Described more fully on [my blog](http://e-scribe.com/news/230), but the gist is: this model becomes a sort of mini-app in your admin, allowing you to record and track issues related to your other applications. Sorting still needs some work. UPDATED 2007-03-14: Fixed repeat in Admin.list_display (thanks, burly!); added Admin.list_filter; changed app list (why did I call that `PROJECTS`, anyway?) to omit "django.*" apps
This snippet creates thumbnails on-demand from a ImageField with any size using dynamics methods, like ``get_photo_80x80_url`` or ``get_photo_640x480_filename``, etc. It assumes you have an `ImageField` in your Model called `photo` and have this in your models.py: import re from os import path from PIL import Image GET_THUMB_PATTERN = re.compile(r'^get_photo_(\d+)x(\d+)_(url|filename)$') `models.py` example: import re from os import path from PIL import Image from django.db import models GET_THUMB_PATTERN = re.compile(r'^get_photo_(\d+)x(\d+)_(url|filename)$') class Photo(models.Model): photo = models.ImageField(upload_to='photos/%Y/%m/%d') <snippet here> Example usage: >>> photo = Photo(photo="/tmp/test.jpg") >>> photo.save() >>> photo.get_photo_80x80_url() u"http://media.example.net/photos/2008/02/26/test_80x80.jpg" >>> photo.get_photo_80x80_filename() u"/srv/media/photos/2008/02/26/test_80x80.jpg" >>> photo.get_photo_64x64_url() u"http://media.example.net/photos/2008/02/26/test_64x64.jpg" >>> photo.get_photo_64x64_filename() u"/srv/media/photos/2008/02/26/test_64x64.jpg"
This is the approach I've taken to access instances of child models from their parent. Functionally it's very similar to snippets [1031](http://www.djangosnippets.org/snippets/1031/) and [1034](http://www.djangosnippets.org/snippets/1034/), but without the use of `django.contrib.contenttypes`. Usage: class Post(ParentModel): title = models.CharField(max_length=50) objects = models.Manager() children = ChildManager() def __unicode__(self): return self.title def get_parent_model(self): return Post class Article(Post): text = models.TextField() class Photo(Post): image = models.ImageField(upload_to='photos/') class Link(Post): url = models.URLField() In this case, the `Post.children` manager will return a queryset containing instances of the appropriate child model, rather than instances of `Post`. >>> Post.objects.all() [<Post: Django>, <Post: Make a Tumblelog>, <Post: Self Portrait>] >>> Post.children.all() [<Link: Django>, <Article: Make a Tumblelog>, <Photo: Self Portrait>]
"Make fixture" command. Highly useful for making test fixtures. Use it to pick only few items from your data to serialize, restricted by primary keys. By default command also serializes foreign keys and m2m relations. You can turn off related items serialization with `--skip-related` option. How to use: python manage.py makefixture will display what models are installed python manage.py makefixture User[:3] or python manage.py makefixture auth.User[:3] or python manage.py makefixture django.contrib.auth.User[:3] will serialize users with ids 1 and 2, with assigned groups, permissions and content types. python manage.py makefixture YourModel[3] YourModel[6:10] will serialize YourModel with key 3 and keys 6 to 9 inclusively. Of course, you can serialize whole tables, and also different tables at once, and use options of dumpdata: python manage.py makefixture --format=xml --indent=4 YourModel[3] AnotherModel auth.User[:5] auth.Group
This is a little improvement to the [idea](http://www.djangosnippets.org/snippets/540/) from sheats a few days ago. I like it over the previous solutions because it doesn't involve doing anything other than running `./manage.py shell` inside your project directory. You don't have to create any files anywhere or remember to call anything, and `ipython` still works fine outside of a Django project. Throw this code in `~/.ipython/ipy_user_conf.py` (`ipythonrc` has apparently been deprecated).
This is a great way to pack extra data into a model object, where the structure is dynamic, and not relational. For instance, if you wanted to store a list of dictionaries. The data won't be classically searchable, but you can define pretty much any data construct you'd like, as long as it is JSON-serializable. It's especially useful in a JSON heavy application or one that deals with a lot of javascript. **Example** (models.py): from django.db import models from jsonfield import JSONField class Sequence(models.Model): name = models.CharField(maxlength=25) list = JSONField() **Example** (shell): fib = Sequence(name='Fibonacci') fib.list = [0, 1, 1, 2, 3, 5, 8] fib.save() fib = Sequence.objects.get(name='Fibonacci') fib.list.append(13) print fib.list [0, 1, 1, 2, 3, 5, 8, 13] fib.get_list_json() "[0, 1, 1, 2, 3, 5, 8, 13]" *Note:* You can only save JSON-serializable data. Also, dates will be converted to string-timestamps, because I don't really know what better to do with them. Finally, I'm not sure how to interact with forms yet, so that realm is a bit murky.
This template tag provides an easy way to render objects in your template, even if you don't know ahead of time what type they are. For example, if you've got a search page with a result list comprised of objects from various models, you can simply loop through them and render them using the tag. The tag will choose the best template and render the object for you. The tag's docstring has all the details. I hope you find this as useful as I have. Questions, comments, complaints welcome.
These three classes allows you to use enumerations (choices) in more natural model-like style. You haven't to use any magic numbers to set/get field value. And if you would like to make your enumeration a full-fledged django-model, migration should be easy. Note, that you can subclass Item to add some context-specific attributes to it, such as `get_absolute_url()` method for instance. Examples are provided in the form of `doctest` in the second half of the snippet.
If you're like me, you've got a models with a lot of fields/foreignkeys and often only want to edit a portion of the model in a form. Add this method to your custom form class and use it in place of the save() method.
Daniel Roseman's snippet, updated will all fixes mentioned in the comments of the first version + some other things to make it work under Django 1.4. South, and dumpdata are working. There's an ugly int(....) at the validate function in order to cast each value as an integer before comparing it to default choices : I needed this, but if you're storing strings values, just remove the int(......) wrapper. ------------------------------------- Orginal readme Usually you want to store multiple choices as a manytomany link to another table. Sometimes however it is useful to store them in the model itself. This field implements a model field and an accompanying formfield to store multiple choices as a comma-separated list of values, using the normal CHOICES attribute. You'll need to set maxlength long enough to cope with the maximum number of choices, plus a comma for each. The normal get_FOO_display() method returns a comma-delimited string of the expanded values of the selected choices. The formfield takes an optional max_choices parameter to validate a maximum number of choices.
Add this as a superclass of any Django model to allow making copies of instances of that model: class Entry(models.Model, CloneableMixin): [...] e = Entry.objects.get(...) e_clone = e.clone() e_clone.title = 'Cloned Entry' e.save() The new object is saved during the clone process and ManyToMany relations are copied as well.
Usually you want to store multiple choices as a manytomany link to another table. Sometimes however it is useful to store them in the model itself. This field implements a model field and an accompanying formfield to store multiple choices as a comma-separated list of values, using the normal CHOICES attribute. You'll need to set maxlength long enough to cope with the maximum number of choices, plus a comma for each. The normal get_FOO_display() method returns a comma-delimited string of the expanded values of the selected choices. The formfield takes an optional max_choices parameter to validate a maximum number of choices.
I know you're thinking, *what the heck could that title mean?* I often find myself wanting to filter and order by the result of a COUNT(*) of a query using a method similar to the [entry_count example](http://www.djangoproject.com/documentation/db-api/#extra-select-none-where-none-params-none-tables-none). Writing this many times is tedious and hardcoding the table and column names made me cringe, I also wanted the counts to result from more complex queries. This is a method you can add to your custom Manager to do this easily. It's not an ideal syntax, but it's good for the amount of code required. Example: suppose we have some articles we want to filter and order by comments and visit logs to show the most popular... class ArticleManager(models.Manager): count_related = _count_related class Article(models.Model): pub_date = models.DateTimeField(auto_now_add=True) objects = ArticleManager() class Comment(models.Model): article = models.ForeignKey(Article) is_spam = models.BooleanField(default=False) class Visit(models.Model): article = models.ForeignKey(Article) referrer = models.URLField(verify_exists=False) search_query = models.CharField(maxlength=200) Notice how the ArticleManager is given the `count_related` method. Now you can find the most popular like so... Order by non-spam comments: Article.objects.count_related(Comment.objects.filter( is_spam=False)).order_by('-comment__count') Order by incoming non-search-engine links: Article.objects.count_related(Visit.objects.filter( referrer__isnull=False, search_query__isnull=True), 'links').order_by('-links') Order by total visits: Article.objects.count_related(Visit).order_by('-visit__count') Note: Doesn't work if `query` contains joins or for many-to-many relationships, but those could be made to work identically if there's demand.
Runs model methods on save, create, update, delete Similar to Rails hooks **Usage:** *in models.py* from myproject.hooks import connect_hooks class MyModel(models.Model): #... # only on first save of a newly created object def before_create(self): print self def after_create(self): print self # not on first save of a newly created object def before_update(self): print self def after_update(self): print self # any save, new object or update def before_save(self): print self def after_save(self): print self # delete, self is still available after delete def before_delete(self): print self def after_delete(self): print self **connect_hooks(MyModel)**
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'