Melodia/archiver/listfield.py

57 lines
1.3 KiB
Python

'''
Testing documentation
'''
from django.db import models
import re, itertools
class IntegerListField(models.TextField):
"""
Store a list of integers in a database string.
Format is:
[<int_1>, <int_2>, <int_3>, ... , <int_n>]
"""
description = "Field type for storing lists of integers."
__metaclass__ = models.SubfieldBase
def __init__(self, *args, **kwargs):
super(IntegerListField, self).__init__(*args, **kwargs)
#Convert database to python
def to_python(self, value):
if isinstance(value, list):
return value
#Process a database string
#Validation first
if len(value) <= 0:
return []
if value[0] != '[' or value[-1] != ']':
raise ValidationError("Invalid input to parse a list of integers!")
#Note that any non-digit string is a valid separator
_csv_regex = "[0-9]"
csv_regex = re.compile(_csv_regex)
#Synonymous to:
#string_list = filter(None, csv_regex.findall(value))
string_list = itertools.ifilter(None, csv_regex.findall(value))
value_list = [int(i) for i in string_list]
return value_list
#Convert python to database
def get_prep_value(self, value):
if not isinstance(value, list):
raise ValidationError("Invalid list given to put in database!")
separator_string = ", "
list_elements = separator_string.join(map(str, value))
return "[" + list_elements + "]"