common model privacy

A BooleanField indicating privacy is common on models, but the name of the field and whether the field being True indicates private or public both may change across models. If there is more than one potentially private model, a common interface is needed. A commonly-named method would do the job with `[a for a in MyModel.objects.all() if not a.is_private()]`, but it would still retrieve private instances from the database only to filter them out. This approach puts the name of the privacy field and whether that field being True indicates private or public in a tuple attribute of the model class. A chainable method is added to all QuerySet objects. example use: class MyModel(models.Model): is_public = models.BooleanField(default=True) # ... privacy_field = ("is_public", False) \>\>\> publicMyModels = MyModel.objects.all().exclude_private() \>\>\> values = publicMyModels.values()

• models
• querysets

Sun 11 Jul 2010 Read More

Automatic Paragraphs

I just converted the autop filter from Drupal (which is itself based on a Wordpress filter) from PHP to Python. I had to change the format of the regular expressions a bit and make them raw strings, but otherwise the function is unchanged. It should work exactly like the original function.

• filter
• text
• format

Sun 11 Jul 2010 Read More

pygments stylize

Simple tag to enable easy parsing of inline code within a template. Usage: {% stylize "language" %}...language text...{% endstylize %}. Make sure to set the language for Pygments to parse as the first argument to the tag. You will also need to include a copy of the CSS that Pygments uses. The [Pygments](http://pygments.org/) library is required for this tag.

• pygments
• templatetags

Sun 11 Jul 2010 Read More

XhtmlDegraderMiddleware

The XhtmlDegraderMiddleware class is designed to make it easier to deploy XHTML contents onto the World Wide Web. The correct MIME media type for sending XHTML is `application/xhtml+xml` -- the `text/html` media type is also acceptable provided [certain guidelines](http://www.w3.org/TR/2002/REC-xhtml1-20020801/#guidelines) are followed. The vast majority of web browsers released from 2002 onwards have good XHTML support; this includes Mozilla Firefox, Opera, and Apple Safari. Two notable exceptions are Internet Explorer 7.0 and Netscape Navigator 4.8; instead of displaying XHTML, they present the user with a download dialog instead. The role of the XHTML Degrader, then, is to automatically detect when browsers do not support XHTML, and to degrade the contents into something they're capable of rendering. **How it works** XhtmlDegraderMiddleware checks the content type of all HTTP responses. If the XHTML media type is set, the `Accept` request header is examined to determine whether the user agent actually supports XHTML. If so, the contents is sent unaltered. If not, a number of silent changes are made to make the response more friendly to XHTML-challenged browsers and web crawlers. Firstly, the `Content-Type` header is set to the HTML media type. Any XML processing instructions are removed, and a `DOCTYPE` is added if none is present. In the case of Internet Explorer, this should ensure the content is rendered in "standards compliance" mode. Empty elements are made to have a space before their trailing slash. N.B. If an HTTP response is already set to `text/html`, or set to any media type other than `application/xhtml+xml`, the middleware will have no effect. Note also that if you use GZipMiddleware, you should ensure that it appears in your MIDDLEWARE_CLASSES setting before XhtmlDegraderMiddleware, to allow the XHTML Degrader to act first.

• middleware
• xhtml

Sun 11 Jul 2010 Read More

SAS70 Compliant Password Validator

Validator to verify a password is SAS70 compliant: greater than or equal to eight characters, and contains at least three out of the four characters( Uppercase, Lowercase, Number, Special Character ).

• validator

Sun 11 Jul 2010 Read More

Querying on existence of a relationship

When you have two models joined by a foreign key, it's common to want to retrieve a set of objects from the "target" of the foreign key based on whether there are any objects "pointing" to them. This snippet demonstrates how to do so, using the `extra` method of the default model manager. Note that this is probably more efficient than using two ORM methods (e.g., selecting all values from one table, and using an `id__in` lookup on the other) since it does the whole thing in one query and avoids instantiating any intermediate objects.

• models
• orm
• foreign-keys

Sun 11 Jul 2010 Read More

Judge login require by url

Simple code , judge login require by url

• url
• login
• require

Sun 11 Jul 2010 Read More

Never cache a group of URLs

This is a special URL patterns replacement that prevents caching of any URL listed within it. We needed this in Review Board to prevent the JSON API function results from being cached in Internet Explorer.

• urls
• cache
• url
• patterns

Sun 11 Jul 2010 Read More

Using descriptors for lazy attribute caching

Python's [descriptor][1] protocol can seem a bit esoteric at first; however, it can be invaluable in handling everyday idioms and patterns - something that the Django framework authors have taken advantage of in numerous occasions (e.g.: [auth middleware][2]). One such idiom I see and use often and would like to generalize is the attribute-existence check-or-set routine illustrated here: def get_foo(self): if not hasattr(self, '_foo'): self._foo = init_foo() return self._foo Rather than coding this up multiple times (either for a given class or across many unrelated classes), I would prefer to delegate this repetitive work to a descriptor and remain [DRY][3]. The means to this end is implemented as a variation on the Python `property` construct, and is intentionally over simplistic (I leave the details of the heavy lifting up to the reader). The basic premise shown in source here is simply straight-forward Python, a quick and dirty example of how it could be utilized within a Django context is shown here: from django.db import models from cacheprop import CacheProperty2 ARTIFACT_TYPES = ( ('F', _('File')), ('D', _('Directory')), ('A', _('Alias')), ) class Artifact(models.Model): # model fields name = models.CharField(maxlength=64) type = models.CharField(maxlength=1, choices=ARTIFACT_TYPES) file_metadata = CacheProperty2( lambda self: self.filemetadata_set.get(artifact__id=self.id) ) class FileMetadata(models.Model): byte_size = models.IntegerField() artifact = models.ForeignKey(Artifact, unique=True) [1]: http://users.rcn.com/python/download/Descriptor.htm [2]: http://code.djangoproject.com/browser/django/trunk/django/contrib/auth/middleware.py [3]: http://c2.com/cgi/wiki?DontRepeatYourself

• python
• descriptors

Sun 11 Jul 2010 Read More

Ordering Models in Django Site administration screen

The models in the Site Administration screen are listed alphabetically. If you need to order them differently, say, in the order of creation of objects or some other 'workflow' criterion, you can use the instructions in this snippet.

• admin

Sun 11 Jul 2010 Read More

Revisiting Pygments and Markdown

A variation on a theme, inspired by [snippet 39][39] and [snippet 119][119]. The intent is to provide a more generic and simple mechanism for combining [Markdown][markdown] with [Pygments][pygments]. Common scenarios could include blogging or commenting. Snippet 119 seemed too specific and perhaps not as efficient, needing to process the HTML twice to accomplish it's ends. The one snag in the implementation is the need to use a tag other than `code` as a wrapper. See the comments for details. You will need the [BeautifulSoup][soup] module installed. Sample usage: from django.db import models class Blog(models.Model): '''Bare bones blogging model''' title = models.CharField(maxlength=255) slug = models.SlugField(maxlength=255, prepopulate_from=('title',)) pub_date = models.DateTimeField() # the cooked view, cached for quick retrieval blog = models.TextField() # the raw markdown-encoded text, saved for subsequent edits markdown = models.TextField() def save(self): from datetime import datetime if not self.id and not self.pub_date: self.pub_date = datetime.now() self.blog = pygmented_markdown(self.markdown) super(Blog, self).save() [39]: http://www.djangosnippets.org/snippets/39/ [119]: http://www.djangosnippets.org/snippets/119/ [soup]: http://www.crummy.com/software/BeautifulSoup/ [markdown]: http://www.freewisdom.org/projects/python-markdown/Installation [pygments]: http://pygments.org/

• pygments
• beautifulsoup
• markdown

Sun 11 Jul 2010 Read More

Email on new comments

I know ubernostrum has the nice comment_utils, but I need something that would notify the owner of the comment's content object (where the model has a foreignkey field to django.contrib.auth.models.User), but I didn't need all the moderation stuff. I stuck this in my models.py, where YOURMODEL is the name of the model object with comments attached, and a user field.

• email
• comments

Sun 11 Jul 2010 Read More

Email on new comments

In response to [#366](/snippets/366/), this is a subclass of the `CommentModerator` class from `comment_utils` which does nothing except email the "owner" of an object whenever a new comment is posted on it; all other moderation options remain inactive.

• email
• comments

Sun 11 Jul 2010 Read More

Markup Selection in Admin

This method lets you define your markup language and then processes your entries and puts the HTML output in another field on your database. I came from a content management system that worked like this and to me it makes sense. Your system doesn't have to process your entry every time it has to display it. You would just call the "*_html" field in your template. Requires: Django .96 [Markdown](http://cheeseshop.python.org/pypi/Markdown/1.6 "Python Package Index: Markdown") [Textile](http://cheeseshop.python.org/pypi/textile "Python Package Index: Textile")

• admin
• model
• markup
• markdown
• textile

Sun 11 Jul 2010 Read More

Yet another SQL debugging facility

Inspired by http://www.djangosnippets.org/snippets/159/ This context processor provides a new variable {{ sqldebug }}, which can be used as follows: {% if sqldebug %}...{% endif %} {% if sqldebug.enabled %}...{% endif %} This checks settings.SQL_DEBUG and settings.DEBUG. Both need to be True, otherwise the above will evaluate to False and sql debugging is considered to be disabled. {{ sqldebug }} This prints basic information like total number of queries and total time. {{ sqldebug.time }}, {{ sqldebug.queries.count }} Both pieces of data can be accessed manually as well. {{ sqldebug.queries }} Lists all queries as LI elements. {% for q in sqldebug.queries %} <li>{{ q.time }}: {{ q }}</li> {% endfor %} Queries can be iterated as well. The query is automatically escaped and contains <wbr> tags to improve display of long queries. You can use {{ q.sql }} to access the unmodified, raw query string. Here's a more complex example. It the snippet from: http://www.djangosnippets.org/snippets/93/ adjusted for this context processor. {% if sqldebug %} <div id="debug"> <p> {{ sqldebug.queries.count }} Quer{{ sqldebug.queries|pluralize:"y,ies" }}, {{ sqldebug.time }} seconds {% ifnotequal sql_queries|length 0 %} (<span style="cursor: pointer;" onclick="var s=document.getElementById('debugQueryTable').style;s.display=s.display=='none'?'':'none';this.innerHTML=this.innerHTML=='Show'?'Hide':'Show';">Show</span>) {% endifnotequal %} </p> <table id="debugQueryTable" style="display: none;"> <col width="1"></col> <col></col> <col width="1"></col> <thead> <tr> <th scope="col">#</th> <th scope="col">SQL</th> <th scope="col">Time</th> </tr> </thead> <tbody> {% for query in sqldebug.queries %}<tr class="{% cycle odd,even %}"> <td>{{ forloop.counter }}</td> <td>{{ query }}</td> <td>{{ query.time }}</td> </tr>{% endfor %} </tbody> </table> </div> {% endif %}

• sql
• debug
• queries
• db
• database
• contextprocessor

Sun 11 Jul 2010 Read More