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https://github.com/mikedp/configmanager

Python classes to trivialise persisting app data
https://github.com/mikedp/configmanager

linux persistent-data-structure pyqt5 python qt5

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Python classes to trivialise persisting app data

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README 

        
# ConfigManager

There are numerous method for persisting application configuration data in Python:

  * Windows style 'INI' files

  * Binary blobs

  * XML/YAML/JSON formatted files



This small project provides two simple classes to persist application data without the user needing to provide anything other than a destination file path and (possibly) a list of items to persist:

  * **ConfigManager**: A class that can be used for CLI and non-GUI apps.

  * **QTConfigManager**: A class that can be used with QT5 app to persist/restore specific active GUI elements.



`ConfigManager` (CM) is a Python class to trivialise persisting app data from CLI or GUI applications. Your application merely creates an instance of ConfigManager, creates and assigns values to its attributes and calls 'save_config' (as it closes) to write the data to the configuration file.  Subsequent runs of your appliction will read the configuration file on startup, and re-create the previous attributes with the previous values.



Internally, ConfigManager uses JSON to store it's data. New attributes can be created as normal by simple assignment. If you try to assign a non-existent attribute to a variable with =, it will assign 'None' rather than generate an exception.  You can use `CM.assign('attrb', DefaultValue)` to simultaneously create and assign an attribute - if it doesn't already exist (current value is None), the default value is used.  Attributes can be any normal Python data type[^1] and all attributes are saved _except_ private ones (attributes starting with '_'), with the exception of `_comment`, which can be used as a _header_ for the saved config.

[^1]: Any type from bool, str, bytes, int, float, complex, list, tuple, dict or set.



`QTConfigManager` (QM) is a similar python class but extended to specifically persist/restore the values of QT5 GUI elements.  This can be used to save/restore the complete state of GUI based applications between different runs, users etc.

A simple list of the GUI item names is sufficient to identify the items to persist.

## Notes:

  1. Only widgets from one form can currently be saved automatically, though its quite feasible to save/restore widgets from other forms individually as additional QM.attributes, see last example.

  2. You can use `save_qt()` and `restore_qt()` to temporarily save/restore state in a running application 

  1. Only QT5 (PyQT) framework is supported, though it should be relatively straightforwards to swap this for TKinter, WxPython or PyGObject support.

  2. Only the most common QT5 widgets are currently supported, but others can be added as required.



## Example Usage

#### Basic config file

```

import ConfigManager

...

# Creates a configuration file at /home/$USER/.config/MyApp/myapp.config

config = ConfigManager('MyApp', 'myapp')



# Basic assign values

config.user = "Mike"

config.position = {'X': 24.5, 'Y': -16.1}



# and save

config.save_config()

```

#### Better usage - accepts persisted data on re-start

```

# Create/use configuration file at /home/$USER/.config/MyApp/myapp.config

config = ConfigManager('MyApp', 'myapp')

# Now, after creation, config.user is 'Mike' and config.position is {'X': 24.5 ...



# Assign default value 'Dave' if config.user doesn't already exist

config.user = config.assign("user", "Dave")  # config.user is aready set to 'Mike'



# Assign new default value if config.position doesn't exist

global_position = config.assign("position", {'X': 0.00, 'Y': 0.00})

# Both global_position and config.position are unchanged at {'X':24.5...

 

config._counter = 100   # Won't be saved with configuration file



global_uid = config.uid  # config.uid doesn't exist yet so both global_uid and config.uid are set None

global_guid = config.assign('guid', 12345678) # Both global_guid and config.guid set 12345678

# or simply

config.assign('another_guid', 987654321) # Initialises config.another_guid if it doesn't already exist



# and save

config.save_config()

```

#### QTConfigManager example

```

import QTConfigManager

...

WDGT_LIST = ['cbComboBox', 'leLineEdit', 'rbRadioBtn1',...] # List of QT5 widgets to save



# Create/use configuration file at /home/$USER/.config/MyApp/myguiapp.config

qt_config = QTConfigManager(self, 'MyApp', 'myguiapp') # self is owner of widgets



# Change the comment

qt_config._comment = "MyGUIApp: DO NOT HAND EDIT"  #  Appears at the top of the saved file



# Load list of items to save if not found (1st run)

qt_config.assign('ui_list', WDGT_LIST)

...

# and save

qt_config.save_config()

```

#### Saving GUI items from secondary form

```

WDGT_LIST = ['cbComboBox', 'leLineEdit', 'rbRadioBtn1',...] # List of QT5 widgets to save

# Create/use configuration file at /home/$USER/.config/MyApp/myguiapp.config

qt_config = QTConfigManager(self, 'MyApp', 'myguiapp') # self is owner of widgets

# Change the comment

qt_config._comment = "MyGUIApp: DO NOT HAND EDIT"  #  Appears at the top of the saved file

# Load list of items to save if not found (1st run)

qt_config.assign('ui_list', WDGT_LIST)

...

# Get GUI items from another form (MyForm2)

WDGT_LIST2 = ['cbCheckBox1', 'sbSpinBox2',...]

# Get GUI items from Myform2

qt_config.form2 = qt_config.save_qt(WDGT_LIST2, MyForm2) # This will be saved later when .save_config() is called

...

# Restore values to MyForm2

qt_config.restore_qt(qt_config.form2, MyForm2) # Make sure MyForm2 exists first

...

qt_config.save_config()

```