FilesExpand file tree

 master

/

command.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

64 lines (47 loc) · 1.44 KB

 master

/

command.py

Copy path

Top

File metadata and controls

• Code
• Blame

64 lines (47 loc) · 1.44 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

"""

*TL;DR

Encapsulates all information needed to perform an action or trigger an event.

*Examples in Python ecosystem:

Django HttpRequest (without `execute` method):

https://docs.djangoproject.com/en/2.1/ref/request-response/#httprequest-objects

"""

import os

class MoveFileCommand:

def __init__(self, src, dest):

self.src = src

self.dest = dest

def execute(self):

self.rename(self.src, self.dest)

def undo(self):

self.rename(self.dest, self.src)

def rename(self, src, dest):

print("renaming {} to {}".format(src, dest))

os.rename(src, dest)

def main():

"""

>>> from os.path import lexists

>>> command_stack = [

... MoveFileCommand('foo.txt', 'bar.txt'),

... MoveFileCommand('bar.txt', 'baz.txt')

... ]

# Verify that none of the target files exist

>>> assert not lexists("foo.txt")

>>> assert not lexists("bar.txt")

>>> assert not lexists("baz.txt")

# Create empty file

>>> open("foo.txt", "w").close()

# Commands can be executed later on

>>> for cmd in command_stack:

... cmd.execute()

renaming foo.txt to bar.txt

renaming bar.txt to baz.txt

# And can also be undone at will

>>> for cmd in reversed(command_stack):

... cmd.undo()

renaming baz.txt to bar.txt

renaming bar.txt to foo.txt

>>> os.unlink("foo.txt")

"""

if __name__ == "__main__":

import doctest

doctest.testmod()