Flask_SQLAlchemy 声称我的值不是布尔值？

Question

我运行进入如下错误：

  File "/home/sandbox/.local/lib/python3.6/site-packages/sqlalchemy/sql/sqltypes.py", line 1973, in _strict_as_bool
    raise TypeError("Not a boolean value: %r" % (value,))
sqlalchemy.exc.StatementError: (builtins.TypeError) Not a boolean value: 'True'
[SQL: INSERT INTO projects (status) VALUES (?)]
[parameters: [{'status': 'True'}]]
127.0.0.1 - - [12/May/2022 21:53:22] "POST / HTTP/1.1" 500 -

我在我的主要路线上尝试了从 0|1、FALSE|TRUE、False|True 开始的所有运行布尔值输入。我还尝试在引号之间放入布尔值。我做错了什么？

import os
from flask import Flask
from flask import render_template
from flask import request
from flask import redirect
from flask_sqlalchemy import SQLAlchemy

database_file = "sqlite:///DATA/DATA.db"

app = Flask(__name__)
app.config["SQLALCHEMY_DATABASE_URI"] = database_file
db = SQLAlchemy(app)

class Projects(db.Model):
    __tablename__="projects"
    status = db.Column(db.Boolean, default=False, nullable=False, primary_key=True)

    def __repr__(self):
        return f"projects('{self.status}')"

db.create_all()

@app.route("/", methods=["GET", "POST"])
def home():
    if request.form:
        status = Projects(status=request.form.get("status"))
        db.session.add(status)
        db.session.commit()
    return render_template("home.html")

我的基本路线如下

{% extends "layout.html" %}

{% block body %}
<h1> Add new project </h1>
    <form method="POST" action="/">
      <select name="status" placeholder="Project Status">
        <option value=False> Not Active  </option>
        <option value=True> Active </option>
        </select>
      <input type="submit" value="Register Data">
    </form>

{% endblock %}

Answer 1

您遇到的问题是表单提交将选择值作为字符串返回 - 字面上 "True" 或 "False" - 而 SQL 驱动程序需要布尔类型。

有一个Python标准库函数distutils.util.strtobool which can safely convert a representation of a true or false value into a boolean type, raising a ValueError if someone puts something naughty into your API (this is much preferred to using eval() which shouldn't be used on untrusted input).

我会将您的路线更新为如下内容：

# At the top
from distutils.util import strtobool

@app.route("/", methods=["GET", "POST"])
def home():
    if request.form:
        try:
            form_status = strtobool(request.form.get("status").lower())
            status = Projects(status=form_status)
            db.session.add(status)
            db.session.commit()
        except ValueError:
            # Handle the error - e.g. flash a message to the user
            flash("Invalid input")
    return render_template("home.html")

strtobool 需要注意的一件事是 distutils 现在已从 Python 3.10 开始弃用，并将在 3.12 中删除。显示了它作为一个函数的实现，这是非常简单的，因此对于任何预计会持续到 Python 3.12.

之后的代码，都值得将其包含在您自己的实用程序函数中

Flask_SQLAlchemy 声称我的值不是布尔值？

Flask_SQLAlchemy is claiming my value is not boolean?

python

flask

sqlalchemy

flask-sqlalchemy