[Tutor] I need to ignore an error let the script continue to run

[Mark Lawrence]

On 05/05/2020 21:28, Jim wrote:
> On 5/5/20 9:38 AM, Jim wrote:
>> On 5/5/20 3:01 AM, Alan Gauld via Tutor wrote:
>>> On 05/05/2020 03:41, Jim wrote:
>>>
>>>> It seems try/except will not process the keys after the missing one.
>>>
>>> You need to wrap each bit that needs to continue in try/except.
>>> Clunky I agree.
>>>
>>>> 'Recepient username: ' + header['to'].addresses[0].username+'\n',
>>>> 'Sender name: ' + header['from'].addresses[0].display_name
>>>>
>>>> They don't look like keys, but they do resolve to the info I want if it
>>>> is in the header.
>>>
>>> They aren't keys they are accessing attributes of some class that is
>>> returned. You could check the return value from header first using an if
>>> test. Or you could just wrap those two calls in their own try/except.
>>>
>>> Or you could use get() and return a dummy instance of whatever class it
>>> is with whatever default values you need.
>>>
>>> So several solutions only you can decide which suits you best.
>>
>> OK, thanks, I'll give them a try and see which on works best.
>>
> 
> It seems every time I tried to test the return value from header I would 
> get an error, so I went the try/except route. This what I ended up with:
> 
> def parse_header(msg):
>      with open('/home/jfb/' + email_msg, 'rb') as fp:
>          header = BytesHeaderParser(policy=default).parse(fp)
>          #  Now the header items can be accessed as a dictionary:
>          try:
>              username =  header['to'].addresses[0].username + '\n'
>          except:

Never use a bare except as in the long term it's asking for trouble, 
catch what you know can occur and let anything else raise it's own 
exception.

>              username = ' Blank \n'
> 
>          try:
>              sender =  header['to'].addresses[0].display_name + '\n'
>          except:
>              sender = ' Blank \n'
> 
>          return ['To: ' + header['to']+'\n' ,
>          'From: ' + header['from']+'\n',
>          'Subject: ' + header['subject']+'\n',
>          'Return-Path: ' + header['return-path']+'\n' ,
>          #These do not exist in some headers'
>          'Recepient username: ' + username,
>          'Sender name: ' + sender,
>          ]
> This works when every thing is in the header and when the last two are 
> missing, so thanks for your help.
> 
> Regards,  Jim
> 



-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence