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All snippets written in Python

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Variable._resolve_lookup monkeypatch

There are times when you want to hook into the Variable class of django.template to get extra debugging, or even to change its behavior. The code shown is working code that does just that. You can monkeypatch template variable resolution by calling patch_resolver(). I recommend using it for automated tests at first. My particular version of _resolve_lookup does two things--it provides some simple tracing, and it also simplifies variable resolution. In particular, I do not allow index lookups on lists, since we never use that feature in our codebase, and I do not silently catch so many exceptions as the original version, since we want to err on the side of failure for tests. (If you want to do monkeypatching in production, you obviously want to be confident in your tests and have good error catching.) As far as tracing is concerned, right now I am doing very basic "print" statements, but once you have these hooks in place, you can do more exotic things like warn when the same object is being dereferenced too many times, or even build up a graph of object interrelationships. (I leave that as an exercise to the reader.) If you want to see what the core _resolve_lookup method looks like, you can find it in django/templates/__init__.py in your installation, or also here (scroll down to line 701 or so): [source](http://code.djangoproject.com/browser/django/trunk/django/template/__init__.py)

  • template
  • variable
  • resolve
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UserProfileForm

We often need to use a Profile form and we want to be able to modify the first_name, last_name and sometimes the email address. Here is how I do it. In this case I want to check the email so I did a specific form for it. But it is quite easy to add it.

  • user
  • profile
  • form
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CSV Exporting of Model Data

This is a basic model view for exporting data from models. It is designed so that you can provide the GET variables used for searching/filtering within listdisplay pages in the admin, and the code will filter the same way. It allows the output of model data in various formats using serializers or templates.

  • models
  • export
  • csv
  • data
  • reports
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Limit the output of a field

This is a really simple snippet , but is not documented well ... Whit this , you can limit the output of one field in 25 characters before you test that is equal or over 30 characters! Note that the snippet cut the text and add three points at the end (...) Enjoy!

  • form
  • field
  • output
  • limit
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decorator for method attribute assignment

A bit cleaner syntax for method attribute assignment; used in models for 'short_description'. >from mysite.polls.models import Poll >poll = Poll.objects.get(pk=1) >poll.was_published_today.short_description >>>'Published today?'

  • models
  • decorator
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Fix for GZipMiddleware when serving files or streaming or using iterators

A simple replacement for Django's default GZipMiddleware which breaks when trying to serve files or pass any kind of iterators to the HttpResponse object. Simply replace GZipMiddleware with the provided middleware and set response.dontgzip = True when returning the response, and it will then be ignored by the middleware.

  • files
  • gzip
  • streaming
  • gzipmiddleware
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django-mptt enabled FilteredSelectMultiple m2m widget

If you are using django-mptt to manage content (eg heirarchical categories) then it needs a bit of help to make a nice admin interface. For many-to-many fields, Django provides the quite nice FilteredSelectMultiple widget (a two-pane selection list with search box) but it only renders 'flat' lists... if you have a big category tree it's going to be confusing to know what belongs to what. Also, list items are sorted alphabetically in the js, which won't be what you want. This snippet extends FilteredSelectMultiple to show the tree structure in the list. You'll also need the js from this snippet: [#1780](http://www.djangosnippets.org/snippets/1780/) For usage details see my blog at: [http://anentropic.wordpress.com](http://anentropic.wordpress.com/2009/11/05/more-django-mptt-goodness-filteredselectmultiple-m2m-widget/)

  • widget
  • mptt
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pyText2Pdf - Python script to convert plain text into PDF file. Modified to work with streams.

This is "pyText2Pdf" - Python script to convert plain text into PDF file. Originally written by Anand B Pillai. It is taken from http://code.activestate.com/recipes/189858/ Modified to work with streams. Example: produce PDF document from text and output it as HTTPResponse object. import StringIO input_stream = StringIO.StringIO(text) result = StringIO.StringIO() pdfclass = pyText2Pdf(input_stream, result, "PDF title") pdfclass.Convert() response = HttpResponse(result.getvalue(), mimetype="application/pdf") response['Content-Disposition'] = 'attachment; filename=pdf_report.pdf' return response

  • django
  • tools
  • python
  • pdf
  • converter
  • text2pdf
  • adobe
  • acrobat
  • processing
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MPTTModelAdmin

This builds on a couple of other people's hacks to effectively manage django-mptt models via the admin. One problem you find is if you use the actions drop-down menu to ‘delete selected’ items from your mptt model… the bulk actions bypass the model’s delete method so your left/right values for the tree aren’t updated. What you need is a way to automatically rebuild the tree after a bulk action. This code provides that facility. Full details on my blog: [http://anentropic.wordpress.com/2009/10/26/](http://anentropic.wordpress.com/2009/10/26/making-admin-bulk-delete-action-work-with-django-mptt/)

  • admin
  • mptt
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Middleware: Record ownership screener

UPDATE: 'ORDER BY' in de regex is now optional If enabled while coding just keep track of your console output for: <<< WARNING >>> Query execution without ownership clause, called from "process_response" Happy coding Regards, Gerard.

  • middleware
  • user
  • permission
  • ownership
  • created_by
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django redirects middleware a bit more fleixble

This is replace for django.contrib.redirects.RedirectFallbackMiddleware which redirects exact matches as well as startswith matches for the redirect.old_path I had a problem with my urls, because are dynamically generic, so I can't create one redirect entry on the database for each possible url. So I made django redirects to search any redirect with the exact match or any database entry being the head of my url, for example: I have django redirects which redirects /calendars/3434/ --> / . But when I have a 404 on /calendars/3434/c/2009/10/23/ now it redirects properly. So my redirects now acts as /calendars/3434/*

  • generic
  • redirects
  • contrib
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Custom model field for mysql time type.

Django does not have a suitable model field can process time type in mysql, the DateTimeField built-in django can not process more than 24 hours. That's why the code born. **Simply usage** `from myapp.models import TimeAsTimeDeltaField, SECONDS_PER_MIN, SECONDS_PER_HOUR, SECONDS_PER_DAY class EstimatedTime: days = None hours = None minutes = None seconds = None class Case(models.Model): estimated_time = TimeAsTimeDeltaField(null=True, blank=True) def get_estimated_time(self): estimated_time = EstimatedTime() if self.estimated_time: total_seconds = self.estimated_time.seconds + (self.estimated_time.days * SECONDS_PER_DAY) days = total_seconds / SECONDS_PER_DAY hours = total_seconds / SECONDS_PER_HOUR - days * 24 minutes = total_seconds / SECONDS_PER_MIN - hours * 60 - days * 24 * 60 seconds = total_seconds % SECONDS_PER_MIN estimated_time.days = days estimated_time.hours = hours estimated_time.minutes = minutes estimated_time.seconds = seconds return estimated_time else: return estimated_time

  • models
  • orm
  • database
  • field
  • timedelta
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Rails-like environments using Django

This is a replacement for settings.py, which moves the actual settings files into a directory called "env" and establishes different versions for different settings of the environment variable DJANGO_ENV. At runtime, the specified development environment can be found and loaded into the local context of settings.py, which is then picked up by whatever routine manage.py is kicking off.

  • django
  • rails
  • environment
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Wrappable text

Sometimes you have an uncontrolled amount of text in a horizontally constrained space. The wrappable filter places zero-width breaking spaces into the given text so that it can wrap at any point, as necessary for the containing width. Sometimes better than eliding (chopping long text...) or cropping/scrolling overflow.

  • template
  • filter
  • typography
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