Reading the article/message in elisp

Reading the article/message in elisp

[husain]

Hello,

If I am in

  - the summary page, with the cursor on an unopen article line, or in
  - the summary page, with an open article, or in
  - an article

I would like to be able to read the article content in elisp and execute
processes based on that. For example, if the message has
TO:person@work.xyz, or CC:person@work.xyz, then I would like to open the
person's profile page.

Is there a gnus elisp function that allows me to access the article
programmatically?

Thanks.

Re: Reading the article/message in elisp

[Emanuel Berg]

husain wrote:

> I would like to be able to read the article content in elisp
> and execute processes based on that. For example, if the
> message has TO:person@work.xyz, or CC:person@work.xyz, then
> I would like to open the person's profile page.

You can use `message-fetch-field' to get headers, as in:

(defun message-yank-subject ()
  (interactive)
  (save-excursion
    (let ((subj (message-fetch-field "Subject")))
      (when subj
        (message-goto-body)
        (insert (format "%s\n" subj)) ))))

More examples:
  https://dataswamp.org/~incal/emacs-init/gnus/message-header.el

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> We would like an arbitrary header access function where the
> header is provided as an argument, as in
>
> (defun gnus-article-header-value (hdr)
>   "Get the value of HDR for the current article."
>   (with-current-buffer gnus-original-article-buffer
>     (gnus-fetch-field hdr) ))
>
>  only one that works from anywhere, where the article is
> fetched from what article is selected (or, lacking that, where
> the point is) in the summary buffer.

There are quite a few functions defined in gnus-sum named
"gnus-summary-article-..." (some are defsubsts, some even macros) that
one can use.  I don't know whether a general access function as you
describe exists.  It won't make a programming task much easier, though.

Note that I don't know much about this, I only looked a bit at the code
in "gnus-sum.el".

Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

Michael Heerdegen wrote:

>>> It will then be the summary buffer article at point, not
>>> the selected one. If one is selected, it would make more
>>> sense to operate on that.
>>
>> Probably, but how that works I don't know, this
>>
>> (gnus-summary-article-number)
>>
>> is 20086 in the summary buffer but opening that up and
>> doing the same thing in that buffer (the article buffer)
>> I get 20085, but not point nor highlight has moved in the
>> summary buffer ... ?
>
> Looks like this function is useful only when called with the
> summary buffer current.

But as long as there is a summary buffer one could use point
to determine what article to act upon, so, if someone would
solve that practically, then a similar, improved version of
that function would be callable from wherever in Emacs and
still find and article and, from there, a header field value.

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Emanuel Berg]

Michael Heerdegen wrote:

>>>> The function `mail-header-subject' works but then you
>>>> don't get to select the header.
>>>
>>> What does "you don't get to select the header" mean?
>>
>> You only get the Subject header.
>
> With this accessor function, yes. And with the others, you
> get the other struct fields. Not sure what your question is.

We would like an arbitrary header access function where the
header is provided as an argument, as in

(defun gnus-article-header-value (hdr)
  "Get the value of HDR for the current article."
  (with-current-buffer gnus-original-article-buffer
    (gnus-fetch-field hdr) ))

 only one that works from anywhere, where the article is
fetched from what article is selected (or, lacking that, where
the point is) in the summary buffer.

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> Michael Heerdegen wrote:
>
> >> The function `mail-header-subject' works but then you don't
> >> get to select the header.
> >
> > What does "you don't get to select the header" mean?
>
> You only get the Subject header.

With this accessor function, yes.  And with the others, you get the
other struct fields.  Not sure what your question is.

Michael.

Re: Reading the article/message in elisp

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> >   (gnus-data-header (gnus-data-find (gnus-summary-article-number)))
> >
> > It will then be the summary buffer article at point, not the
> > selected one. If one is selected, it would make more sense
> > to operate on that.
>
> Probably, but how that works I don't know, this
>
> (gnus-summary-article-number)
>
> is 20086 in the summary buffer but opening that up and doing
> the same thing in that buffer (the article buffer) I get
> 20085, but not point nor highlight has moved in the
> summary buffer ... ?

Looks like this function is useful only when called with the summary
buffer current.

Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

>   (gnus-data-header (gnus-data-find (gnus-summary-article-number)))
>
> It will then be the summary buffer article at point, not the
> selected one. If one is selected, it would make more sense
> to operate on that.

Probably, but how that works I don't know, this

(gnus-summary-article-number)

is 20086 in the summary buffer but opening that up and doing
the same thing in that buffer (the article buffer) I get
20085, but not point nor highlight has moved in the
summary buffer ... ?

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Emanuel Berg]

Michael Heerdegen wrote:

>> The function `mail-header-subject' works but then you don't
>> get to select the header.
>
> What does "you don't get to select the header" mean?

You only get the Subject header.

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> The function `mail-header-subject' works but then you don't
> get to select the header.

What does "you don't get to select the header" mean?

Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

Michael Heerdegen wrote:

>>>> However, how will you get the specific header data out of
>>>> the result? Don't know ...
>>>
>>> I think the header object is a struct of type
>>> `mail-header' ("nnheader.el").
>>
>> But try to extract with `mail-header', it complains about
>> the data not being a list.
>
> Did you try with the function `mail-header'? I meant the
> accessor functions for the struct: `mail-header-subject',
> `mail-header-from', etc.

Yes, I tried the function `mail-header' ...

The function `mail-header-subject' works but then you don't
get to select the header.

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> >> However, how will you get the specific header data out of
> >> the result? Don't know ...
> >
> > I think the header object is a struct of type `mail-header'
> > ("nnheader.el").
>
> But try to extract with `mail-header', it complains about the
> data not being a list.

Did you try with the function `mail-header'?  I meant the accessor
functions for the struct: `mail-header-subject', `mail-header-from',
etc.

Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

Michael Heerdegen wrote:

>> However, how will you get the specific header data out of
>> the result? Don't know ...
>
> I think the header object is a struct of type `mail-header'
> ("nnheader.el").

But try to extract with `mail-header', it complains about the
data not being a list.

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> However, how will you get the specific header data out of
> the result? Don't know ...

I think the header object is a struct of type `mail-header'
("nnheader.el").

Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

Get data like this:

  (gnus-data-header (gnus-data-find (gnus-summary-article-number)))

It will  then be the summary buffer article at point, not the
selected one. If one is selected, it would make more sense to
operate on that.

However, how will you get the specific header data out of
the result? Don't know ...

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Michael Heerdegen]

Husain Alshehhi <husain@alshehhi.io> writes:

> I suppose that gnus-with-article-buffer works, almost. In the case that
> I am in gnus summary page [...]

I'm not sure what information is known by Gnus at that moment.  In the
summary, internally each article is identified with a number.  This
should be more or less (car (gnus-summary-work-articles 1)).

One could try to find information using that article number, e.g.

  (gnus-summary-article-header
    (car (gnus-summary-work-articles 1)))

will return an object containing the most important header data.  Try
with M-:.

Not sure what else Gnus knows, maybe you will have to fetch the header
for that article from the server.  Depends on what information you need,
and in what situations.  But I could also only try to find the relevant
functions in the source code (see "gnus-sum.el").


Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

Husain Alshehhi wrote:

>> In a temp buffer, no, but you can access the article buffer
>> using eg `gnus-with-article' or `gnus-with-article-buffer',
>> or even `gnus-with-article-headers' if you only care about
>> the headers.
>
> I suppose that gnus-with-article-buffer works, almost.
> In the case that I am in gnus summary page, with the point
> on an unopened article, when I run the following:
>
>         (defun husain--test-gnus-with-article-buffer()
>           (interactive)
>           (gnus-with-article-buffer
>             (message "%s" (message-fetch-field "Subject"))))
>
> It fails to read the subject. However, it works very well
> after I open the article. I think this solves 95% of the
> cases I run into.

If there isn't an article open, you can do that - with code -
from the summary buffer before you fetch the field. If there
is no article buffer and no summary buffer it is hard to think
of a use case and moreover it will be hard to determine, in
a way that makes sense, what mail or post the user refers to
when hitting the command.

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Husain Alshehhi]

Robert Pluim <rpluim@gmail.com> writes:

>
> In a temp buffer, no, but you can access the article buffer using eg
> `gnus-with-article' or `gnus-with-article-buffer', or even
> `gnus-with-article-headers' if you only care about the headers.

I suppose that gnus-with-article-buffer works, almost. In the case that
I am in gnus summary page, with the point on an unopened article, when I
run the following:

        (defun husain--test-gnus-with-article-buffer()
          (interactive)
          (gnus-with-article-buffer
            (message "%s" (message-fetch-field "Subject"))))

It fails to read the subject. However, it works very well after I open
the article. I think this solves 95% of the cases I run into.

Thank you.

Re: Reading the article/message in elisp

[Michael Heerdegen]

Robert Pluim <rpluim@gmail.com> writes:

>     Husain>         (defun husain--test-message-subject-yank ()
>     Husain>           (interactive)
>     Husain>           (save-excursion
>     Husain>             (let ((subj (message-fetch-field "Subject")))
>     Husain>               (if subj
>     Husain>                   (message subj)
>     Husain>                 (gnus-summary-show-article)
>     Husain>                 (gnus-summary-select-article-buffer)
>     Husain>                 (message (message-fetch-field "Subject"))))))
>
>     Husain> this still doesn't work as intended because it does not
>     Husain> restore the window if the point is in a gnus-summary
>     Husain> buffer pointing to an article not open.
>
>     Husain> Is there a gnus function that can build the message in a
>     Husain> temp buffer?
>
> In a temp buffer, no, but you can access the article buffer using eg
> `gnus-with-article' or `gnus-with-article-buffer', or even
> `gnus-with-article-headers' if you only care about the headers.

And you want to call `message' like (message "%s" ...) here, Husain:

When the ... can be arbitrary text, `message' will barf when the argument
accidentally contains %-sequences, like in

 (message "D'Oh, didn't expect a %-sequence here")


Michael.

Re: Reading the article/message in elisp

[Emanuel Berg]

Robert Pluim wrote:

> In a temp buffer, no, but you can access the article buffer
> using eg `gnus-with-article' or `gnus-with-article-buffer',
> or even `gnus-with-article-headers' if you only care about
> the headers.

You mean like this?

(defun gnus-article-header-value (hdr)
  "Get the value of HDR for the current article."
  (with-current-buffer gnus-original-article-buffer
    (gnus-fetch-field hdr) ))

:)

More:
  https://dataswamp.org/~incal/emacs-init/gnus/article.el

-- 
underground experts united
https://dataswamp.org/~incal

Re: Reading the article/message in elisp

[Robert Pluim]

>>>>> On Wed, 12 Jul 2023 04:59:08 +0000, Husain Alshehhi <husain@alshehhi.io> said:

    Husain> Emanuel Berg <incal@dataswamp.org> writes:
    >> You can use `message-fetch-field' to get headers, as in:
    >> 
    >> (defun message-yank-subject ()
    >> (interactive)
    >> (save-excursion
    >> (let ((subj (message-fetch-field "Subject")))
    >> (when subj
    >> (message-goto-body)
    >> (insert (format "%s\n" subj)) ))))
    >> 
    >> More examples:
    >> https://dataswamp.org/~incal/emacs-init/gnus/message-header.el

    Husain> Thank you. message-fetch-field works if the point is in a message
    Husain> buffer. I was not aware of this option. But when the point is in a
    Husain> gnus-summary buffer, then

    Husain>         (message-fetch-field "Subject")

    Husain> returns nil. Even with something like:

    Husain>         (defun husain--test-message-subject-yank ()
    Husain>           (interactive)
    Husain>           (save-excursion
    Husain>             (let ((subj (message-fetch-field "Subject")))
    Husain>               (if subj
    Husain>                   (message subj)
    Husain>                 (gnus-summary-show-article)
    Husain>                 (gnus-summary-select-article-buffer)
    Husain>                 (message (message-fetch-field "Subject"))))))

    Husain> this still doesn't work as intended because it does not restore the
    Husain> window if the point is in a gnus-summary buffer pointing to an article
    Husain> not open.

    Husain> Is there a gnus function that can build the message in a temp buffer?

In a temp buffer, no, but you can access the article buffer using eg
`gnus-with-article' or `gnus-with-article-buffer', or even
`gnus-with-article-headers' if you only care about the headers.

Robert
-- 

Re: Reading the article/message in elisp

[Husain Alshehhi]

Emanuel Berg <incal@dataswamp.org> writes:

> You can use `message-fetch-field' to get headers, as in:
>
> (defun message-yank-subject ()
>   (interactive)
>   (save-excursion
>     (let ((subj (message-fetch-field "Subject")))
>       (when subj
>         (message-goto-body)
>         (insert (format "%s\n" subj)) ))))
>
> More examples:
>   https://dataswamp.org/~incal/emacs-init/gnus/message-header.el

Thank you. message-fetch-field works if the point is in a message
buffer. I was not aware of this option. But when the point is in a
gnus-summary buffer, then

        (message-fetch-field "Subject")

returns nil. Even with something like:

        (defun husain--test-message-subject-yank ()
          (interactive)
          (save-excursion
            (let ((subj (message-fetch-field "Subject")))
              (if subj
                  (message subj)
                (gnus-summary-show-article)
                (gnus-summary-select-article-buffer)
                (message (message-fetch-field "Subject"))))))

this still doesn't work as intended because it does not restore the
window if the point is in a gnus-summary buffer pointing to an article
not open.

Is there a gnus function that can build the message in a temp buffer?