 702) is very similar to the code of the non-GUI application we saw months ago, so you should be already familiar with it.
Finally, I had to convert posix date to year - at line 760… this function comes from googling how to do it, and merely copies someone else’s idea. The beauty of the modern world where information is few clicks away!
This is the end of my brief overview of fixrhygtk. which has a huge space for improvement and to correct any bugs. For example, when it fills sort information by asking the user about the artist names, these choices could be permanently saved, so that if, at another time, the same artist is encountered, you don’t need to ask the user again. Another major point is localisation. The current code is not written for easy changing of language. Lines like:
confirm_text = “Rhythmbos is currently running.”
requires changes to the source code – which is not the way it should be.
There’s also no proper installation procedure: it will run from its folder, but if you want to install it system-wide, there are a few commands you have to enter at the CLI (including the schema for the settings – see https://askubuntu.com/questions/251712/how-can-i-install-a-gsettings-schema-without-root-privileges). Even better, a package for a PPA could be created. I tried this last bit, with no luck. I read many web pages and tutorials on this, but I couldn’t figure out the proper way of doing it for a Python application. Which brings me to the concluding thought – which was also the one at the beginning of this project: the open source community. I don’t have the time, the skills and the patience to move forward from here, but I am happy if anyone else will do it. The whole project is available for download at: http://www.paolopelloni.com/download/fixrhygtk.tar.xz feel free to use it, improve it and share it. I hope others will benefit from it as I am benefiting from the whole OSS world!
This is the end of my little story and again I want to thank Ronnie and Full Circle Magazine for the precious information, Greg D. Walters for teaching me Python and motivating me to use it and of course the whole open source world starting from the rhythmbox team!