In my django project i have to check if a database/table exist before starting application, i don't know how is better insert the code for check.
I try to add in views.py into login function a try except block but i was try to find an elegant and more effective solution.
Thanks in advance
To check before the app starts then you can use the AppConfig.ready() function. This gets called before the application starts, but after your project has started. If you want to check before the project starts then you will have to hook into the method you use to start your project, eg within wsgi.py or even manage.py
AppConfig.ready() docs Note that the docs specifically say
avoid interacting with the database in your ready() implementation.
But your use case may justify doing this.
The ready function is called when you run the commands from manage.py eg
manage.py shell / manage.py migrate / etc
It won't get called when your site is visited of course. If you want to run a DB check in response to a visitor action then that code should go into your view
You put the ready() function in your apps.py:
from django.apps import AppConfig
from django.db import connection
class MyAppConfig(AppConfig):
name = 'MyApp'
def ready(self):
print("i am the ready function and the database test code goes here")
# put your test code here, eg you could read all the tables from sqlite
with connection.cursor() as cursor:
cursor.execute("SELECT name FROM sqlite_master;")
rows=cursor.fetchall()
print (rows)
You can write your custom django admin commands and run it by using python manage.py your_command right before calling python manage.py runserver. There are detailed examples at the official documentation.
One of the advantages of using commands is that testing commands are fairly easy. Django has a package for calling commands django.core.management.call_command which enables funtionally test your command.
I started a new Django 1.8 project and realized that I missed something (i had done the initial migrations). I dropped the database (postgreSQL) and deleted migration folders from all my apps in order to start from scratch.
Now, when I 'syncdb' I get this error:
django.db.utils.ProgrammingError: relation "auth_group" does not exist
and when I makemigrations I get this:
No changes detected
What am I doing wrong?
Probably you should try to create migrations modules (folders named migrations with empty file named __init__.py inside of each directory) for your apps. And then run manage.py makemigrations again.
The problem is on no changes detected. Please execute these commands with your app name. I guess you didn't add it (just like the mistake I did):
python manage.py makemigrations myappname
python manage.py migrate myappname
The above error occurs when you have django.contrib.admin among the installed applications.
Run these commands in their respective order.
**
./manage.py makemigrations
./manage.py migrate auth
./manage.py migrate**
That worked for me perfectly.
Doing ./manage.py migrate auth first didn't work for me, and every ./manage.py command was throwing this error. My problem was that I was doing stuff with the Group manager in module scope.
If you have code like this in module scope:
customers_group = Group.objects.get(name='customers')
Move it inside a function that is called at runtime instead.
def xyz():
...
customers_group = Group.objects.get(name='customers')
I had the similar problem with Django2.2 migrations. I will post what helped in case someone is looking to fix this.
I commented out all urls to apps(like my_app.urls, your_app.urls) in main project urls.py and then ran makemigrations, it worked.
I think this error is due to some forms/views referring to model/fields that are not yet created. It seems django traverses urls.py to before making migrations
It can be either:
one of the pip dependencies from requirements.txt was using South
had this error when running tests which do migration in Django 1.8. Found the lib with issue by running tests in verbose mode. Consider upgrading the library to newer version.
manage.py test -v 3
one of the /migrations folder might still has old South migrations files.
It can be because others are still adding migrations when you are trying to upgrade Django. Use the following to make sure that the expected migrations files are present in each app.
manage.py showmigrations
One of your paths ("pointing urls.py on your core folder along with the settings.py") makes that problem occur importing django.contrib.auth and directly using methods and properties of "auth" after calling those views
Remove all migrations except "init.py" of each apps
Go to projects urls.py and comment out all the paths
run "heroku run python manage.py makemigrations"
run "heroku run python manage.py migrate"
What i have done?
I have written a small application in django with few models with sqlite3 as backend. Now i want to write a python code that clears the database elements based on certain condition.
Question:
How can i achieve the above requirement?
I think the cleanest way to do this is to write your own django-admin command.
You can then run the command using manage.py:
python manage.py your_command
Having a command that can be run in shell, you can easily put in into your crontab. Optionally django-admin commands can receive command line arguments, if needed.
I am a newbie at Django and everytime I try to run
python panel/manage.py startapp %app% (panel is my project) it gives me the error:
Error: '%app%' conflicts with the name of an existing Python module and cannot be used as an app name. Please try another name.
Am I doing something wrong?
Surely companies or contacts or stats is not the name of an existing Python module?
This is a fun one - your project and your app need to have different names. You probably created a project, then tried to startapp with the same name.
I was confused as well, until I realized that a Django project is a container for applications; this sequence makes it a bit clearer:
# first create a Project (container).
django-admin.py startproject Project
# create multiple apps
cd Project
python manage.py startapp polls
python manage.py startapp hello
...
Perhaps you need to
cd panel
python manage.py startapp yourappname
I'm not sure running the command from a directory above your project will work properly.
I had the same issue because I was trying to "restart" my app after carrying out changes, but startapp is meant to be used once to create a new app. To view changes, syncronize app with DB with python manage.py migrate and restart the server with python manage.py runserver instead.
From the django-admin docs
(manage.py does essentially the same thing as django-admin)
startapp <app_label> [destination]
django-admin startapp
Creates a Django app directory structure for
the given app name in the current directory or the given destination.
By default the directory created contains a models.py file and other
app template files. (See the source for more details.) If only the app
name is given, the app directory will be created in the current
working directory.
If the optional destination is provided, Django will use that existing
directory rather than creating a new one. You can use ‘.’ to denote
the current working directory.
For example:
django-admin startapp myapp /Users/jezdez/Code/myapp
This message is displayed if you run "startapp" twice with the same app name. As pointed out above by the OP it doesn't reload the app, it creates one.
You should choose different names for your project and app in Codes:
django-admin startproject **my_project**
python manage.py startapp **my_app**
You need to create the directory before using the commands. Suppose you want a polls app inside apps folder.
mkdir apps apps/polls
python manage.py startapp polls apps/polls
I guess maybe you have already created the app's dir in panel dir manually. The command 'startapp' is to create an app automatically. If you already have one there, it fails.
I reproduced the issue and there's actually something not working as I expected.
I wonder if we stumbled upon a Django's bug, or a limitation that I don't understand.
Having a project called "project" and an empty folder app/newapp
…I tried:
python manage.py startapp newapp apps/newapp
It returns:
CommandError: 'newapp' conflicts with the name of an existing Python module and cannot be used as an app name. Please try another name.
But if I target ANY other route in which the last folder is not called the same name as the app I'm starting, it works.
So I ended up doing:
python manage.py startapp newapp apps/main
Using Django 2.1.3.
if you want to make an empty directory that will contain your new app
project-dir
└── blog
├── __init__.py
├── ...
├── blog-ext #this empty dir that will contain the new app
└── views.py
so instead of typing :
python manage.py newapp blog/blog-ext
it should be :
django-admin startapp newapp blog/blog-ext
Try classic "mysite" or "myproject". You can delete it anytime you want, so if it will accepted, then all your privious ideas conflict with Python modules.
Edit: I tried all your ideas, there was no error for me. So, if you installed support libraries or modules for django, then some of them can contains such names.
this error is because of the name conflicts between the app name and project name.you had given same name for your app and project .your project and app need to be different name .if you had given the same name the above mentioned error will occur .
understand the difference between app and project
Projects vs. apps
What’s the difference between a project and an app? An app is a Web application that does something – e.g., a Weblog system, a database of public records or a simple poll app. A project is a collection of configuration and apps for a particular Web site. A project can contain multiple apps. An app can be in multiple projects.
first create the project.
then create the app.
NOTE: name for app and project should be different
first create a project with projectname
django-admin.py startproject Projectname .
Then create app with appname. (to create your app make sure you are in the same directory manage.py and type this command)
python manage.py startapp Appname
It's the process how I got my doubt clear.
First, I created a directory inside my project directory and put __init__.py, models.py, admin.py, apps.py & views.py.
Then I ran python manage.py runserver & It work well.
Then as suggested on that page I used startapp command. I got this error :
CommandError: 'ucportal' conflicts with the name of an existing Python
module and cannot be used as an app name. Please try another name.
After that I deleted that directory and ran startapp command with same name and it worked fine.
So 'startapp' command is to create an app automatically. If you already have one there, it fails.
Answer given by #DAG worked for me.
I ran into this issue while trying to set up a Wagtail project.
Before creating the app, I had created and activated a virtualenv (using virtualenvwrapper) with the same name: $APPNAME. When I then ran wagtail start $APPNAME, Django looks for naming conflics in the $PYTHONPATH which in this instance points to /Users/User/.virtualenvs.
Naturally, this results in a conflict as /Users/User/.virtualenvs/$APPNAME already exists.
None of these answers helped me. In the end I ended up creating an app with a different name and then just renaming the directory to the app name I wanted all along. Note that you also will need to change the class name in apps.py to match your app name.
Just Simply Use This command
for Django Project Creation
python -m django startproject name_of_django_Project
for Django App Creation
python -m django startapp App_name
I had the same issue when working with wagtail cms. I got this error even there is no such a created app. This occurs when there is an app already that has the same name you need to create inside the site-packages directory.
Once you get this error, you need to check the following directory,
C:\Users\{user}\AppData\Local\Programs\Python\Python38-32\Lib\site-packages
If there is a package with the name same you want to create then you need to remove that package. Also make sure to check that package is important or not before deleting.
The application directory should be created first.
Example: apps/practice
The command appears to be duplicated, but it is correct.
Example: python manage.py startapp practice ./apps1/practice
I can't sign in to Django admin with any of the superusers I've created. Tried creating new superusers, changing passwords, etc. - no error messages for any of these processes, but still can't sign in.
I'm not sure if it's related, but I also can't run django-admin.py commands. Here is what I've done so far:
$ django-admin.py validate
Error: Settings cannot be imported, because environment variable DJANGO_SETTINGS_MODULE is undefined.
$ export DJANGO_SETTINGS_MODULE=mysite.settings
$ django-admin.py validate
Error: Could not import settings 'mysite.settings' (Is it on sys.path? Does it have syntax errors?): No module named mysite.settings
sys.path shows ['/Users/joerobinson/Sites/django/mysite' ... (other stuff on path)]
Is there something else I need to do to register the mysite module?
python manage.py runserver works fine.
Conclusion
For the question about logging in to django admin, I did not have django.contrib.auth.backends.ModelBackend included in my AUTHENTICATION_BACKENDS - adding this allowed me to sign in to admin.
I'm still working on the django-admin.py configuration question (which appears to not be related), and will reopen it in a separate question.
In my case, I had "SESSION_COOKIE_SECURE = True" because I was trying SSL configurations. Just commenting this line worked.
Well, to answer one of your questions, the parent folder of mysite is what needs to be on the python path. Adding mysite itself to your python path will expose the contents of mysite, not the mysite module to python.
As for runserver working / passwords not working, I haven't a clue. Have you customized anything with authentication?
Can you start the shell and try authenticating with your superuser?
http://docs.djangoproject.com/en/dev/topics/auth/#django.contrib.auth.authenticate
You said in a comment that "is_staff was set appropriately... same problem." -- does that mean you were able to log in with the first superuser to set is_staff??
I ran into a similair problem but, I couldn't login on the admin interface even after removing the database and creating it from scratch. The problem was caused by a real silly mistake.
Don't run python manage.py testserver by accident. Make sure you use python manage.py runserver.