这只是Flask调试过程的一部分吗？这是因为Flask服务器正在读取它正在写入的文件吗？我没有正确关闭连接吗？
从what I can gather errno（9）表示：
（错误的文件编号），当您使用的文件描述符无效时。文件描述符指的是没有打开文件，或者对仅为写入（或读取）打开的文件发出读取（或写入）请求。 如果你正在进行套接字编程，那么套接字描述符已经关闭，然后你可以对它进行任何操作，你可能会得到这个错误。
我使用的是Virtualenv 15.1.0，Python 3.6.0和Flask 0.12＆amp;
$ pip freeze
appdirs==1.4.2
click==6.7
Flask==0.12
itsdangerous==0.24
Jinja2==2.9.5
MarkupSafe==0.23
packaging==16.8
pyparsing==2.1.10
requests==2.13.0
six==1.10.0
Werkzeug==0.11.15
这是我写的代码，它在退出服务器时调用错误：
from flask import Flask, render_template, request, jsonify
import sqlite3
app = Flask(__name__)
connection = sqlite3.connect('database.db')
connection.execute('CREATE TABLE IF NOT EXISTS films (title TEXT, rating INTEGER)')
connection.close() <------------------ IMPROPER CLOSURE?
@app.route('/')
def index():
return render_template("base.html")
@app.route('/movie', methods = ['POST'])
def add_movie_function():
connection = sqlite3.connect('database.db')
cursor = connection.cursor()
title = request.form['title']
rating = request.form['rating']
try:
query = 'INSERT INTO films (title, rating) VALUES (?, ?)'
cursor.execute(query, (title, rating))
connection.commit()
message = 'Successfully inserted title and rating data into movies table!'
except:
connection.rollback()
message = 'There was an issue with inserting data into the movies table :('
finally:
connection.close() <------------------ IMPROPER CLOSURE?
return message
@app.route('/movies', methods = ['GET'])
def list_all_movies():
connection = sqlite3.connect('database.db')
cursor = connection.cursor()
try:
cursor.execute('SELECT * FROM films')
connection.commit()
search_result = jsonify(cursor.fetchall())
except:
search_result = 'An error occured getting all the film titles'
finally:
connection.close() <------------------ IMPROPER CLOSURE?
return search_result
app.run(debug = True)
......这是完整的追溯：
(venv) 66 Wed Mar 08 15:29:11$ export FLASK_APP=simpleFlaskAPI.py
(venv) 67 Wed Mar 08 15:42:08$ flask run
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger pin code: 230-157-201
127.0.0.1 - - [08/Mar/2017 15:42:21] "GET /movies HTTP/1.1" 200 -
^C * Serving Flask app "simpleFlaskAPI"
Traceback (most recent call last):
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/bin/flask", line 11, in <module>
sys.exit(main())
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/flask/cli.py", line 507, in main
cli.main(args=args, prog_name=name)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/flask/cli.py", line 374, in main
return AppGroup.main(self, *args, **kwargs)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/click/core.py", line 697, in main
rv = self.invoke(ctx)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/click/core.py", line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/click/core.py", line 895, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/click/core.py", line 535, in invoke
return callback(*args, **kwargs)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/click/decorators.py", line 64, in new_func
return ctx.invoke(f, obj, *args[1:], **kwargs)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/click/core.py", line 535, in invoke
return callback(*args, **kwargs)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/flask/cli.py", line 432, in run_command
use_debugger=debugger, threaded=with_threads)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 708, in run_simple
inner()
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 670, in inner
fd=fd)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 564, in make_server
passthrough_errors, ssl_context, fd=fd)
File "/Users/username/python/lesson4/python-minicamp-homework-4/venv/lib/python3.6/site-packages/werkzeug/serving.py", line 474, in __init__
socket.SOCK_STREAM)
File "/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socket.py", line 460, in fromfd
nfd = dup(fd)
OSError: [Errno 9] Bad file descriptor
如果这是异常的，我应该向Flask的人提交错误报告吗？
谢谢！
根据Pipskweak的建议更新，我修改了脚本：
from flask import Flask, render_template, request, jsonify
import sqlite3
app = Flask(__name__)
connection = sqlite3.connect('database.db')
connection.execute('CREATE TABLE IF NOT EXISTS films (title TEXT, rating INTEGER)')
connection.close()
@app.route('/')
def index():
return render_template("base.html")
@app.route('/movie', methods = ['POST'])
def add_movie_function():
data = None
try:
connection = sqlite3.connect('database.db')
with connection:
cursor = connection.cursor()
title = request.form['title']
rating = request.form['rating']
query = 'INSERT INTO films (title, rating) VALUES (?, ?)'
data = cursor.execute(query, (title, rating))
connection.commit()
message = 'Successfully inserted title and rating data into movies table!'
except sqlite3.Error as e:
if connection:
connection.rollback()
message = 'There was an issue with inserting data into the movies table :('
raise ValueError('sqlite3: {}'.format(e))
finally:
if connection:
connection.close()
print(message)
if data:
print(data)
return message
@app.route('/movies', methods = ['GET'])
def list_all_movies():
data = None
try:
connection = sqlite3.connect('database.db')
with connection:
cursor = connection.cursor()
data = cursor.execute('SELECT * FROM films')
connection.commit()
search_result = jsonify(cursor.fetchall())
except sqlite3.Error as e:
if connection:
search_result = 'An error occured getting all the film titles'
raise ValueError('sqlite3: {}'.format(e))
finally:
if connection:
connection.close()
print(search_result)
if data:
print(data)
return search_result
app.run(debug = True)
# if __name__ == '__main__':
# print('__name__ == "__main__"')
# app.run(debug = True)
OF注意：在if __name_ == ...和export FLASK_APP...调用flask时，使用flask run不会在Flask中调用调试器模式。然而，将python3 scriptname.py与if name == main一起使用会调用调试器 - 所以我怀疑Flask在这里有什么不妥之处？
我还调整了脚本以在python 2中运行（只有几个打印语句和except sqlite3.Error, e:语法）并尝试使用虚拟环境在Flask（使用调试器模式）中运行它，并且python脚本可以正常工作html，当我退出Flask服务器时，没有OSError：[Errno 9]错误的文件描述符。那么，这是一个我应该向Flask人报告的错误吗？
FWIW：
$ pip freeze
appdirs==1.4.3
click==6.7
Flask==0.12
itsdangerous==0.24
Jinja2==2.9.5
MarkupSafe==1.0
packaging==16.8
pyparsing==2.2.0
requests==2.13.0
six==1.10.0
Werkzeug==0.11.15
答案 0 :(得分：1)
因此，try，except，finally语句可能会导致一些问题。
你想拍这个吗？它对异常和关闭连接有点具体。
def query_db(sql_statement):
try:
# connect to database
conn = sqlite3.connect('database.db')
with conn:
cur = conn.cursor()
data = cur.execute(sql_statement)
# commit the changes
conn.commit()
except sqlite3.Error, e:
# if an error has occured, rollback the changes
if conn:
conn.rollback()
# print the error out. Probably useful.
raise ValueError('sqlite3: {}'.format(e))
finally:
# lastly, close the database, probably a good idea.
if conn:
conn.close()
if data:
return data
另外，您错过了if
app.run()声明
if __name__ == "__main__":
app.run(debug=True)