本文介绍了Kivy和Flask线程在Python2中相互阻塞的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有以下设置:Kivy 1.11.1，Flask 1.1.1和Python 2.7.13.我想获取一个JSON请求，但是在Kivy GUI运行时，我被Flask应用程序卡住了，无法获取请求.即使在单独的线程中运行，它们也会相互阻塞.
I have the following setup: Kivy 1.11.1, Flask 1.1.1 and Python 2.7.13. I want to fetch a JSON request but I am stuck at Flask app does not fetch requests while the Kivy GUI is running. Even when run in separate threads they block each other.
主要的api脚本，例如eg_api.py:
The main api script eg_api.py:
#!/usr/bin/python2.7 python2.7
# -*- coding: utf-8 -*-
# kivy modules first, if not Kivy may cause problems
import kivy
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.label import Label
from kivy.uix.popup import Popup
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.screenmanager import ScreenManager, Screen
kivy.require('1.10.0')
# common modules
import re
import sys
import time
import signal
import threading
from datetime import datetime
# Flask & similar modules
from flask import Flask
from flask import request
from flask_restful import reqparse, abort, Api, Resource
from flask_httpauth import HTTPBasicAuth
import json, ast
import urlparse
import eventlet
from eventlet import wsgi
# imports from other files
from eg_wrapper import Actions
# async server setup
eventlet.monkey_patch()
app = Flask(__name__)
api = Api(app)
auth = HTTPBasicAuth()
# user access setup
USER_DATA = {
"admin": "SuperSecretPwd"
}
# global variable
data_json = None
@auth.verify_password
def verify(username, password):
if not (username and password):
return False
return USER_DATA.get(username) == password
def start_Flask():
print("Starting Flask...")
#app.run(port=5000, debug=False) #specify separate port to run Flask app
wsgi.server(eventlet.listen(('', 5000)), app) # deploy as an eventlet WSGI server
def signal_handler(signal, frame):
print " CTRL + C detected, exiting ... "
exit(0)
####################### flask classes #########################
class Load(Resource):
@auth.login_required
def post(self):
print "********** class Load(Resource): *****************"
data = request.json
print data
lw = Actions()
data_json = lw.Parse_Load_Request(data)
res = {'data': data_json}
return res, 201
####################### resource calls #######################
api.add_resource(Load, '/load')
########################## kivy screen classes ###############################
class MainScreen(Screen):
pass
########################## kivy popup classes ###############################
# main screen
class MainScreen(Screen):
def __init__(self, **kwargs):
self.name="MAIN SCREEN"
super(Screen, self).__init__(**kwargs)
# popup
class MessageBox10(Popup):
def __init__(self, obj, **kwargs):
super(MessageBox10, self).__init__(**kwargs)
self.obj = obj
# popup
class MessageBox20(Popup):
def __init__(self, obj, **kwargs):
super(MessageBox20, self).__init__(**kwargs)
self.obj = obj
class Kivy(App):
w_MessageBox10_1 = "Message_10_1"
w_MessageBox10_2 = "Message_10_2"
w_MessageBox10_3 = "Message_10_3"
w_MessageBox10_4 = "Message_10_4"
w_MessageBox20_1 = "Message_20_1"
w_MessageBox20_2 = "Message_20_2"
w_MessageBox30_1 = "Message_30_1"
w_MessageBox30_2 = "CONFIRM"
w_MessageBox30_3 = "CANCEL"
def do(self):
print "do something"
def cancel(self):
print "load cancelled by user"
def exit(self):
print "exiting..."
exit(1)
def enter(self):
# open the init file and write the parameters
print "********** def enter(self): popup = MessageBox20(self) *************************"
popup = MessageBox20(self)
popup.open()
def build(self):
sm = Builder.load_string("""
ScreenManager
MainScreen:
size_hint: 1, .7
auto_dismiss: False
title: app.w_MessageBox10_1
title_align: "center"
BoxLayout:
orientation: "vertical"
Label:
text: app.w_MessageBox10_2
BoxLayout:
orientation: "horizontal"
spacing: 10
size_hint: 1, .5
Button:
text: app.w_MessageBox30_2 # CONFIRM
on_press:
app.enter()
Button:
text: app.w_MessageBox30_3 # CANCEL
on_press:
app.exit()
<MessageBox20>:
size_hint: 1, .7
auto_dismiss: False
title: app.w_MessageBox20_1
title_align: "center"
BoxLayout:
orientation: "vertical"
Label:
text: app.w_MessageBox20_2
BoxLayout:
orientation: "horizontal"
spacing: 10
size_hint: 1, .5
Button:
text: app.w_MessageBox30_2 # "CONFIRM"
on_press:
app.do()
root.dismiss()
Button:
text: app.w_MessageBox30_3 # "CANCEL"
on_press:
app.cancel()
root.dismiss()
""")
return sm
if __name__ == '__main__':
#CTRL+C signal handler
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGTERM, signal_handler)
# start the first thread
t1 = threading.Thread(target=start_Flask)
t1.start()
# start the second thread
t2 = threading.Thread(target=Kivy().run)
t2.start()
# join the two threads
t1.join()
t2.join()
包装脚本eg_wrapper.py:
The wrapping script eg_wrapper.py:
#!/usr/bin/python2.7 python2.7
#!/bin/sh -i
# -*- coding: utf-8 -*-
"""
This program executes actions called by eg_api.py.
"""
import os
import signal
import re
import json, ast
import sys
import subprocess
import multiprocessing
from subprocess import PIPE, STDOUT
from datetime import datetime
# to solve the send_file issue
import eventlet
eventlet.monkey_patch()
class Actions:
def Parse_Load_Request(self, request): # parse the JSON data
timestamp = datetime.now()
code = "200"
id_code = "0000"
data = request
task = ""
res={}
list_of_tasks = []
print "********** def Parse_Load_Request(self, r): print data without uni-code chars *****************************"
data = ast.literal_eval(json.dumps(data)) # Removing uni-code chars
print "********** def Parse_Load_Request(self, r): print keys for data *****************************"
print(data.keys()) # print all the keys in the dictionary first
res["code"] = code
res["timestamp"] = str(timestamp)
res["id"] = id_code
res["data"] = str(list_of_tasks)
res["task"] = task
return res
def signal_handler(signal, frame):
exit(1)
def main():
# CTRL+C signal handler
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGTERM, signal_handler)
#the sys.argv parameter is a list of arguments from the command line
ex = Actions()
sys.exit(app.exec_())
if __name__ == "__main__":
# define the stuff
global mainProcess, mainProcessPid
# execute main
main()
过程
我运行eg_api.py，并且Flask和Kivy确实以线程开始.他们启动并运行，eventlet正在监听，并且带有第一个弹出窗口的Kivy窗口启动.然后，我发送请求.
I run the eg_api.py and Flask and Kivy do start as threads. They get up and run, eventlet is listening and the Kivy window with the first popup gets up. Then I send the request.
输出
(py2) parovelb@Latitude-E6510:~/Desktop/Python2$ python eg_api.py
[INFO ] [Logger ] Record log in /home/parovelb/.kivy/logs/kivy_19-12-23_34.txt
[INFO ] [Kivy ] v1.10.1
[INFO ] [Python ] v2.7.15rc1 (default, Nov 12 2018, 14:31:15)
[GCC 7.3.0]
[INFO ] [Factory ] 194 symbols loaded
[INFO ] [Image ] Providers: img_tex, img_dds, img_sdl2, img_pil, img_gif (img_ffpyplayer ignored)
[INFO ] [Text ] Provider: sdl2
Starting Flask...
(15549) wsgi starting up on http://0.0.0.0:5000
[INFO ] [Window ] Provider: sdl2(['window_egl_rpi'] ignored)
[INFO ] [GL ] Using the "OpenGL" graphics system
[INFO ] [GL ] Backend used <gl>
[INFO ] [GL ] OpenGL version <3.3 (Compatibility Profile) Mesa 19.0.8>
[INFO ] [GL ] OpenGL vendor <nouveau>
[INFO ] [GL ] OpenGL renderer <NVA8>
[INFO ] [GL ] OpenGL parsed version: 3, 3
[INFO ] [GL ] Shading version <3.30>
[INFO ] [GL ] Texture max size <8192>
[INFO ] [GL ] Texture max units <16>
[INFO ] [Window ] auto add sdl2 input provider
[INFO ] [Window ] virtual keyboard not allowed, single mode, not docked
[INFO ] [Base ] Start application main loop
[INFO ] [GL ] NPOT texture support is available
********** def enter(self): popup = MessageBox20(self) *************************
do something
exiting...
[INFO ] [Base ] Leaving application in progress...
(15549) accepted ('192.168.3.88', 53418)
********** class Load(Resource): *****************
{u'position': u'b1', u'tasks': [{u'code': u'24258146312', u'actionDescription': u'Preleva 20ml di glucosio dalla sacca', u'barcode': u'000001', u'results': [u'returnCode'], u'actions': [{u'returnCode': u'200', u'type': u'CONFIRM', u'label': u'Conferma'}, {u'returnCode': u'400', u'type': u'ABORT', u'label': u'Annulla'}], u'itemName': u'Glucosio 100ml'}, {u'code': u'24258146313', u'actionDescription': u'Leggi il barcode e il codice RFID', u'itemName': u'Glucosio 100ml', u'barcode': u'000001', u'results': [u'returnCode', u'barcode', u'rfid'], u'actions': [{u'returnCode': u'200', u'type': u'CONFIRM', u'label': u'Conferma'}, {u'returnCode': u'400', u'type': u'ABORT', u'label': u'Annulla'}], u'type': u'BARCODE_CHECK'}, {u'code': u'24258146314', u'itemName': u'Glucosio 100ml', u'actionDescription': u'Posiziona la sacca nello slot 1', u'actions': [{u'returnCode': u'200', u'type': u'CONFIRM', u'label': u'Conferma'}, {u'returnCode': u'400', u'type': u'ABORT', u'label': u'Annulla'}], u'results': [u'returnCode']}], u'weight': u'133.15'}
********** def Parse_Load_Request(self, r): *****************************
********** def Parse_Load_Request(self, r): print data without uni-code chars *****************************
********** def Parse_Load_Request(self, r): print keys for data *****************************
['position', 'tasks', 'weight']
192.168.3.88 - - [23/Dec/2019 11:08:44] "POST /load HTTP/1.1" 201 247 0.004312
问题
当我发送请求时，Flask不会提取请求.当我按下第一个弹出窗口的按钮时，Flask仍未获取请求.当我按下第二个弹出窗口上的按钮时，Flask仍未获取请求.无论我如何启动线程，Kivy都会阻止Flask.我检查了此线程，但我没有帮助.我在做什么错了?
Flask does not fetch the request when I send it. When I press the button of the first popup, Flask still does not fetch the request. When I press the button on the second popup, Flask still does not fetch the request. Kivy blocks Flask no matter the order how I start the threads. I checked this thread but I does not help. What am I doing wrong?
推荐答案
这并不完全是问题的答案，但它是Flask阻止Kivy的替代解决方案，反之亦然.我尝试了多处理，似乎可以完成工作.希望对您有所帮助，如果有专家级的编码人员决定升级答案，欢迎这样做.
It is no exactly the answer to the question but it is an alternative solution to the Flask blocking Kivy and vice versa. I gave it a try with multiprocessing and it seems it does the work. Hope it helps somebody and if some expert coder decide to upgrade the answer is welcome to do so.
代码
#!/usr/bin/python2.7 python2.7
# -*- coding: utf-8 -*-
# kivy modules first, if not Kivy may cause problems
import kivy
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.label import Label
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.screenmanager import ScreenManager, Screen
kivy.require('1.10.0')
# common modules
import sys
import signal
from multiprocessing import Process
# Flask & similar modules
from flask import Flask
from flask_restful import reqparse, abort, Api, Resource
import eventlet
from eventlet import wsgi
# async server setup
eventlet.monkey_patch()
app = Flask(__name__)
api = Api(app)
def start_Flask():
print("Starting Flask...")
# deploy as an eventlet WSGI server on port 5000
wsgi.server(eventlet.listen(('', 5000)), app)
def signal_handler(signal, frame):
# for fetching CTRL+C and relatives
print " CTRL + C detected, exiting ... "
exit(1)
# Kivy screen class
class MainScreen(Screen):
def __init__(self, **kwargs):
self.name="MAIN SCREEN"
super(Screen, self).__init__(**kwargs)
# Kivy app class
class Kivy(App):
w_MessageBox10_1 = "MAIN SCREEN"
w_MessageBox10_2 = "One golden glance of what should be"
w_MessageBox30_2 = "CHORUS"
w_MessageBox30_3 = "EXIT"
# exit button action
def exit(self):
print "exiting... one shaft of light will show the way..."
p1.terminate() # terminate Flask by pressing on cancel
exit(1)
# do magic button action
def do_magic(self):
# your code goes here or maybe not
print "***** it's a kind of magic *************************"
# Kivy UI builder file
def build(self):
sm = Builder.load_string("""
ScreenManager
MainScreen:
size_hint: 1, .7
auto_dismiss: False
title: app.w_MessageBox10_1
title_align: "center"
BoxLayout:
orientation: "vertical"
Label:
text: app.w_MessageBox10_2
BoxLayout:
orientation: "horizontal"
spacing: 10
size_hint: 1, .5
Button:
text: app.w_MessageBox30_2 # DO MAGIC
on_press:
app.do_magic()
Button:
text: app.w_MessageBox30_3 # EXIT
on_press:
app.exit()
""")
return sm
if __name__ == '__main__':
# #CTRL+C signal handler
signal.signal(signal.SIGINT, signal_handler)
signal.signal(signal.SIGTERM, signal_handler)
global p1
p1 = Process(target=start_Flask) # assign Flask to a process
p1.start() # run Flask as process
Kivy().run() # run Kivy UI
这篇关于Kivy和Flask线程在Python2中相互阻塞的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！