Arbitrary auto-generated primary keys

Auto-incremented primary keys are the default in Django and they are supported natively in most databases but for anything more complex things are less trivial. DB sequences are not standard, may not be available and even if they are, they are typically limited to simple integer sequence generators. This snippet bypasses the problem by allowing arbitrary auto-generated keys in Python. The implementation needs to determine whether an IntegrityError was raised because of a duplicate primary key. Unfortunately this information is not readily available, it can be found only by sniffing the DB-specific error code and string. The current version works for MySQL (5.1 at least); comments about how to determine this in other databases will be incorporated in the snippet.

• mysql
• sequence
• uuid
• auto decrement
• auto increment
• primary key

Tue 25 Jan 2011 Read More

Querystring Builder - create urls with GET params

Save the code as app_name/templatetags/urlbuilder.py. Supply your view with a dictionary of "default" query params, likely taken from the request. Then, in the template: `{% load urlbuilder %} {% url some-url as base_url %}` That sets you up. Then you can make links. For example: <th><a href="{% build_url base_url query_params sort=name %}">Name</a></th> Say query_params has: page: 2, filter: active, sort: id The above tag would spit out /base/url?page=2&filter=active&sort=name The tag also has support for using a variable as the replacement key. Say "filter_key" is a variable available to the template with the value "filter": {% build_url base_url query_params filter_key default %} Using the above example, that would output /base/url?page=2&filter=default&sort=id

• tag
• templatetag
• url
• parameter
• querystring
• GET
• param

Tue 25 Jan 2011 Read More

Simple View Middleware to allow a Prefilter

This allows you to define a 'prefilter' function in your view modules which will be invoked before any view in that same. This provides an easy place to decorate the request or modify arguments. For simplicity it doesn't allow configuration of the name of the prefilter function. I also skipped recursing into parent modules since that's somewhat edgecase.

• middleware
• process_view
• prefilter
• beforefilter

Tue 25 Jan 2011 Read More

Resolve URLs to view name and args/kwargs

This is an expanded version of ["Resolve URLs to view name"](http://djangosnippets.org/snippets/1378/) without the monkey-patching. Simply pass in a URL such as '/events/rsvp/some_conference/' and you'll get back the view name or function (if name isn't available) and the arguments to it, eg 'events_rsvp', [], {'event_slug':'some_conference'}. Example (blatantly copied from previous snippet): === urlconf ==== urlpatterns = patterns('' (r'/some/url', 'app.views.view'), url(r'/some/other/(?P<url>\w+)', 'app.views.other.view', name='this_is_a_named_view'), url(r'/yet/another/(?P<url>\w+)/(\d+)', 'app.views.yetanother.view', name='one_with_args'), ) === example usage in interpreter === >>> from some.where import resolve_to_name >>> print resolve_to_name('/some/url') ('app.views.view',[],{}) >>> print resolve_to_name('/some/other/url') ('this_is_a_named_view',[],{'url':'url'}) >>> print resolve_to_name('/yet/another/url/5') ('one_with_args',[5],{'url':'url'}) From [fahhem.com](http://fahhem.com/) and [Recrec Labs](http://recreclabs.com/)

• url
• resolve
• name
• args
• kwargs

Tue 25 Jan 2011 Read More

example code howto post to PLURK API

example code howto post to PLURK API.

• task
• plurk

Sat 22 Jan 2011 Read More

django-admin custom filter: IS NULL/IS NOT NULL

A simple django-admin filter to allow a boolean-like filter for IS NULL/IS NOT NULL. By default it applies to CharField, IntegerField, and FileField, but you can change this by editing NullFilterSpec.fields.

• filter
• admin
• null
• filterspec

Thu 20 Jan 2011 Read More

Extend generic view object_list to support paginate_by via cookies

You can use this view to have a possibility to use ?paginate_by=x on your generic lists. Example usage in urls.py: `url('^list/', object_list_with_paginate_by, {'queryset': Invoice.objects.all(), 'template_name': 'invoices/list.html', 'paginate_by': 10}, 'invoices.list')` 10 is the default objects count per page. For the first time parameter paginate_by is set in URL, we have to get it straight from there. If the parameter is set, then also set the cookie for later requests without the parameter If the parameter is not set, then we try the cookie or default value

• object_list
• cookies
• paginate_by

Thu 20 Jan 2011 Read More

Infakt.pl - API

How connect to API Infakt.pl from Python. Snippet is django command managment. Use: e.g: python manage.py sync_clients_from_infakt

Thu 20 Jan 2011 Read More

Left Outer join Q object

QLeftOuterJoin object allows you to create 'LEFT OUTER JOIN' sql query. It is very usefull if you have to define ForeignKey to 'null=True' (select_related will not work with null=True). You are allowed to use QLeftOuterJoin like Q object. Example: `QLeftOuterJoin('thread_last_post', Post, 'pk', Thread, 'last_post')` It will generates SQL like: LEFT OUTER JOIN appname_post AS thread_last_post ON thread_last_post.id = appname_thread.last_post_id Table could be model or string.

• sql
• q
• query
• join

Thu 20 Jan 2011 Read More

Decorator to modify reverse() to render SSL urls

This snippet monkey-patches Django's reverse() method (use for generating URLs from vew functions and parameters) to allow certain areas of your site to automatically have URLs with the correct SSL domain in place. This saves you from having to use unnecessary redirects to guide users to an SSL-encrypted version of a page. This should still be used alongside a redirect-based method (such as [this snippet](http://www.djangosnippets.org/snippets/85/)) to ensure that the user can't access an unencrypted version of the page Simply add the code to the files mentioned in the code. This obviously won't work anywhere that doesn't use reverse(), the admin app seems to be an example of this.

• url
• ssl
• reverse
• permalink

Wed 19 Jan 2011 Read More

SSL Decorator

Wrote this some time ago when I couldn't find one already completed. Came up in the IRC channel so I decided to post it. Easy enough to use. `from ssldecorator import ssl_required` `@ssl_required` `def your_view(request):` ` ''' your code here '''` You can place a variable in your settings.py to change the SSL domain (ie, if you have SSL running on secure.yourdomain.com instead of www.yourdomain.com).. `SSL_DOMAIN = 'https://secure.yourdomain.com'` Note: please include a proper URL. If https isn't used, the decorator will add it.

• ssl
• decorator

Wed 19 Jan 2011 Read More

TLS(SSL) middleware, per URL pattern or whole site

Allows url patterns to include a boolean indicating whether a view requires TLS(SSL). The accompanying middleware handles the redirects needed to make sure that it upholds this requirement. **WARNING**: this monkey-patches some Django internals and is difficult to test since Django's TestClient does not support TLS. If you use this make sure you test it thouroughly. Add this to your Django settings USE_TLS = True # The default for this setting is False. URL pattern usage url(r'^login$', 'myproject.login.index', {'require_tls': True}, name='login-index'), Use `require_tls` True to force the middleware to perform redirects needed to make sure your are serving this view using https. Use `require_tls` False to force the middleware to redirect to http. Be careful with this setting, this may not behave as you expect. If you don't care if the view is served via https or http then do not include `require_tls` in the pattern. If you wish to have every view in the site served with TLS then specify the following Django setting ALWAYS_USE_TLS = True # Django setting, use TLS for every view

• middleware
• http
• ssl
• https
• tls

Wed 19 Jan 2011 Read More

Unlimited-length CharField

Unlimited-length character fields in Postgres perform the same as limited-length fields, and the Postgres manual suggests not arbitrarily limiting these fields. Unfortunately, Django does not provide a way to access unlimited-length character fields except using TextField, which is rendered differently in forms and in the admin, and has different connotations. LongCharField is a way to avoid putting arbitrary max_length values where they aren't required. It will only work with databases that allow VARCHAR with no numeric parameters, such as Postgres. MySQL won't work.

• text
• field
• postgres
• charfield
• length
• max_length
• unlimited
• varchar

Wed 19 Jan 2011 Read More

Feet and Inches FormField/Widget

Feet and Inches Widget/Field allows users to enter a value in feet, inches and fractional inches and have that value stored as a decimal in your database of choice. I have this code broken out into separate files, but you can always combine to suit your needs. I have designated file delineation with a single line comment and the name of the file as referenced in the import statements. The INCH_DECIMALS and INCH_FRACTION constants may be modified to allow smaller increments. My needs for this implementation only required accuracy to 1/16. Hope this helps someone learn how to use the MultiWidget and MultiValueFields! Happy Coding.

• widget
• multiwidget
• multifield
• feet
• inches

Wed 19 Jan 2011 Read More

get_cache_or_query - Shortcut to common cache signature

Replaces something like this: cache_key = 'game1' the_game = cache.get(cache_key) if not the_game: the_game = Game.objects.get(id=1) cache.set(cache_key, the_game, 60*24*5) With this: the_game = get_cache_or_query('game1', Game, seconds_to_cache=60*24*5, id=1)

• cache
• optimization
• get_cache_or_object

Tue 18 Jan 2011 Read More