我在树莓派上使用 Raspbian。我有一个 Python 脚本 (LCD.py)，它使用 supervisord 控制作为服务运行的 LCD。
我希望能够在我的网页上输入一条消息并将其显示在 LCD 上。我认为这意味着我必须更改 LCD.py 脚本读取的一些变量，可能是更改模式的标志，然后使用服务器执行的另一个 Python 脚本 (CGI.py) 更改消息本身。
最好的方法是什么？还是我应该做一些完全不同的事情？我认为它与普通 CGI 类型的东西不同，因为我不能在每个页面加载时执行脚本，它需要在后台运行（用于滚动、闪烁等）
编辑：到目前为止，感谢您的帮助，今晚我回家后将发布我的 LCD 守护程序代码。
我对此有了更进一步的了解，我尝试使用 SimpleXMLRPCServer 和线程，目前这不起作用。我认为这是因为线程实际上并不同时运行。这是我正在测试的服务器代码：
from SimpleXMLRPCServer import SimpleXMLRPCServer
from SimpleXMLRPCServer import SimpleXMLRPCRequestHandler
import threading
import time
globalMessage = "Hi, I havnt been changed!"
# Restrict to a particular path.
class RequestHandler(SimpleXMLRPCRequestHandler):
rpc_paths = ('/RPC2',)
# Create server
server = SimpleXMLRPCServer(("localhost", 8000),
requestHandler=RequestHandler)
server.register_introspection_functions()
# Register an instance; all the methods of the instance are
# published as XML-RPC methods (in this case, just 'div').
class serverFunctions:
def setMessage(self, message):
global globalMessage
globalMessage = message
print(globalMessage)
class serverThread(threading.Thread):
def run(self):
server.register_instance(serverFunctions())
# Run the server's main loop
server.serve_forever()
print("test");
class lcdThread(threading.Thread):
def run(self):
global globalMessage
while(1):
oldMessage = globalMessage
if(oldMessage != globalMessage): print("Message has changed")
else: print ("Message has not changed")
print(globalMessage)
time.sleep(1)
serverThread().start()
#lcdThread().start()
和我的客户代码：
import xmlrpclib
s = xmlrpclib.ServerProxy('http://localhost:8000')
print s.setMessage("hello world")
如果我取消注释我的 lcdThread().start() 行，我认为它卡在 lcd while 循环中并且服务器没有响应。多处理会有什么不同吗？请您详细说明 exec() 函数，我将如何使用 exec() 更改不同脚本中的全局变量？
编辑：这是我的 LCD.py 代码，它是一个守护进程，我试图设置的消息变量大约是一半。
#!/usr/bin/python
from Adafruit_CharLCD import Adafruit_CharLCD
from subprocess import *
from time import sleep, strftime
from datetime import datetime
from datetime import timedelta
from os import system
from os import getloadavg
from glob import glob
import RPi.GPIO as GPIO
#Variables
lcd = Adafruit_CharLCD() #Stores LCD object
cmdIP = "ip addr show eth0 | grep inet | awk '{print $2}' | cut -d/ -f1" #Current IP
cmdHD = "df -h /dev/sda1 | awk '{print $5}'" # Available hd space
cmdSD = "df -h / | awk '{print $5}'" # Available sd space
cmdRam = "free -h"
temp = 0
#Run shell command
def run_cmd(cmd):
p = Popen(cmd, shell=True, stdout=PIPE)
output = p.communicate()[0]
return output
#Initalises temp device
def initialise_temp():
#Initialise
system("sudo modprobe w1-gpio")
system("sudo modprobe w1-therm")
#Find device
devicedir = glob("/sys/bus/w1/devices/28-*")
device = devicedir[0]+"/w1_slave"
return device
#Gets temp
def get_temp(device):
f = open (device, 'r')
sensor = f.readlines()
f.close()
#parse results from the file
crc=sensor[0].split()[-1]
temp=float(sensor[1].split()[-1].strip('t='))
temp_C=(temp/1000.000)
temp_F = ( temp_C * 9.0 / 5.0 ) + 32
#output
return temp_C
#Gets time
def get_time():
return datetime.now().strftime('%b %d %H:%M:%S\n')
#Gets uptime
def get_uptime():
with open('/proc/uptime', 'r') as f:
seconds = float(f.readline().split()[0])
array = str(timedelta(seconds = seconds)).split('.')
string = array[0]
return string
#Gets average load
def get_load():
array = getloadavg()
average = 0
for i in array:
average += i
average = average / 3
average = average * 100
average = "%.f" % average
return str(average + "%")
#def get_ram():
def get_ram():
ram = run_cmd(cmdRam)
strippedRam = ram.replace("\n"," ");
splitRam = strippedRam.split(' ')
totalRam = int(splitRam[52].rstrip("M"))
usedRam = int(splitRam[59].rstrip("M"))
percentage = "%.f" % ((float(usedRam) / float(totalRam)) * 100)
return percentage + "%"
#Gets the SD usage
def get_sd():
sd = run_cmd(cmdSD)
strippedSD = sd.lstrip("Use%\n")
return strippedSD
#Gets the HD usage
def get_hd():
hd = run_cmd(cmdHD)
strippedHD = hd.lstrip("Use%\n")
return strippedHD
#This is the variable im trying to set
#def get_message():
# message = "hello"
# return message
def scroll():
while(1):
lcd.scrollDisplayLeft()
sleep(0.5)
#Message and IP - PERFECT
def screen1():
ipaddr = run_cmd(cmdIP)
lcd.message('Raspberry Pi\n')
lcd.message('IP: %s' % (ipaddr))
#Uptime - tick
def screen2():
uptime = get_uptime()
lcd.message('Total Uptime\n')
lcd.message('%s' % (uptime))
#Ram and load - PERFECT
def screen3():
ram = get_ram()
lcd.message('Ram Used: %s\n' % (ram))
load = get_load()
lcd.message('Avg Load: %s' % (load))
#Temp and time - tick time
def screen4():
time = get_time();
lcd.message('Temp %s\n' % (temp))
lcd.message('%s' % (time))
#HD and SD usage - PERFECT
def screen5():
sd = get_sd()
lcd.message('SD Used: %s\n' % (sd))
hd = get_hd()
lcd.message('HD Used: %s' % (hd))
#Web message
#def screen6():
# message = get_message()
# lcd.message(message)
#Pause and clear
def screenPause(time):
sleep(time)
#In here to reduce lag
global temp
temp = str(get_temp(device));
lcd.clear()
###########################################################################################################
try:
#Initialise
lcd.begin(16,2)
device = initialise_temp()
lcd.clear()
#Main loop
while(1):
screen1()
screenPause(5)
screen2()
screenPause(5)
screen3()
screenPause(5)
screen5()
screenPause(5)
screen4()
screenPause(5)
except KeyboardInterrupt:
GPIO.cleanup()
谢谢乔