小编pra*_*659的帖子

我已经编写了下面的代码来处理整个应用程序中的嵌套事务。但是当它回滚一次之后，所有事务都会回滚，直到我重新启动应用程序为止。

# method_a starts a transaction and calls method_b
def method_a():
    session.begin(subtransactions=True)
    try:
        method_b()
        session.commit()  # transaction is committed here
    except:
        session.rollback() # rolls back the transaction


# method_b also starts a transaction, but when
# called from method_a participates in the ongoing
# transaction.
def method_b():
    session.begin(subtransactions=True)
    try:
        session.add(SomeObject('bat', 'lala'))
        session.commit()  # transaction is not committed yet
    except:
        session.rollback() # rolls back the transaction, in this case
                       # the one that was initiated in method_a().


# create a Session …

我已经使用flask框架配置了python服务器.现在我想从桌面应用程序向服务器发送请求.我的服务器位置是:http://127.0.0.1:5000/

我编写的代码可以在浏览器中运行,但我想从我的桌面应用程序访问该代码.

import flask,flask.views import os import functools 
app=flask.Flask(__name__)

app.secret_key="xyz" users={'pravin':'abc'}
class Main(flask.views.MethodView):
    def get(self):
        return flask.render_template('index.html')
    def post(self):
        if 'logout' in flask.request.form:
            flask.session.pop('username',None)
            return flask.redirect(flask.url_for('index'))
        required=['username','passwd']
        for r in required:
        if r not in flask.request.form:
            flask.flash("Error: {0} is required.".format(r))
            return flask.redirect(flask.url_for('index'))

        username=flask.request.form['username']
        password=flask.request.form['passwd']
        if username in users and users[username]==password:
            flask.session['username']=username
        else:
            flask.flash("Username doesn`t exist or incorrect password.")

        return flask.redirect(flask.url_for('index'))

app.add_url_rule("/",view_func=Main.as_view("index"),methods=["GET","POST"])
app.debug=True
app.run()

form_shift 是表格名称

tblSession是QTableWidget对象

shift_id=form_shift.tblSession.item(1,0).text()

错误：

AttributeError: 'NoneType' object has no attribute 'text'