packaging an application with PyInstaller when CSS_PATH is used

[nnako]

Hi,

I want to package my application based on the textual GUI framework into a single executable file. For this I want to use PyInstaller and a dedicated spec file. My project tree looks like this:

¦   build__application.py
¦   build__application.spec
¦   setup.bat
¦   
+---src
¦   ¦   application.py
¦   ¦   application.tcss
¦   ¦   application_config.toml
¦   ¦   

Within my application.py I use the following relevant code to set the CSS_PATH attribute of textual's App class:

# in application.py


# the application
class ApplicationApp(App):
    def __init__(self, config=None, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # static location relative to this source module
        CSS_PATH = "application.tcss"

The build runs well (no errors and no warnings) and creates the executable file within the respective dist folder:

+---build
¦   ¦   +---dist
¦   ¦           application.exe
¦   ¦           

In order to be certain to have the configurable files (one configuration file and one CSS file used by textual) where the executable looks for them, I copy them over from the src folder to the dist folder.

+---build
¦   ¦   +---dist
¦   ¦           application.exe
¦   ¦           application.tcss
¦   ¦           application_config.toml
¦   ¦           

Now, after walking into the dist folder and starting the application.exe, I get the following error message by textual:

StylesheetError: unable to read CSS file 'C:\\Users\\nnako\\AppData\\Local\\Temp\\_MEI154962\\application.tcss'

For me, it looks like textual does not look for the CSS file within the source module's folder and not look for it within the current folder when executing application.exe. But it looks in the temporary folder where PyInstaller causes the respective files to be treated as within the "base" folder.

So, I identify the "base" folder PyInstaller uses and tell textual to look in there for the CSS file:

# in application.py


# identify the base dir when executing from a frozen file
if getattr(sys, "frozen", False):
    _BASE_DIR = sys._MEIPASS
else:
    _BASE_DIR = os.path.dirname(os.path.abspath(__file__))


# printout folder path for debug
print("\n" + _BASE_DIR + "\n")


# the application
class ApplicationApp(App):
    def __init__(self, config=None, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # dynamically adapt the absolute CSS file location
        CSS_PATH = os.path.join(_BASE_DIR, "application.tcss")

And additionally, tell PyInstaller to deposit the CSS file within the base folder when creating the executable file:

# in application.spec


from PyInstaller.utils.hooks import collect_data_files
datas = [
    ('application.tcss', ".")
    ]

But still, textual does not find the CSS file but continues to output the following:

C:\Users\nnako\AppData\Local\Temp\_MEI154962

╭──────────────────────────────────── Traceback (most recent call last) ────────────────────────────────────╮
│ in app_prelude:2952                                                                                       │
│                                                                                                           │
│ in read_all:298                                                                                           │
│                                                                                                           │
│ in read:283                                                                                               │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────╯
StylesheetError: unable to read CSS file 'C:\\Users\\nnako\\AppData\\Local\\Temp\\_MEI154962\\application.tcss'

Is there a way to tell textual to look for a CSS file within the same folder as where the executable file is located when defining it's location via CSS_PATH attribute?

[Haran]

Sorry for necroposting, but I've just came up to this discussion from Google while facing the same problem. And as long as this is a question, not an answer, I had to figure out the way. So here is solution if someone else stumbles upon similar issue.

The issue is caused by the fact, that when packaged (compiled) app is executed, its "location" is not the location of executable file, that's why it cannot find it.

Solution for Textualize/Trogon. For main Textualize it is probably very similar, you just want to adjust instantiated class name from Trogon to something else (probably Textualize):

1. Pack tcss/scss file alongside the executable file (or copy it directly)
2. Determine the actual location of the executable

import sys
from pathlib import Path

# this one is what I use and import
from trogon import tui, Trogon

# frozen attribute indicates packaged (compiled) app
def get_application_root() -> str:
    if getattr(sys, 'frozen', False):
        return os.path.dirname(sys.executable)
    return str(Path(__file__).parent)

3. Monkey patch the var

# This should be placed before @tui decorator in my case
# and for Textualize this should come before App instantiation
# [!] Don't forget to adjust value of the tcss/scss file 
Trogon.CSS_PATH = os.path.join(get_application_root(), 'trogon.scss')

Now after pyinstaller -w -F ... don't forget to put tcss/scss file to the same folder and it should run without StylesheetError