Question

我试图为与Google App引擎配合使用的WTForms制作一个独特的验证器。我有一个名为Question的模型和一个名为＆＃39; slug＆＃39;我需要独特。我在Stackoverflow上发现了这个非常好的例子，但是它使用了SQLAlchemy。我想看看是否有人可以帮我弄清楚如何使用Google App Engine而不是SQLAlchemy。

SQLAlchemy示例：Unique validator in WTForms with SQLAlchemy models

class Unique(object):
    """ validator that checks field uniqueness """
    def __init__(self, model, field, message=None):
        self.model = model
        self.field = field
        if not message:
            message = u'this element already exists'
        self.message = message

    def __call__(self, form, field):         
        check = self.model.query.filter(self.field == field.data).first()
        if check:
            raise ValidationError(self.message)

我认为＆＃34;检查＆＃34;需要更改行以使用GAE吗？但是我把这样的东西传递给对象并不是最好的。

我知道GAE查询会像...... Question.query（Question.slug = slug）

Answer 1

我能够做到这一点......

class UniqueValidator(object):
""" validator that checks field uniqueness """
def __init__(self, model, field, message=None):
    self.model = model
    self.field = field
    if not message:
        message = u'Existing element with the same value.'
    self.message = message

def __call__(self, form, field):
    existing = self.model.query(getattr(self.model,self.field) == field.data).get()
    if 'id' in form:
        id = int(form.id.data)
    else:
        id = None
    if existing and (id is None or id != existing.key.id()):
        raise ValidationError(self.message)

和

class QuestionEditForm(Form):
id = HiddenField('id')
question = TextField('Question', [validators.Required(),
                                  validators.Length(min=4, max=225)])
slug = TextField('Slug', validators = [validators.Required(),
                                       validators.length(max=200),
                                       UniqueValidator(
                                           Question,
                                           'slug',
                                           'Existing slug with the same value.'
                                       )])`enter code here`

适用于Google App Engine的唯一验证器（WTForms）

1 个答案: