Support forwarding feed entry like gnus

[ParetoOptimalDev]

gnus generates an email from what elfeed calls a feed entry with gnus-summary-mail-forward.

What it does is given:

gnus article (elfeed feed entry equivalent)

From: old.reddit.com
Subject: docker_tramp vs tramp-container for remote dockers
Newsgroups: r.emacs
Date: Mon, 24 Apr 2023 16:27:18 +0000 (3 hours, 18 minutes, 7 seconds ago)
Attachment: [2. text/plain]...

u/FrozenOnPluto comments

Thanks for reading folks!

I've just updated to an experimental Emacs build (30.0.50) and prayed on first run .. but my existing massive .
emacs came up pretty well, only a couple of gnits. One of the warnings was not to use docker-tramp anymore
due to the built in tramp-container.el

At a quick glance of the .el and errors it produces, I'm getting the feeling that was designed around local
containers (Docker running locally with the Emacs), but not for a remote container

For example, I use Tramp via multi-hop, so that I can ssh to a server where the containers are running, and run
the docker ps and open a shell within the images _over there_

So a bookmark would look something like:

/ssh:[foo@someserver.com](mailto:foo@someserver.com)|docker:bar@container:/path/within/docker

tramp-container.el looks like the same syntax (/docker) as docker-tramp, but I wonder if it only works locally?

I'll have to try docker-tramp again and see if remote still works there, or am I out of luck on this astoundingly
handy behaviour. (or perhaps a local docker daemon can reach out to remote docker daemons, or I can run some
ssh tunnels to pretend local is remote, or something..)

edit: Looks like I had a defcustom override for the docker tramp so it was using 'sudo docker' on the target very
old system; so I added a override tramp-docker-program for the new module, but still no dice. (Currently
experimenting with things like /ssh:foo@someserver.com|sudo::|docker:bar@containername:/path but still no
dice)

link

It inserts this email below with I think M-x compose-mail:

forward email draft generated

To: 
Subject: [r.emacs] docker_tramp vs tramp-container for remote dockers
Gcc: "nnimap+LocalMail:pareto.optimal@mailfence.com/Sent Items"
From: ParetoOptimalDev <pareto.optimal@mailfence.com>
--text follows this line--

-------------------- Start of forwarded message --------------------
Subject: docker_tramp vs tramp-container for remote dockers
From: old.reddit.com
Date: Mon, 24 Apr 2023 16:27:18 +0000

<#multipart type=alternative>
<#part type=text/plain disposition=inline nofile=yes>
<p><a href="https://old.reddit.com/u/FrozenOnPluto">u/FrozenOnPluto</a> <a
href="https://old.reddit.com/r/emacs/comments/12xo758/docker_tramp_vs_trampcontainer_for_remote_dockers/">comments</a></p>
<!-- SC_OFF --><div class="md"><p>Thanks for reading folks!</p> <p>I've just updated to an experimental Emacs build
(30.0.50) and prayed on first run .. but my existing massive .emacs came up pretty well, only a couple of gnits. One
of the warnings was not to use docker-tramp anymore due to the built in tramp-container.el</p> <p>At a quick glance of
the .el and errors it produces, I'm getting the feeling that was designed around local containers (Docker running
locally with the Emacs), but not for a remote container</p> <p>For example, I use Tramp via multi-hop, so that I can
ssh to a server where the containers are running, and run the docker ps and open a shell within the images _over
there_</p> <p>So a bookmark would look something like:</p> <p>/ssh:[<a
href="mailto:foo@someserver.com">foo@someserver.com</a>](mailto:<a
href="mailto:foo@someserver.com">foo@someserver.com</a>)|docker:bar@container:/path/within/docker</p>
<p>tramp-container.el looks like the same syntax (/docker) as docker-tramp, but I wonder if it only works locally?</p>
<p>I'll have to try docker-tramp again and see if remote still works there, or am I out of luck on this astoundingly
handy behaviour. (or perhaps a local docker daemon can reach out to remote docker daemons, or I can run some ssh
tunnels to pretend local is remote, or something..)</p> <p>edit: Looks like I had a defcustom override for the docker
tramp so it was using 'sudo docker' on the target very old system; so I added a override tramp-docker-program for the
new module, but still no dice. (Currently experimenting with things like /ssh:<a
href="mailto:foo@someserver.com">foo@someserver.com</a>|sudo::|docker:bar@containername:/path but still no dice)</p>
</div><!-- SC_ON -->

https://old.reddit.com/r/emacs/comments/12xo758/docker_tramp_vs_trampcontainer_for_remote_dockers/
<#part type=text/html nofile=yes>
<html><head></head><body>
<p><a href="https://old.reddit.com/u/FrozenOnPluto">u/FrozenOnPluto</a> <a href="https://old.reddit.com/r/emacs/comments/12xo758/docker_tramp_vs_trampcontainer_for_remote_dockers/">comments</a></p> <!-- SC_OFF --><div class="md"><p>Thanks for reading folks!</p>
<p>I've just updated to an experimental Emacs build (30.0.50) and prayed on first run .. but my existing massive .emacs came up pretty well, only a couple of gnits. One of the warnings was not to use docker-tramp anymore due to the built in tramp-container.el</p>
<p>At a quick glance of the .el and errors it produces, I'm getting the feeling that was designed around local containers (Docker running locally with the Emacs), but not for a remote container</p>
<p>For example, I use Tramp via multi-hop, so that I can ssh to a server where the containers are running, and run the docker ps and open a shell within the images _over there_</p>
<p>So a bookmark would look something like:</p>
<p>/ssh:[<a href="mailto:foo@someserver.com">foo@someserver.com</a>](mailto:<a href="mailto:foo@someserver.com">foo@someserver.com</a>)|docker:bar@container:/path/within/docker</p>
<p>tramp-container.el looks like the same syntax (/docker) as docker-tramp, but I wonder if it only works locally?</p>
<p>I'll have to try docker-tramp again and see if remote still works there, or am I out of luck on this astoundingly handy behaviour. (or perhaps a local docker daemon can reach out to remote docker daemons, or I can run some ssh tunnels to pretend local is remote, or something..)</p>
<p>edit: Looks like I had a defcustom override for the docker tramp so it was using 'sudo docker' on the target very old system; so I added a override  tramp-docker-program for the new module, but still no dice. (Currently experimenting with things like /ssh:<a href="mailto:foo@someserver.com">foo@someserver.com</a>|sudo::|docker:bar@containername:/path but still no dice)</p>
</div><!-- SC_ON -->
<p><a href="https://old.reddit.com/r/emacs/comments/12xo758/docker_tramp_vs_trampcontainer_for_remote_dockers/">link</a></p>
</body></html>
<#/multipart>
-------------------- End of forwarded message --------------------

I don't even need it to be full featured and embed html/multipart honestly, just having a function as part of elfeed to copy the elfeed buffer and open up compose-mail would be fine. I'll probably write that for myself, but I figured others trialing elfeed out from gnus or other users in general might find this useful.

My main point of sharing since I started using a feed reader and gnus has been forwarding feeds in emails and I guess others likely do it often as well.