A generic tagging application for Django projects, which allows association of a number of tags with any Django model instance and makes retrieval of tags simple.
Contents
Official releases are made available from http://code.google.com/p/django-tagging/
Download the .zip distribution file and unpack it. Inside is a script named setup.py. Enter this command:
python setup.py install
...and the package will install automatically.
A Windows installer is also made available - download the .exe distribution file and launch it to install the application.
An uninstaller will also be created, accessible through Add/Remove Programs in your Control Panel.
Alternatively, if you'd like to update Django Tagging occasionally to pick up the latest bug fixes and enhancements before they make it into an official release, perform a Subversion checkout instead. The following command will check the application's development branch out to an tagging-trunk directory:
svn checkout http://django-tagging.googlecode.com/svn/trunk/ tagging-trunk
Add the resulting folder to your PYTHONPATH or symlink (junction, if you're on Windows) the tagging directory inside it into a directory which is on your PYTHONPATH, such as your Python installation's site-packages directory.
You can verify that the application is available on your PYTHONPATH by opening a Python interpreter and entering the following commands:
>>> import tagging >>> tagging.VERSION (0, 3, 'pre')
When you want to update your copy of the Django Tagging source code, run the command svn update from within the tagging-trunk directory.
Caution!
The development version may contain bugs which are not present in the release version and introduce backwards-incompatible changes.
If you're tracking trunk, keep an eye on the CHANGELOG and the backwards-incompatible changes wiki page before you update your copy of the source code.
Once you've installed Django Tagging and want to use it in your Django applications, do the following:
- Put 'tagging' in your INSTALLED_APPS setting.
- Run the command manage.py syncdb.
The syncdb command creates the necessary database tables and creates permission objects for all installed apps that need them.
That's it!
Some of the application's behaviour can be configured by adding the appropriate settings to your project's settings file.
The following settings are available:
Default: False
A boolean that turns on/off forcing of all tag names to lowercase before they are saved to the database.
Default: 50
An integer which specifies the maximum length which any tag is allowed to have. This is used for validation in the django.contrib.admin application and in any forms automatically generated using ModelForm.
New in developement version
Your Django models can be registered with the tagging application to access some additional tagging-related features.
Note
You don't have to register your models in order to use them with the tagging application - many of the features added by registration are just convenience wrappers around the tagging API provided by the Tag and TaggedItem models and their managers, as documented further below.
To register a model, import the tagging module and call its register function, like so:
from django.db import models
import tagging
class Widget(models.Model):
name = models.CharField(max_length=50)
tagging.register(Widget)
The following argument is required:
The model class to be registered.
An exception will be raised if you attempt to register the same class more than once.
The following arguments are optional, with some recommended defaults - take care to specify different attribute names if the defaults clash with your model class' definition:
The name of an attribute in the model class which will hold a tag descriptor for the model. Default: 'tags'
See TagDescriptor below for details about the use of this descriptor.
The name of an attribute in the model class which will hold a custom manager for accessing tagged items for the model. Default: 'tagged'.
See ModelTaggedItemManager below for details about the use of this manager.
When accessed through the model class itself, this descriptor will return a ModelTagManager for the model. See ModelTagManager below for more details about its use.
When accessed through a model instance, this descriptor provides a handy means of retrieving, updating and deleting the instance's tags. For example:
>>> widget = Widget.objects.create(name='Testing descriptor') >>> widget.tags [] >>> widget.tags = 'toast, melted cheese, butter' >>> widget.tags [<Tag: butter>, <Tag: melted cheese>, <Tag: toast>] >>> del widget.tags >>> widget.tags []
A manager for retrieving tags used by a particular model.
Defines the following methods:
get_query_set() -- as this method is redefined, any QuerySets created by this model will be initially restricted to contain the distinct tags used by all the model's instances.
cloud(*args, **kwargs) -- creates a list of tags used by the model's instances, with count and font_size attributes set for use in displaying a tag cloud.
See the documentation on Tag's manager's cloud_for_model method for information on additional arguments which can be given.
related(self, tags, *args, **kwargs) -- creates a list of tags used by the model's instances, which are also used by all instance which have the given tags.
See the documentation on Tag's manager's related_for_model method for information on additional arguments which can be given.
usage(self, *args, **kwargs)) -- creates a list of tags used by the model's instances, with optional usages counts, restriction based on usage counts and restriction of the model instances from which usage and counts are determined.
See the documentation on Tag's manager's usage_for_model method for information on additional arguments which can be given.
Example usage:
# Create a ``QuerySet`` of tags used by Widget instances Widget.tags.all() # Retrieve a list of tags used by Widget instances with usage counts Widget.tags.usage(counts=True) # Retrieve tags used by instances of WIdget which are also tagged with # 'cheese' and 'toast' Widget.tags.related(['cheese', 'toast'], counts=True, min_count=3)
A manager for retrieving model instance for a particular model, based on their tags.
related_to(obj, queryset=None, num=None) -- creates a list of model instances which are related to obj, based on its tags. If a queryset argument is provided, it will be used to restrict the resulting list of model instances.
If num is given, a maximum of num instances will be returned.
with_all(tags, queryset=None) -- creates a QuerySet containing model instances which are tagged with all the given tags. If a queryset argument is provided, it will be used as the basis for the resulting QuerySet.
with_any(tags, queryset=None) -- creates a QuerySet containing model instances which are tagged with any the given tags. If a queryset argument is provided, it will be used as the basis for the resulting QuerySet.
Tags are represented by the Tag model, which lives in the tagging.models module.
The Tag model has a custom manager which has the following helper methods:
update_tags(obj, tag_names) -- updates tags associated with an object.
tag_names is a string containing tag names with which obj should be tagged.
If tag_names is None or '', the object's tags will be cleared.
add_tag(obj, tag_name) -- associates a tag with an an object.
tag_name is a string containing a tag name with which obj should be tagged.
get_for_object(obj) -- returns a QuerySet containing all Tag objects associated with obj.
usage_for_model(model, counts=False, min_count=None, filters=None) -- returns a list of Tag objects associated with instances of model.
If counts is True, a count attribute will be added to each tag, indicating how many times it has been associated with instances of model.
If min_count is given, only tags which have a count greater than or equal to min_count will be returned. Passing a value for min_count implies counts=True.
To limit the tags (and counts, if specified) returned to those used by a subset of the model's instances, pass a dictionary of field lookups to be applied to model as the filters argument.
cloud_for_model(Model, steps=4, distribution=LOGARITHMIC, filters=None, min_count=None) -- returns a list of the distinct Tag objects associated with instances of Model, each having a count attribute as above and an additional font_size attribute, for use in creation of a tag cloud (a type of weighted list).
steps defines the number of font sizes available - font_size may be an integer between 1 and steps, inclusive.
distribution defines the type of font size distribution algorithm which will be used - logarithmic or linear. It must be either tagging.utils.LOGARITHMIC or tagging.utils.LINEAR.
To limit the tags displayed in the cloud to those associated with a subset of the Model's instances, pass a dictionary of field lookups to be applied to the given Model as the filters argument.
To limit the tags displayed in the cloud to those with a count greater than or equal to min_count, pass a value for the min_count argument.
New in development version
usage_for_queryset(queryset, counts=False, min_count=None) -- Obtains a list of tags associated with instances of a model contained in the given queryset.
If counts is True, a count attribute will be added to each tag, indicating how many times it has been used against the Model class in question.
If min_count is given, only tags which have a count greater than or equal to min_count will be returned.
Passing a value for min_count implies counts=True.
Objects may be tagged using the update_tags helper function:
>>> from shop.apps.products.models import Widget >>> from tagging.models import Tag >>> widget = Widget.objects.get(pk=1) >>> Tag.objects.update_tags(widget, 'house thing')
Retrieve tags for an object using the get_for_object helper function:
>>> Tag.objects.get_for_object(widget) [<Tag: house>, <Tag: thing>]
Tags are created, associated and unassociated accordingly when you use update_tags and add_tag:
>>> Tag.objects.update_tags(widget, 'house monkey') >>> Tag.objects.get_for_object(widget) [<Tag: house>, <Tag: monkey>] >>> Tag.objects.add_tag(widget, 'tiles') >>> Tag.objects.get_for_object(widget) [<Tag: house>, <Tag: monkey>, <Tag: tiles>]
Clear an object's tags by passing None or '' to update_tags:
>>> Tag.objects.update_tags(widget, None) >>> Tag.objects.get_for_object(widget) []
To retrieve all tags used for a particular model, use the get_for_model helper function:
>>> widget1 = Widget.objects.get(pk=1) >>> Tag.objects.update_tags(widget1, 'house thing') >>> widget2 = Widget.objects.get(pk=2) >>> Tag.objects.update_tags(widget2, 'cheese toast house') >>> Tag.objects.usage_for_model(Widget) [<Tag: cheese>, <Tag: house>, <Tag: thing>, <Tag: toast>]
To get a count of how many times each tag was used for a particular model, pass in True for the counts argument:
>>> tags = Tag.objects.usage_for_model(Widget, counts=True)
>>> [(tag.name, tag.count) for tag in tags]
[('cheese', 1), ('house', 2), ('thing', 1), ('toast', 1)]
To get counts and limit the tags returned to those with counts above a certain size, pass in a min_count argument:
>>> tags = Tag.objects.usage_for_model(Widget, min_count=2)
>>> [(tag.name, tag.count) for tag in tags]
[('house', 2)]
You can also specify a dictionary of field lookups to be used to restrict the tags and counts returned based on a subset of the model's instances. For example, the following would retrieve all tags used on Widgets created by a user named Alan which have a size greater than 99:
>>> Tag.objects.usage_for_model(Widget, filters=dict(size__gt=99, user__username='Alan'))
New in development version
The usage_for_queryset method allows you to pass a pre-filtered queryset to be used when determining tag usage:
>>> Tag.objects.usage_for_queryset(Widget.objects.filter(size__gt=99, user__username='Alan'))
Tag input from users is treated as follows:
Examples:
| Tag input string | Resulting tags | Notes |
|---|---|---|
| apple ball cat | [apple], [ball], [cat] | No commas, so space delimited |
| apple, ball cat | [apple], [ball cat] | Comma present, so comma delimited |
| "apple, ball" cat dog | [apple, ball], [cat], [dog] | All commas are quoted, so space delimited |
| "apple, ball", cat dog | [apple, ball], [cat dog] | Contains an unquoted comma, so comma delimited |
| apple "ball cat" dog | [apple], [ball cat], [dog] | No commas, so space delimited |
| "apple" "ball dog | [apple], [ball], [dog] | Unclosed double quote is ignored |
The relationship between a Tag and an object is represented by the TaggedItem model, which lives in the tagging.models module.
TaggedItem objects have the following fields:
The TaggedItem model has a custom manager which has the following helper methods, which accept either a QuerySet or a Model class as one of their arguments. To restrict the objects which are returned, pass in a filtered QuerySet for this argument:
get_by_model(queryset_or_model, tag) -- creates a QuerySet containing instances of the specififed model which are tagged with the given tag or tags.
get_intersection_by_model(queryset_or_model, tags) -- creates a QuerySet containing instances of the specified model which are tagged with every tag in a list of tags.
get_by_model will call this function behind the scenes when you pass it a list, so you can use get_by_model instead of calling this method directly.
get_union_by_model(queryset_or_model, tags) -- creates a QuerySet containing instances of the specified model which are tagged with any tag in a list of tags.
Objects may be retrieved based on their tags using the get_by_model manager method:
>>> from shop.apps.products.models import Widget >>> from tagging.models import Tag >>> house_tag = Tag.objects.get(name='house') >>> TaggedItem.objects.get_by_model(Widget, house_tag) [<Widget: pk=1>, <Widget: pk=2>]
Passing a list of tags to get_by_model returns an intersection of objects which have those tags, i.e. tag1 AND tag2 ... AND tagN:
>>> thing_tag = Tag.objects.get(name='thing') >>> TaggedItem.objects.get_by_model(Widget, [house_tag, thing_tag]) [<Widget: pk=1>]
Functions which take tags are flexible when it comes to tag input:
>>> TaggedItem.objects.get_by_model(Widget, Tag.objects.filter(name__in=['house', 'thing'])) [<Widget: pk=1>] >>> TaggedItem.objects.get_by_model(Widget, 'house thing') [<Widget: pk=1>] >>> TaggedItem.objects.get_by_model(Widget, ['house', 'thing']) [<Widget: pk=1>]
Pass in a QuerySet to restrict the objects returned:
# Retrieve all Widgets which have a price less than 50, tagged with 'house'
TaggedItem.objects.get_by_model(Widget.objects.filter(price__lt=50), 'house')
# Retrieve all Widgets which have a name starting with 'a', tagged with any
# of 'house', 'garden' or 'water'.
TaggedItem.objects.get_union_by_model(Widget.objects.filter(name__startswith='a'),
['house', 'garden', 'water'])
Tag-related utility functions are defined in the tagging.utils module:
Parses tag input, with multiple word input being activated and delineated by commas and double quotes. Quotes take precedence, so they may contain commas.
Returns a sorted list of unique tag names.
See tag input for more details.
Given list of Tag instances, creates a string representation of the list suitable for editing by the user, such that submitting the given string representation back without changing it will give the same list of tags.
Tag names which contain commas will be double quoted.
If any tag name which isn't being quoted contains whitespace, the resulting string of tag names will be comma-delimited, otherwise it will be space-delimited.
Utility function for accepting tag input in a flexible manner.
If a Tag object is given, it will be returned in a list as its single occupant.
If given, the tag names in the following will be used to create a Tag QuerySet:
- A string, which may contain multiple tag names.
- A list or tuple of strings corresponding to tag names.
- A list or tuple of integers corresponding to tag ids.
If given, the following will be returned as-is:
- A list or tuple of Tag objects.
- A Tag QuerySet.
Add a font_size attribute to each tag according to the frequency of its use, as indicated by its count attribute.
steps defines the range of font sizes - font_size will be an integer between 1 and steps (inclusive).
distribution defines the type of font size distribution algorithm which will be used - logarithmic or linear. It must be one of tagging.utils.LOGARITHMIC or tagging.utils.LINEAR.
The tagging.fields module contains fields which make it easy to integrate tagging into your models and into the django.contrib.admin application.
A CharField that actually works as a relationship to tags "under the hood".
Using this example model:
class Link(models.Model):
...
tags = TagField()
Setting tags:
>>> l = Link.objects.get(...) >>> l.tags = 'tag1 tag2 tag3'
Getting tags for an instance:
>>> l.tags 'tag1 tag2 tag3'
Getting tags for a model - i.e. all tags used by all instances of the model:
>>> Link.tags 'tag1 tag2 tag3 tag4 tag5'
This field will also validate that it has been given a valid list of tag names, separated by a single comma, a single space or a comma followed by a space.
The tagging.forms module contains a Field for use with Django's forms library which takes care of validating tag name input when used in your forms.
A form Field which is displayed as a single-line text input, which validates that the input it receives is a valid list of tag names.
When you generate a form for one of your models automatically, using the ModelForm class, any tagging.fields.TagField fields in your model will automatically be represented by a tagging.forms.TagField in the generated form.
The tagging.views module contains views to handle simple cases of common display logic related to tagging.
Description:
A view that displays a list of objects for a given model which have a given tag. This is a thin wrapper around the django.views.generic.list_detail.object_list view, which takes a model and a tag as its arguments (in addition to the other optional arguments supported by object_list), building the appropriate QuerySet for you instead of expecting one to be passed in.
Required arguments:
- queryset_or_model: A QuerySet or Django model class for the object which will be listed.
- tag: The tag which objects of the given model must have in order to be listed.
Optional arguments:
Please refer to the object_list documentation for additional optional arguments which may be given.
- related_tags: If True, a related_tags context variable will also contain tags related to the given tag for the given model.
- related_tag_counts: If True and related_tags is True, each related tag will have a count attribute indicating the number of items which have it in addition to the given tag.
Template context:
Please refer to the object_list documentation for additional template context variables which may be provided.
- tag: The Tag instance for the given tag.
The following sample URLconf demonstrates using this generic view to list items of a particular model class which have a given tag:
from django.conf.urls.defaults import *
from tagging.views import tagged_object_list
from shop.apps.products.models import Widget
urlpatterns = patterns('',
url(r'^widgets/tag/(?P<tag>[^/]+)/$',
tagged_object_list,
dict(queryset_or_model=Widget, paginate_by=10, allow_empty=True,
template_object_name='widget'),
name='widget_tag_detail'),
)
The following sample view demonstrates wrapping this generic view to perform filtering of the objects which are listed:
from myapp.models import People
from tagging.views import tagged_object_list
def tagged_people(request, country_code, tag):
queryset = People.objects.filter(country__code=country_code)
return tagged_object_list(request, queryset, tag, paginate_by=25,
allow_empty=True, template_object_name='people')
The tagging.templatetags.tagging_tags module defines a number of template tags which may be used to work with tags.
Retrieves a list of Tag objects associated with a given model and stores them in a context variable.
Usage:
{% tags_for_model [model] as [varname] %}
The model is specified in [appname].[modelname] format.
Extended usage:
{% tags_for_model [model] as [varname] with counts %}
If specified - by providing extra with counts arguments - adds a count attribute to each tag containing the number of instances of the given model which have been tagged with it.
Examples:
{% tags_for_model products.Widget as widget_tags %}
{% tags_for_model products.Widget as widget_tags with counts %}
Retrieves a list of Tag objects for a given model, with tag cloud attributes set, and stores them in a context variable.
Usage:
{% tag_cloud_for_model [model] as [varname] %}
The model is specified in [appname].[modelname] format.
Extended usage:
{% tag_cloud_for_model [model] as [varname] with [options] %}
Extra options can be provided after an optional with argument, with each option being specified in [name]=[value] format. Valid extra options are:
- steps
- Integer. Defines the range of font sizes.
- min_count
- Integer. Defines the minimum number of times a tag must have been used to appear in the cloud.
- distribution
- One of linear or log. Defines the font-size distribution algorithm to use when generating the tag cloud.
Examples:
{% tag_cloud_for_model products.Widget as widget_tags %}
{% tag_cloud_for_model products.Widget as widget_tags with steps=9 min_count=3 distribution=log %}
Retrieves a list of Tag objects associated with an object and stores them in a context variable.
Usage:
{% tags_for_object [object] as [varname] %}
Example:
{% tags_for_object foo_object as tag_list %}
Retrieves a list of instances of a given model which are tagged with a given Tag and stores them in a context variable.
Usage:
{% tagged_objects [tag] in [model] as [varname] %}
The model is specified in [appname].[modelname] format.
The tag must be an instance of a Tag, not the name of a tag.
Example:
{% tagged_objects comedy_tag in tv.Show as comedies %}