Django的Form功能生成HTML标签验证用户数据（显示错误信息）HTML Form提交保留上次提交数据初始化页面显示内容

Django form 流程

1、创建类，继承form.Form

2、页面根据类的对象自动创建html标签

3、提交，request.POST

封装到类的对象里，obj=UserInfo(request.POST)

4、用户输入是否合法

obj.is_valid()

5、全部合法，获取全部内容

obj.clean()

6、只有有不合法

obj.errors

1、创建Form类

from django.forms import Formfrom django.forms import widgetsfrom 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) )

2、View函数处理

from django.shortcuts import render, redirectfrom .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('')

3、生成HTML

<form action="/" method="POST" enctype="multipart/form-data"> <p>{{ form.user }} {{ form.user.errors }}</p> <p>{{ form.gender }} {{ form.gender.errors }}</p> <p>{{ form.city }} {{ form.city.errors }}</p> <p>{{ form.pwd }} {{ form.pwd.errors }}</p> <input type="submit"/></form>

<form method="POST" enctype="multipart/form-data"> {% csrf_token %}  {{ form.xxoo.label }} {{ form.xxoo.id_for_label }} {{ form.xxoo.label_tag }} {{ form.xxoo.errors }} <p>{{ form.user }} {{ form.user.errors }}</p> <input type="submit" /> </form>

Form类

创建Form类时，主要涉及到 【字段】 和 【插件】，字段用于对用户请求数据的验证，插件用于自动生成HTML;

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：2015-09-01TimeField(BaseTemporalField) 格式：11:12DateTimeField(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)CheckboxInputSelectNullBooleanSelectSelectMultipleRadioSelectCheckboxSelectMultipleFileInputClearableFileInputMultipleHiddenInputSplitDateTimeWidgetSplitHiddenDateTimeWidgetSelectDateWidget

常用选择插件

# 单radio，值为字符串# user = fields.CharField(# initial=2,# widget=widgets.RadioSelect(choices=((1,'上海'),(2,'北京'),))# ) # 单radio，值为字符串# user = fields.ChoiceField(# choices=((1, '上海'), (2, '北京'),),# initial=2,# widget=widgets.RadioSelect# ) # 单select，值为字符串# user = fields.CharField(# initial=2,# widget=widgets.Select(choices=((1,'上海'),(2,'北京'),))# ) # 单select，值为字符串# user = fields.ChoiceField(# choices=((1, '上海'), (2, '北京'),),# initial=2,# widget=widgets.Select# ) # 多选select，值为列表# user = fields.MultipleChoiceField(# choices=((1,'上海'),(2,'北京'),),# initial=[1,],# widget=widgets.SelectMultiple# ) # 单checkbox# user = fields.CharField(# widget=widgets.CheckboxInput()# ) # 多选checkbox,值为列表# user = fields.MultipleChoiceField(# initial=[2, ],# choices=((1, '上海'), (2, '北京'),),# widget=widgets.CheckboxSelectMultiple# )

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 Formfrom django.forms import widgetsfrom django.forms import fieldsfrom 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 formsfrom django.forms import fieldsfrom django.forms import widgetsfrom django.forms import models as form_modelfrom django.core.exceptions import ValidationErrorfrom 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())

自定义验证规则

方式一：

from django.forms import Formfrom django.forms import widgetsfrom django.forms import fieldsfrom 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 refrom django.forms import Formfrom django.forms import widgetsfrom django.forms import fieldsfrom django.core.exceptions import ValidationError # 自定义验证规则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'}))

方法三：自定义方法

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 Formfrom django.forms import widgetsfrom 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]

初始化数据

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。

1、Form

from django.forms import Formfrom django.forms import widgetsfrom django.forms import fieldsfrom django.core.validators import RegexValidator class MyForm(Form): user = fields.CharField()  city = fields.ChoiceField( choices=((1, '上海'), (2, '北京'),), widget=widgets.Select )

2、Views

from django.shortcuts import render, redirectfrom .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('') else: return redirect('')

3、HTML

<form method="POST" enctype="multipart/form-data"> {% csrf_token %} <p>{{ form.user }} {{ form.user.errors }}</p> <p>{{ form.city }} {{ form.city.errors }}</p>  <input type="submit"/></form>

基于form的django图片上传

第一种，直接上传

views

class TestimgForm(forms.Form): title = fields.CharField() img = fields.FileField()def testimg(request): import os,time if request.method == 'GET': img = TestimgForm() return render(request, 'backend/testimg.html',{'img':img}) else: obj = TestimgForm(request.POST, request.FILES)	if obj.is_valid():	 img = request.FILES.get('img') time = time.strftime('%Y%m%d%H%M%S') ext = os.path.splitext(img.name)[1]	 file_path = os.path.join('upload/article',time+ext) #将图片重命名 f = open(file_path,'wb') for line in imgs.chunks(): f.write(line) f.close()	 return HttpResponse('上传成功')

第二种，写入数据库

html

<!DOCTYPE html><html lang="en"><head> <title>Title</title></head><body><form action="testimg" method="post" enctype="multipart/form-data"> {% csrf_token %} {{ img }} <input type="submit" value="提交"/></form></body></html>

views

class TestimgForm(forms.Form): title = fields.CharField() img = fields.FileField()def testimg(request): import os,time if request.method == 'GET': img = TestimgForm() return render(request, 'backend/testimg.html',{'img':img}) else: obj = TestimgForm(request.POST, request.FILES)		if obj.is_valid():		title = obj.cleaned_data['title'] img = obj.cleaned_data['img'] time = time.strftime('%Y%m%d%H%M%S') ext = os.path.splitext(img.name)[1]		img.name = time + ext Imgtest.objects.create(title=title,img=img)		return HttpResponse('上传成功')

models.py

class Imgtest(models.Model): title = models.CharField(verbose_name='标题',max_length=32,) img = models.ImageField(verbose_name='缩略图',upload_to="./article/", help_text="大小200*200，不超过200k", default="/upload/article/common.jpg")

完整代码

class TestimgForm(forms.Form): title = fields.CharField() img = fields.FileField()def testimg(request): import os,time if request.method == 'GET': img = TestimgForm() return render(request, 'backend/testimg.html',{'img':img}) else: obj = TestimgForm(request.POST, request.FILES) if obj.is_valid(): #(request.FILES['file']) # title = request.FILES.get('title') # img = request.FILES.get('img') title = obj.cleaned_data['title'] img = obj.cleaned_data['img'] time = time.strftime('%Y%m%d%H%M%S') ext = os.path.splitext(img.name)[1] img.name = time + ext # Imgtest.objects.create(title=title,img=img) # img是对象（文件大小，文件名称,文件内容。。。） # file_path = os.path.join('upload/article',time+ext) file_path = os.path.join('upload/article', img.name) f = open(file_path,'wb') for line in img.chunks(): f.write(line) f.close() return HttpResponse('...')

Form定制化

定制错误信息

mail = forms.EmailField(error_messages={'required':u'邮箱不能为空'})

定制错误规则

mobile = forms.CharField(validators=[mobile_validate,],

error_messages={'required':u'手机不能为空'})

from django.shortcuts import renderfrom django import formsimport refrom django.core.exceptions import ValidationErrordef 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 UserInfo(forms.Form): email = forms.EmailField(error_messages={'required':u'邮箱不能为空'}) host = forms.CharField(error_messages={'required':u'主机不能为空'}) port = forms.CharField(error_messages={'required':u'端口不能为空'}) mobile = forms.CharField(validators=[mobile_validate,], #定义错误规则函数 error_messages={'required':u'手机不能为空'}, widget=forms.TextInput(attrs={'class':'form-control', #定义class 'placeholder':u'请输入手机号'})) beizhu = forms.CharField(required=False, #备注允许为空 widget=forms.Textarea(attrs={'class':'form-control', #定义为多行输入框 'placeholder':u'请输入备注'})) user_type_choice = ( (0,u'普通用户'), (1,u'高级用户'), ) user_type = forms.IntegerField(widget=forms.widgets.Select(choices=user_type_choice,attrs={'class':'form-control'}))

保存用户输入内容

obj = AccountForm.LoginForm(request.POST)

Form表单验证以及错误信息

错误信息格式：

普通格式：

from django.shortcuts import render,HttpResponsefrom web.forms import account as AccountForm def login(request): obj = AccountForm.LoginForm(request.POST) if request.method == 'POST': if obj.is_valid(): all_data = obj.clean() else: #用于Form表单提交 error = obj.errors #print error['username'][0] #print error['password'][0] return render(request, 'account/login.html',{'obj':obj,'error':error})  return render(request, 'account/login.html',{'obj':obj})

创建一个simple_tag，使其输 error['username'][0]

{% load xx %}<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title></title></head><body> <form action="/login/" method="post"> <p>{{ obj.username }} {% error_msg error.username %} </p> <p>{{ obj.password }} {% error_msg error.password %} </p> <input type="submit" value="提交"> </form>

JSON格式

def login(request): obj = AccountForm.LoginForm(request.POST) if request.method == 'POST': if obj.is_valid(): all_data = obj.clean() else: #用于Ajaxerror = obj.errors.as_json() #print errorreturn HttpResponse(error) return render(request, 'account/login.html',{'obj':obj,'error':error}) return render(request, 'account/login.html',{'obj':obj})

Form生成select标签

静态select

动态select

当增加数据库数据时

不会更新，除非关闭程序，重新载入才会更新

解决方法：利用面向对象类的静态字段

from django import formsimport json class ImportForm(forms.Form): #静态selectHOST_TYPE_LIST = ( (0,'物理机'),(1,'虚拟机'),) host_type = forms.IntegerField( widget=forms.Select(choices=HOST_TYPE_LIST) ) hostname = forms.CharField()  #动态select # admin_dic = ((1,'yangmv'),(1,"bob"),) # w_obj = open('db_admin','w') # w_obj.write(json.dumps(admin_dic)) # w_obj.close()f_obj = open('db_admin','r') data = f_obj.read() data_tuple = json.loads(data) admin = forms.IntegerField( widget=forms.Select(choices=data_tuple) )  def __init__(self,*args,**kwargs): super(ImportForm,self).__init__(*args,**kwargs) tmp = open('db_admin') data = tmp.read() data_tuple = json.loads(data) self.fields['admin'].widget.choices = data_tuple

再次增加数据库数据，直接刷新页面即可读取到新数据

优化后代码

from django import formsimport json class ImportForm(forms.Form): admin = forms.IntegerField(widget=forms.Select()) def __init__(self,*args,**kwargs): super(ImportForm,self).__init__(*args,**kwargs) tmp = open('db_admin') data = tmp.read() data_tuple = json.loads(data) self.fields['admin'].widget.choices = data_tuple

使用models获取select数据

class Select(models.Model): username = models.CharField(max_length=16) password = models.CharField(max_length=32)<body> <form action="/home/"> <p>{{ obj.admin }}</p> </form></body>def home(request): obj = HomeForm.ImportForm() return render(request, 'home/home.html',{'obj':obj})

models.Select.objects.all().values_list('id','username')