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python

python

python
Realtime chat app using Django Daphne Nginx Redis
Create your virtual environment. download package in this order Django==3.0.8 djangorestframework==3.11.0 websocket-client==0.57.0 redis==3.5.3 asgiref==3.2.10 channels-redis==2.4.2 channels==3.0.1 Then create a Django project named ChatApp. django-admin startproject ChatApp After installing channels, add channels to your installed apps. INSTALLED_APPS = [ 'chat.apps.ChatConfig', 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', # add django channels 'channels' , ] Set the ASGI application to your default ASGI file in the project. ASGI_APPLICATION = 'ChatApp.asgi.application' Create a new app that will have all the chat functionality. python manage.py startapp chat And add your app to the installed apps in settings.py. And add chat/urls.py from django.urls import path, include from chat import views as chat_views urlpatterns = [ path("chat", chat_views.chatPage, name="chat-page"), ] And add chat/routing.py from django.urls import re_path from chat.consumers import ChatConsumer # Here, "ws" is routing to the URL ChatConsumer which # will handle the chat functionality. websocket_urlpatterns = [ re_path(r'ws$', ChatConsumer.as_asgi()), ] And add chat/consumers.py import json from channels.generic.websocket import AsyncWebsocketConsumer class ChatConsumer(AsyncWebsocketConsumer): async def connect(self): self.roomGroupName = "group_chat_gfg" await self.channel_layer.group_add( self.roomGroupName, self.channel_name ) await self.accept() async def disconnect(self, close_code): await self.channel_layer.group_discard( self.roomGroupName, self.channel_name ) async def receive(self, text_data): text_data_json = json.loads(text_data) message = text_data_json["message"] username = text_data_json["username"] await self.channel_layer.group_send( self.roomGroupName, { "type": "sendMessage", "message": message, "username": username, }) async def sendMessage(self, event): message = event["message"] username = event["username"] await self.send(text_data=json.dumps({"message": message, "username": username})) And add ChatApp/asgi.py * Has anyone had problem like this? Traceback (most recent call last): File "/path/to/my/env/bin/daphne", line 11, in <module> sys.exit(CommandLineInterface.entrypoint()) File "/path/to/my/env/lib/python3.6/site-packages/daphne/cli.py", line 161, in entrypoint cls().run(sys.argv[1:]) File "/path/to/my/env/lib/python3.6/site-packages/daphne/cli.py", line 222, in run application = import_by_path(args.application) File "/path/to/my/env/lib/python3.6/site-packages/daphne/utils.py", line 12, in import_by_path target = importlib.import_module(module_path) File "/path/to/my/env/lib/python3.6/importlib/__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "<frozen importlib._bootstrap>", line 994, in _gcd_import File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 665, in _load_unlocked File "<frozen importlib._bootstrap_external>", line 678, in exec_module File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed File "./my_project/asgi.py", line 5, in <module> application = get_default_application() File "/path/to/my/env/lib/python3.6/site-packages/channels/routing.py", line 33, in get_default_application module = importlib.import_module(path) File "/path/to/my/env/lib/python3.6/importlib/__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "<frozen importlib._bootstrap>", line 994, in _gcd_import File "<frozen importlib._bootstrap>", line 971, in _find_and_load File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 665, in _load_unlocked File "<frozen importlib._bootstrap_external>", line 678, in exec_module File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed File "./my_project/routing.py", line 4, in <module> from channels.auth import AuthMiddlewareStack File "/path/to/my/env/lib/python3.6/site-packages/channels/auth.py", line 12, in <module> from django.contrib.auth.models import AnonymousUser File "/path/to/my/env/lib/python3.6/site-packages/django/contrib/auth/models.py", line 2, in <module> from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager File "/path/to/my/env/lib/python3.6/site-packages/django/contrib/auth/base_user.py", line 47, in <module> class AbstractBaseUser(models.Model): File "/path/to/my/env/lib/python3.6/site-packages/django/db/models/base.py", line 100, in __new__ app_config = apps.get_containing_app_config(module) File "/path/to/my/env/lib/python3.6/site-packages/django/apps/registry.py", line 244, in get_containing_app_config self.check_apps_ready() File "/path/to/my/env/lib/python3.6/site-packages/django/apps/registry.py", line 127, in check_apps_ready raise AppRegistryNotReady("Apps aren't loaded yet.") django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet. Then visit this page. Django apps aren't loaded yet when using asgi I'm tring to run my django project with usage of asgi instead of wsgi. I have set up my routing.py and asgi.py as follows: routing.py from django.conf.urls import url from channels.routing import https://stackoverflow.com/questions/53683806/django-apps-arent-loaded-yet-when-using-asgi   ChatApp/settings.py CHANNEL_LAYERS = { "default": { "BACKEND": "channels.layers.InMemoryChannelLayer" } }   Using Redis: CHANNEL_LAYERS = { 'default': { 'BACKEND': 'channels_redis.core.RedisChannelLayer', 'CONFIG': { "hosts": [('127.0.0.1', 6379)] }, }, }   * Deploying Django Channels: how to keep Daphne running after exiting shell on web server Deploying Django Channels: how to keep Daphne running after exiting shell on web server As practice, I'm trying to deploy Andrew Godwin's multichat example with Django Channels 2.1.1 on DigitalOcean Ubuntu 16.04.4. However, I don't know how to exit the Ubuntu server without Channels' ... https://stackoverflow.com/questions/50192967/deploying-django-channels-how-to-keep-daphne-running-after-exiting-shell-on-web   Nginx 1. Windows location @django { proxy_pass http://127.0.0.1:1234; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Proto $scheme; proxy_read_timeout 600s; # this next line adds the Host header so that apache knows which vHost to serve # the $host variable is automatically set to the hostname Nginx is responding to proxy_set_header Host $host; #Websocket support proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; } 2. Linux with Daphne Make service-name.service [Unit] Description=Indifference Daphne Service After=network.target [Service] Type=simple User=indifference WorkingDirectory=/home/indifference/path/to/indifference ExecStart=/home/indifference/path/to/bin/daphne -p 3333 indifference.asgi:application access-log=/data/logs/indifference/daphne/access.log [Install] WantedBy=multi-user.target chmod 755 service-name.service systemctl daemon-reload systemctl enable service-name.service systemctl start service-name.service Update nginx.conf  upstream channels-indifference-backend { server localhost:3333; } ... location /ws { proxy_pass http://channels-indifference-backend; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; proxy_redirect off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Host $server_name; } Still not working? Just restart it. systemctl stop service-name.service systemctl start service-name.service systemctl status service-name.service   Windows Django - dev Create a folder called config config/ commonsettings.py dev.py prod.py make sure that in dev.py and prod.py you import everything from commonsettings.py like this: from .commonsettings import * dev.py sample INSTALLED_APPS = [ ... # 'channels', ... ] ASGI_APPLICATION = None then if you want to run the dev.py settings: python manage.py runserver --settings=config.dev In order to run your asgi application, simply point Daphne to your ASGI application, and optionally set a bind address and port (defaults to localhost, port 8000): daphne -b 0.0.0.0 -p 9001 myproject.asgi:application Nginx WS config is the same with 2. Linux with Daphne * Use ASGI to deploy Django, StreamingHttpResponse cannot be accessed. Async support for StreamingHttpResponse was only added in Django 4.2.   You can check the program with this: https://www.phenomena.com/chat   Ref. Realtime chat app using Django - GeeksforGeeks A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions. https://www.geeksforgeeks.org/realtime-chat-app-using-django/ Django Channel Custom Authentication Middleware __call__() missing 2 required positional arguments: 'receive' and 'send' I am writing a custom authentication middleware for django channels class TokenAuthMiddleware: def __init__(self, inner): # Store the ASGI application we were passed self.inner = https://stackoverflow.com/questions/64625473/django-channel-custom-authentication-middleware-call-missing-2-required-po Configuring ASGI Django Application using Daphne and Nginx Server Adding Daphne to preexisting project. https://ritiktaneja.medium.com/configuring-asgi-django-application-using-daphne-and-nginx-server-59a90456fe17 Channels cannot be used with StreamingHttpResponse So you’re saying that this exact code works if you run it under a wsgi container? https://forum.djangoproject.com/t/channels-cannot-be-used-with-streaminghttpresponse/10105/4
John Doe · March 2, 2023, 6:55 a.m.
django daphne nginx redis
python
How to include only needed modules in pyinstaller?
For this you need to create a separate environment, because currently you are reading all the modules you have installed on your computer. To create environment run commands 1 - if you don't have one, create a requirements.txt file that holds all packages that you are using, you could create one with: pip freeze > requirements.txt 2 - create env folder: python -m venv projectName 3 - activate the environment: source projectName/bin/activate 4 - install them: pip install -r requirements.txt alternatively if you know you are using only wxpython you could just pip install wxpython 5 - then finally you can run pyinstaller on your main script with the --path arg as explained in this answer: pyinstaller --paths projectName/lib/python3.7/site-packages script.py   How to include only needed modules in pyinstaller? I'm using pyinstaller to generate an .exe file for my single python file, but the size is more than 30MB and the startup is very slow. From what I have gathered is that pyinstaller by default bundl... https://stackoverflow.com/questions/55312146/how-to-include-only-needed-modules-in-pyinstaller
John Doe · Feb. 23, 2023, 8:36 p.m.
python
Django migrate gets error "table already exists"
1. Remove all migration files in <appname>/migrations 2. Remove all data in django_migrations table where app = <appname> 3.  python manage.py makemigrations <appname> 4.  python manage.py migrate --fake <appname> 5. If you have a field to alter, then alter the field <field> on <appname> and then again python manage.py makemigrations <appname> 6. python manage.py migrate <appname> Child's play.   0003이 실제로 적용된 가장 최근의 마이그레이션이라 가정할 때에는? --fake를 이용하여 현재 상태는 0003이다 라고 장고가 인식하게끔 해주어야 한다. python manage.py migrate --fake <appname> 0003 그 후 평소 하던대로 진행.   django 1.7 migrate gets error "table already exists" I am trying to apply a migration but am getting the error: django.db.utils.OperationalError: (1050, "Table 'customers_customer' already exists") I get this by issuing the following command: ... https://stackoverflow.com/questions/25924858/django-1-7-migrate-gets-error-table-already-exists How to redo a migration on django 1.8 after using --fake Something went wrong on my migrations, I added a new datetimefield to a model then I used makemigrations and migrate. python manage.py makemigrations python manage.py migrate But after this the m... https://stackoverflow.com/questions/30626886/how-to-redo-a-migration-on-django-1-8-after-using-fake
John Doe · Jan. 12, 2023, 9:59 p.m.
django migration
python
Fix SSL error when install packages using pip
Q : pip install fails with "connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)"   A : pip install gensim config --global http.sslVerify false Just install any package with the "config --global http.sslVerify false" statement You can ignore SSL errors by setting pypi.org and files.pythonhosted.org as well as the older pypi.python.org as trusted hosts. $ pip install --trusted-host pypi.org --trusted-host pypi.python.org --trusted-host files.pythonhosted.org <package_name> Note: Sometime during April 2018, the Python Package Index was migrated from pypi.python.org to pypi.org. This means "trusted-host" commands using the old domain no longer work, but you can add both. Permanent Fix Since the release of pip 10.0, you should be able to fix this permanently just by upgrading pip itself: $ pip install --trusted-host pypi.org --trusted-host pypi.python.org --trusted-host files.pythonhosted.org pip setuptools Or by just reinstalling it to get the latest version: $ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py (… and then running get-pip.py with the relevant Python interpreter). pip install <otherpackage> should just work after this. If not, then you will need to do more, as explained below. You may want to add the trusted hosts and proxy to your config file. pip.ini (Windows) or pip.conf (unix) [global] trusted-host = pypi.python.org pypi.org files.pythonhosted.org Alternate Solutions (Less secure) Most of the answers could pose a security issue. Two of the workarounds that help in installing most of the python packages with ease would be: Using easy_install: if you are really lazy and don't want to waste much time, use easy_install <package_name>. Note that some packages won't be found or will give small errors. Using Wheel: download the Wheel of the python package and use the pip command pip install wheel_package_name.whl to install the package. https://stackoverflow.com/questions/25981703/pip-install-fails-with-connection-error-ssl-certificate-verify-failed-certi/26062583
John Doe · Jan. 12, 2023, 3:28 a.m.
ssl pip
python
How do I check which version of Python is running my script?
This information is available in the sys.version string in the sys module: >>> import sys Human readable: >>> print(sys.version) # parentheses necessary in python 3. 2.5.2 (r252:60911, Jul 31 2008, 17:28:52) [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] For further processing, use sys.version_info or sys.hexversion: >>> sys.version_info (2, 5, 2, 'final', 0) # or >>> sys.hexversion 34014192 To ensure a script runs with a minimal version requirement of the Python interpreter add this to your code: assert sys.version_info >= (2, 5) This compares major and minor version information. Add micro (=0, 1, etc) and even releaselevel (='alpha','final', etc) to the tuple as you like. Note however, that it is almost always better to "duck" check if a certain feature is there, and if not, workaround (or bail out). Sometimes features go away in newer releases, being replaced by others. or Use platform's python_version from the stdlib: from platform import python_version print(python_version()) # 3.9.2 https://stackoverflow.com/questions/1093322/how-do-i-check-which-version-of-python-is-running-my-script
John Doe · Jan. 12, 2023, 1:19 a.m.
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