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Server Side Cursors for Django's psycopg2 Backend

Based on discussion on [http://thebuild.com/blog/2010/12/14/using-server-side-postgresql-cursors-in-django/](http://thebuild.com/blog/2010/12/14/using-server-side-postgresql-cursors-in-django/) and [http://thebuild.com/blog/2010/12/13/very-large-result-sets-in-django-using-postgresql/](http://thebuild.com/blog/2010/12/13/very-large-result-sets-in-django-using-postgresql/) but instead implements them via extending the psycopg2 backend which allows you to use all of django's machinery without having to resort to using raw cursors. Usage: qs = Model.objects.all() with server_side_cursors(qs, itersize=100): for item in qs.iterator(): item.value if random_reason_to_break: break Setup: In your own project create the package hierarchy myproject.db.backends.postgresql_psycopg2 and place the code in base.py. In your settings.py set the database ENGINE to be 'myproject.db.backends.postgresql_psycopg2'. If you using south you'll have to let it know its a postgresql_psycopg2 backend by adding to SOUTH_DATABASE_ADAPTERS (see south documentation). Note: Make sure your using psycopg >= 2.4 for efficient named (server side) cursor iteration.

  • django
  • server
  • backend
  • cursors
  • named
  • psycopg2
  • side
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Debug SQL Query in Template

before this works, you'll need to satisfy all the criteria for getting debug information in your template context: Have 'django.core.context_processors.debug' in your TEMPLATE_CONTEXT_PROCESSORS setting (it was there in the default settings, last time I checked). Have your current IP in your INTERNAL_IPS setting. Use RequestContext when rendering the current template (if you're using a generic view, you're already using RequestContext). [Manuale Django](http://www.darioagliottone.it/django-guida/)

  • sql
  • template
  • debug
  • debugging
  • sql_queries
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Template Tag to protect the E-mail address

This is a Django Template Tag to protect the E-mail address you publish on your website against bots or spiders that index or harvest E-mail. It uses a substitution cipher with a different key for every page load. It basically produce a equivalent Javascript code for an email address. This code when executed by browser make it mailto link. **Usage** `{% encrypt_email user.email %}` **More Info ** [Template Tag to protect the E-mail address](http://www.nitinh.com/2010/02/django-template-tag-to-protect-the-e-mail-address/)

  • template
  • django
  • javascript
  • email
  • template-tag
  • obfuscate
  • bots
  • spider
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SSL Middleware for Webfaction

*NOTE Stephen updated his original snippet http://www.djangosnippets.org/snippets/85/ to work with WebFaction, please use his version now* This code is 95% from Stephen Zabel's snippet at http://www.djangosnippets.org/snippets/85/. However, his snippet, as it was, wouldn't work when enabling SSL for the admin site on Webfaction. For some reason, the default request.is_secure() doesn't behave properly with Webfaction's setup and redirects. One thing Webfaction does do is add X-Forwarded-ssl='on' to any https requests. So instead of using request.is_secure(), I've just used that. To setup the admin site with SSL on Webfaction, do the following: 1. Install this middleware wherever you like, and add it to settings.py 2. In your Webfaction panel, create your 'django' application ("application" in the Webfaction sense, not the Django sense) 3. Create two sites. The first, your main site (which I'll call example.com), should use the application 'django' mounted at '/'. Do *not* have HTTPS enabled on this site. 4. For the second site, also use the application 'django', and again mount it to '/', but this time enable HTTPS. 5. In your urls.py, modify the admin URL as follows: `(r'^admin/', include('django.contrib.admin.urls'), {'SSL':True} )` That should be it! The admin section of the site now requires SSL (as specified in urls.py), and if anyone tries to access the admin via regular http, a redirect to https will occur.

  • ssl
  • webfaction
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Generic admin action export selected rows to excel

Based on [http://djangosnippets.org/snippets/1697/](http://djangosnippets.org/snippets/1697/) but improved with multiline fields, and unicode chars. Also it generates an xls file, not a csv one. Requires, pyExcelerator *Usage:* Add the code to your project, e.g. a file called actions.py in the project root. Register the action in your apps admin.py: from myproject.actions import export_as_xls class MyAdmin(admin.ModelAdmin): actions = [export_as_xls]

  • export
  • admin-actions
  • xls
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Multiple inheritance of newforms and modelforms

If you try to use multiple inheritance with a modelform (to mix in some fields from an already existing form class for example) you'll get the following rather terrifying error: > "Error when calling the metaclass bases metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases" The solution is to first create the ModelForm, then create a NEW class that inherits from both the ModelForm and the form you want to mixin, then finally apply the recipe from here: [http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204197](http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/204197)

  • newforms
  • inheritance
  • modelforms
  • multipleinheritance
  • metaclasses
  • metaclass
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Decorator

[Understanding Python Decorators in 12 Easy Steps!] (http://simeonfranklin.com/blog/2012/jul/1/python-decorators-in-12-steps/)

  • decorator
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Controller Class for Views

I wanted to be able to share common code among a subset of views without copy-and-pasting the code or the same function into each view, so I decided to wrap a class around the views so that the common code (i.e. loading a model that each of the views would affect) can go in the __init__ of that class. I created the controller_view function above to allow the urls to access those class methods. It would be called something like this: url(r'^someview$', controller_view(SomeController, 'someview'), name='someview'), Where the SomeController inherits (or is structured like) the Controller class above and implements __init__ and someview as methods. I'm new to Django so it's entirely possible I've missed something that already does this or that makes this unnecessary. If so, let me know so that I can figure out how to do this right, otherwise, hopefully this is helpful to someone else out there.

  • urls
  • views
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Base64Field: base64 encoding field for storing binary data in Django TextFields

This Base64Field class can be used as an alternative to a BlobField, which is not supported by Django out of the box. The base64 encoded data can be accessed by appending _base64 to the field name. This is especially handy when using this field for sending eMails with attachment which need to be base64 encoded anyways. **Example use:** class Foo(models.Model): data = Base64Field() foo = Foo() foo.data = 'Hello world!' print foo.data # will 'Hello world!' print foo.data_base64 # will print 'SGVsbG8gd29ybGQh\n'

  • django
  • model
  • field
  • base64
  • blob
  • base64field
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Add querystring parameters to path (template tag)

`<h3>Page: {{ page.number }} of {{ page.paginator.num_pages }}</h3> {% if page.has_previous or page.has_next %} <div> {% if page.has_previous %} <a href="{% url_add_query page=page.previous_page_number %}">{% endif %}&laquo; Previous {% if page.has_previous %}</a>{% endif %} | {% if page.has_next %} <a href="{% url_add_query page=page.next_page_number %}">{% endif %} Next &raquo;{% if page.has_next %}</a>{% endif %} </div> {% endif %}`

  • template
  • templatetag
  • pagination
  • request
  • querystring
  • query-string
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