问题
Using the code linked here, I had created a custom prefix for my bot a couple months ago. However, I ran into an issue when I was finally getting into DM responses. Due to the custom prefix, I have been receiving this error and traceback whenever someone dms my bot:
Ignoring exception in on_message
Traceback (most recent call last):
File "C:\Users\bagle\AppData\Local\Programs\Python\Python36-32\lib\site-packages\discord\ext\commands\bot.py", line 802, in get_prefix
ret = list(ret)
TypeError: 'NoneType' object is not iterable
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "C:\Users\bagle\AppData\Local\Programs\Python\Python36-32\lib\site-packages\discord\client.py", line 333, in _run_event
await coro(*args, **kwargs)
File "C:\Users\bagle\AppData\Local\Programs\Python\Python36-32\lib\site-packages\discord\ext\commands\bot.py", line 943, in on_message
await self.process_commands(message)
File "C:\Users\bagle\AppData\Local\Programs\Python\Python36-32\lib\site-packages\discord\ext\commands\bot.py", line 939, in process_commands
ctx = await self.get_context(message)
File "C:\Users\bagle\AppData\Local\Programs\Python\Python36-32\lib\site-packages\discord\ext\commands\bot.py", line 853, in get_context
prefix = await self.get_prefix(message)
File "C:\Users\bagle\AppData\Local\Programs\Python\Python36-32\lib\site-packages\discord\ext\commands\bot.py", line 810, in get_prefix
"returning either of these, not {}".format(ret.__class__.__name__))
TypeError: command_prefix must be plain string, iterable of strings, or callable returning either of these, not NoneType
At first, I thought this was due to a bit of code I had previously added, where if the bot was offline, once it came back on it would add the prefix to the server (since, like I said, I'm using a custom prefix for each server). This code is as seen below:
def get_prefix(client, message):
try:
with open('prefixes.json', 'r') as f:
prefixes = json.load(f)
return prefixes[str(message.guild.id)]
except KeyError: # if the guild's prefix cannot be found in 'prefixes.json'
with open('prefixes.json', 'r') as k:
prefixes = json.load(k)
prefixes[str(message.guild.id)] = 'bl!'
with open('prefixes.json', 'w') as j:
json.dump(prefixes, j, indent = 4)
with open('prefixes.json', 'r') as t:
prefixes = json.load(t)
return prefixes[str(message.guild.id)]
except: # I added this when I started getting dm error messages
pass
At the time I did not find this to be an issue, but now that I have discovered this error, I realize that I cannot do commands related to DMs until this is fixed. Thank you in advance.
回答1:
Something I would recommend you to do is to make a default prefix in bot DMs. Let's say you want the default prefix to be ., change your get_prefix function to:
def get_prefix(client, message):
try:
with open('prefixes.json', 'r') as f:
prefixes = json.load(f)
return prefixes[str(message.guild.id)]
except KeyError: # if the guild's prefix cannot be found in 'prefixes.json'
with open('prefixes.json', 'r') as k:
prefixes = json.load(k)
prefixes[str(message.guild.id)] = 'bl!'
with open('prefixes.json', 'w') as j:
json.dump(prefixes, j, indent = 4)
with open('prefixes.json', 'r') as t:
prefixes = json.load(t)
return prefixes[str(message.guild.id)]
except: # I added this when I started getting dm error messages
return '.' # This will return "." as a prefix. You can change it to any default prefix.
来源：https://stackoverflow.com/questions/65333249/discord-py-error-message-whenever-user-dms-bot