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

[Jim]

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:
             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