简短理解:后端提供了一个类:from django import forms,继承此类定义子类。子类中定义和form表单中提交到name名称一样的字段。django就可以帮做验证。验证后返回三个信息:是否通过;所有正确信息;所有错误信息。
例如:
自己写前端html后端Form类进行验证
views.py
from django.forms import Form
from django.forms import widgets
from django.forms import fields
class MyForm(Form):
user = fields.CharField(
widget=widgets.TextInput(attrs={'id': 'i1', 'class': 'c1'})
)
gender = fields.ChoiceField(
choices=((1, '男'), (2, '女'),),
initial=2,
widget=widgets.RadioSelect
)
city = fields.CharField(
initial=2,
widget=widgets.Select(choices=((1,'上海'),(2,'北京'),))
)
pwd = fields.CharField(
widget=widgets.PasswordInput(attrs={'class': 'c1'}, render\_value=True)
)
views.py 函数处理
from django.shortcuts import render, redirect
from .forms import MyForm
def index(request):
if request.method == "GET":
obj = MyForm()
return render(request, 'index.html', {'form': obj})
elif request.method == "POST":
obj = MyForm(request.POST, request.FILES)
if obj.is_valid():
values = obj.clean()
print(values)
else:
errors = obj.errors
print(errors)
return render(request, 'index.html', {'form': obj})
else:
return redirect('http://www.google.com')
对应html
其它html标签
1、Django内置字段如下:
Field
required=True, 是否允许为空
widget=None, HTML插件
label=None, 用于生成Label标签或显示内容
initial=None, 初始值
help_text='', 帮助信息(在标签旁边显示)
error_messages=None, 错误信息 {'required': '不能为空', 'invalid': '格式错误'}
show_hidden_initial=False, 是否在当前插件后面再加一个隐藏的且具有默认值的插件(可用于检验两次输入是否一直)
validators=[], 自定义验证规则
localize=False, 是否支持本地化
disabled=False, 是否可以编辑
label_suffix=None Label内容后缀
CharField(Field)
max_length=None, 最大长度
min_length=None, 最小长度
strip=True 是否移除用户输入空白
IntegerField(Field)
max_value=None, 最大值
min_value=None, 最小值
FloatField(IntegerField)
…
DecimalField(IntegerField)
max_value=None, 最大值
min_value=None, 最小值
max_digits=None, 总长度
decimal_places=None, 小数位长度
BaseTemporalField(Field)
input_formats=None 时间格式化
DateField(BaseTemporalField) 格式:2015-09-01
TimeField(BaseTemporalField) 格式:11:12
DateTimeField(BaseTemporalField)格式:2015-09-01 11:12
DurationField(Field) 时间间隔:%d %H:%M:%S.%f
…
RegexField(CharField)
regex, 自定制正则表达式
max_length=None, 最大长度
min_length=None, 最小长度
error_message=None, 忽略,错误信息使用 error_messages={'invalid': '…'}
EmailField(CharField)
…
FileField(Field)
allow_empty_file=False 是否允许空文件
ImageField(FileField)
…
注:需要PIL模块,pip3 install Pillow
以上两个字典使用时,需要注意两点:
- form表单中 enctype="multipart/form-data"
- view函数中 obj = MyForm(request.POST, request.FILES)
URLField(Field)
…
BooleanField(Field)
…
NullBooleanField(BooleanField)
…
ChoiceField(Field)
…
choices=(), 选项,如:choices = ((0,'上海'),(1,'北京'),)
required=True, 是否必填
widget=None, 插件,默认select插件
label=None, Label内容
initial=None, 初始值
help_text='', 帮助提示
ModelChoiceField(ChoiceField)
… django.forms.models.ModelChoiceField
queryset, # 查询数据库中的数据
empty_label="---------", # 默认空显示内容
to_field_name=None, # HTML中value的值对应的字段
limit_choices_to=None # ModelForm中对queryset二次筛选
ModelMultipleChoiceField(ModelChoiceField)
… django.forms.models.ModelMultipleChoiceField
TypedChoiceField(ChoiceField)
coerce = lambda val: val 对选中的值进行一次转换
empty_value= '' 空值的默认值
MultipleChoiceField(ChoiceField)
…
TypedMultipleChoiceField(MultipleChoiceField)
coerce = lambda val: val 对选中的每一个值进行一次转换
empty_value= '' 空值的默认值
ComboField(Field)
fields=() 使用多个验证,如下:即验证最大长度20,又验证邮箱格式
fields.ComboField(fields=[fields.CharField(max_length=20), fields.EmailField(),])
MultiValueField(Field)
PS: 抽象类,子类中可以实现聚合多个字典去匹配一个值,要配合MultiWidget使用
SplitDateTimeField(MultiValueField)
input_date_formats=None, 格式列表:['%Y--%m--%d', '%m%d/%Y', '%m/%d/%y']
input_time_formats=None 格式列表:['%H:%M:%S', '%H:%M:%S.%f', '%H:%M']
FilePathField(ChoiceField) 文件选项,目录下文件显示在页面中
path, 文件夹路径
match=None, 正则匹配
recursive=False, 递归下面的文件夹
allow_files=True, 允许文件
allow_folders=False, 允许文件夹
required=True,
widget=None,
label=None,
initial=None,
help_text=''
GenericIPAddressField
protocol='both', both,ipv4,ipv6支持的IP格式
unpack_ipv4=False 解析ipv4地址,如果是::ffff:192.0.2.1时候,可解析为192.0.2.1, PS:protocol必须为both才能启用
SlugField(CharField) 数字,字母,下划线,减号(连字符)
…
UUIDField(CharField) uuid类型
…
注:UUID是根据MAC以及当前时间等创建的不重复的随机字符串
import uuid
# make a UUID based on the host ID and current time
>>> uuid.uuid1() # doctest: +SKIP
UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')
# make a UUID using an MD5 hash of a namespace UUID and a name
>>> uuid.uuid3(uuid.NAMESPACE\_DNS, 'python.org')
UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')
# make a random UUID
>>> uuid.uuid4() # doctest: +SKIP
UUID('16fd2706-8baf-433b-82eb-8c7fada847da')
# make a UUID using a SHA-1 hash of a namespace UUID and a name
>>> uuid.uuid5(uuid.NAMESPACE\_DNS, 'python.org')
UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')
# make a UUID from a string of hex digits (braces and hyphens ignored)
>>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')
# convert a UUID to a string of hex digits in standard form
>>> str(x)
'00010203-0405-0607-0809-0a0b0c0d0e0f'
# get the raw 16 bytes of the UUID
>>> x.bytes
b'\\x00\\x01\\x02\\x03\\x04\\x05\\x06\\x07\\x08\\t\\n\\x0b\\x0c\\r\\x0e\\x0f'
# make a UUID from a 16-byte string
>>> uuid.UUID(bytes=x.bytes)
UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')
2、Django内置插件:
TextInput(Input)
NumberInput(TextInput)
EmailInput(TextInput)
URLInput(TextInput)
PasswordInput(TextInput)
HiddenInput(TextInput)
Textarea(Widget)
DateInput(DateTimeBaseInput)
DateTimeInput(DateTimeBaseInput)
TimeInput(DateTimeBaseInput)
CheckboxInput
Select
NullBooleanSelect
SelectMultiple
RadioSelect
CheckboxSelectMultiple
FileInput
ClearableFileInput
MultipleHiddenInput
SplitDateTimeWidget
SplitHiddenDateTimeWidget
SelectDateWidget
# 单radio,值为字符串
在使用选择标签时,需要注意choices的选项可以从数据库中获取,但是由于是静态字段 ***获取的值无法实时更新***,那么需要自定义构造方法从而达到此目的。
方式一:
from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
class MyForm(Form):
user = fields.ChoiceField(
# choices=((1, '上海'), (2, '北京'),),
initial=2,
widget=widgets.Select
)
def \_\_init\_\_(self, \*args, \*\*kwargs):
super(MyForm,self).\_\_init\_\_(\*args, \*\*kwargs)
# self.fields\['user'\].widget.choices = ((1, '上海'), (2, '北京'),)
# 或
self.fields\['user'\].widget.choices = models.Classes.objects.all().value\_list('id','caption')
方式二:
使用django提供的ModelChoiceField和ModelMultipleChoiceField字段来实现
from django import forms
from django.forms import fields
from django.forms import widgets
from django.forms import models as form_model
from django.core.exceptions import ValidationError
from django.core.validators import RegexValidator
class FInfo(forms.Form):
authors = form_model.ModelMultipleChoiceField(queryset=models.NNewType.objects.all())
# authors = form_model.ModelChoiceField(queryset=models.NNewType.objects.all())
方式一:
from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
class MyForm(Form):
user = fields.CharField(
validators=[RegexValidator(r'^[0-9]+$', '请输入数字'), RegexValidator(r'^159[0-9]+$', '数字必须以159开头')],
)
方式二:
import re
from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.exceptions import ValidationError
def mobile_validate(value):
mobile_re = re.compile(r'^(13[0-9]|15[012356789]|17[678]|18[0-9]|14[57])[0-9]{8}$')
if not mobile_re.match(value):
raise ValidationError('手机号码格式错误')
class PublishForm(Form):
title = fields.CharField(max\_length=20,
min\_length=5,
error\_messages={'required': '标题不能为空',
'min\_length': '标题最少为5个字符',
'max\_length': '标题最多为20个字符'},
widget=widgets.TextInput(attrs={'class': "form-control",
'placeholder': '标题5-20个字符'}))
# 使用自定义验证规则
phone = fields.CharField(validators=\[mobile\_validate, \],
error\_messages={'required': '手机不能为空'},
widget=widgets.TextInput(attrs={'class': "form-control",
'placeholder': u'手机号码'}))
email = fields.EmailField(required=False,
error\_messages={'required': u'邮箱不能为空','invalid': u'邮箱格式错误'},
widget=widgets.TextInput(attrs={'class': "form-control", 'placeholder': u'邮箱'}))
django2.1 Form验证大体流程:obj.is_vaild--> self.is_bound--> self.errors--> self.full_clean--> self._clean_fields--> self._clean_form--> slef._post_clean
"""
obj.is_vaild: 入口中self.is_bound代表数据不能为None和字段也是不能为None
self._errors: 默认是None,必执行self.full_clean()方法-->self._errors = ErrorDict(),self.cleaned_data = {},空字典赋值给错误信息
接着执行self._clean_fields() -->循环self.fields.items() 拿到字段名字和field正则匹配的规则,初步验证开始拿到用户提交的数据跟正则匹配,
----->重点环节(反射if hasattr(self, 'clean_%s' % name),这里就可以根据定义的字段名字,我们可以开始自己定义这个函数自定义验证)如果没成功验证必须抛出ValidationError这个错(局部钩子)
接着执行self._clean_form() ---->self.clean()(返回self.cleaned_data)什么事都没干,这里又是一个钩子,我们自己定义可以对整个字段进行验证 ,否则报错抛出必须是ValidationError(全局钩子)
接着执行self._post_clean()----->直接pass了又是一个钩子,这里还可以再一次的进行验证,可以和self.clean()一样
"""
方法三:自定义方法clean_字段名 (验证后的钩子)
from django import forms
from django.forms import fields
from django.forms import widgets
from django.core.exceptions import ValidationError
from django.core.validators import RegexValidator
class FInfo(forms.Form):
username = fields.CharField(max\_length=5,
validators=\[RegexValidator(r'^\[0-9\]+$', 'Enter a valid extension.', 'invalid')\], )
email = fields.EmailField()
def clean\_username(self):
"""
Form中字段中定义的格式匹配完之后,执行此方法进行验证
:return:
"""
value = self.cleaned\_data\['username'\]
if "666" in value:
raise ValidationError('666已经被玩烂了...', 'invalid')
return value
方式四:同时生成多个标签进行验证
from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
############## 自定义字段 ##############
class PhoneField(fields.MultiValueField):
def __init__(self, *args, **kwargs):
# Define one message for all fields.
error_messages = {
'incomplete': 'Enter a country calling code and a phone number.',
}
# Or define a different message for each field.
f = (
fields.CharField(
error_messages={'incomplete': 'Enter a country calling code.'},
validators=[
RegexValidator(r'^[0-9]+$', 'Enter a valid country calling code.'),
],
),
fields.CharField(
error_messages={'incomplete': 'Enter a phone number.'},
validators=[RegexValidator(r'^[0-9]+$', 'Enter a valid phone number.')],
),
fields.CharField(
validators=[RegexValidator(r'^[0-9]+$', 'Enter a valid extension.')],
required=False,
),
)
super(PhoneField, self).__init__(error_messages=error_messages, fields=f, require_all_fields=False, *args,
**kwargs)
def compress(self, data\_list):
"""
当用户验证都通过后,该值返回给用户
:param data\_list:
:return:
"""
return data\_list
############## 自定义插件 ##############
class SplitPhoneWidget(widgets.MultiWidget):
def __init__(self):
ws = (
widgets.TextInput(),
widgets.TextInput(),
widgets.TextInput(),
)
super(SplitPhoneWidget, self).__init__(ws)
def decompress(self, value):
"""
处理初始值,当初始值initial不是列表时,调用该方法
:param value:
:return:
"""
if value:
return value.split(',')
return \[None, None, None\]
在Web应用程序中开发编写功能时,时常用到获取数据库中的数据并将值初始化在HTML中的标签上。
views.py
# Form
from django.forms import Form
from django.forms import widgets
from django.forms import fields
from django.core.validators import RegexValidator
class MyForm(Form):
user = fields.CharField()
city = fields.ChoiceField(
choices=((1, '上海'), (2, '北京'),),
widget=widgets.Select
)
from django.shortcuts import render, redirect
from .forms import MyForm
def index(request):
if request.method == "GET":
values = {'user': 'root', 'city': 2}
obj = MyForm(values)
return render(request, 'index.html', {'form': obj})
elif request.method == "POST":
return redirect('http://www.google.com')
else:
return redirect('http://www.google.com')
html
verify_obj = MyFm(request.POST)
django中的Form一般有两种功能:
Form 对象生成html标签写法
views.py
from django.shortcuts import render, HttpResponse
from django.views import View
from django import forms
class MyFm(forms.Form):
username = forms.CharField()
pwd = forms.CharField()
email = forms.EmailField()
class FormTest(View):
def get(self, request):
verify_obj = MyFm()
return render(request, 'fm.html', {'verify_obj':verify_obj})
fm.html
<form action="/formtest/" method="post">
{% csrf\_token %}
<p>{{ verify\_obj.username }} {{ verify\_obj.errors.username.0 }}</p>
<p>{{ verify\_obj.pwd }} {{ verify\_obj.errors.pwd.0 }}</p>
<p>{{ verify\_obj.email }} {{ verify\_obj.errors.email.0 }}</p>
<input type="submit" value="提交">
</form>
django渲染后html
<form action="/formtest/" method="post">
<input type="hidden" name="csrfmiddlewaretoken" value="WhvU9JWIRIuk8Mjq0JJ1xCnId1ek6Rbee8kVgzyA0oHhUSIK3qZPu76opft70DPa">
<p><input type="text" name="username" required id="id\_username"> </p>
<p><input type="text" name="pwd" required id="id\_pwd"> </p>
<p><input type="email" name="email" required id="id\_email"> </p>
<input type="submit" value="提交">
</form>
error_messages= {'错误类型':'中文提示字符串'}
# 用来验证前端post提交过来数据的类
class MyFm(forms.Form):
username = forms.CharField(error_messages={'required':'用户名不允许为空'})
pwd = forms.CharField(
max_length=16,
min_length=8,
error_messages={'required': '密码不能为空', 'min_length': '密码长度不能小于8', 'max_length': '密码长度不能大于16'}
)
email = forms.EmailField(error_messages={'required': '邮箱不能为空', 'invalid': '邮箱格式错误'})
# 请求处理
class FormTest(View):
def get(self, request):
verify_obj = MyFm()
return render(request, 'fm.html', {'verify_obj':verify_obj})
def post(self, request):
# 获取所有数据
# 每条数据请求的验证
# 成功显示正确信息
# 失败,给出错误提示
# 验证时将request.POST 传递给验证类,实例化验证对象
verify_obj = MyFm(request.POST)
verify\_result = verify\_obj.is\_valid() # 验证是否通过,返回True/False(所验证的字段内置了相关正则表达式,然后执行clean\_字段,clean(\_\_all\_\_),post\_clean)
post\_dict = verify\_obj.clean() # 将获取到到的key value 转换为字典 必须在执行is\_valid()以后调用
cleaned\_data = verify\_obj.cleaned\_data # 将获取到到的符合要求的信息(也是字典) 必须在执行is\_valid()以后调用
# 如果是注册,向数据库内写入时,直接传参给Modle \*\*cleaned\_data 即可
verify\_errors = verify\_obj.errors # 获取所有错误信息(html标签字符串) 示例:<ul class="errorlist"><li>email<ul class="errorlist"><li>Enter a valid email address.</li></ul></li></ul>
verify\_errors\_json = verify\_obj.errors.as\_json() # 获取所有错误信息(html标签字符串) 示例:{"email": \[{"message": "Enter a valid email address.", "code": "invalid"}\]}
print(verify\_errors\_json) # code 表示错误类型,如无效、不许为空....message 表示对应code的提示字符串
# code : invalid/required .....
# return HttpResponse(verify\_result)
if not verify\_result:
return render(request, 'fm.html', {'verify\_obj': verify\_obj})
<form action="/formtest/" method="post">
{% csrf\_token %}
{# #}
{{ verify_obj.username }} {{ verify_obj.errors.username.0 }}
{{ verify_obj.pwd }} {{ verify_obj.errors.pwd.0 }}
{{ verify_obj.email }} {{ verify_obj.errors.email.0 }}
出错提示
html中也可以根据Form 对象自动生成table ul p 等html标签,直接将验证字段全部生成
{{ verify\_obj.as\_p }}
{{ verify\_obj.as\_ul }}
<table>
{{ verify\_obj.as\_table }}
</table>
---------------------------------------------------------------------------------
原理:
Form表单本身(本例:class MyFm(forms.Form):)只做输入的值是否合法,
生成html标签是里面插件功能实现的。例如
forms.CharField(xxx…)的父类 Field中的父类里面有TextInput等方法生成
from django import forms
from django.forms import widgets
class MyFm(forms.Form):
username = forms.CharField(
error_messages={'required':'用户名不允许为空'},
widget=widgets.Textarea(attrs={'class': 'form_username',
'placeholder': '用户名'})
)
pwd = forms.CharField(
max_length=16,
min_length=8,
error_messages={'required': '密码不能为空', 'min_length': '密码长度不能小于8', 'max_length': '密码长度不能大于16'},
widget=widgets.PasswordInput(attrs={})
)
email = forms.EmailField(error_messages={'required': '邮箱不能为空', 'invalid': '邮箱格式错误'})
重写父类Form 构造方法,增加更新外键字段时,选项自动更新。
class UserInfoForm(forms.Form):
username = fields.CharField(max_length=32)
email = fields.EmailField()
user_type = fields.ChoiceField(
choices=models.UserType.objects.values_list('id', 'caption')
)
def \_\_init\_\_(self, \*args, \*\*kwargs):
super(UserInfoForm, self).\_\_init\_\_(\*args, \*\*kwargs)
self.fields\['user\_type'\].choices = models.UserType.objects.values\_list('id', 'caption')
当UserType里面的数据更新的时候,生成字段会自动更新
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