Integrating Remote email2rss into macOS

This article provides a guide for creating an Apple Script that registers as the default handler for the feed URI schema on a local machine. The script forwards all URIs to a remote instance and registers it into rss2email. It also contains some useful notes about running rss2email on remote host.

Create and register proxy application

The first section of this article describes the process of creating an application that serves as a proxy to add feeds to a remote rss2email on a specific host.

The integration is achieved using Apple Script. The first step of integration is creating a new script with the following content:

property rss2emailHost : "some.host.net"
property sshAuthSocket : ""

on open location feedUri
	try
		if {feedUri does not start with "feed:"} then
			display alert "Unexpected feed URI: " & feedUri
			return
		end if

		set feedUri to (items 6 thru -1 of feedUri) as string

		if {feedUri is ""} then
			display alert "Empty feed URI"
			return
		end if

		set feedQueryQuestion to "Please Enter Feed name for: " & feedUri
		set feedQueryTitle to "Enter name for new RSS feed"
		set feedQueryButtons to {"Reject", "Save", "Save via Web Archive"}

		set feedQuery to display dialog feedQueryQuestion default answer "" buttons feedQueryButtons with title feedQueryTitle default button 1

		set clickedButton to the button returned of the feedQuery
		set feedName to text returned of the feedQuery

		if ({feedName is ""} or {clickedButton is "Reject"}) then
			return
		end if

		if {clickedButton is "Save via Web Archive"} then
			set feedUri to "https://web.archive.org/web/" & feedUri
		end if

		set sshCmd to "ssh " & rss2emailHost & " r2e add " & feedName & " " & feedUri & " 2>&1"

		if {sshAuthSocket is not ""} then
			set sshCmd to "env SSH_AUTH_SOCK=" & sshAuthSocket & " " & sshCmd
		end if

		set sshOutput to do shell script sshCmd
		if {sshOutput is not ""} then
			display alert sshOutput
		end if
	on error errMsg
		display alert errMsg
	end try
end open location

replace some.host.net with the name of the host that was used.

Note that the script supports the use of a custom ssh-agent socket, which can be configured via the sshAuthSocket parameter. This parameter expects the full path to the socket or an empty string.

This script should be saved as application into ~/Application folder.

Once saved as an application, the URI handler should be added by adding code below into Contents/Info.plist inside the application after the last CFBundle… key-value pair.

	<key>CFBundleURLTypes</key>
	<array>
		<dict>
			<key>CFBundleURLName</key>
			<string>RSS feed</string>
			<key>CFBundleURLSchemes</key>
			<array>
				<string>feed</string>
			</array>
		</dict>
	</array>

When the application is launched for the first time, this script gets registered as an available handler for the feed URI Schema. The application can now be configured as the default handler for the this schema through SwiftDefaultApps or a similar application, or by manually editing ~/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist.

Notes on Remote Settings

The article’s script provides two buttons: Save and Save via Web Archive. The latter uses Web Archive as a source of feed, which can be useful when the remote host blocks your server for some reason.

However, this approach may introduce a delay that depends on the crawling cycle of the Web Archive. The crawling cycle can be controlled via the line below in crontab. It is important to note that each call suggests, but does not enforce, crawling of the provided URL.¹

~	~	*	*	*	r2e opmlexport | xq -r '.opml.body.outline[]."@xmlUrl"' | grep 'https:\/\/web.archive.org\/web\/' | sed -e 's/\/web\//\/save\//' | xargs curl --fail --silent -o /dev/null || echo Update Web Archive for rss2email fails