Commentaires voulus pour mon premier champ personnalisé django!

Question

Bonjour, J'ai créé mon premier champ de django personnalisé. C'est un champ de numéro de sécurité sociale (Cpr) suivant la syntaxe danois. Comme je suis nouveau à la fois python et django, j'aimerais avoir des commentaires sur le code!

import django.forms as f 
from datetime import datetime 
import json 
from django.utils.safestring import mark_safe 
from django.core.exceptions import ValidationError 

# Globals 
YEAR = datetime.now().year   
FIELDS = (
    {'name' : "cpr_date", 'size': 2, 'maxlength': 2, 'renderfunc': None, 
     'field': f.IntegerField(min_value=1, max_value=31) 
    }, 
    {'name' : "cpr_month", 'size': 2, 'maxlength': 2, 'renderfunc': None, 
     'field': f.IntegerField(min_value=1, max_value=12), 
    },  
    {'name' : "cpr_year", 'size': 4, 'maxlength': 4, 
     'renderfunc': 'render_age', 
     'field': f.IntegerField(min_value=YEAR-120, max_value=YEAR), 
    }, 
    {'name' : "cpr_digits", 'size': 4, 'maxlength': 4, 
     'renderfunc': 'render_gender', 
     'field': f.IntegerField(min_value=1000, max_value=9999), 
    }, 
) 

class CprWidget(f.widgets.MultiWidget): 
    """Widget showing date, month, year and 4-last-digit fields for a danish cpr 
    number. 
    """ 
    def __init__(self, attrs=None): 
     widgets = [f.widgets.TextInput(field) for field in FIELDS] 
     super(CprWidget, self).__init__(widgets, attrs) 

    def decompress(self, v): 
     """Decompresses widget values to json before save""" 
     if v: return json.loads(v) 
     return [None, None, None, None] 

    def render(self, name, value, attrs=None): 
     """Extends with details rendered from parts of Cpr number""" 
     values = self.decompress_value(value) 
     output = super(CprWidget, self).render(name, value, attrs) 
     extra_output = "" 
     all_is_valid = True 
     i = 0 
     for field in FIELDS: 
      try: 
       value = values[i] 
       if value == None: 
        raise ValueError 
       fieldinst = field['field'] 
       fieldinst.validate(value) 
       fieldinst.run_validators(value) 
       if field['renderfunc']: 
        func = getattr(self, field['renderfunc']) 
        extra_output = extra_output + func(value) 
      except (IndexError, ValueError, ValidationError): 
       all_is_valid = False 
      finally: 
       i = i + 1 
     if all_is_valid: 
      extra_output = extra_output + self.render_cpr(values) 
     return output + mark_safe(extra_output) 

    def render_gender(self, value): 
     """Renders male or female based on last digit of Cpr""" 
     last_digit = int(str(value)[3]) 
     gender = (('Male','Female')[last_digit % 2 == 0]) 
     return self.render_line("Gender", gender) 

    def render_age(self, value): 
     """Renders age""" 
     return self.render_line("Age", YEAR-value) 

    def render_cpr(self, values): 
     """Renders full Cpr number""" 
     cpr = "%02d%02d%s-%s" % (
      int(values[0]), int(values[1]), str(values[2])[2:4], values[3]) 
     return self.render_line("Cpr", cpr) 

    def render_line(self, title, value): 
     """Renders a line with title and value""" 
     return "<br /><b>%s: </b>%s" % (title, value) 

    def decompress_value(self, value): 
     """Decompress values from value if needed""" 
     if not isinstance(value, list): 
      value = self.decompress(value) 
     return value 

    def format_output(self, rendered_widgets): 
     """Format html for widgets""" 
     labels = [u'Date', u'Month', u'Year', u'Digits'] 
     labels.reverse() 
     html = u'' 
     for w in rendered_widgets: html += labels.pop() + ': ' + str(w) 
     return html 

class CprField(f.MultiValueField): 
    """Field extending MultiValueField with date, month, year and 4-last-digit 
    fields for a danish cpr number. 
    """ 
    widget = CprWidget 
    def __init__(self, required=False, widget=None, label=None, initial=None): 
     fields = [field['field'] for field in FIELDS] 
     super(CprField, self).__init__(fields=fields, widget=widget, label=label 
      ,initial=initial, required=required) 

    def compress(self, data_list): 
     """Compress field values to json""" 
     return json.dumps(data_list) 

Answer 1

Y at-il une raison particulière pour laquelle vous combinez un widget Date avec le numéro CprP? Il semble qu'ils sont deux choses distinctes, et Django a déjà un SelectDateWidget décent. Je ne suis pas familier avec le nombre Cpr danois, mais à moins que la date fasse partie du nombre, ils devraient vraiment être deux champs séparés.