Develop Reference

How to solve Django app name conflict with external library

I made a big mistake by creating an app inside my Django project called requests that happened a long time ago and the system has already been running for years. now I need to use the requests library and it is being imported like import requests as mentioned in the documentation ... and of course whenever I do this import it imports my app instead of the library .. so how to solve this?

You can try importing the requests/__init__.py file directly as shown in docs: https://docs.python.org/3/library/importlib.html#importing-a-source-file-directly.
Example:
import sys
import importlib.util
module_name = 'requests'
# declare the full path to requests/__init__.py file below
module_path = '/path/to/virtualenv/site-packages/requests/__init__.py'
spec = importlib.util.spec_from_file_location(module_name, module_path)
requests = importlib.util.module_from_spec(spec)
sys.modules[module_name] = requests
spec.loader.exec_module(requests)
print(requests.post) # should not raise error

Failed to import defined modules in __init__.py

My directory looks like this :
- HttpExample:
- __init__.py
- DBConnection.py
- getLatlong.py
I want to import DBConnection and import getLatlong in __init__.py. There is no error in my __init__.py until I run it, I received :
System.Private.CoreLib: Exception while executing function: Functions.HttpExample. System.Private.CoreLib: Result: Failure
Exception: ModuleNotFoundError: No module named 'getLatlong'
I'm trying to use function in getLatlong to use the information input by user from __init__.py to getLatlong. Below is the code:
__init__.py :
from getLatlong import result
from DBConnection import blobService, container_name, account_key, file_path
def main(req: func.HttpRequest) -> func.HttpResponse:
logging.info('Python HTTP trigger function processed a request.')
section = req.params.get('section')
bound = req.params.get('bound')
km_location = req.params.get('km_location')
location = req.params.get('location')
if not section:
try:
req_body = req.get_json()
except ValueError:
pass
else:
section = req_body.get('section')
if section and bound and km_location:
result(section, km_location, bound, location).getResult() #HERE
return func.HttpResponse(f"Hello {section}, {bound}!")
#elif section is None or bound is None or km_location is None:
# return func.HttpResponse("All values are mandatory!")
I am also receiving compile error at getLatlong to import DBConnection to this class. The following values will pass to getLatlong.py. The code :
from DBConnection import blobService, container_name, account_key, file_path #Another import error here says : Unable to import DBConnection
class result:
def __init__(self, section, bound, km_location, location):
self.section = section
self.bound = bound
self.km_location = km_location
self.location = location
def getResult(self):
print(self.section)
print(self.bound)
print(self.km_location)
print(self.location)
I've tried every way to import these files before I lost my mind..

You get these errors, because Python does not know where to look for the files you want to import. Depending on which Python version you are using, I see three ways to solve this:
You could add HttpExample to your PYTHONPATH and than your imports should work as you have them currently.
Another way would be to use the sys module and append the path to HttpExample, e.g.
import sys
sys.path.append('PATH/TO/HttpExample')
But you would have to do this in all files, where you want to import something from the parent folder.
Or you use relative imports, which have been available since Python 2.5 (See PEP238). Those are only available in modules, but as you have your __init__.py file, it should work. For relative imports you are using dots . to tell Python where to look for the import. One dot . tells Python to look for the desired import in the parent folder. You could also use .. to go up two levels. But one level should be enough in your case.
So in your case changing your code to this, should solve your problem.
In __init.py__:
from .getLatlong import result
from .DBConnection import blobService, container_name, account_key, file_path
In getLangLong.py:
from .DBConnection import blobService, container_name, account_key, file_path

You could try from __app__.HttpExample import getLatlong.
There is a document about how to import module in the Shared Code folder. Check this doc:Folder structure.
It says Shared code should be kept in a separate folder in __app__. And in my test this could work for me.

How to patch a module that hasn't been imported by parent package's __init__.py

I'm trying to test a tool I'm building which uses some jMetalPy functionality. I had/have a previous version working but I am now trying to refactor out some external dependencies (such as the aforementioned jMetalPy).
Project Code & Structure
Here is a minimalist structure of my project.
MyToolDirectory
¦--/MyTool
¦----/__init__.py
¦----/_jmetal
¦------/__init__.py
¦------/core
¦--------/quality_indicator.py
¦----/core
¦------/__init__.py
¦------/run_manager.py
¦----/tests
¦------/__init__.py
¦------/test_run_manager.py
The _jmetal directory is to remove external dependency on the jMetalPy package - and I have copied only the necessary packages/modules that I need.
Minimal contents of run_manager.py
# MyTool\core\run_manager.py
import jmetal
# from jmetal.core.quality_indicators import HyperVolume # old working version
class RunManager:
def __init__(self):
pass
#staticmethod
def calculate_hypervolume(front, ref_point):
if front is None or len(front) < 1:
return 0.
hv = jmetal.core.quality_indicator.HyperVolume(ref_point)
# hv = HyperVolume(ref_point)
hypervolume = hv.compute(front)
return hypervolume
Minimal contents of test_run_manager.py
# MyTool\tests\test_run_manager.py
import unittest
from unittest.mock import MagicMock, Mock, patch
from MyTool import core
class RunManagerTest(unittest.TestCase):
def setUp(self):
self.rm = core.RunManager()
def test_calculate_hypervolume(self):
ref_points = [0.0, 57.5]
front = [None, None]
# with patch('MyTool.core.run_manager.HyperVolume') as mock_HV: # old working version
with patch('MyTool.core.run_manager.jmetal.core.quality_indicator.HyperVolume') as mock_HV:
mock_HV.return_value = MagicMock()
res = self.rm.calculate_hypervolume(front, ref_points)
mock_HV.assert_called_with(ref_points)
mock_HV().compute.assert_called_with(front)
Main Question
When I run a test with the code as-is, I get this error message:
E ModuleNotFoundError: No module named 'MyTool.core.run_manager.jmetal'; 'MyTool.core.run_manager' is not a package
But when I change it to:
with patch('MyTool.core.run_manager.jmetal.core') as mock_core:
mock_HV = mock_core.quality_indicator.HyperVolume
mock_HV.return_value = MagicMock()
res = self.rm.calculate_hypervolume(front, ref_points)
mock_HV.assert_called_with(ref_points)
mock_HV().compute.assert_called_with(front)
... now the test passes. What gives?!
Why can't (or rather, how can) I surgically patch the exact class I want (i.e., HyperVolume) without patching out an entire sub-package as well? Is there a way around this? There may be code in jmetal.core that needs to run normally.
Is the reason this isn't working only because there is no from . import quality_indicator statement in jMetalPy's jmetal\core\__init__.py ?
Because even with patch('MyTool.core.run_manager.jmetal.core.quality_indicator) throws:
E AttributeError: <module 'jmetal.core' from 'path\\to\\venv\\lib\\site-packages\\jmetal\\core\\__init__.py'> does not have the attribute 'quality_indicator'
Or is there something I'm doing wrong?
In the case that it is just about adding those import statements, I could do that in my _jmetal sub-package, but I was hoping to let the user default to their own jMetalPy installation if they already had one by adding this to MyTool\__init__.py:
try:
import jmetal
except ModuleNotFoundError:
from . import _jmetal as jmetal
and then replacing all instances of import jmetal with from MyTool import jmetal. However, I'd run into the same problem all over again.
I feel that there is some core concept I am not grasping. Thanks for the help.

import file by url route python

Im trying to import files on Flask app in base of url route. I started to coding python few days ago so i havent idea if i doing it well. I write this on :
#app.route('/<file>')
def call(file):
__import__('controller.'+file)
hello = Example('Hello world')
return hello.msg
And i have other file called example.py into a controller folder that contains this:
class Example:
def __init__(self, msg):
self.msg = msg
So i start from terminal the app and i try to enter to localhost:5000/example.
Im trying to show in screen Hello world but give me the next error:
NameError: global name 'Example' is not defined
Thanks for all!

__import__ returns the newly imported module; names from that module are not added to your globals, so you need to get the Example class as an attribute from the returned module:
module = __import__('controller.'+file)
hello = module.Example('Hello world')
__import__ is rather low-level, you probably want to use importlib.import_module() instead:
import importlib
module = importlib.import_module('controller.'+file)
hello = module.Example('Hello world')
If you need to dynamically get the classname too, use getattr():
class_name = 'Example'
hello_class = getattr(module, class_name)
hello = hello_class('Hello world')
The Werkzeug package (used by Flask) offers a helpful functions here: werkzeug.utils.import_string() imports an object dynamically:
from werkzeug.utils import import_string
object_name = 'controller.{}:Example'.format(file)
hello_class = import_string(object_name)
This encapsulates the above process.
You'll need to be extremely careful with accepting names from web requests and using those as module names. Please do sanitise the file argument and only allow alphanumerics to prevent relative imports from being used.
You could use the werkzeug.utils.find_modules() function to limit the possible values for file here:
from werkzeug.utils import find_modules, import_string
module_name = 'controller.{}'.format(file)
if module_name not in set(find_modules('controller')):
abort(404) # no such module in the controller package
hello_class = import_string(module_name + ':Example')

I think you might not add the directory to the file, add the following code into the previous python program
# Add another directory
import sys
sys.path.insert(0, '/your_directory')
from Example import Example

There are two ways for you to do imports in Python:
import example
e = example.Example('hello world')
or
from example import Example
e = Example('hello world')

Python 2.7: Dynamic module import in an imported module based on given variable

There are given two versions of a storage. Based on the version, I need to select the proper interface module to get the result.
The file structure looks like this:
lib/
__init__.py
provider.py
connection.py
device.py
storage/
__init__.py
interface_v1.py # interface for storage of version 1
interface_v2.py # interface for storage of version 2
main.py
The main.py imports provider.py, that should import one of the interfaces listed in the storage subpackage depending on the version of the storage.
main.py:
from lib.provider import Provider
from lib.connection import Connection
from lib.device import Device
connection = Connection.establish(Device)
storage_version = Device.get_storage_version()
massage = Provider.get_data(connection)
provider.py should import an interface to the storage based on storage_version and implement provide some functions:
from storage import interface
class Provider(object):
def __init_(self):
self.storage = interface.Storage
def get_data(self, connection):
return self.storage.get_data()
def clear_storage(self, connection):
self.storage.clear_storage()
This example is not complete, but should be sufficient for the problem explanation.
Additional question:
Is it possible to use storage.__init__ to use import just the
subpackage?
How to proper implement Factory in Python?

Assuming the interface_v1 and interface_v2 bith impleement a class StorageClassI guess something like this:
import storage.interface_v1
import storage.interface_v2
class Provider(object):
def __init__(self , version):
if version == 1:
self.storage = storage.interface_v1.StorageClass
else:
self.storage = storage.interface_v2.StorageClass
Would be the best solution - but https://docs.python.org/2/library/functions.html#import should provide a way to import a module based on name.