├── test
├── __init__.py
└── test_functional.py
├── commandbus
├── __init__.py
├── _exception.py
└── _model.py
├── Pipfile
├── setup.py
├── .gitignore
├── LICENSE
├── README.md
└── Pipfile.lock
/test/__init__.py:
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1 |
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/commandbus/__init__.py:
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1 | from ._exception import *
2 | from ._model import Command, CommandHandler, CommandBus
3 |
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/Pipfile:
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1 | [[source]]
2 |
3 | verify_ssl = true
4 | name = "pypi"
5 | url = "https://pypi.python.org/simple"
6 |
7 |
8 | [dev-packages]
9 |
10 | coverage = "*"
11 | pytest = "*"
12 |
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/commandbus/_exception.py:
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1 | class CommandBusException(Exception):
2 | pass
3 |
4 |
5 | class CommandAlreadyExistException(CommandBusException):
6 | pass
7 |
8 |
9 | class CommandHandlerDoesNotExistException(CommandBusException):
10 | pass
11 |
12 |
13 | class CommandExecutionAlreadyInProgressException(CommandBusException):
14 | pass
15 |
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/setup.py:
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1 | from setuptools import setup, find_packages
2 |
3 | setup(
4 | name="commandbus",
5 | version="1.0.1",
6 | packages=find_packages(),
7 | author="Petru Rares Sincraian",
8 | author_email="psincraian@gmail.com",
9 | description="Command Bus Pattern in Python made easy",
10 | keywords="commandbus command bus python pattern patterns",
11 | url="https://github.com/psincraian/commandbus",
12 | license="MIT",
13 | )
14 |
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/.gitignore:
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1 | # Created by .ignore support plugin (hsz.mobi)
2 | .idea/
3 | __pycache__/
4 | *.py[cod]
5 | *$py.class
6 | *.so
7 | .Python
8 | build/
9 | develop-eggs/
10 | dist/
11 | downloads/
12 | eggs/
13 | .eggs/
14 | lib/
15 | lib64/
16 | parts/
17 | sdist/
18 | var/
19 | wheels/
20 | *.egg-info/
21 | .installed.cfg
22 | *.egg
23 | MANIFEST
24 | *.manifest
25 | *.spec
26 | pip-log.txt
27 | pip-delete-this-directory.txt
28 | htmlcov/
29 | .tox/
30 | .coverage
31 | .coverage.*
32 | .cache
33 | nosetests.xml
34 | coverage.xml
35 | *.cover
36 | .hypothesis/
37 | *.mo
38 | *.pot
39 | *.log
40 | .static_storage/
41 | .media/
42 | local_settings.py
43 | instance/
44 | .webassets-cache
45 | .scrapy
46 | docs/_build/
47 | target/
48 | .ipynb_checkpoints
49 | .python-version
50 | celerybeat-schedule
51 | *.sage.py
52 | .env
53 | .venv
54 | env/
55 | venv/
56 | ENV/
57 | env.bak/
58 | venv.bak/
59 | .spyderproject
60 | .spyproject
61 | .ropeproject
62 | /site
63 | .mypy_cache/
64 | *.pytest_cache
65 |
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/LICENSE:
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1 | MIT License
2 |
3 | Copyright (c) 2018 Petru Rares Sincraian
4 |
5 | Permission is hereby granted, free of charge, to any person obtaining a copy
6 | of this software and associated documentation files (the "Software"), to deal
7 | in the Software without restriction, including without limitation the rights
8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 | copies of the Software, and to permit persons to whom the Software is
10 | furnished to do so, subject to the following conditions:
11 |
12 | The above copyright notice and this permission notice shall be included in all
13 | copies or substantial portions of the Software.
14 |
15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 | SOFTWARE.
22 |
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/commandbus/_model.py:
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1 | from abc import abstractmethod, ABC
2 |
3 |
4 | class Command:
5 | pass
6 |
7 |
8 | class CommandHandler(ABC):
9 | @abstractmethod
10 | def handle(self, cmd: Command):
11 | pass
12 |
13 |
14 | class CommandBus:
15 | def __init__(self):
16 | self._commands = {}
17 | self._executing = False
18 |
19 | def subscribe(self, cmd: type, handler: CommandHandler):
20 | if cmd in self._commands:
21 | from commandbus import CommandAlreadyExistException
22 | raise CommandAlreadyExistException
23 | self._commands[cmd] = handler
24 |
25 | def publish(self, cmd: Command):
26 | if cmd.__class__ not in self._commands:
27 | from commandbus import CommandHandlerDoesNotExistException
28 | raise CommandHandlerDoesNotExistException()
29 | if self._executing:
30 | from commandbus import CommandExecutionAlreadyInProgressException
31 | raise CommandExecutionAlreadyInProgressException()
32 | self._executing = True
33 | try:
34 | self._commands[cmd.__class__].handle(cmd)
35 | finally:
36 | self._executing = False
37 |
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/README.md:
--------------------------------------------------------------------------------
1 | commandbus
2 |
3 | 
4 | 
5 |
6 |
7 | ## 📜 About
8 | Command bus is a pattern from CQRS. In this pattern we have three components:
9 |
10 | * `Command`: represents the desired action to be done, like `RegisterUserCommand`.
11 | * `CommandHandler`: retrieves the data from the command and executes all the actions to accomplish the command
12 | objective. In the previous case creates a new user and saves it do database.
13 | * `CommandBus`: routes the command to the handler
14 |
15 | ## ⚒️ Installation
16 | Installation is so easy, you only need to execute
17 | ```
18 | pip install commandbus
19 | ```
20 |
21 | ## 🚀 Using commandbus
22 | Using command is as easy as type
23 | ```python3
24 | from commandbus import Command, CommandHandler, CommandBus
25 |
26 | class SomeCommand(Command):
27 | pass
28 |
29 | class SomeCommandHandler(CommandHandler):
30 | def __init__(self):
31 | self.called = False
32 |
33 | def handle(self, cmd: Command):
34 | self.called = True
35 |
36 | bus = CommandBus()
37 | handler = SomeCommandHandler()
38 | bus.subscribe(SomeCommand, handler)
39 | assert not handler.called
40 | bus.publish(SomeCommand())
41 | assert handler.called
42 | ```
43 |
44 |
45 | ## 🚩 License
46 | The code is available under the MIT license.
47 |
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/test/test_functional.py:
--------------------------------------------------------------------------------
1 | import pytest
2 |
3 | from commandbus import Command, CommandHandler, CommandBus, CommandExecutionAlreadyInProgressException, \
4 | CommandAlreadyExistException, CommandHandlerDoesNotExistException
5 |
6 |
7 | class SomeCommand(Command):
8 | pass
9 |
10 |
11 | class SomeCommandHandler(CommandHandler):
12 | def __init__(self):
13 | self.called = False
14 |
15 | def handle(self, cmd: Command):
16 | self.called = True
17 |
18 |
19 | class SomeCommandCallsAnotherCommandHandler(CommandHandler):
20 | def __init__(self, bus):
21 | self._bus = bus
22 |
23 | def handle(self, cmd: Command):
24 | self._bus.publish(SomeCommand())
25 |
26 |
27 | @pytest.fixture
28 | def bus():
29 | return CommandBus()
30 |
31 |
32 | def test_handle_command(bus):
33 | handler = SomeCommandHandler()
34 | bus.subscribe(SomeCommand, handler)
35 | assert not handler.called
36 | bus.publish(SomeCommand())
37 | assert handler.called
38 |
39 |
40 | def test_should_throw_exception_when_call_another_command_inside_a_command(bus):
41 | handler = SomeCommandCallsAnotherCommandHandler(bus)
42 | bus.subscribe(SomeCommand, handler)
43 | with pytest.raises(CommandExecutionAlreadyInProgressException):
44 | bus.publish(SomeCommand())
45 |
46 |
47 | def test_should_throw_command_already_exists_exception(bus):
48 | handler = SomeCommandHandler()
49 | bus.subscribe(SomeCommand, handler)
50 | with pytest.raises(CommandAlreadyExistException):
51 | bus.subscribe(SomeCommand, handler)
52 |
53 |
54 | def test_should_throw_command_does_not_exist_exception(bus):
55 | with pytest.raises(CommandHandlerDoesNotExistException):
56 | bus.publish(SomeCommand)
57 |
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