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All snippets written in Python

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Friendly ID(Python 3.X)

This is just modified version of [friendly id](https://djangosnippets.org/snippets/1249/) for make this script compatible with python 3.x Invoice numbers like "0000004" are a little unprofessional in that they expose how many sales a system has made, and can be used to monitor the rate of sales over a given time. They are also harder for customers to read back to you, especially if they are 10 digits long. This is simply a perfect hash function to convert an integer (from eg an ID AutoField) to a unique number. The ID is then made shorter and more user-friendly by converting to a string of letters and numbers that wont be confused for one another (in speech or text). To use it: import friendly_id class MyModel(models.Model): invoice_id = models.CharField(max_length=6, null=True, blank=True, unique=True) def save(self, *args, **kwargs): super(MyModel, self).save(*args, **kwargs) # Populate the invoice_id if it is missing if self.id and not self.invoice_id: self.invoice_id = friendly_id.encode(self.id) self.save() if self.id and not self.invoice_id When an object from this model is saved, an invoice ID will be generated that does not resemble those surrounding it. For example, where you are expecting millions of invoices the IDs generated from the AutoField primary key will be: obj.id obj.invoice_id 1 TTH9R 2 45FLU 3 6ACXD 4 8G98W 5 AQ6HF 6 DV3TY ... 9999999 J8UE5 The functions are deterministic, so running it again sometime will give the same result, and generated strings are unique for the given range (the default max is 10,000,000). Specifying a higher range allows you to have more IDs, but all the strings will then be longer. You have to decide which you need: short strings or many strings :-) This problem could have also been solved using a random invoice_id generator, but that might cause collisions which cost time to rectify, especially when a decent proportion of the available values are taken (eg 10%). Anyhow, someone else has now already written this little module for you, so now you don't have to write your own :-)

  • database
  • field-id
  • invoice-id
  • invoice
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query builder

""" Takes arguments & constructs Qs for filter() We make sure we don't construct empty filters that would return too many results We return an empty dict if we have no filters so we can still return an empty response from the view """

  • query
  • queryset
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Django chunked queryset iterator

The function slices a queryset into smaller querysets containing chunk_size objects and then yield them. It is used to avoid memory error when processing huge queryset, and also database error due to that the database pulls whole table at once. Concurrent database modification wouldn't make some entries repeated or skipped in this process.

  • django
  • python
  • database
  • queryset
  • iterator
  • memoryerror
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Mixin to enable admin permissions without using PermissionsMixin and models

Implements necessary permission checks on a user model to be compatible with django admin, but just return true on all permissions without actually checking it against anything. Useful when you have a user model that should always be allowed to use django admin, and you don't care about using django's own PermissionsMixin and don't want to have those models added to your database.

  • admin
  • mixin
  • permissions
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Cachable Django Paginator

This is a modificated version of `CachedPaginator` by **daniellindsley** [https://djangosnippets.org/snippets/1173/](https://djangosnippets.org/snippets/1173/) ([web-arhive-link](https://web.archive.org/web/20150927100427/https://djangosnippets.org/snippets/1173/)). Which not only cache `result_objects`, but the `total_count` of the `queryset` too (usefull if computating the count is an expensive operation too).

  • django
  • cache
  • pagination
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Dead Code Finder

Rough check for unused methods in our apps. Scans models, views, utils, api, forms and signals files for what look like methods calls, then looks at all of our classes' methods to ensure each is called. Do not trust this blindly but it's a good way to get leads on what may be dead code. Assumes a setting called `LOCAL_APPS` so it only bothers to look at the code you've written rather than everything in `INSTALLED_APPS`.

  • refactor
  • cleanup
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AvaliabilityAtDateListFilter

If your model have two dates, start and end of something, you may want to have filter which allow you to show objects which last on specific day.

  • filter
  • admin
  • changelist
  • list_filter
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Crypt-SHA512 password hasher

Password hashing method using the crypt-sha512 algorithm, To be able to generate password compatible with the crypt-sha512 method avaiable in the standard crypt function since glib2.7 and used on modern linux distros. This provides compatibility with programs and systems that use the glibc crypt library for encrypting passwords (such as shadow passwords used by modern Linux distributions) while providing extra security than the regular crypt-sha1 mechanism (available in Django as CryptPasswordHasher) To use it you just need to add something like this to your django settings file: --- PASSWORD_HASHERS = [ 'utils.hashers.CryptSHA512PasswordHasher', 'django.contrib.auth.hashers.PBKDF2PasswordHasher', 'django.contrib.auth.hashers.PBKDF2SHA1PasswordHasher', 'django.contrib.auth.hashers.BCryptSHA256PasswordHasher', 'django.contrib.auth.hashers.BCryptPasswordHasher', 'django.contrib.auth.hashers.SHA1PasswordHasher', 'django.contrib.auth.hashers.MD5PasswordHasher', 'django.contrib.auth.hashers.UnsaltedSHA1PasswordHasher', 'django.contrib.auth.hashers.UnsaltedMD5PasswordHasher', 'django.contrib.auth.hashers.CryptPasswordHasher', ] --- You need to keep the standard hashers on the list to be able to convert existing passwords to the new method. The next time a user login after the modification the password will be converted automatically to first hasher on the list. Thanks mmoreaux for his improvements!!

  • password
  • hash
  • crypt
  • sha512
  • 1.9
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Generate iCal VTIMEZONE block with DAYLIGHT and STANDARD components, based on pytz zoneinfo data

In the last few days I spent a lot of time trying to find a library or repository of some kind that could help me generate the required DAYLIGHT and STANDARD components of ical VTIMEZONE blocks. Since I couldn't find anything, I cobbled together this snippet to poke around in pytz timezone information and output the bare minimum I needed to make my ICS files compliant and useful (DST transitions for this year and the next). I promise it's (superficially) tested against "real" ICS files, but that's all. UPDATE: Thanks to @ariannedee for a much improved version (see comment for details)

  • pytz
  • timezones
  • ical
  • icalendar
  • ics
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Filter changelist by a numeric field using a number of common value ranges

## How to use Use this [admin filter](https://docs.djangoproject.com/en/1.8/ref/contrib/admin/#django.contrib.admin.ModelAdmin.list_filter) together with a numeric field to allow filtering changlist by field values range (in this case, age groups): For example, to group customers by age groups: class Customer(models.Model): # ... age = models.IntegerField() age.list_lookup_range = ( (None, _('All')), ([0, 2], '0-2'), ([2, 4], '2-4'), ([4, 18], '4-18'), ([18, 65], '18-65'), ([65, None], '65+'), )) class CustomerAdmin(admin.ModelAdmin): list_filter = [('age', ValueRangeFilter), ] ## Inspiration [This snippet](https://djangosnippets.org/snippets/587/) (for django < 1.4) inspired me to make this work for newer django versions.

  • filter
  • admin
  • field
  • range
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