使用Flask和Flask-MongoAlchemy时的WTForms语法

Question

I am testing out Python framework Flask and Flask-MongoAlchemy with MongoDB (of course). As I'm building multiple documents in my test app, I like to get the forms validated us WTForms .

Can anyone share with me an example on how to create the object references in a SelectField()?

class Parent(db.Document):
    title = db.StringField()
    description = db.StringField()

class Object(db.Document):
    parent = db.DocumentField(Parent)
    title = db.StringField()

@app.route('/object/new', methods=['GET', 'POST'])
def new_object():
    form = ObjectForm(obj=Object)
    form.parent.choices = [(???) for p in Parent.query.all()]  #<-- #1 correct syntax I like to understand, '(t._id, t.title)' didn't work.
    if form.validate_on_submit():
        form.save()
        return redirect(url_for('...'))
    return ....

class ObjectForm(wtf.Form):
    parent = wtf.SelectField(u'Parent')  #<-- #2 do I need to add anything special?

Any suggestion would be great! Or link to an online example. Thanks!

Answer 1

It's documented in WTForms documentation of the SelectField quoted here for convenience:

Select fields keep a choices property which is a sequence of (value, label) pairs.

I'm not sure about form.parent.choices syntax but the code looks like:

form.parent.choices = [(1, 'parent name 1'), (2, 'parent name 2'), (3, 'parent name 3'), (4, 'parent name 4')]