scifi_wallpaper_mgr_nick3499

Python3: SciFi Wallpaper Manager: csv.reader(), datetime, shlex.split(), subprocess.run(), click

This repo has been made available under the open source MIT license.

Application tested using:

• Linux 5.4.0-14-generic
• Ubuntu 20.04 (Focal Fossa, dev branch)
• Python 3.8.2rc1
• GNU Bash 5.0.11 (x86_64-pc-linux-gnu)

Methods used:

• csv.reader()
• datetime.datetime.now().day
• shlex.split()
• subprocess.run()
• click.command(), option(), group(), echo()

init.py

A Python application root directory should contain an empty __init__.py file which basically indicates that the application is a Python module.

img/

One thing missing from this repo is an application subdirectory which contains at least 31 image files which are used as wallpaper images day by day. This repo features the cyberpunk genre.

help

$ python3 scifi_wallpaper.py --help

The Bash string above will print command line help to the terminal emulator.

click.group(), click.option(), click.command()

@click.group()
@click.option('--background/--no-background', default=False)
def scifi_wallpaper(background):
    ...

@scifi_wallpaper.command()
def center():
    ...

@scifi_wallpaper.command()
def tile():
    ...

@scifi_wallpaper.command()
def artists():
    ...

• click.group() decorator method is used to group similar methods within the same module. For this app, it will group() three other methods with the scifi_wallpaper() method.
• click.option() decorator method makes the --background command line option available.
• @scifi_wallpaper.command() decorators are used to bind the additional methods to scifi_wallpaper() as commands.

click facilitates the execution of specific methods as commands in the command line:

• $ python3 scifi_wallpaper.py --background center sets the background wallpaper image as centered.
• $ python3 scifi_wallpaper.py --background tile sets the wallpaper to tile mode.
• $ python3 scifi_wallpaper.py --background artists prints a list of artists from a CSV database.

Image Name Database

.getlist

csv/img.csv is generated by sourcing the .getlist shell script which creates the database by redirecting stdout $ ls img > img.csv then juxtaposing status with date for the comparison of its moment of creation.

$ . .getlist

#! /bin/sh

ls img > csv/img.csv
sudo chown 1000:1000 csv/img.csv
sudo chmod 700 csv/img.csv
printf "\033[1;34mFile status:\033[0m\n"
stat csv/img.csv | grep Change
printf "\033[1;34mCurrent date:\033[0m\n"
date

.getlist prints something similar to the terminal emulator:

File status:
Change: 2020-02-23 17:20:54.515495972 -0600
Current date:
Sun 23 Feb 2020 05:20:54 PM CST

with open()

    image_database = 'csv/img.csv'
    with open(image_database) as _file:
        _reader = reader(_file)
        specific_row = [row for i, row in enumerate(_reader, 1)
                        if i == (datetime.now().day)]
        click.echo(f"wallpaper file: \x1b[0;36m{specific_row[0][0]}\x1b[0m")

    cli_args = 'gsettings set org.gnome.desktop.background picture-uri \
file:///home/foo/scripts/scifi_wallpaper/img/' + specific_row[0][0]
    cli_args_list = split(cli_args)
    run(cli_args_list)

• image_database has the path csv/img.csv assigned to it.
• image_database then becomes an argument passed to with open() which creates a file object.
• _file is the file object, or handle, which is passed to the csv.reader() method. csv.reader() returns _reader.
• [row for i, row in enumerate(_reader, 1) if i == (datetime.now().day)] comprehension prints the record or row in _reader which corresponds with the current date number of the current month, and is stored in specific_row. Specifically, it is the image filename which will be set as the desktop background picture to be displayed, using gsettings.
• click.echo() is basically an enhanced form of the print() method, which will print the selected image filename to the terminal.
• cli_args is assigned the command line string which sets the background image. For example: gsettings set org.gnome.desktop.background picture-uri file:///home/foo/scripts/scifi_wallpaper/img/d03-nivanh-chanthara-breach.jpg.
• cli_args_list: cli_args is then passed to the shlex.split() method which splits the string into a list of individual command line strings, and assigns the result to cli_args_list. For example: ['gsettings', 'set', 'org.gnome.desktop.background', 'picture-uri', 'file:///home/nick/.userpy/scifi_wallpaper/img/d03-nivanh-chanthara-breach.jpg']
• finally, cli_args_list is passed to subprocess.run(), for the command line strings to be passed to the terminal emulator for execution.

Standalone Application

if __name__ == '__main__':
    scifi_wallpaper()

That if statement will call the scifi_wallpaper() method if the application runs as a standalone app. But if it were to be imported into another module, its __name__ would no longer be __main__ and it would need to be called with using dot syntax to link it: scifi_wallpaper.scifi_wallpaper().

.sfwall

As an option, a shell script can be added to a directory on the path to execute the script.

#! /bin/sh

/bin/python3 /home/foo/scripts/scifi_wallpaper/scifi_wallpaper.py --background $1

Then the application can be executed with one of the following:

• $ .sfwall center
• $ .sfwall tile
• $ .sfwall artists

cURL and GraphicsMagick

cURL and GraphicsMagick can be used to download and resize large images so they can be conveniently centered to fit a desktop background. For example, if the desktop screen resolution was 1600 x 900 and the downloaded JPG image was 1920 x 1080:

$ curl https://imagecdn.farflung.com/xysohsokdoechad.jpg -o cyberpunk_2077_no-tell_motel.jpg

-o is cURL's output option which enables file renaming, so the downloaded image is named cyberpunk_2077_no-tell_motel.jpg.

$ gm -resize 1600x cyberpunk_2077_no-tell_motel.jpg

The 1600x argument tells GraphicsMagick to resize the image from 1920 wide to 1600 wide and conform image height to aspect ratio.