la-catch

Decorator and context manager to catch exception(s) and call a function to handle the error.

install

pip install la-catch

syntax

Catch(exceptions, callback, *args, **kwargs)

exceptions - Exception or Tuple of exceptions to be captured
callback - function to be called in case of exceptions being raised or a return value to be returned in case of exceptions
*args - Any extra arguments are passed to context manager callback
**kwargs - Any extra keywords are passed to context manager callback

usage

There is two ways to use catch:

• Context Manager
• Decorator

context manager

Catch exception and do nothing:

from la_catch import Catch

def func():
    with Catch(TypeError):
        raise TypeError("example")

Catch exception and call callback passing exception:

from la_catch import Catch

def on_error(exception):
    print(exception)

def func():
    with Catch(TypeError, callback=on_error):
        raise TypeError("example")

Catch exception and call callback passing keywords arguments and exception:

from la_catch import Catch

def on_error(message, exception):
    print(message, exception)

def func():
    with Catch(TypeError, callback=on_error, message="WARNING:"):
        raise TypeError("example")

Catch multiple exceptions:

from la_catch import Catch

def func():
    with Catch((TypeError, FileNotFoundError)):
        raise FileNotFoundError("example")

decorator

Catch exception and return None:

from la_catch import Catch

@Catch(TypeError)
def func():
    raise TypeError("example")

Catch exception and return a value:

from la_catch import Catch

@Catch(TypeError, callback=10)
def func():
    raise TypeError("example")

Catch exception and call callback passing exception:

from la_catch import Catch

def on_error(exception):
    print(exception)

@Catch(TypeError, callback=on_error)
def func():
    raise TypeError("example")

Catch exception and call callback passing decorated function arguments and exception:

from la_catch import Catch

def on_error(message, exception):
    print(message, exception)

@Catch(TypeError, callback=on_error)
def func(message="WARNING:"):
    raise TypeError("example")

Chain catchs:

from la_catch import Catch

def on_file_not_found_error(exception):
    print(exception)

def on_typerror(exception):
    print(exception)

@Catch(FileNotFoundError, callback=on_file_not_found_error)
@Catch(TypeError, callback=on_typerror)
def func():
    raise FileNotFoundError("example")
    raise TypeError("example")

notes

Initialization arguments are used by context manager and ignored by decorators, because:

• Had to decide a priority between intialization arguments and function arguments
• Passing default values to callback would need me to know the function arguments
• When chaining decorators, wasn't possible to discover the function parameters because decorators would give (*args, **kwargs)
• When chaining decorators, wasn't possible to discover the default values because decorators would give (*args, **kwargs)