如何将查询结果发送到WTForm字段？

我使用带有多对多表的SQLalchemy来管理博客帖子标签.我需要帮助将标记值呈现到TextArea表单字段中,以便对其进行编辑.现在,当我渲染时,我看到了查询查询.

模型

Tag和Post之间的关系在`tags’中定义

class Tag(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(50), unique=True)
url = db.Column(db.String(120), unique=True)

def __init__(self, name, url):
    self.name = name
    self.url = url

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(80))
    body = db.Column(db.Text)
    pub_date = db.Column(db.DateTime)
    tags = db.relationship('Tag', secondary=posts_tags, backref='posts', lazy='dynamic')


class Tag(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50), unique=True)
    url = db.Column(db.String(120), unique=True)

我的问题是在WTF中渲染标签字段.我在字段中显示查询而不是结果.

我看到两种方法可以修复,但我不知道该怎么办….

a.)在视图中,通过标签进行交互并显示值.
b.)在自定义字段中,以某种方式传递post id并在rend字段之前运行查询.像这样……

Field Hack可行,但知道如何动态地将Post ID传递给该字段.*

class TagListField(Field):
    widget = TextArea()

    def _value(self):
        q = Post.query.join(posts_tags, (posts_tags.c.post_id == {{ NEED HELP HERE}}))
        taglist = []
        for p in q:
            for t in p.tags:
                taglist.append(t.name)
        taglist
        return ", ".join(taglist)

    def process_formdata(self, valuelist):
        if valuelist:
            self.data = [x.strip() for x in valuelist[0].split(',')]
        else:
            self.data = []

希望看到视图和字段选项……谢谢并提前…

解决方法:

您正在错误地使用_value,它用于显示数据,而不是用于设置数据.

数据在表单上设置,而不是在字段上设置.

class TagListField(Field):
    widget = TextInput()

    def _value(self):
        if self.data:
            return u', '.join(self.data)
        else:
            return u''

    def process_formdata(self, valuelist):
        if valuelist:
            self.data = [x.strip() for x in valuelist[0].split(',')]
        else:
            self.data = []


class PostForm(Form):
    title = StringField(u'title', validators=[DataRequired()])
    body = StringField(u'Text', widget=TextArea())
    pub_date = DateTimeField(u'date create')
    topic = QuerySelectField(query_factory=enabled_topics, allow_blank=True)
    tags = TagListField(u'Tags') # here you use your custom field

    # a method to set the tags
    def fill_tags(self, tags):
        self.tags.data = tags
    # and from the view that is creating the form you send the list of tags

在你看来：

form = PostForm()
form.fill_tags([tag.name for tag in post.tags.all()])

标签：flask-wtforms,wtforms,python,sqlalchemy,flask
来源： https://codeday.me/bug/20191003/1846722.html