https://github.com/meshy/django-sans-db
Limit database access in Django code and template renders
https://github.com/meshy/django-sans-db
database django python
Last synced: 8 months ago
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Limit database access in Django code and template renders
- Host: GitHub
- URL: https://github.com/meshy/django-sans-db
- Owner: meshy
- License: mit
- Created: 2020-08-29T20:22:08.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2023-09-01T22:37:38.000Z (over 2 years ago)
- Last Synced: 2025-03-20T17:01:50.686Z (9 months ago)
- Topics: database, django, python
- Language: Python
- Homepage: https://pypi.org/project/django-sans-db/
- Size: 206 KB
- Stars: 6
- Watchers: 2
- Forks: 1
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# Django sans DB
Tools for limiting access to the database in parts of your Django code.
## Installation
```
pip install django-sans-db
```
If you wish to use the `{% sansdb %}` template tag,
you will need to add `"sans_db"` to your `INSTALLED_APPS`.
## Usage
### Context manager
You can block access to your database for a section of your code using `block_db`:
```python
from sans_db.context_managers import block_db
User.objects.create(...) # Works outside of block_db()
with block_db():
User.objects.get() # Raises DatabaseAccessBlocked
```
If you have multiple entries in your Django `DATABASES` setting,
then `block_db` will default to blocking all of them.
If you wish to block access to a subset of your databases,
pass a list of their aliases (the keys in the `DATABASES` dictionary).
```python
from sans_db.context_managers import block_db
with block_db(databases=["replica"]):
User.objects.using("primary").create(...) # This DB isn't blocked.
User.objects.using("replica").get() # Raises DatabaseAccessBlocked
```
### Decorator
You can decorate functions and methods with `block_db` to block database access in them. Eg:
```python
from sans_db.context_managers import block_db
class MyClass:
def allowed(self):
User.objects.create(...) # Works outside of block_db()
@block_db()
def not_allowed(self):
User.objects.create(...) # Raises DatabaseAccessBlocked
```
### Template backend
You can block access to the database when rendering Django templates with our custom template backend.
Note: Currently, only Django templates are supported.
You can block database access in all of your templates
by setting your templates backend to `"sans_db.template_backends.django_sans_db.DjangoTemplatesSansDB"`
For example:
```python
# settings.py
TEMPLATES = [
{
"BACKEND": "sans_db.template_backends.django_sans_db.DjangoTemplatesSansDB",
"APP_DIRS": True,
"OPTIONS": {...},
},
]
```
Attempts to query the database will now cause a `sans_db.exceptions.DatabaseAccessBlocked` to be raised.
Please refer to Django's docs on [support for template engines](https://docs.djangoproject.com/en/4.0/topics/templates/#support-for-template-engines)
for details on how to set this up as a secondary template renderer.
### Template tag
You can block DB access in a portion of your template
by wrapping it with the `{% sansdb %}` template tag.
The template tag accepts database aliases as either strings, or variables.
If passed as a variable, either strings or iterables of strings are accepted.
If no aliases are passed, all databases will be blocked.
Note: `DatabaseAccessBlocked` is raised when an attempt is made to access the DB.
To block all databases:
```django
{% load sansdb %}
{% sansdb %}
{# ... #}
{% endsansdb %}
```
To block a list of databases named in the template:
```django
{% load sansdb %}
{% sansdb "second_db" "third_db" %}
{# ... #}
{% endsansdb %}
```
To block a list of databases from a context variable:
```django
{% load sansdb %}
{% sansdb databases %}
{# ... #}
{% endsansdb %}
```