摘要：你打了個(gè)響指然后開始致力于你想寫的棒極了的網(wǎng)絡(luò)應(yīng)用程序你寫完一些頁面最后你需要著手處理令人討厭的任務(wù)處理和驗(yàn)證表單輸入進(jìn)入開始但是為什么我需要另一個(gè)框架呢好吧一些網(wǎng)絡(luò)應(yīng)用程序框架采用數(shù)據(jù)庫模型和表單處理相結(jié)合的方法同時(shí)這對很基本的創(chuàng)建更新視

你打了個(gè)響指, 然后開始致力于你想寫的棒極了的 Python 網(wǎng)絡(luò)應(yīng)用程序. 你寫完一些頁面, 最后你需要著手處理令人討厭的任務(wù)：處理和驗(yàn)證表單輸入. 進(jìn)入（開始）WTForms.

但是, 為什么我需要另一個(gè)框架呢？好吧, 一些網(wǎng)絡(luò)應(yīng)用程序框架采用數(shù)據(jù)庫模型和表單處理相結(jié)合的方法. 同時(shí)這對很基本的創(chuàng)建/更新視圖函數(shù)是很方便的, 可能性是不是每個(gè)你需要的表單都能直接映射到一個(gè)數(shù)據(jù)庫模型. 也許你已經(jīng)使用通用的表單處理框架, 只是你想要定制這些表單域的 HTML 代碼生成, 并且定義屬于你的驗(yàn)證器.

使用 WTForms, 你能生成屬于你的表單域的 HTML 代碼, 此外我們允許你在模板中定制它. 這允許你維持獨(dú)立的代碼和展現(xiàn), 并把這些凌亂的參數(shù)保留在 Python 代碼之外. 因?yàn)槲覀儬幦∷神詈? 同樣的, 你應(yīng)該可以在你喜歡的任意的模板引擎中這么做.

  
備注: 本人未過四級, 翻譯水平有限, 歡迎指正.

安裝 WTForms 最簡單的方式是使用 easy_install 和 pip:

basheasy_install WTForms
# or
pip install WTForms

pythonfrom wtforms import Form, BooleanField, StringField, validators

class RegistrationForm(Form):
    username     = StringField("Username", [validators.Length(min=4, max=25)])
    email        = StringField("Email Address", [validators.Length(min=6, max=35)])
    accept_rules = BooleanField("I accept the site rules", [validators.InputRequired()])

pythonclass ProfileForm(Form):
    birthday  = DateTimeField("Your Birthday", format="%m/%d/%y")
    signature = TextAreaField("Forum Signature")

class AdminProfileForm(ProfileForm):
    username = StringField("Username", [validators.Length(max=40)])
    level    = IntegerField("User Level", [validators.NumberRange(min=0, max=10)])

pythondef register(request):
    form = RegistrationForm(request.POST)
    if request.method == "POST" and form.validate():
        user = User()
        user.username = form.username.data
        user.email = form.email.data
        user.save()
        redirect("register")
    return render_response("register.html", form=form)

pythondef edit_profile(request):
    user = request.current_user
    form = ProfileForm(request.POST, user)
    if request.method == "POST" and form.validate():
        form.populate_obj(user)
        user.save()
        redirect("edit_profile")
    return render_response("edit_profile.html", form=form)

python>>> from wtforms import Form, StringField, validators
>>> class UsernameForm(Form):
...     username = StringField("Username", [validators.Length(min=5)], default=u"test")
...
>>> form = UsernameForm()
>>> form["username"]

>>> form.username.data
u"test"
>>> form.validate()
False
>>> form.errors
{"username": [u"Field must be at least 5 characters long."]}

python>>> form2 = UsernameForm(username=u"Robert")
>>> form2.data
{"username": u"Robert"}
>>> form2.validate()
True

pythondef change_username(request):
    user = request.current_user
    form = ChangeUsernameForm(request.POST, user, username="silly")
    if request.method == "POST" and form.validate():
        user.username = form.username.data
        user.save()
        return redirect("change_username")
    return render_response("change_username.html", form=form)

pythonclass ChangeEmailForm(Form):
    email = StringField("Email", [validators.Length(min=6, max=120), validators.Email()])

pythonclass ChangeEmailForm(Form):
    email = StringField("Email", [
        validators.Length(min=6, message=_(u"Little short for an email address?")),
        validators.Email(message=_(u"That"s not a valid email address."))
    ])

python>>> from wtforms import Form, StringField
>>> class SimpleForm(Form):
...   content = StringField("content")
...
>>> form = SimpleForm(content="foobar")
>>> str(form.content)
""
>>> unicode(form.content)
u""

python>>> form.content(style="width: 200px;", class_="bar")
u""

pythonclass LoginForm(Form):
    username = StringField("Username")
    password = PasswordField("Password")

form = LoginForm()

jinja

    
{{ form.username.label }}: {{ form.username(class="css_class") }}
    
{{ form.password.label }}: {{ form.password() }}

django{% load wtforms %}

    

        {{ form.username.label }}:
        {% form_field form.username class="css_class" %}
    
    

        {{ form.password.label }}:
        {{ form.password }}
    

html

    

        Username:
        
    
    

        Password:
        
    

jinja


    
{{ form.username.label }}: {{ form.username(class="css_class") }}
    {% if form.username.errors %}
        
{% for error in form.username.errors %}
{{ error }}
{% endfor %}
    {% endif %}

    
{{ form.password.label }}: {{ form.password() }}
    {% if form.password.errors %}
        
{% for error in form.password.errors %}
{{ error }}
{% endfor %}
    {% endif %}

jinja{% if form.errors %}
    

        {% for field_name, field_errors in form.errors|dictsort if field_errors %}
            {% for error in field_errors %}
                
{{ form[field_name].label }}: {{ error }}
            {% endfor %}
        {% endfor %}
    
{% endif %}

pythonfrom wtforms.validators import ValidationError

def is_42(form, field):
    if field.data != 42:
        raise ValidationError("Must be 42")

class FourtyTwoForm(Form):
    num = IntegerField("Number", [is_42])

pythonclass FourtyTwoForm(Form):
    num = IntegerField("Number")

    def validate_num(form, field):
        if field.data != 42:
            raise ValidationError(u"Must be 42")