Another means of updating a subset of a model's fields

Based on the UPDATE query section of `Model.save()`, this is another means of limiting the fields which are used in an UPDATE statement and bypassing the check for object existence which is made when you use `Model.save()`. Just make whatever changes you want to your model instance and call `update`, passing your instance and the names of any fields to be updated. Usage example: import datetime from forum.models import Topic from forum.utils.models import update topic = Topic.objects.get(pk=1) topic.post_count += 1 topic.last_post_at = datetime.datetime.now() update(topic, 'post_count', 'last_post_at') (Originally intended as a comment on [Snippet 479](/snippets/479/), but comments aren't working for me)

• model
• db
• update

Sun 11 Jul 2010 Read More

Table of Contents

Simple template filter that extracts from a text ids, replaces '_' with spaces and produces hyperlinked Table of Contents. More info and usage example please see at [http://www.mysoftparade.com/blog/autogenerated-toc/](http://www.mysoftparade.com/blog/autogenerated-toc/)

• toc
• table-of-contents

Sun 11 Jul 2010 Read More

Filter for adding quote marks

A template filter for adding curly quotes around a string. The filter understands enough HTML to put the quotes inside an initial paragraph begin and ending paragraph end, if they exist. Put the code inside a file in a templatetags subdir in your app, add a {% load myfile %} statement and you're ready to go with {{somebodysays|addquotes}}. Of course, beware the script kiddies, be careful with escaping.

• templatetag
• quotes

Sun 11 Jul 2010 Read More

Renderer decorator

You can use this as a decorator for your views, this way you can return a simple dictionary and the decorator will do the rest. **@TODO:** Automatically set the template based on the app/view request

• shortcut
• render

Sun 11 Jul 2010 Read More

Pattern to integer list function

This function can be util for transform pattern strings like these to list: >>> pattern_to_list('42-45') [42, 43, 44, 45] >>> pattern_to_list('15,49-52') [15, 49, 50, 51, 52] >>> pattern_to_list('0-13') [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13] You can use also the list to pattern function at [http://www.djangosnippets.org/snippets/496/](http://www.djangosnippets.org/snippets/496/)

• list
• integer

Sun 11 Jul 2010 Read More

Integer list to pattern function

This function can be util for transform pattern lists like these to strings: >>> list_to_pattern([42, 43, 44, 45]) '42-45' >>> list_to_pattern([15, 49, 50, 51, 52]) '15,49-52' >>> list_to_pattern([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]) '0-13' You can use also the pattern to list function at [http://www.djangosnippets.org/snippets/495/](http://www.djangosnippets.org/snippets/495/)

• list
• integer

Sun 11 Jul 2010 Read More

SeparatedValuesField

A Django newforms field which takes another newforms field during initialization and validates every item in a comma-separated list with this field class. Please use it like this: from django.newforms import EmailField emails = CommaSeparatedValuesField(EmailField) You would be able to enter a string like "[email protected],[email protected]" because every email address would be validated when clean() is executed. This of course also applies to any other Field class. You can define the sepator (default: ",") during initialization with the `separator` parameter like this: from django.newforms import EmailField` emails = SeparatedValuesField(EmailField, separator="###")

• newforms
• field
• comma
• separated

Sun 11 Jul 2010 Read More

function_tag

register any python function as a tag with an optional name. usage: in templatetags: @function_tag() def foo(arg): return do_something(arg) in template: {% foo arg %} or {% foo arg as variable %}{{ variable.bar }}

• tag
• function

Sun 11 Jul 2010 Read More

Cache Manager

I had a problem: too many fetches from the DB. So, how to reduce load on the database without major changes to the code? Cache Manager is the answer. I've managed to reduce number of DB hits as much as 80% in some cases (dictionaries, complex relations). It is using standard cache mechanisms. I'm using it with mathopd. This is a very simple solution, instead of standard Manager, put this in your model definition as: `objects = CacheManager()` Then everythere elase in the code instead of all() or get(...) call all_cached() or get_cached(). I've kept original methods intact, to have an dual access, when you really, really must have frest data from the DB, and you can't wait for cache to expire. This is much easier to work with, then manually getting fetched data from the cache.No change to your existing code 9except model) and voila! Additionally if you have some data, you would like to store with your serialized object (e.g. related data, dynamic dictionaries), you can do this in the model method '_init_instance_cache'). Drop me an email if you find this useful. :)

• cache
• model
• manager

Sun 11 Jul 2010 Read More

blocksetter

Sometimes you need to set a little bit more complex variable in the template (e.g. Title), that is being used more than once. this simple tag defines "blockset" tag. {% blockset variable-name %}{%endblockset} everything inside body (between blockset/endblockset) is being assigned to the variable "variable-name". I have found this quite useful with translations, or setting the title, where you out several variables into one sentence. Drop me an email if you will find this useful.

• templatetag
• block
• set

Sun 11 Jul 2010 Read More

NewForms Readonly / Edit Pattern

This is a little base class that I use to display forms in a readonly mode. Providing a simple javascript on the front end to allow a user to click an **edit** link that will show/hide the actual form. To use it simply inherit from it. Then in your templates do the following: `{{ form.as_readonly_table }}` **Other Notes** * **form.html** `{% for field in bound_fields %} {% include "newforms/field.html" %} {% endfor %}` * **field.html** `{% if field.errors %} <tr> <td>&nbsp;</td> <td>{{ field.errors }}</td> </tr> {% endif %} <tr> <th style="text-align:right"> <label for="id_{{ field.name }}">{{ field.label }}{% if field.field.required %}<span class="required"><sup>*</sup></span>{% endif %}</label> </th> <td>{{ field }} {% if field.help_text %} <p class="helptext">({{ field.help_text }})</p> {% endif %} </td> </tr>`

• template
• newforms
• readonly
• edit-mode

Sun 11 Jul 2010 Read More

Mathematical Captcha

Simple mathematical captcha where human is asked to solve a simple mathematical calculation like 2+3=?. Don't require database access or external libraries like PIL. To use MathCaptchaForm subclass it and add your fields. For example of usage and discussion about security of this captcha comparing with traditional image captcha please see my blog entry [Improved Mathematical Captcha](http://www.mysoftparade.com/blog/improved-mathematical-captcha/)

• captcha

Sun 11 Jul 2010 Read More

BirthYearField

A form field to prompt for a year of birth with suitable sanity checks. Usage eg: yob = BirthYearField(label="What year were you born?")

• form
• field
• year
• birth

Sun 11 Jul 2010 Read More

OwnerField

This is a little helper for associating an owner to a newly created object, in this case making the assumption that the current user is always the owner. It removes the necessity of adding a custom save hook to your model. get_current_user comes from this middleware trick to cache the current user: http://code.djangoproject.com/wiki/CookBookThreadlocalsAndUser

• model
• user
• field
• owner
• ownerfield

Sun 11 Jul 2010 Read More

Link filter

Almost too dumb to be worth posting but its saved me a lot of typing. Instead of: <div> <a href="{{ object.get_absolute_url }} class="object-icon">{{ object }}</a> </div> just put: <div>{{ object|link }}</div>

• filter
• links

Sun 11 Jul 2010 Read More