Form组件
Django的Form主要具有一下几大功能:
- 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
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、内置字段
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 下面有介绍具体用法 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 *注:继承field的字段 field里面的参数都可以用 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) *等同于CharField加上validators 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 *上传文件 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) *单选下拉框 ... 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) *多选下拉框 ... 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) *被继承 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) *一下生成三个输入框 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 提交时是文件路径 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 ... Django内置字段
2、内置插件
* 插件用于生成HTML,所有的插件都可以用attrs={'class':'c1'}创建默认值 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
3、表单验证
处理文件:
from django import forms class Verification(forms.Form): # 跟表单提交的name值一一对应进行验证 user = forms.CharField(error_messages={'required':'用户名不能为空'}) pwd = forms.CharField( max_length=12, min_length=6, error_messages={'required': '密码不能为空','min_length':'密码长度不能小于6位', 'max_length': '密码长度不能大于12位'} ) email = forms.EmailField(error_messages={'required':'用户名不能为空','invalid':'邮箱格式不正确'}) def login(request): if request.method == "GET": obj = Verification() return render(request,'login.html',{'obj':obj}) elif request.method == "POST": # 获取用户所有数据 # 每条数据请求的验证 # 成功:获取所有的正确的信息 # 失败:显示错误信息 obj = Verification(request.POST) result = obj.is_valid() # 进行验证 True/False if result: print(obj.cleaned_data) # 用户提交的正确信息 else: print(obj.errors.as_json) # 所有错误信息 obj.errors return render(request, 'login.html',{'obj':obj}) # 传入obj return redirect('/login/')
HTML文件:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="/login/" method="post"> {% csrf_token %} <p>用户:{{ obj.user }}{{ obj.errors.user.0 }}</p> <p>密码:{{ obj.pwd }}{{ obj.errors.pwd.0 }}</p> <p>邮箱:{{ obj.email }}{{ obj.errors.email.0 }}</p> <input type="submit" name="提交" /> </form> </body> </html>
其他标签使用:
<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> 其他标签有
补充:cleaned_data(字典格式)创建和更新
models.UserInfo.objects.create(**obj.cleaned_data) models.UserInfo.objects.filter(id=1).update(**obj.cleaned_data)
4、更多验证方式:
验证文件:
from django import forms from django.forms import widgets from django.forms import fields class Verification(forms.Form): # 跟表单提交的name值一一对应进行验证 user = fields.CharField( widget=widgets.Textarea(attrs={'class':'c1'}), # 定制样式,变成长框输入,添加样式class=c1 label="用户名:" # 左边显示信息 ) pwd = fields.CharField( max_length=12, min_length=6, widget=widgets.PasswordInput() # 定制密码格式 ) f = fields.FileField() # 上传文件 p = fields.FilePathField(path='app01') # 显示路径 提交数据为路径值 email = fields.EmailField() city1 = fields.ChoiceField( # 单选下拉框 choices=[(0, '上海'), (1, '广州'), (2, '东莞')] ) city2 = fields.MultipleChoiceField( # 多选下拉框 choices=[(0, '上海'), (1, '广州'), (2, '东莞')] )
HTML文件:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="/login/" method="post"> {% csrf_token %} <p>{{ obj.user }}{{ obj.errors.user.0 }}</p> <p>{{ obj.pwd }}{{ obj.errors.pwd.0 }}</p> <p>{{ obj.email }}{{ obj.errors.email.0 }}</p> <p>{{ obj.f }}{{ obj.errors.f.0 }}</p> <p>{{ obj.p }}</p> <p>{{ obj.city1 }}</p> <p>{{ obj.city2 }}</p> <input type="submit" name="提交" /> </form> </body> </html>
5、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
6、初始默认显示数据
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
验证文件:
from django import forms from django.forms import widgets from django.forms import fields class Verification(forms.Form): # 跟表单提交的name值一一对应进行验证 user = fields.CharField( widget=widgets.Textarea(attrs={'class':'c1'}), # 定制样式,变成长框输入,添加样式class=c1 label="用户名:" # 左边显示信息 ) pwd = fields.CharField( max_length=12, min_length=6, widget=widgets.PasswordInput() # 定制密码格式 ) # f = fields.FileField() # 上传文件 p = fields.FilePathField(path='app01') # 显示路径 提交数据为路径值 email = fields.EmailField() city1 = fields.ChoiceField( # 单选下拉框 choices=[(0, '上海'), (1, '广州'), (2, '东莞')] ) city2 = fields.MultipleChoiceField( # 多选下拉框 choices=[(0, '上海'), (1, '广州'), (2, '东莞')] )
处理文件:
def login(request): if request.method == "GET": # 从数据库中吧数据获取到 dic = { "user": 'r1', 'pwd': '123123', 'email': 'sdfsd', 'city1': 1, 'city2': [1, 2] } # obj = Verification({'user':'James','pwd':'123123'}) # 设置初始默认显示 obj = Verification(initial=dic) # 设置初始默认显示 return render(request, 'login.html', {'obj': obj}) elif request.method == "POST": obj = Verification(request.POST) result = obj.is_valid() # 进行验证 True/False if result: print(obj.cleaned_data) # 用户提交的正确信息 else: print(obj.errors.as_json) # 所有错误信息 obj.errors return render(request, 'login.html',{'obj':obj}) # 传入obj return redirect('/login/')
HTML文件:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form action="/login/" method="post"> {% csrf_token %} <p>{{ obj.user }}{{ obj.errors.user.0 }}</p> <p>{{ obj.pwd }}{{ obj.errors.pwd.0 }}</p> <p>{{ obj.email }}{{ obj.errors.email.0 }}</p> {# <p>{{ obj.f }}{{ obj.errors.f.0 }}</p>#} <p>{{ obj.p }}</p> <p>{{ obj.city1 }}</p> <p>{{ obj.city2 }}</p> <input type="submit" name="提交" /> </form> </body> </html>
7、Form操作动态Select数据
其他文件:
from django.db import models class UserType(models.Model): name = models.CharField(max_length=32) class User(models.Model): user = models.CharField(max_length=32) pwd = models.CharField(max_length=32) ut = models.ForeignKey(to='UserType', to_field='id', related_name='b', related_query_name='a', limit_choices_to={'id__gt':1})
from app01.forms import UserInfoForm def index(request): obj = UserInfoForm() return render(request,'index.html',{'obj':obj})
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <p>{{ obj.user }}</p> <p>{{ obj.pwd }}</p> <p>{{ obj.user_type }}</p> </body> </html>
① 在app下创建forms.py文件做验证:
from django import forms from django.forms import fields from django.forms import widgets from app01 import models class UserInfoForm(forms.Form): user = fields.CharField( required=False, widget = widgets.Textarea(attrs={'class':'c1'}) ) pwd = fields.CharField( max_length=12, widget = widgets.PasswordInput(attrs={'class':'c1'}) ) user_type = fields.ChoiceField( # choices=[(1,'普通用户'),(2,'超级用户'),], choices=models.UserType.objects.values_list('id','name'), widget = widgets.Select )
执行Django程序,访问页面,可以获得动态的select选择框;但是会遇到问题,当UserType增加数据后,页面select选择框的内容并没有做改变,除非重启Django程序;这里涉及到实例变量和类变量,当实例化的时候,需要对类变量(静态字段)user_type进行重构
② 对forms.py进行修改:
from django import forms from django.forms import fields from django.forms import widgets from app01 import models class UserInfoForm(forms.Form): user = fields.CharField( required=False, widget = widgets.Textarea(attrs={'class':'c1'}) ) pwd = fields.CharField( max_length=12, widget = widgets.PasswordInput(attrs={'class':'c1'}) ) user_type = fields.ChoiceField( choices=[], widget = widgets.Select ) user_type2 = fields.CharField( widget=widgets.Select(choices=[],), ) # def __init__(self,*args,**kwargs): super(UserInfoForm,self).__init__(*args,**kwargs) # 执行父类重构 self.fields['user_type'].choices = models.UserType.objects.values_list('id', 'name') self.fields['user_type2'].widget.choices = models.UserType.objects.values_list('id', 'name')
8、添加自定义验证,重构钩子
Form数据验证顺序:
- 先正则检查字段
- 然后执行_clean_%s 检查各个字段
- 执行_clean_form
- 最后执_post_clean
对于错误信息:
- obj.errors里面有一个“__all__”来存放整体错误信息
- 单个字段存放单个的错误信息
① 寻找钩子
Form通过obj.is_valid()进行表单验证,通过self.errors查到forms.py文件的full_clean()
def full_clean(self): ...... self._clean_fields() self._clean_form() self._post_clean()
def full_clean(self): self._clean_fields() self._clean_form() self._post_clean() def _clean_fields(self): #单个字段钩子 try: if isinstance(field, FileField): initial = self.initial.get(name, field.initial) value = field.clean(value, initial) else: value = field.clean(value) self.cleaned_data[name] = value if hasattr(self, 'clean_%s' % name): value = getattr(self, 'clean_%s' % name)() self.cleaned_data[name] = value except ValidationError as e: self.add_error(name, e) def _clean_form(self): #整体钩子 try: cleaned_data = self.clean() except ValidationError as e: self.add_error(None, e) else: if cleaned_data is not None: self.cleaned_data = cleaned_data def _post_clean(self): """ An internal hook for performing additional cleaning after form cleaning is complete. Used for model validation in model forms. """ pass
② 注册用户,自定义验证已存在用户不能注册
class RegisterForm(forms.Form): user = fields.CharField() email = fields.EmailField() def clean_user(self): #验证用户是否已经存在 c = models.UserInfo.objects.filter(name=self.cleaned_data["user"]) if not c: return self.cleaned_data["user"] else: #用户名已存在,触发错误,提示用户名存在 raise ValidationError(message="用户名已经存在", code="a001") def clean_email(self): return self.cleaned_data["email"]
③ 用户登录验证,自定义整体错误,用户名或密码错误
from django.core.exceptions import ValidationError class RegisterForm(forms.Form): user = fields.CharField() email = fields.EmailField() def clean(self): #整体错误输出 #判断是否存在 c = models.UserInfo.objects.filter(name=self.cleaned_data['user'],pwd=self.cleaned_data['pwd']) if c : return self.cleaned_data #返回正常值 else: raise ValidationError(message='用户名或密码错误') #触发错误,错误发给整体而非某个字段
如果错误可以通过obj.errors获取错误的信但是通过_clean_form验证整体的错误信息在obj.errors里面有一个“__all__”来存放整体错误信息
打印整体错误信息:
from app01.forms import RegisterForm def login(request): if request.method == "GET": obj = RegisterForm() return render(request, 'login.html', {'obj': obj}) elif request.method == "POST": obj = RegisterForm(request.POST) result = obj.is_valid() if result: print(obj.cleaned_data) else: print(obj.errors['__all__']) #整体的错误信息打印 return render(request, 'login.html',{'obj':obj}) # 传入obj
from app01.forms import RegisterForm from django.core.exceptions import NON_FIELD_ERRORS def login(request): if request.method == "GET": obj = RegisterForm() return render(request, 'login.html', {'obj': obj}) elif request.method == "POST": obj = RegisterForm(request.POST) result = obj.is_valid() if result: print(obj.cleaned_data) else: print(obj.errors[NON_FIELD_ERRORS]) #整体的错误信息打印 return render(request, 'login.html',{'obj':obj}) # 传入obj
④ _post_clean还可自定制这个方法
9、Ajax提交验证(序列化)
关于Django中的序列化主要应用在将数据库中检索的数据返回给客户端用户,特别的Ajax请求一般返回的为Json格式;之前表单用form提交数据验证没有什么问题,现在我们要做在Ajax的情况下,如何去做:
其他文件:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <form id="fm"> {% csrf_token %} <p>用户:<input type="text" name="username"/></p> <p>密码:<input type="password" name="password"/></p> <p><input type="button" id="btn" value="Ajax提交"></p> </form> <script src="/static/jquery-1.12.4.js"></script> <script> $(function () { $('#btn').click(function () { $.ajax({ url:'/login/', type:'POST', data:$('#fm').serialize(), success:function (arg) { console.log(arg) arg = JSON.parse(arg) console.log(arg) console.log(arg['error']['username'][0]) },error:function () { } }) }) }) </script> </body> </html>
from django import forms from django.forms import fields from django.forms import widgets from app01 import models class LoginForm(forms.Form): username = fields.CharField() password = fields.CharField( max_length=20, min_length=12, )
处理文件:
import json from app01.forms import LoginForm def login(request): if request.method == "GET": return render(request, 'login.html') elif request.method == "POST": data = {'status':True,'error':None,'data':None} obj = LoginForm(request.POST) result = obj.is_valid() if result: print(obj.cleaned_data) else: from django.forms.utils import ErrorDict print(type(obj.errors)) #整体的错误信息打印 # < class 'django.forms.utils.ErrorDict'> data['error'] = obj.errors return HttpResponse(json.dumps(data)) # 传入obj
EroorDict信息:
@html_safe @python_2_unicode_compatible class ErrorDict(dict): """ A collection of errors that knows how to display itself in various formats. The dictionary keys are the field names, and the values are the errors. """ def as_data(self): return {f: e.as_data() for f, e in self.items()} def as_json(self, escape_html=False): return json.dumps({f: e.get_json_data(escape_html) for f, e in self.items()}) def as_ul(self): if not self: return '' return format_html( '<ul class="errorlist">{}</ul>', format_html_join('', '<li>{}{}</li>', ((k, force_text(v)) for k, v in self.items())) ) def as_text(self): output = [] for field, errors in self.items(): output.append('* %s' % field) output.append('\n'.join(' * %s' % e for e in errors)) return '\n'.join(output) def __str__(self): return self.as_ul()
武sir说课上说 ErrorDict不是Dict的格式,无法用json.dumps进行序列化,所以上面代码是错误的;但是,我个人测试的结果是可以打印出错误信息的,这点暂时存疑
浏览器: {"data": null, "status": true, "error": {"password": ["This field is required."], "username": ["This field is required."]}} Object {data: null, status: true, error: Object}data: nullerror: Objectstatus: true__proto__: Object This field is required.
用as_json()把ErrorDict转换为字符串然后传入data字典
处理文件:
import json from app01.forms import LoginForm def login(request): ---snip--- else: print(type(obj.errors.as_json())) #整体的错误信息打印 # <class 'str'> data['error'] = obj.errors.as_json() #把ErrorDict格式的obj.error转换为字符串格式 return HttpResponse(json.dumps(data)) # 传入
浏览器打印:
{"status": true, "data": null, "error": "{\"username\": [{\"code\": \"required\", \"message\": \"This field is required.\"}], \"password\": [{\"code\": \"required\", \"message\": \"This field is required.\"}]}"} Object {status: true, data: null, error: "{"username": [{"code": "required", "message": "Thi…equired", "message": "This field is required."}]}"} data: null error: "{"username": [{"code": "required", "message": "This field is required."}], "password": [{"code": "required", "message": "This field is required."}]}" status: true
从上面可看到error打印出来的格式还是字符串,由于之前用as_json进行过一次序列化,json.dumps后又进行一次序列化;进行了两次序列化,所以反序列化时也需要两次
用as_data()通过自定制json方法进行序列化
处理文件:
import json from django.core.exceptions import ValidationError class JsonCustomEncoder(json.JSONEncoder): def default(self, field): if isinstance(field, ValidationError): return {'code':field.code,'messages':field.messages} else: return json.JSONEncoder.default(self, field) from app01.forms import LoginForm def login(request): ---snip--- else: print(type(obj.errors.as_data())) #as_data虽然变成了字典,但是也不能直接dump # <class 'dict'> print(obj.errors.as_data()) #里面包含了ValidationError类型序列化会报错 # 'password': [ValidationError(['This field is required.'])], 'username': [ # ValidationError(['This field is required.'])]} data['error'] = obj.errors.as_data() data = json.dumps(data, cls=JsonCustomEncoder) #自定义JsonCustomEncoder方法序列化 return HttpResponse(json.dumps(data)) # 传入
补充:由于json.dumps时无法处理datetime日期,所以可以通过自定义处理器来做扩展,如:
import json from datetime import date from datetime import datetime class JsonCustomEncoder(json.JSONEncoder): def default(self, field): if isinstance(field, datetime): return field.strftime('%Y-%m-%d %H:%M:%S') elif isinstance(field, date): return field.strftime('%Y-%m-%d') else: return json.JSONEncoder.default(self, field) v = {'k':123,'k1':datetime.now()} ds = json.dumps(v, cls=JsonCustomEncoder)
serializers对QuerySet类型数据序列化
from app01 import models from django.core import serializers def index(request): v = models.User.objects.all() #QuerySet类型 # print(v) # <QuerySet[{'pwd': '123', 'user': 'root'}]> # json.dumps(v) #直接dumps会报错 data = serializers.serialize("json", v) #serializers方法 print(type(data)) # [{"model": "app01.user", "pk": 1, "fields": {"user": "root", "pwd": "123"}},] # < class 'str'> #类型 return HttpResponse('OK')
QuerySet类型列表、字典序列化
from app01 import models def index(request): v = models.User.objects.values_list('user','pwd') #QuerySet类型 print(v) # < QuerySet[('root', '123')] > # json.dumps(v) #直接dumps会报错 data = list(v) json.dumps(data) return HttpResponse('OK')
如果values()取出来的值包含时间类型或其他,则依然不能进行dumps,需要跟之前自定制序列化方法结合起来使用
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《第二十二章》
来源:https://www.cnblogs.com/lianzhilei/p/6370085.html