Circular reference with Django ORM and Postgres without breaking NOT NULL FK constraints

The recipe uses deferred constraint validation to create circular references across database tables. The example requires Postgres (MySQL doesn't support deferred constraints). To achieve this, the following is required: * Insertions must be performed in a transaction. Foreign key constraints will be validated at the end of the transactions, allowing for insertion of rows with FKs pointing to rows that don't exist yet. * Primary keys need to be generated before insertion. That's what `prefetch_id` does by pulling the next value from the `*_id_seq` sequence.

• django
• orm
• postgres

Thu 26 Mar 2015 Read More

Testing (and mocking) http requests to APIs etc.

You can test how your django app behaves depending on what kind of response it gets from the API. It assumes were're using the python requests library.

• http
• testing
• requests
• mock

Wed 25 Mar 2015 Read More

Load dynamically loaded form javascript assets using dajax

I am used to load forms directly into modals using dajax but I found out I had to load the scripts using an ajax call from the browser. You can see here an example of a dynamically loaded form and the function used to load the scripts.

• ajax
• javascript
• forms
• script
• dynamically-loaded-form
• form-assets
• dajax

Sun 22 Feb 2015 Read More

Testing email sending

How I assert email is being sent correctly

• email
• testing

Fri 20 Mar 2015 Read More

Decorator @not_login_required

This is a simple django snippet! It is the *opposite of @login_required* decorator for Django views Example **@not_login_required** ``` def login_page(request): ... ```

• decorator

Thu 12 Feb 2015 Read More

Deferrable function cache decorator

A variant of https://djangosnippets.org/snippets/2850/ that allows expensive calls to be deferred to an asynchronous process.

• cache
• memoize
• django-rq
• redis

Tue 10 Feb 2015 Read More

Django Template - obfuscate a javascript string

Obfuscate javascript strings. * Convert * `{{'Pita Hummus'|js_obfuscate_string}}` * to something like * `'P4itzga Hnumg7mubs'.replace(/[4zgn7b]/g,'')` Making it hard to text-search for strings in your code.

• obfuscation

Sun 08 Feb 2015 Read More

Image compression and conversion to JPG format before uploading the file

I've reimplemented the code I found somewhere on the web within my models file. The earlier version was incapable of converting all formats to JPG while this code converts all formats and compresses all of them successfully.

• django
• image
• upload
• imagefield
• compression

Wed 25 Feb 2015 Read More

Basic Auth Middleware for Python 3.4

This code based on Basic Auth Middleware by joshsharp. URL : https://djangosnippets.org/snippets/2468/

Thu 22 Jan 2015 Read More

Decorate class-based views with regular decorators

Decorating a whole view involves overriding the dispatch method so you can decorate it, even if all you do is a passthrough. This creates a class decorator for decorating CBVs. For example, if you want to make a view require a login: @decorate_dispatch(login_required) class MyCBV(TemplateView): ...

Thu 01 Jan 2015 Read More

Alias Field

A "fake" model field which is an alias to another underlying database field. Mirrors everything including queryset lookups, instance attributes, even if the field has been used on the model already (this isn't possible just by using db_column).

Wed 10 Dec 2014 Read More

Readonly Select Widget Replacement

This is for situations where a ModelForm is needed on an existing object, but we want to disable ForeignKey widgets, and only use them as a display. Usage: save the code in the top half of the example above into a file somewhere in your django project, in this example we will call it customwidget.py The second half shows an example usage, but setting the widget and queryset in the __init__ method of the form. If the queryset returned by the ForeignKey model (Example.objects.all() ) is small, you can omit the __init__ code.

Wed 29 Sep 2021 Read More

FileField mismatches

Consistency check on file fields between database and filesystem

Tue 09 Dec 2014 Read More

geodjango Metric Buffer

GEOSGeometry.buffer() accepts a distance argument which is in the unit of the coordinate reference system of the geometry. It is often necessary, however, to specify the buffer size in a more down-to-earth coordinate system, for example meters. with_metric_buffer(geom, buf_size) implements this functionality.

Mon 01 Dec 2014 Read More

decorator for runsnake

1. Add this decorator to whatever function: @profile('/tmp/0123test.prof') def test_function(): pass 2. If it's a django view function, let it run once. 3. Use "runsnake" to open the ".prof" file. Sweet.

Wed 19 Nov 2014 Read More