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Admin change language

This snippet adds a select language drop down menu in the admin bar (just after Documentation link). For this approach it's necessary to copy from admin templates the admin/base.html to the project templates (keeping the admin directory), changing just line 25 ad shown. Then it's necessary to create specified admin/change_language.html template.

  • admin
  • language
  • change
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Greek uppercase tag for django

Tag to correctly uppercase Greek characters with accent, copy the code in your templatetags folder in a file of your choice, load it in your templates {% load yourfile %} and use it as {% string|gruppercase %} the code works also with other languages, it won't modify anything (eg {% ukwork|gruppercase %} as it transforms only Greek characters (unless your language contains Greek characters).

  • tag
  • django
  • templates
  • uppercase
  • greek
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Inherit the standard url tag to include domain name

This module extends the standard `url' template tag in Django and adds support for fully qualified domain name URLs. It also can be extended with simple URL load balancing techniques if desired. See my blog for the background story: <http://atodorov.org/blog/2013/12/22/django-template-tag-inheritance-howto/>

  • template
  • tag
  • templatetag
  • url
  • inheritance
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Multiple emails form field

Validate form field that include email or emails separated by 'token' kwargs, by default ',' a comma. Return a list [] of email(s). Check validity of the email(s) from django EmailField regex (tested with 1.3, but normally will also work with 1.5)

  • multiple
  • email
  • validation
  • form
  • field
  • list
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Lazy context processor.

Sometimes you have context variables that are needed on many pages in a site, but not all. You only want them to be evaluated when actually needed, especially if they are expensive calculations that do DB queries etc. The pattern to use is shown: put a callable into the context, not the final value, and also wrap the callable with memoize_nullary.

  • template
  • contextprocessor
  • lazy
  • context-processor
  • memoize
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keeptags: strip all HTML tags from output except a specified list of elements

Django has several filters designed to sanitize HTML output, but they're either too broad (striptags, escape) or too narrow (removetags) to use when you want to allow a specified set of HTML tags in your output. Thus keeptags was born. Some of the code is essentially ripped from the Django removetags function. It's not perfect--for example, it doesn't touch attributes inside elements at all--but otherwise it works well.

  • filter
  • html
  • escape
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Decorator to execute a method only once

Beware if using Amazon Simple Queue Service to execute Celery tasks which send email messages! Sometimes SQS messages are duplicated which results in multiple copies of the messages being sent. This is a simple decorator which uses a cache backend to prevent the task from executing twice in a specified period. For example: @task @execute_once_in(3600*24*7) def cron_first_week_follow_up(): """ Send a follow-up email to new users! """ pass For more info see <http://atodorov.org/blog/2013/12/06/duplicate-amazon-sqs-messages-cause-multiple-emails/> <http://atodorov.org/blog/2013/12/11/idempotent-django-email-sender-with-amazon-sqs-and-memcache/>

  • django
  • email
  • decorator
  • amazon
  • queue
  • celery
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Multiple querysets

This is an upgrade of snippet [1103](http://www.djangosnippets.org/snippets/1103/). Exemplary usage: class Blog(models.Model): name = models.CharField(max_length=100) def __unicode__(self): return self.name class Post(models.Model): title = models.CharField(max_length=50) blog = models.ForeignKey(Blog) def __unicode__(self): return self.title class Meta: abstract=True class Article(Post): text = models.TextField() class Link(Post): url = models.URLField() blog = Blog(name="Exemplary blog") blog.save() Article(title="#1", text="Exemplary article 1", blog=blog).save() Article(title="#2", text="Exemplary article 2", blog=blog).save() Link(title="#3", url="http://exemplary.link.com/", blog=blog).save() qs1 = Article.objects.all() qs2 = Link.objects.all() qsseq = QuerySetSequence(qs1, qs2) # those all work also on IableSequence len(qsseq) len(QuerySetSequence(qs2, qs2)) qsseq[len(qs1)].title # this is QuerySetSequence specific qsseq.order_by('blog.name','-title') excluded_homo = qsseq.exclude(title__contains="3") # homogenic results - returns QuerySet type(excluded_homo) excluded_hetero = qsseq.exclude(title="#2") # heterogenic results - returns QuerySetSequence type(excluded_hetero) excluded_hetero.exists() You can implement more `QuerySet` API methods if needed. If full API is implemented it makes sense to also subclass the `QuerySet` class.

  • queryset
  • chain
  • iterable
  • indexable
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Run and cache only one instance of a heavy request

I have many heavy views which run slowly when accessed at same time in multiple threads. I make this decorator to allow run only one view at the time and cache returned result. Other threads will wait to complete first thread and use response from the cache if executed thread put it to cache. Also I take idea of MintCache to refresh staled cache and return cached (stale) response while response refreshed in the cache. Usage: @single_cacheable(cache_timeout=60, stale_timeout=30, key_template='my_heavy_view-{arg1}-{arg2}') def heavy_view(request, arg1, arg2): response = HttpResponse() ... your code here # cache timeout may be set from inside of view response._cache_timeout = cache_time return responce The "key_template" is a template for cache key. Some my views have additinal parameter "cache_time" which set from parent page and request.path is different for these pages but they need to be cached not depending of this parameter. Variable "key_template" in the example used named agrument, if you have no named paramaters you need to use 'my_heavy_view-{1}-{2}-{...}' where {1},{2}, {...} arguments of view. The line with setting "key" variable may be changed to: key = "sc_"+request.get_full_path() if you need to take full URL path as cache key.

  • cache
  • decorator
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Manual CSRF check for Django Facebook canvas applications

The way to manually control CSRF correctness for FB applications. Automatic check cannot be used because FB does POST on your canvas URL when initializing your application without CSRF token. If you still want to use Django CSRF stuff do manual checks. You only need to perform manual check when there is no correct signed_request present in your request - correct request means you really deal with FB. Use facebook_csrf_check to verify POST requests when signed_request is absent.

  • django
  • python
  • post
  • facebook
  • csrf
  • fb
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Admin action for a generic "CSV Export" (fix for unicode)

Based on [#2369](https://djangosnippets.org/snippets/2369/) Save the snippet as actions.py within your django app, and then add an action on any model you want in it's ModelAdmin definition. Example usage: from actions import export_as_csv_action class YourModelAdmin(admin.ModelAdmin): list_display = (...) list_filter = [...] actions = [export_as_csv_action("CSV Export", fields=[...])] - Unicode fix (requires unidecode)

  • admin
  • export
  • csv
  • action
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regex search in admin forms

Despite warning coming from django developers, I'm still using admin classes to quickly get into reverse engineering databases. One feature is missing: searching into fields thanks to a regex. One dirty solution I found is to overwrite get_search_results. But most of the code comes from django itself. If anyone has a better idea ;) **Usage:** 1. works since get_search_results is part of ModelAdmin (1.5 if I remember well) 2. Inherit your Admin class from RegexModelAdmin 3. enclose by / the field you want to regex with: `search_fields = ['/field/', ]`

  • admin
  • search
  • regex
  • field
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Truncate HTML without breaking tags

Put it in appname/templatetags/truncatehtml.py and load it with {% load truncatehtml %}, then for instance {{ some_story|truncatehtml:100 }} to truncate the story to 100 characters. Tags are not counted in the length given, and character entities count as one character. The filter should never break an open-tag text close-tag sequence without adding in the close tag. It will also preserve character entities. It won't sanitize the HTML, though: garbage in, garbage out. There's a bit more info about how it works in a [blog post](http://ole-laursen.blogspot.com/2009/05/safe-truncation-of-html.html) I wrote.

  • template
  • filter
  • truncate
  • html
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