python - 如果我有 PPP 连接，如何通过 python 脚本识别，如果有，打开 LED？

Question

我使用的是 Orange Pi 2g IoT 板，没有图形界面和发行版 Ubuntu 16.04。该板有一个 2G 调制解调器，可以通过 Python 脚本向我的 Firebase 应用程序发送 URL，但有时无法建立连接。它是通过 wvdial 的 pppd 连接。如果我的调制解调器 2G 已连接，我想了解硬件(avulse LED 开/关)。

谁能帮我解决这个问题？

非常感谢!

Answer 1

如果可以使用外部 python 包:pip install netifaces。

有了这个包，你可以测试接口(interface)是否存在，然后测试能不能上google。此代码未经测试，但应该让您非常接近。

import netifaces
import requests

ppp_exists = False
try:
    netifaces.ifaddresses('ppp0') # this assumes that you only have one ppp instance running
    ppp_exists = True
except:
    ppp_exists = False

# you have an interface, now test if you have a connection
has_internet = False
if ppp_exists == True:
    try:
        r = requests.get('http://www.google.com', timeout=10) # timeout is necessary if you can't access the internet
        if r.status_code == requests.codes.ok:
            has_internet = True
        else:
            has_internet = False
    except requests.exceptions.Timeout:
        has_internet = False

if ppp_exists == True and has_internet == True:
    # turn on LED with GPIO
    pass
else:
    # turn off LED with GPIO
    pass

更新

您可以使用 ifconfig 将输出记录到文本文件中

os.system('ifconfig > name_of_file.txt')

然后，您可以随意解析它。这是一种检查以确保 ppp 接口(interface)存在的方法。

import os
import netifaces

THE_FILE = './ifconfig.txt'

class pppParser(object):
    """
    gets the details of the ifconfig command for ppp interface
    """

    def __init__(self, the_file=THE_FILE, new_file=False):
        """
        the_file is the path to the output of the ifconfig  command
        new_file is a boolean whether to run the os.system('ifconfig') command
        """
        self.ppp_exists = False
        try:
            netifaces.ifaddresses('ppp0') # this assumes that you only have one ppp instance running
            self.ppp_exists = True
        except:
            self.ppp_exists = False
        if new_file:
            open(the_file, 'w').close() # clears the contents of the file
            os.system('sudo ifconfig > '+the_file)
        self.ifconfig_text = ''
        self.rx_bytes = 0
        with open(the_file, 'rb') as in_file:
            for x in in_file:
                self.ifconfig_text += x

    def get_rx_bytes(self):
        """
        very basic text parser to gather the PPP interface data.
        Assumption is that there is only one PPP interface
        """
        if not self.ppp_exists:
            return self.rx_bytes
        ppp_text = self.ifconfig_text.split('ppp')[1]
        self.rx_bytes = ppp_text.split('RX bytes:')[1].split(' ')[0]
        return self.rx_bytes

只需调用 pppParser().get_rx_bytes()