Python程序表现不一致

Question

Python程序表现不一致

vicent_chen

411411

发布于
2017-09-17

更新于
2017-10-12

今天写一个小Python玩具的时候碰到了一个奇怪的问题

环境

Ubuntu 16.04
Python3

问题

如果手动运行这个程序，一切正常
如果是开机下启动的话，程序运行后能够正常从Bing获取图片，但是壁纸并不会被修改，终端运行gsettings 查看壁纸的路径是默认路径

源代码

这段代码的主要功能是上Bing抓一张背景图片，保存到本地，并且设置这张图片为壁纸

为了不用每天都手动运行这个程序，开头setup部分将这个py文件添加到了~/.profile(准确来说应该是登陆启动)
中间(web resource getter)是抓取的代码，考虑到开机没有联网的情况，用while循环在外面裹了一下
接着(wall paper switcher)是设置壁纸的代码
最后是让线程睡到明天12点

#!/usr/bin/python3

import urllib.request
import urllib.error
import re
import os
import time
import datetime


def log(string):
    logPath = os.path.abspath(os.path.dirname(__file__)) + '/log'
    with open(logPath, 'a') as log:
        log.write(string + '\n')

# wallpaper absolute path
wallPaperPath = os.path.abspath(os.path.dirname(__file__)) + '/wallpaper.jpg'

# simple setup
# automatically run when login
# warning: make sure there's a wallpaper.jpg after running this program for the first time
# warning: otherwise it may continue to add command into ~/.profile
if not os.path.exists(wallPaperPath):
    log('[SETUP]: ' + 'echo "' + os.path.abspath(__file__) + ' &" >>  ~/.profile')
    os.system('echo "' + os.path.abspath(__file__) + ' &" >>  ~/.profile')

# run
while True:
    # web resource getter
    while True:
        try:
            # open www.bing.com(actually http://www.bing.com/?mkt=zh-CN)
            with urllib.request.urlopen('http://www.bing.com/') as response:
                page = response.read().decode('utf-8')
            # extract the URL of wall paper
            urlPrefix = 'http://www.bing.com'
            patternString = 'g_img={url: "(.*?)"'
            pattern = re.compile(patternString)
            result = pattern.findall(page)
            wallPaperURL = urlPrefix + result[0]
            # get the wall paper
            with urllib.request.urlopen(wallPaperURL) as response:
                with open(wallPaperPath, "wb") as file:
                    file.write(response.read())
            log('[ RUN ]: Download Picture Done')
            break  # exist the loop
        # when cannot connect to the internet
        except urllib.error.URLError as urlError:
            time.sleep(20)  # wait 20 seconds
            log('[ERROR]: URLError')
            continue  # continue the loop
        # other errors
        except Exception as e:
            time.sleep(20)  # wait 20 seconds
            log('[ERROR]: Exception')
            continue  # continue the loop
    
    # wall paper switcher
    # test  current wallpaper
    sysWallpaper = os.popen('gsettings get org.gnome.desktop.background picture-uri').read().strip()
    configWallpaper = '\'file://' + wallPaperPath + '\''
    # spare no effort to change the wallpaper :)
    while not sysWallpaper == configWallpaper:
        # change wallpaper through command line
        os.system('gsettings set org.gnome.desktop.background picture-uri "file://' + wallPaperPath + '"')
        log('[ RUN ]: ' + 'gsettings set org.gnome.desktop.background picture-uri "file://' + wallPaperPath + '"')
        time.sleep(5)
        # test current wallpaper again
        sysWallpaper = os.popen('gsettings get org.gnome.desktop.background picture-uri').read().strip()
    log('[ RUN ]: Change Wallpaper Done')
    # set next run time
    # never tested
    tomorrow = datetime.datetime.replace(datetime.datetime.now() + datetime.timedelta(days=1), hour=0, minute=0, second=0)
    delta = tomorrow - datetime.datetime.now()
    time.sleep(delta.seconds)