Is email.message.get() case insensitive for the header name?

[Chris Green]

Peter Otten <__peter__ at web.de> wrote:
> On 14/02/2021 21:50, Chris Green wrote:
> 
> > It isn't clear from the documentation. Does email.message.get() care
> > about the case of the header it's getting?
> >
> > I checking mailing list mails and the "List-Id:" header is a bit
> > 'mixed', i.e. it can be List-Id:, or List-ID: or list-id:, will
> > email.message.get("List-Id:", "unknown") find all of them?
> Let's have a look:
> 
> >>> import email.message
> >>> email.message.get
> Traceback (most recent call last):
>   File "<pyshell#19>", line 1, in <module>
>     email.message.get
> AttributeError: module 'email.message' has no attribute 'get'
> 
> 
> OK, you probably meant
> 
> >>> email.message.Message.get
> <function Message.get at 0x031AEBB0>
> 
> 
> Enter the inspect module for a quick glance at the method's source:
> 
> >>> import inspect
> >>> print(inspect.getsource(email.message.Message.get))
>     def get(self, name, failobj=None):
>         """Get a header value.
> 
>         Like __getitem__() but return failobj instead of None when the
> field
>         is missing.
>         """
>         name = name.lower()
>         for k, v in self._headers:
>             if k.lower() == name:
>                 return self.policy.header_fetch_parse(k, v)
>         return failobj
> 
> Both the `name` argument and the header keys are converted to lowercase
> before the comparison, so yes, the method is case-insensitive (whether
> it should be casefold() doesn't matter for ascii-strings).

Excellent, thank you.

-- 
Chris Green
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