如何使用“编辑配置文件”路由的现有数据预先填写 Flask WTForms 表单？

Question

问题

每当我向属性form.[any-field-name].data写入数据时，写入的数据就会出现在表单中，这正是我想要的。但是，如果在呈现表单时对表单字段进行了更改，则新值似乎只存储在form.[any-field-name].raw_data 中。 form.[any-field-name].data 仅显示在用户有机会在字段中键入新值之前写入.data 的原始值。

显然我可以从.raw_data 获取结果，但这会破坏拥有表单验证库的目的。如何优雅地为用户预先填写表单字段，同时允许 Flask-WTForms 接受来自这些相同字段的新数据？

仅供参考：这与典型的“编辑个人资料”路线有点不同，因为每次编辑个人资料时，我的应用都会创建一个新的 UserVersion 记录。

Flask 路线

@app.route("/edit_user", methods=["GET", "POST"])
@login_required
def edit_user_self():
    """Edit user account that is currently logged in."""

    # get latest version of currently logged in user
    user_version = current_user.user_versions[0]

    # instantiate form and fill with existing data
    form = EditUserForm()
    form.username.data = user_version.username
    form.email.data = user_version.email
    form.addr_housenumber.data = user_version.addr_housenumber
    form.addr_street.data = user_version.addr_street
    form.addr_unit.data = user_version.addr_unit
    form.addr_city.data = user_version.addr_city
    form.addr_state.data = user_version.addr_state
    form.addr_postcode.data = user_version.addr_postcode

    if not form.validate_on_submit():
        return render_template("edit_user.html", form=form)
    else:
        # create new user version
        new_user_version = UserVersion(user=current_user,
            username = form.username.data,
            password = user_version.password,
            email = form.email.data,
            addr_housenumber = form.addr_housenumber.data,
            addr_street = form.addr_street.data,
            addr_unit = form.addr_unit.data,
            addr_city = form.addr_city.data,
            addr_state = form.addr_state.data,
            addr_postcode = form.addr_postcode.data
        )

        db.session.add(new_user_version)
        db.session.commit()

        flash("Changes saved")
        return redirect("/view_user")

表单模型

class EditUserForm(FlaskForm):
    username = StringField(
        "Username", validators=[DataRequired(message="Please enter a username")]
    )
    email = StringField(
        "Email",
        validators=[
            DataRequired(),
            Email(message="Please enter a valid email address"),
        ],
    )
    addr_housenumber = StringField("Housenumber", validators=[Length(max=80)])
    addr_housename = StringField("Housename", validators=[Length(max=80)])
    addr_conscriptionnumber = StringField(
        "Conscription Number", validators=[Length(max=80)]
    )
    addr_street = StringField("Street", validators=[Length(max=80)])
    addr_place = StringField("Place", validators=[Length(max=80)])
    addr_postcode = StringField("Postcode", validators=[Length(max=80)])
    addr_city = StringField("City", validators=[Length(max=80)])
    addr_country = StringField("Country", validators=[Length(max=80)])
    addr_hamlet = StringField("Hamlet", validators=[Length(max=80)])
    addr_suburb = StringField("Suburb", validators=[Length(max=80)])
    addr_subdistrict = StringField("Subdistrict", validators=[Length(max=80)])
    addr_province = StringField("Province", validators=[Length(max=80)])
    addr_state = StringField("State", validators=[Length(max=80)])
    addr_door = StringField("Door", validators=[Length(max=80)])
    addr_unit = StringField("Unit", validators=[Length(max=80)])
    addr_floor = StringField("Floor", validators=[Length(max=80)])
    addr_block = StringField("Block", validators=[Length(max=80)])
    submit = SubmitField("Save")

库版本

• Flask 1.1.2
• Flask WTForms 0.14.3
• Flask SQLAlchemy 2.1

Answer 1

你可以使用

your_form = FormObject(obj=your_instance)
# your_instance should have the same attributes that a FormObject has
# data will be stored in the html <input> value attribute

--------- 旧答案 我为此使用placeholder。您可以通过以下方式预先填写edit_user_self：

form.username.render_kw({'placeholder':user_version.email})

否则你可以像这样在 jinja 中做到这一点：

{{wtf.form_field(form.email,
 placeholder=user_version.email)}}

但要这样做，您应该将附加信息传递给 jinja 模板。

Answer 2

你需要交换你的逻辑。测试表单提交并首先验证，否则预填充并返回表单：

@app.route('/submit', methods=['GET', 'POST'])
def submit():
    form = MyForm()
    
    if form.validate_on_submit():
        #Validate and Process submitted form first:
        new_user_version = UserVersion(user=current_user,
                                       username = form.username.data)

        db.session.add(new_user_version)
        db.session.commit()
        return redirect('/success')

    user_version = current_user.user_versions[0]
    #Pre-populate your form here:
    form.username.data = user_version.username

    return render_template('submit.html', form=form)