为什么我的错误没有被except捕获？

Question

我整天都在尝试解决这个问题，做了很多研究，尝试了很多不同的方法，但都没有奏效。我目前有一个代码可以使用 bluepy 连接到蓝牙 BLE 设备，当它连接时可以正常工作，但有时它不会连接并且不会出错，只是被 [00:00:00: 00:00] 正在连接，并且没有显示在“例外”中。当我发送一个新命令时，有时会起作用，但由于我没有收到错误，也没有任何东西我不确定何时需要发送新命令。

下面是代码：

#!/usr/bin/env python
from bluepy import *
import paho.mqtt.client as mqtt
import struct

### Variables

mqtt_client = ""
mqtt_port = 
mqtt_user = ""
mqtt_password = ""
mqtt_path = ""

####  Don't edit below here

open = "\x00\xff\x00\x00\x9a\x0d\x01\x00\x96"
close = "\x00\xff\x00\x00\x9a\x0d\x01\x64\xf2"

def shade_command(fble, fcmd):
      try:
        print "["+ fble + "] Connecting"
        dev = btle.Peripheral(fble)
        print "["+ fble + "] Connected!"
        chs = dev.getCharacteristics()
        for ch in chs:
          if ch.uuid == "0000fe51-0000-1000-8000-00805f9b34fb":
            ch.write(fcmd)
        dev.disconnect
        print  "["+ fble + "] Disconnected"
      except:
        print "["+ fble + "] Error Connecting"

# The callback for when the client receives a CONNACK response from the server.
def on_connect(client, userdata, flags, rc):
    print("Connected to MQTT with result code "+str(rc))

    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    client.subscribe(mqtt_path + "/#")

# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
    if msg.payload == "open":
        address = msg.topic.replace(mqtt_path + "/", "")
        result = shade_command(address, open)
        if result == True:
          print msg.topic + "/status"
          client.publish(msg.topic + "/status", "on", qos=0, retain=False)
    if msg.payload == "close":
        address = msg.topic.replace(mqtt_path + "/", "")
        result = shade_command(address, close)
        if result == True:
          client.publish(msg.topic + "/status", "off", qos=0, retain=False)
          print msg.topic + "/status"

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message

client.username_pw_set(mqtt_user, password=mqtt_password)
client.connect(mqtt_client, mqtt_port, 60)

问题发生在这里：

def shade_command(fble, fcmd):
      try:
        print "["+ fble + "] Connecting"
        dev = btle.Peripheral(fble)
        print "["+ fble + "] Connected!"
        chs = dev.getCharacteristics()
        for ch in chs:
          if ch.uuid == "0000fe51-0000-1000-8000-00805f9b34fb":
            ch.write(fcmd)
        dev.disconnect
        print  "["+ fble + "] Disconnected"
      except:
        print "["+ fble + "] Error Connecting"

当我尝试连接到 MAC 地址但不工作时，我没有收到错误，只需在这部分代码之后停止：

        print "["+ fble + "] Connecting"
        dev = btle.Peripheral(fble)

我看到的最后一件事是 [00:00:00:00:00] 连接，仅此而已！我期待看到异常代码。

下面是一个输出示例，当我发送 MQTT 命令时它首先尝试连接，但没有任何反应，它只是停止，然后我发送了另一个命令并且它有效，我知道它在显示“正在连接”时有效，“连接的！”和“断开连接”

[02:B3:CD:3D:C5:34] Connecting
[02:B3:CD:3D:C5:34] Connecting
[02:B3:CD:3D:C5:34] Connected!
[02:B3:CD:3D:C5:34] Disconnected

编辑 1：

尝试使用下面的异常代码但没有用：

except btle.BTLEException as e:

编辑 2：

感谢@hardillb，现在我知道 paho mqtt 是捕获错误并忽略它们的那个，我添加了这段代码，现在我可以看到错误发生的时间：

def on_log(client, userdata, level, buff):  # mqtt logs function
    print buff

client.on_log = on_log

出现错误时显示如下：

Caught exception in on_message: global name 'traceback' is not defined

Answer 1

谢谢 hardillb 看起来在函数之外有 try/except 就可以了！

新的代码是这样的：

功能：

def shade_command(fble, fcmd):
    print "["+ fble + "] Connecting"
    dev = btle.Peripheral(fble)
    print "["+ fble + "] Connected!"
    chs = dev.getCharacteristics()
    for ch in chs:
      if ch.uuid == "0000fe51-0000-1000-8000-00805f9b34fb":
        ch.write(fcmd)
    dev.disconnect
    print  "["+ fble + "] Disconnected"

调用函数：

def on_message(client, userdata, msg):
    if msg.payload == "open":
        try:
          address = msg.topic.replace(mqtt_path + "/", "")
          result = shade_command(address, open)
          print msg.topic + "/status"
          client.publish(msg.topic + "/status", "on", qos=0, retain=False)
        except:
          print "Error"