Re: [PATCH] Make `smtpmail-try-auth-method' a generic function.

[Stefan Monnier]

I can install that, but I'm not sure if it should go into
emacs-26 or master.


        Stefan


Cesar Crusius <address@hidden> writes:

> This allows for extra authentication mechanisms (such as XOAuth2) to
> be added without having to advise any functions.
>
> * lisp/mail/smtpmail.el: Turn `smtpmail-try-auth-method' into a
> generic function.
> ---
>  lisp/mail/smtpmail.el | 33 +++++++++++++++++++++++++++++++--
>  1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
> index 20cbeb5f4e..46c1639832 100644
> --- a/lisp/mail/smtpmail.el
> +++ b/lisp/mail/smtpmail.el
> @@ -181,7 +181,25 @@ This is relative to `smtpmail-queue-dir'."
>  
>  (defconst smtpmail-auth-supported '(cram-md5 plain login)
>    "List of supported SMTP AUTH mechanisms.
> -The list is in preference order.")
> +The list is in preference order.
> +
> +New mechanisms can be added by defining a method implementing the
> +`smtpmail-try-auth-method' generic function for that mechanism, and
> +then adding the mechanism to this list.  As an example, the code below
> +adds support for XOAuth2 authentication (assuming that there is an
> +appropriate auth source extension that can provide the correct user
> +and password):
> +
> +\(cl-defmethod smtpmail-try-auth-method
> +    (process (mech (eql xoauth2)) user password)
> +  (smtpmail-command-or-throw
> +   process
> +   (concat \"AUTH XOAUTH2 \"
> +           (base64-encode-string
> +            (concat \"user=\" user \"\\1auth=Bearer \" password \"\\1\\1\") 
> t))
> +   235))
> +
> +\(add-to-list 'smtpmail-try-auth-method 'xoauth2)")
>  
>  (defvar smtpmail-mail-address nil
>    "Value to use for envelope-from address for mail from ambient buffer.")
> @@ -539,7 +557,18 @@ The list is in preference order.")
>         (funcall save-function))
>       result))))
>  
> -(defun smtpmail-try-auth-method (process mech user password)
> +(cl-defgeneric smtpmail-try-auth-method (process mech user password)
> +  "Try to authenticate to an SMTP process.
> +Authenticate to PROCESS using the MECH authentication mechanism, with
> +the given USER and PASSWORD. Implementations should either return the
> +result code from the authentication command, or throw 'done with an
> +error string. (This is usually done by calling
> +`smtpmail-command-or-throw' as the last step in the function.)")
> +
> +(cl-defmethod smtpmail-try-auth-method (process mech user password)
> +  "Default `smtpmail-try-auth-method' implementation.
> +This implementation provides support for the SMTP authentication
> +mechanisms 'cram-md5, 'login, and 'plain."
>    (let (ret)
>      (cond
>       ((or (not mech)
> -- 
> 2.15.0