基于Django Form源码开发自定义Form组件

import copy
import re

class ValidateError(Exception):
    def __init__(self, detail):
        self.detail = detail

# ###################### 插件
class TextInput(object):
    def __str__(self):
        return "<input type='text' />"

class EmailInput(object):
    def __str__(self):
        return "<input type='email' />"

# ###################### 内部包含正则，用于验证
class Fild(object):
    def __init__(self,required=True,error_message=None,widget=None):
        self.error_message=error_message
        self.widget=widget
        self.required=required

    def __str__(self):
        return str(self.widget)

class CharFiled(Fild):
    def valid(self, val):
        if self.required:
            if not val:
                msg = self.error_message['required']
                raise ValidateError(msg)
        return val

class EmailFiled(Fild):
    REG = "^\w+@\w+$"
    def valid(self, val):
        if self.required:
            if not val:
                msg = self.error_message['required']
                raise ValidateError(msg)
        result = re.match(self.REG, val)
        if not result:
            msg = self.error_message.get('invalid', '格式错误')
            raise ValidateError(msg)
        return val

# ###################### Form，获取用户提交内容+获取定义的字段对象
class Form(object):
    def __init__(self,data):
        self.data=data
        self.clean_data={}
        self.errors={}
        self.fields=copy.deepcopy(self.__class__.declare_field)

    def __new__(cls, *args, **kwargs):
        declare_field={}
        for field_name, field in cls.__dict__.items():
            if isinstance(field,Fild):
                declare_field[field_name]=field

        cls.declare_field=declare_field
        return object.__new__(cls)

    def is_valid(self):
        for field_name,field in self.fields.items():
            try:
                val=self.data.get(field_name)
                field.valid(val)
                method = getattr(self, "cleaned_%s" % field_name, None)
                if method:
                    val=method(val)
                self.clean_data[field_name]=val
            except ValidateError as e:
                self.errors[field_name] = e.detail

        return len(self.errors) == 0

    def __iter__(self):
        return iter(self.fields.values())

class UserForm(Form):
    username=CharFiled(error_message={'required':'用户名不能为空'},widget=TextInput())
    email=EmailFiled(error_message={'required':'邮箱不能为空','invalid':'格式错误'},widget=EmailInput())

#应用
form =UserForm(data={'username':'ctz','email':'ctz@123'})

if form .is_valid():
    print('验证成功',form.clean_data)
else :
    print('验证失败',form.errors)