Question

NEW：

它在没有isseus的情况下工作了40分钟，然后代码本身崩溃了：这是控制台中的outpud

Gradi: 29.0 C  Umidita: 35.0 %
Traceback (most recent call last):
  File "temp.py", line 22, in <module>
    valori='Gradi: {0:0.1f} C  Umidita: {1:0.1f} %'.format(temperature, humidity)
ValueError: Unknown format code 'f' for object of type 'str'

你有什么建议吗？

OLD：

我必须刷新每次由Python脚本重写的HTML页面以获得最新值。有时会发生页面刷新但显示白页，没有数据。我该如何解决这个问题？

import datetime
import sys
import Adafruit_DHT
import time    

a = """<html>
<meta http-equiv="refresh" content="">
<head></head>
<body><p>"""
b = """</p></body>
</html>"""        

try:
    while True:
        file = open("logtemperature.txt", "a")
        web = open('temperatura.html', 'w')
        humidity, temperature = Adafruit_DHT.read_retry(11, 16) #11 modello 16 pin
        valori = 'Gradi: {0:0.1f} C  Umidita: {1:0.1f} %'.format(temperature, humidity)
        print (valori)
        file.write("\n" + valori + " " + str(datetime.datetime.now()))
        web.write(a + "TEMPERATURA INTERNA:" + " " + valori + b)
        time.sleep(1)
        web.close()
        file.close()
        time.sleep(2)
except KeyboardInterrupt:
    file.close()
     web.close()

Answer 1

为了使确实确保文件永远不会是空的或不完整的，当用另一个程序读取文件时，请继续阅读第一个代码块下面。

如果您可以几乎从不拥有空文件或不完整的文件，那么

import datetime
import sys
import Adafruit_DHT
import time


a="""<html>
<meta http-equiv="refresh" content="">
<head></head>
<body><p>"""
b="""</p></body>
</html>"""



while True:
  humidity, temperature = Adafruit_DHT.read_retry(11,16) #11 modello 16 pin
  valori='Gradi: {0:0.1f} C  Umidita: {1:0.1f} %'.format(temperature, humidity)
  print (valori)
  ls="\n"+valori+" "+str(datetime.datetime.now())
  with open("logtemperature.txt","a") as file:
    file.write(ls)
  ws=a+"TEMPERATURA INTERNA:"+" "+valori+b
  with open('temperatura.html','w') as web:
    web.write(ws)
  time.sleep(2)

如果您使用的是Unix / Linux（例如Raspbian），您可以创建自己的准原子写，因为os.rename是原子的，确保temperatura.html始终完整

import os

def atomic_write(filename, bytes):
    shouldnotexist=filename+".deleteme"
    with open(shouldnotexist,"wb") as f:
        f.write(bytes)
    os.rename(shouldnotexist,filename)

替换

with open('temperatura.html','w') as web:
        web.write(ws)

带

atomic_write('temperatura.html', ws)

在Windows上它可能更复杂......

编辑：

要缓解ValueError问题，可以替换

valori='Gradi: {0:0.1f} C  Umidita: {1:0.1f} %'.format(temperature, humidity)

带

try:
    valori='Gradi: {0:0.1f} C  Umidita: {1:0.1f} %'.format(temperature, humidity)
except ValueError:
    valori='Gradi: {0} C  Umidita: {1} % (something saying there was a problem)'.format(temperature, humidity)

从python输入刷新HTML页面

1 个答案: