python-3.x - 如何将 Bootstrap 验证添加到 WTForms

Question

我正在将 WTForms 与 Flask 结合使用，我想集成 Bootstrap Form Validation对于我的表单中的错误。我有一个基本的登录表单设置，如下所示:

class LoginForm(FlaskForm):
    """Login form."""

    email = EmailField(
        "Email Address", validators=[DataRequired(), Email(), Length(min=6, max=40)]
    )
    password = PasswordField(
        "Password", validators=[DataRequired()]
    )

    def __init__(self, *args, **kwargs):
        """Create instance."""
        super(LoginForm, self).__init__(*args, **kwargs)
        self.user = None

    def validate(self):
        """Validate the form."""
        initial_validation = super(LoginForm, self).validate()
        if not initial_validation:
            return False

        self.user = User.query.filter_by(email=self.email.data).first()
        if not self.user:
            self.email.errors.append("Unknown email address!")
            return False

        if not self.user.check_password(self.password.data):
            self.password.errors.append("Invalid password!")
            return False

        if not self.user.verified:
            self.email.errors.append("Please verify your email address!")
            return False
        return True

我的 login.html 模板设置如下:

<form method="POST" action="{{ url_for('public.login') }}" role="form">
                  {{ form.csrf_token }}
                  <div class="form-group">
                    {{ form.email.label(class_="form-control-label") }}
                    <div class="input-group input-group-merge">
                      <div class="input-group-prepend">
                        <span class="input-group-text"><i class="fas fa-user"></i></span>
                      </div>
                      {{ form.email(placeholder="name@example.com", class_="form-control") }}
                    </div>
                  </div>
                  <div class="form-group mb-4">
                    <div class="d-flex align-items-center justify-content-between">
                      <div>
                        {{ form.password.label(class_="form-control-label") }}
                      </div>
                      <div class="mb-2">
                        <a href="{{ url_for('public.recover') }}" class="small text-muted text-underline--dashed border-primary">Lost password?</a>
                      </div>
                    </div>
                    <div class="input-group input-group-merge">
                      <div class="input-group-prepend">
                        <span class="input-group-text"><i class="fas fa-key"></i></span>
                      </div>
                      {{ form.password(placeholder="Password", class_="form-control") }}
                      <div class="input-group-append" onclick="togglePassword()">
                        <span class="input-group-text">
                          <i class="fas fa-eye"></i>
                        </span>
                      </div>
                    </div>
                  </div>
                  <div class="row mt-4">
                    <div class="col-md-auto mt-1 mb-2" align="center">
                      <button type="submit" class="btn btn-sm btn-primary btn-icon rounded-pill">
                        <span class="btn-inner--text">Sign in</span>
                        <span class="btn-inner--icon"><i class="fas fa-long-arrow-alt-right"></i></span>
                      </button>
                    </div>
                    <div class="col-md-auto text-center mt-2">
                      <p class="text-secondary-dark">or</p>
                      </div>
                    <div class="col-md-auto" align="center">
                      <button type="button" class="btn btn-md btn-secondary btn-icon-only">
                          <span class="btn-inner--icon">
                              <i class="fab fa-google"></i>
                          </span>
                      </button>

                      <button type="button" class="btn btn-md btn-secondary btn-icon-only">
                          <span class="btn-inner--icon">
                              <i class="fab fa-linkedin"></i>
                          </span>
                      </button>
                    </div>
                  </div>
                </form>

我想显示我使用 WTForms 验证的错误，但我不确定如何将原始表单元素的类更改为 is-invalid或 is-valid ，以及如何为每个错误创建标签。我研究过宏，但它们似乎也无法修改表单元素。

有人可以指出我正确的方向吗？

Answer 1

我遇到了同样的问题，我想避免使用任何第三个包(flask-bootstrap)，我想出了这个简单的解决方案:

<div class="form-group">
  {{ form.email.label }} <span class="text-danger">*</span>

  {# her #}
  {{ form.email(class="form-control" + (" is-invalid" if form.email.errors else "") + " rounded-0 shadow-none", **{"placeholder": "Your Email", "aria-describedby": "emailHelp", "autocomplete": "off"}) }}


  <small id="emailHelp" class="form-text text-muted">We'll never share your data with anyone else.</small>

  {% if form.email.errors %}
    {% for error in form.email.errors %}
      <div class="invalid-feedback">{{ error }}</div>
    {% endfor %}
  {% endif %}
</div>

诀窍是使用一个简单的 三元表达式结合 字符串连接 .