Hello...
A common occurrence I have with one particular project is that it
requires the user to enter dimensions (for width/depth/height) in Feet
and Inches. Calculations are needed to be performed on that dimension,
so I've been working on a custom field type that takes in a dimension
in Feet/Inches (eg. 1'-10") and saves it to the database as a decimal
number using a regex to parse the input. The field displays to the end-
user as feet-inches at all times (with the eventual goal of writing a
method to be able to optionally display in metric, and interact with
measure.py, and geodjango stuff). What I have so far is definitely not
DRY, but aside from that, I'm having trouble with validation at the
form level. The custom model field itself works properly (from what
I've seen), and I've written a form field clean method which should
work to validate the field. My question is how to hook that form field
back into my model form to work for all the width/depth/height fields.
I'm thinking maybe an override of the init on the modelform (a la
self.fields['depth']...) , but I'm not quite sure where to go from
here...would you help me?
DCML_PATTERN = re.compile(r'^(?P<feet>\d+)(?P<dec_inch>\.?\d*)\'?$')
FTIN_PATTERN = re.compile(r'^(?P<feet>\d+)\'?\s*-?\s*(?P<inch>[0-9]|10|
11)?\"?$')
class FtInField(models.Field):
__metaclass__ = models.SubfieldBase
empty_strings_allowed = False
def db_type(self):
return 'double'
def get_internal_type(self):
return "FtInField"
def to_python(self,value):
if value is u'' or value is None:
return None
if isinstance(value, float):
m = FTDCML_PATTERN.match(str(value))
if m is None:
raise Exception('Must be an integer or decimal
number')
feet = int(m.group('feet'))
dec_inch = float(m.group('dec_inch') or 0)
inch = dec_inch * 12
return "%d\'-%.0f\"" % (feet,inch)
return value
def get_db_prep_value(self,value):
if value is u'' or value is None:
return None
m = FTIN_PATTERN.match(value)
if m is None:
raise Exception('Must be in X\'-Y" Format')
feet = int(m.group('feet'))
inch = int(m.group('inch') or 0)
return (feet + (inch/float(12)))
class FtInField(forms.Field):
def clean(self,value):
super(FtInField, self).clean(value)
if value is u'' or value is None:
raise forms.ValidationError('Enter a dimension in
X\'-Y" format')
m = FTIN_PATTERN.match(value)
if m is None:
raise forms.ValidationError('Must be in X\'-Y" Format')
feet = int(m.group('feet'))
inch = int(m.group('inch') or 0)
value = '%d\'-%.0f"' % (feet,inch)
return value
class ProductClass(models.Model):
productname = models.CharField('Product Name', max_length=60,
blank=True)
depth = FtInField('Depth (Feet/Inches)')
width = FtInField('Width (Feet/Inches)')
height = FtInField('Height (Feet/Inches)')
class ProductClassForm(forms.ModelForm):
depth = FtInField()
width = FtInField()
height = FtInField()
class Meta:
model = ProductClass
class ProductClassAdmin(admin.ModelAdmin):
form = ProductClassForm
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