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Snippets by miracle2k

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Validation for 'unique' and 'unique_together' constraints (different version)

This is a slightly different and extendend version of this snippet: http://www.djangosnippets.org/snippets/260/ Unique constraints for single fields are validated in a clean_FIELD, instead of globally in the form's clean() method, so that the error messages are correctly assigned to each field. Additionally, you can specify mappings for unique_together constraints to assign those error messages to a specific field as well (instead of having them in non_field_errors(), where they would normally be.

  • newforms
  • forms
  • validation
  • unique_together
  • unique
  • constraints
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Automatically trim newforms text fields

Makes sure the value a user entered into a a text-based field is automatically trimmed during form cleaning / validation. The 'field' parameter is expected to be a newforms.fields.Field _instance_.Only modifies str and unicode descending values, and passes everything else on untouched. Example: form = form_for_model(Person) make_trimming(form.fields['name'])

  • newforms
  • strings
  • trim
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Template loader to target a specific template

This is http://djangosnippets.org/snippets/1376/ rewritten as a new class-style Loader, and slightly improved. Allows you to reference templates like this: app_label:some/template/name.html This makes it possible to insert customizations at any point in a template hierarchy. For example, you could replace a block within the base admin template: {% extends "admin:admin/base.html" %} {% block breadcrumbs %}Custom Breadcrumbs-Style{% endblock %}

  • templates
  • loader
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Passing values to a method from a template

A simple trick to let a function be called with exactly ONE argument from a Django template, by passing it via an attribute. Example: class SearchResult(object): @template_callable def highlighted(self, field): return self._xappy_result.highlight(field) result = SearchResult() result.highlighted.title {{ result.highlighted.title }}

  • template
  • templates
  • method
  • call
  • arguments
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"Approved" field with timestamp

I wanted to make the objects of a particular model approvable and store the timestamp of when that happened. In other frameworks/languages, I used to combined those in one "approved_at" field, which would be NULL if an object was currently unapproved. I tried different approaches to implement this in django, and this is the best I came up with so far. Basically, the code in __setattr__ makes sure that the field, once set, will not be updated again. Overriding setattr__() could also be a solution to determining if a field value has changed in save(), a question that seems come up from time to time in #django.

  • newforms
  • models
  • fields
  • forms
  • save
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UTC-based astimezone filter

A version of http://djangosnippets.org/snippets/2388/ which assumes UTC-based dates. This is when you store dates in UTC (as you should), and want to display them in your site's local timezone, and you notice that Django's timesince/time template tags still do not support timezones.

  • timezone
  • utc
  • timezones
  • times
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