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All snippets written in Python

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Prefetch id for Postgresql backend

When uploading a file or image, you need to put it somewhere that's not going to be orphaned by a change in the model. You could use a globally unique value like a uuid, but the django id autofield is a much shorter surrogate field that can be used in a friendly path to the object. The problem with id autofields is that they don't exist when the object is created for the first time - so all files using the id get uploaded to a location 'None' on first save, increasing the likelihood of name collisions. This postgresql only snippet fetches the next id in a way that is safe for concurrent access. This snippet only works on postgresql because neither sqlite or mysql have a nextval equivalent. Instead you would have to lock the table for writes and select the last value inserted incrementing it yourself.

  • models
  • filefield
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Database template loader

This snippet provides getting templates from the model in database. We work with templates as usual (using as a template name value of the field **"slug"**). You can do your own application without "TemplateTypes" model - it's added for ability to filter templates. You can use choices or remove "template_type" field and "TemplateTypes" model at all. For ease of editing, you can connect all this to the admin interface, adding to the field "template_body" widget with syntax highlighting (I used [CodeMirror](http://codemirror.net/)).

  • templates
  • template loader
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Django enumeration for model field choices

The problem with supplying a Django model field with choices parameter is the way you check a value of that field in an object. You do nasty things like this: if model_instance.choice_field == 1: The problem of getting rid of hard-coded numbers is recognized over the internet, but I haven't found any short and understandable solution. Basically, we need a enumeration in python, that is ok to use as the Django `choices` model field argument. I've seen a couple of solutions of DjangoSnippets. Mine is shorter and easier because it only works for integer field choices.

  • choices
  • integer
  • enumeration
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Overcome the bulk_create() size limitation using SQLite

As of django 1.4, the newly introduced `bulk_create()` function has a strong limitation when using SQLite. Namely it causes an error if you want to create more than `999/F` objects, where `F` is the number of fields in the object type. The above `safe_bulk_create(objs)` function solves this issue by splitting the list of objects to appropriately sized bulks. This solution also works fine with other db backends, and according to my experiments, it causes no significant overhead comparing to using `bulk_create()` directly. For more details on the issue, see https://code.djangoproject.com/ticket/17788 Thanks to charettes for pointing out how to calculate the number of fields in an object.

  • bulk_create
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DRY menu Custom Template Tag

This is the description of a custom template tag to create DRY menu. It solves the problem of markup duplication in templates of your site. The menu always has one active option and one or several inactive options. HOW TO USE Define a structure of your menu in a parent template: {% defmenu "menu1" %} {% active %}<span class='active'>__text__</span>{% endactive %} {% inactive %}<a href='__url__'>__text__</a>{% endinactive %} {% opt "opt1" "/opt1/" %}Go to opt1{% endopt %} {% opt "opt2" "/opt2/" %}Go to opt2{% endopt %} {% opt "opt3" "/opt3/" %}Go to opt3{% endopt %} {% enddefmenu %} The menu has it's name (first parameter of the tag 'defmenu'. First parameter of a tag 'opt' is menu option's name. '__text__' inside of 'active'/'inactive' will be substituted by inner text of a tag 'opt' (Go to opt...), '__url__' indide of 'active'/'inactive' will be substituted by second parameter of a tag 'opt' To generate menu with one selected option in child template do: {% menu "menu1" "opt1" %} Here: "menu1" is a name of menu that was defined by 'defmenu' tag, "opt1" is selected option. Result of the applying 'menu' is the next: <span class='active'> Go to opt1</span> <a href='"/opt2/"'>Go to opt2</a> <a href='"/opt3/"'>Go to opt3</a>

  • menu
  • dry
  • menubar
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Add

Based on an answer here: <http://stackoverflow.com/a/6288863>

  • groups
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Decode HTML Template Tag

This is useful if you have a string that is html encoded (i.e. "&lt;p&gt;Hello world!&lt;/p&gt;") and you want to do something more complex than just display it as html, such as using the striptags filter.

  • template
  • tag
  • django
  • templatetag
  • html
  • decode
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Custom Filter using filterspecs

This snippet is based on [#1051](http://djangosnippets.org/snippets/1051/). It adds filtering by existence of at least one related object. It is an example of how to simply subclass the FilterSpec class, in order to build a custom Filter. The comment in the code contains instructions on how to implement it in a real project.

  • django
  • filterspecs
  • custom filters
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Get email and push on couchdb - Model

view/admin.py ` def reactor(request): context = { 'email': read_mailbox() } return render_to_response(_lookup_template('dashboard'), context, context_instance=RequestContext(request)) ` **_Design all.js** ` function (doc) { if (doc.doc_type == 'MailArchive') { emit(doc._id, doc); } } ` **reduce.js** `_count`

  • email
  • couchdb
  • couchdbkit
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Generate a dineromail form in python

This is the code we use on bandtastic.me to build a html that sends users to dineromail to pay with. This code builds a form thats ready to send multiple items.

  • django
  • python
  • dineromail
  • express checkout
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