我目前正在学习 transactions我收到此错误消息:
BadRequestError: Nested transactions are not supported
我不知道如何解决这个问题。任何帮助将不胜感激。
main.py
import webapp2
import jinja2
import os
import datetime
from google.appengine.ext import db
jinja_environment = jinja2.Environment(
loader=jinja2.FileSystemLoader(os.path.dirname(__file__)))
class MainPage(webapp2.RequestHandler):
def get(self):
transaction_status = create_message_txn("Python_Board", "message name", "Message Title", "Here is the message text")
message = Message.all()
template_values = {
'transaction_status': transaction_status,
'message': message,
}
template = jinja_environment.get_template('index.html')
self.response.out.write(template.render(template_values))
class MessageStore(webapp2.RequestHandler):
def post(self):
message = Message()
message.message_title = self.request.get('message_title')
message.message_text = self.request.get('message_text')
photo.put()
self.redirect('/')
class MessageBoard(db.Expando):
pass
class Message(db.Expando):
pass
def create_message_txn(board_name, message_name, message_title, message_text):
board = db.get(db.Key.from_path('MessageBoard', board_name))
if not board:
board = MessageBoard(key_name=board_name)
board.count = 0
message = Message(key_name=message_name, parent=board)
message.title = message_title
message.text = message_text
message.post_date = datetime.datetime.now()
board.count += 1
db.put([board, message])
try:
db.run_in_transaction(create_message_txn, board_name=board_name,
message_name=message_title,
message_title=message_title,
message_text=message_text)
except db.TransactionFailedError, e:
transaction_status = "Transaction failed: %s " %e
app = webapp2.WSGIApplication([('/', MainPage),
('/new_message',MessageStore)], debug=True)
index.html
<html>
<body>
<form action="/new_photo" method="post">
<label for="message_title">Message Title</label>
<div><textarea name="message_title" rows="1" cols="60" id="message_title"></textarea></div>
<label for="message_text">Message Text</label>
<div><textarea name="message_text" rows="3" cols="60" id="message_text"></textarea></div>
<input type="submit" value="Submit">
</form>
<div><hr></hr></div>
<div><b>{{ transaction_status }}</b></div>
<div><hr></hr></div>
{% for m in message(limit=5): %}
<div><b>{{ m.title }}</b></div>
<div>{{ m.text }}</div>
<div>{{ m.date }}</div>
<div><hr></hr></div>
<b>{% endfor %}</b>
</body>
</html>
最佳答案
看起来您正在递归调用create_message_txn
def create_message_txn():
# code happening here
db.run_in_transaction(create_message_txn, board_name=board_name
^ run_in_transaction 调用 create_message_txn，后者调用 run_in_transaction，后者调用 ect...
您可以通过将要作为事务运行的代码分解为单独的函数来解决此问题
关于python - 错误请求错误 : Nested transactions are not supported，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/15603028/