Django基础11（Django中form表单）
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Django基础11（Django中form表单）
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Form介紹?
之前在HTML頁面中利用form表單向后端提交數據時，都會寫一些獲取用戶輸入的標簽并且用form標簽把它們包起來。
與此同時我們在好多場景下都需要對用戶的輸入做校驗，比如校驗用戶是否輸入，輸入的長度和格式等正不正確。如果用戶輸入的內容有錯誤就需要在頁面上相應的位置顯示顯示對應的錯誤信息.。
Django form組件就實現了上面所述的功能。
總結一下，其實form組件的主要功能如下:
- 生成頁面可用的HTML標簽
- 對用戶提交的數據進行校驗
- 保留上次輸入內容
普通的登錄
views.py
def login(request):error_msg = ""if request.method == "POST":username = request.POST.get("username")pwd = request.POST.get("pwd")if username == "SKS" and pwd == "1366768":return HttpResponse("OK")else:error_msg = "用戶名或密碼錯誤"return render(request, "login.html", {"error_msg": error_msg})login.html
<!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><meta http-equiv="x-ua-compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>login</title><style>.error {color: red;}</style> </head> <body> <form action="/login/" method="post">{% csrf_token %}<p><label for="username">用戶名</label><input type="text" name="username" id="username"></p><p><label for="pwd">密碼</label><input type="password" name="pwd" id="pwd"><span class="error"></span></p><p><input type="submit"><span class="error">{{ error_msg }}</span></p> </form> </body> </html>使用form組件
views.py
先定義好一個LoginForm類。
# 定義一個form組件類 class LoginForm(forms.Form):# 驗證的字段及條件username = forms.CharField(min_length=8, label="用戶名")pwd = forms.CharField(min_length=6, label="密碼")def login2(request):# 存儲錯誤信息error_msg = ""# 實例化對象form_obj = LoginForm()# 判斷前端頁面請求是否是POST請求if request.method == "POST":# 將數據傳入form組件類中form_obj = LoginForm(request.POST)# 存儲的正確信息if form_obj.is_valid():username = form_obj.cleaned_data.get("username")pwd = form_obj.cleaned_data.get("pwd")if username == "SKS" and pwd == "1866768":return HttpResponse("OK")else:error_msg = "用戶名或密碼錯誤"return render(request, "login2.html", {"form_obj": form_obj, "error_msg": error_msg})login2.html
<!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><meta http-equiv="x-ua-compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>login</title><style>.error {color: red;}</style> </head> <body> <form action="/login2/" method="post" novalidate>{% csrf_token %}<p>{{ form_obj.username.label }}{{ form_obj.username }}<span class="error">{{ form_obj.username.errors.0 }}</span></p><p>{{ form_obj.pwd.label }}{{ form_obj.pwd }}<span class="error">{{ form_obj.pwd.errors.0 }}</span></p><p><input type="submit"><span class="error">{{ error_msg }}</span></p> </form> </body> </html>看網頁效果發現 也驗證了form的功能：
? 前端頁面是form類的對象生成的? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -->生成HTML標簽功能
? 當用戶名和密碼輸入為空或輸錯之后 頁面都會提示? ? ? ? -->用戶提交校驗功能
? 當用戶輸錯之后 再次輸入 上次的內容還保留在input框? ?-->保留上次輸入內容
Form組件
常用字段演示
initial
初始值，input框里面的初始值。
# 定義一個類繼承forms.Form class LoginForm(forms.Form):username = forms.CharField(min_length=6,label="用戶名",initial="hewm" # 設置默認值方法 )pwd = forms.CharField(min_length=6, label="密碼")error_messages
重寫錯誤信息。
class LoginForm(forms.Form):username = forms.CharField(min_length=6,label="用戶名",initial="hewm",# 重寫錯誤提示信息error_messages={"required": "不能為空","invalid": "格式錯誤","min_length": "用戶名最短6位"})pwd = forms.CharField(min_length=6, label="密碼")password
class LoginForm(forms.Form):...pwd = forms.CharField(min_length=6,label="密碼",# 密文方法 參數attrs：樣式類 render_value=驗證失敗是否回填 widget=forms.widgets.PasswordInput(attrs={'class': 'c1'}, render_value=True) )
radioSelect
單radio值為字符串
class LoginForm(forms.Form):username = forms.CharField(min_length=8,label="用戶名",initial="hewm",error_messages={"required": "不能為空","invalid": "格式錯誤","min_length": "用戶名最短8位"})pwd = forms.CharField(min_length=6, label="密碼")gender = forms.fields.ChoiceField(choices=((1, "男"), (2, "女"), (3, "保密")),label="性別",initial=3,widget=forms.widgets.RadioSelect)單選Select
class LoginForm(forms.Form):...hobby = forms.fields.ChoiceField(choices=((1, "籃球"), (2, "足球"), (3, "乒乓球"), ),label="愛好",initial=3,widget=forms.widgets.Select)多選Select
class LoginForm(forms.Form):...hobby = forms.fields.MultipleChoiceField(choices=((1, "籃球"), (2, "足球"), (3, "雙色球"), ),label="愛好",initial=[1, 3],widget=forms.widgets.SelectMultiple)單選checkbox
class LoginForm(forms.Form):...keep = forms.fields.ChoiceField(label="是否記住密碼",initial="checked",widget=forms.widgets.CheckboxInput)多選checkbox
class LoginForm(forms.Form):...hobby = forms.fields.MultipleChoiceField(choices=((1, "籃球"), (2, "足球"), (3, "雙色球"),),label="愛好",initial=[1, 3],widget=forms.widgets.CheckboxSelectMultiple)關于choice的注意事項：
在使用選擇標簽時，需要注意choices的選項可以從數據庫中獲取，但是由于是靜態字段 ***獲取的值無法實時更新***，那么需要自定義構造方法從而達到此目的。
方式一：
from django.forms import Form from django.forms import widgets from django.forms import fieldsclass MyForm(Form):user = fields.ChoiceField(# choices=((1, '上海'), (2, '北京'),),initial=2,widget=widgets.Select)# 初始化init方法 （執行時間為類實例化時執行）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().values_list('id','caption')方法二
from django import forms from django.forms import fields from django.forms import models as form_modelclass FInfo(forms.Form):authors = form_model.ModelMultipleChoiceField(queryset=models.NNewType.objects.all())# authors = form_model.ModelChoiceField(queryset=models.NNewType.objects.all()) Fieldrequired=True, 是否允許為空widget=None, HTML插件label=None, 用于生成Label標簽或顯示內容initial=None, 初始值help_text='', 幫助信息(在標簽旁邊顯示)error_messages=None, 錯誤信息 {'required': '不能為空', 'invalid': '格式錯誤'}show_hidden_initial=False, 是否在當前插件后面再加一個隱藏的且具有默認值的插件（可用于檢驗兩次輸入是否一直）validators=[], 自定義驗證規則localize=False, 是否支持本地化disabled=False, 是否可以編輯label_suffix=None Label內容后綴CharField(Field)max_length=None, 最大長度min_length=None, 最小長度strip=True 是否移除用戶輸入空白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, 總長度decimal_places=None, 小數位長度BaseTemporalField(Field)input_formats=None 時間格式化 DateField(BaseTemporalField) 格式：2015-09-01 TimeField(BaseTemporalField) 格式：11:12 DateTimeField(BaseTemporalField)格式：2015-09-01 11:12DurationField(Field) 時間間隔：%d %H:%M:%S.%f...RegexField(CharField)regex, 自定制正則表達式max_length=None, 最大長度min_length=None, 最小長度error_message=None, 忽略，錯誤信息使用 error_messages={'invalid': '...'}EmailField(CharField) ...FileField(Field)allow_empty_file=False 是否允許空文件ImageField(FileField) ...注：需要PIL模塊，pip3 install Pillow以上兩個字典使用時，需要注意兩點：- form表單中 enctype="multipart/form-data"- view函數中 obj = MyForm(request.POST, request.FILES)URLField(Field)...BooleanField(Field) ...NullBooleanField(BooleanField)...ChoiceField(Field)...choices=(), 選項，如：choices = ((0,'上海'),(1,'北京'),)required=True, 是否必填widget=None, 插件，默認select插件label=None, Label內容initial=None, 初始值help_text='', 幫助提示ModelChoiceField(ChoiceField)... django.forms.models.ModelChoiceFieldqueryset, # 查詢數據庫中的數據empty_label="---------", # 默認空顯示內容to_field_name=None, # HTML中value的值對應的字段limit_choices_to=None # ModelForm中對queryset二次篩選 ModelMultipleChoiceField(ModelChoiceField)... django.forms.models.ModelMultipleChoiceFieldTypedChoiceField(ChoiceField)coerce = lambda val: val 對選中的值進行一次轉換empty_value= '' 空值的默認值MultipleChoiceField(ChoiceField)...TypedMultipleChoiceField(MultipleChoiceField)coerce = lambda val: val 對選中的每一個值進行一次轉換empty_value= '' 空值的默認值ComboField(Field)fields=() 使用多個驗證，如下：即驗證最大長度20，又驗證郵箱格式fields.ComboField(fields=[fields.CharField(max_length=20), fields.EmailField(),])MultiValueField(Field)PS: 抽象類，子類中可以實現聚合多個字典去匹配一個值，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) 文件選項，目錄下文件顯示在頁面中path, 文件夾路徑match=None, 正則匹配recursive=False, 遞歸下面的文件夾allow_files=True, 允許文件allow_folders=False, 允許文件夾required=True,widget=None,label=None,initial=None,help_text=''GenericIPAddressFieldprotocol='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時候，可解析為192.0.2.1， PS：protocol必須為both才能啟用SlugField(CharField) 數字，字母，下劃線，減號（連字符）...UUIDField(CharField) uuid類型Django form內置字段 內置字段校驗
方式一：
from django.forms import Form from django.forms import widgets from django.forms import fields from django.core.validators import RegexValidatorclass MyForm(Form):user = fields.CharField(validators=[RegexValidator(r'^[0-9]+$', '請輸入數字'), RegexValidator(r'^159[0-9]+$', '數字必須以159開頭')],)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# 自定義驗證規則 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('手機號碼格式錯誤')class PublishForm(Form):title = fields.CharField(max_length=20,min_length=5,error_messages={'required': '標題不能為空','min_length': '標題最少為5個字符','max_length': '標題最多為20個字符'},widget=widgets.TextInput(attrs={'class': "form-control",'placeholder': '標題5-20個字符'}))# 使用自定義驗證規則phone = fields.CharField(validators=[mobile_validate, ],error_messages={'required': '手機不能為空'},widget=widgets.TextInput(attrs={'class': "form-control",'placeholder': u'手機號碼'}))email = fields.EmailField(required=False,error_messages={'required': u'郵箱不能為空','invalid': u'郵箱格式錯誤'},widget=widgets.TextInput(attrs={'class': "form-control", 'placeholder': u'郵箱'}))補充進階
應用Bootstrap樣式
<!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><meta http-equiv="x-ua-compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css"><title>login</title> </head> <body> <div class="container"><div class="row"><form action="/login2/" method="post" novalidate class="form-horizontal">{% csrf_token %}<div class="form-group"><label for="{{ form_obj.username.id_for_label }}"class="col-md-2 control-label">{{ form_obj.username.label }}</label><div class="col-md-10">{{ form_obj.username }}<span class="help-block">{{ form_obj.username.errors.0 }}</span></div></div><div class="form-group"><label for="{{ form_obj.pwd.id_for_label }}" class="col-md-2 control-label">{{ form_obj.pwd.label }}</label><div class="col-md-10">{{ form_obj.pwd }}<span class="help-block">{{ form_obj.pwd.errors.0 }}</span></div></div><div class="form-group"><label class="col-md-2 control-label">{{ form_obj.gender.label }}</label><div class="col-md-10"><div class="radio">{% for radio in form_obj.gender %}<label for="{{ radio.id_for_label }}">{{ radio.tag }}{{ radio.choice_label }}</label>{% endfor %}</div></div></div><div class="form-group"><div class="col-md-offset-2 col-md-10"><button type="submit" class="btn btn-default">注冊</button></div></div></form></div> </div><script src="/static/jquery-3.2.1.min.js"></script> <script src="/static/bootstrap/js/bootstrap.min.js"></script> </body> </html>Django form應用Bootstrap樣式簡單示例 代碼示例批量添加樣式
可通過重寫form類的init方法來實現。
class LoginForm(forms.Form):username = forms.CharField(min_length=8,label="用戶名",initial="張三",error_messages={"required": "不能為空","invalid": "格式錯誤","min_length": "用戶名最短8位"}...def __init__(self, *args, **kwargs):super(LoginForm, self).__init__(*args, **kwargs)for field in iter(self.fields):self.fields[field].widget.attrs.update({'class': 'form-control'})批量添加樣式 代碼示例源碼簡易剖析
views.py文件
def register(request):if request.method == "POST":res = {"user": None, "error_dict": None}form = RegForm(request.POST)# 存儲驗證通過的信息.is_valid()（源碼剖析開始點）if form.is_valid():user = form.cleaned_data.get("user")pwd = form.cleaned_data.get("pwd")email = form.cleaned_data.get("email")avatar = request.FILES.get("avatar")print(user,pwd,email,avatar)print("="*120)if avatar:user = UserInfo.objects.create_user(username=user, password=pwd, email=email, avatar=avatar)else:user = UserInfo.objects.create_user(username=user, password=pwd, email=email)res["user"] = user.usernameelse:print(form.errors)res["error_dict"] = form.errorsreturn JsonResponse(res)form = RegForm()return render(request, 'register.html', locals()) views.py點擊進入forms.py文件
def is_valid(self):"""Returns True if the form has no errors. Otherwise, False. If errors arebeing ignored, returns False."""# 含義：返回布爾值，只要有數據并且沒有錯誤信息就返回Truereturn self.is_bound and not self.errors forms.py點擊self.errors進入forms.py文件中
# 靜態方法 @propertydef errors(self):"Returns an ErrorDict for the data provided for the form"# 判斷self._errors是否為空if self._errors is None:self.full_clean()return self._errors def errors(self):點擊._errors進入forms.py文件中
def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,initial=None, error_class=ErrorList, label_suffix=None,empty_permitted=False, field_order=None, use_required_attribute=None, renderer=None):self.is_bound = data is not None or files is not Noneself.data = data or {}self.files = files or {}self.auto_id = auto_idif prefix is not None:self.prefix = prefixself.initial = initial or {}self.error_class = error_class# Translators: This is the default suffix added to form field labelsself.label_suffix = label_suffix if label_suffix is not None else _(':')self.empty_permitted = empty_permitted# 默認值為Noneself._errors = None # Stores the errors after clean() has been called.# The base_fields class attribute is the *class-wide* definition of# fields. Because a particular *instance* of the class might want to# alter self.fields, we create self.fields here by copying base_fields.# Instances should always modify self.fields; they should not modify# self.base_fields.self.fields = copy.deepcopy(self.base_fields)self._bound_fields_cache = {}self.order_fields(self.field_order if field_order is None else field_order) __init__方法返回def errors(self):
@propertydef errors(self):"Returns an ErrorDict for the data provided for the form"if self._errors is None:self.full_clean() # 這個方法才是真正幫忙執行效驗操作return self._errors 返回errors方法點擊
def full_clean(self):"""Cleans all of self.data and populates self._errors andself.cleaned_data."""self._errors = ErrorDict() # 定義一個保存錯誤信息字典if not self.is_bound: # Stop further processing.returnself.cleaned_data = {}# If the form is permitted to be empty, and none of the form data has# changed from the initial data, short circuit any validation.if self.empty_permitted and not self.has_changed():returnself._clean_fields()self._clean_form()self._post_clean() full_clean方法點擊self._clean_fields()進入
def _clean_fields(self):for name, field in self.fields.items():# self.fields：類似一個字典#for name, field in self.fields.items():解釋分別獲取self.fields的鍵和值分別賦值給 name, field# value_from_datadict() gets the data from the data dictionaries.# Each widget type knows how to retrieve its own data, because some# widgets split data over several HTML fields.if field.disabled:value = self.get_initial_for_field(field, name)else:value = field.widget.value_from_datadict(self.data, self.files, self.add_prefix(name))try:if isinstance(field, FileField): # 如果是文件字段initial = self.get_initial_for_field(field, name)value = field.clean(value, initial)else: # field.clean(value) 之后Dbug運行檢查，為循環判斷錯誤value = field.clean(value)self.cleaned_data[name] = valueif hasattr(self, 'clean_%s' % name):value = getattr(self, 'clean_%s' % name)()self.cleaned_data[name] = valueexcept ValidationError as e:self.add_error(name, e) def _clean_fields(self):方法06后期追加
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轉載于:https://www.cnblogs.com/L5251/articles/8792927.html
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