Flask-WTFform：Flash不显示错误

Question

我试图刷新WTForm验证错误。我发现this snippet并稍微修改了它：

def flash_errors(form): 
    """Flashes form errors""" 
    for field, errors in form.errors.items(): 
     for error in errors: 
      flash(u"Error in the %s field - %s" % (
       getattr(form, field).label.text, 
       error 
      ), 'error') 

这里是我的表单类中的一种：

class ContactForm(Form): 
    """Contact form""" 
    # pylint: disable=W0232 
    # pylint: disable=R0903 
    name = TextField(label="Name", validators=[Length(max=35), Required()]) 
    email = EmailField(label="Email address", 
         validators=[Length(min=6, max=120), Email()]) 
    message = TextAreaField(label="Message", 
          validators=[Length(max=1000), Required()]) 
    recaptcha = RecaptchaField() 

，并查看：

@app.route("/contact/", methods=("GET", "POST")) 
def contact(): 
    """Contact view""" 
    form = ContactForm() 
    flash_errors(form) 
    if form.validate_on_submit(): 
     sender = "%s <%s>" % (form.name.data, form.email.data) 
     subject = "Message from %s" % form.name.data 
     message = form.message.data 
     body = render_template('emails/contact.html', sender=sender, 
           message=message) 
     email_admin(subject, body) 
     flash("Your message has been sent. Thank you!", "success") 

    return render_template("contact.html", 
          form=form) 

然而，没有错误在验证失败一闪而过。我知道我的表单和模板工作正常，因为当数据有效时，我的成功消息闪烁。哪里不对？

Answer 1

有没有错误，但因为你还没有处理的形式，但

尝试把flash_errors上validate_on_submit方法

@app.route("/contact/", methods=("GET", "POST")) 
def contact(): 
    """Contact view""" 
    form = ContactForm() 
    if form.validate_on_submit(): 
     sender = "%s <%s>" % (form.name.data, form.email.data) 
     subject = "Message from %s" % form.name.data 
     message = form.message.data 
     body = render_template('emails/contact.html', sender=sender, 
           message=message) 
     email_admin(subject, body) 
     flash("Your message has been sent. Thank you!", "success") 
    else: 
     flash_errors(form) 

    return render_template("contact.html", 
         form=form)