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You’re Doing That Wrong is a journal of various successes and failures by Dan Sturm.

Remote Screen Sharing Automation

I’ve always found it fairly easy to manage my multiple Macs with tools like Dropbox, the Mac App Store, and iCloud. But trying to manage Macs that are in different physical locations, on different networks, has really put some of my workflows to the test. There are, it seems, some workflow issues that can’t solved by just putting things in Dropbox. Go figure 1 .

For the past few weeks, I’ve been looking around for ways to “get to” my home iMac from my iMac at work. I quickly found I needed more than just “access to the data” on that computer. I needed to control it via some form of screen sharing.

I tried Screens . It didn’t like my company’s port mapping. Nothing I can really do about that.

Someone in our IT department recommended Royal which, according to my research, is an application that does…something.

In true You’re Doing That Wrong fashion, the solution that had the most success was texting my wife at home and asking her to click “Accept” on the iMessage Screen Sharing request that I was sending from my work computer. But after about a half-dozen requests, I knew I needed a better solution.

Solutioneering

The Screen Sharing tools built into iMessage are great. They’re simple, easy to use, and (miraculously) they just work. I don’t need to open ports on my router or run a private VPN, I just open iMessage, select the person I want to Screen Share with, and click “Ask to Share Screen”.

Given my propensity for making very bad, very unsafe automations, you may be imagining that I just created a Keyboard Maestro macro that would watch for the “Incoming Screen Sharing Request” notification and click “Accept”. But even I realized what an awful idea that would be.

Luckily, there’s another menu item in iMessage, just above the “Ask to Share Screen” item. It’s the “Invite to Share My Screen” option. So, I set about making a tool that I could activate remotely, that would call me from my home iMac and offer to share its screen.

Shortcuts & Hazel

The easiest way to get things up and running was to duplicate a few of the things I’d created for my Open on Which Mac tool. I duplicated the iOS Shortcut I’d use to trigger the whole thing, and the Hazel rule watching for the Shortcut’s input.

  1. Sometimes Dropbox is the issue. But that’s a post for another time. ↩
 
 

The only thing I needed to change in the Shortcut and Hazel rule was to swap “URL” for “ScreenShare” in the filename. So, the Destination Path in the shortcut reads: Applications/Batch/openonmac/Dictionary Value-ScreenShare-Current Date.txt .

While I’m currently only going to use the tool to remote into my home iMac from work, leaving the rest of the Shortcut intact will allow me to more easily 2 add the ability to remote into other computers later.

Keyboard Maestro

Now on to the meat of the thing. We start by using the macOS URL scheme for Messages.app to send a message to my Apple ID. By hard-coding my Apple ID into the macro, there’s no way I can accidentally send the invitation to someone else. Which would be very bad.

By opening the url imessage:myappleid@email.com , KM will open Messages.app and create a new iMessage to my Apple ID. Now, it turns out, it’s not enough to just create a new message with a recipient selected. The Screen Sharing menu items aren’t accessible until you actually send something. So I took this as an opportunity to add a bit of transparency to the process. The macro types out the words “Incoming Connection from Dan’s iMac” and hits Return . In addition to making the Screen Sharing tools accessible, I will get an iMessage (everywhere) letting me know that the Screen Sharing Invitation is imminent and it’s coming from the computer I expected.

Next, the macro opens the “Buddies” menu and selects “Invite to Share My Screen”. Within a few seconds, wherever I may be, and invitation to share the screen of my home iMac appears on my desktop and I can click “Connect”.

  1. With one potentially major hurdle. ↩

That was…surprisingly simple.

Not quite

Since Apple is very good about keeping things safe and secure, the Screen Sharing session activates in “Observing” mode. Which is not terribly helpful. Additionally complicating matters, the only way to approve “Control” of the Screen Sharing session to a remote user is to click on the Screen Sharing menu bar icon that indicates a connection is active.

Initially, I tried to click the menu with Keyboard Maestro’s “Click at Found Image” action, but the menu bar icon flashes when connected and it failed more often than it succeeded. After a bit of googling, some poking around in Activity Monitor, and a brief consultation with Dr. Drang , I discovered I could activate the menu and select “Allow Dan to control my screen” with some basic AppleScript. Which looks like this:

tell application "System Events" to tell process "SSInvitationAgent"
    click menu bar item 1 of menu bar 1
    click menu item 2 of menu 1 of menu bar item 1 of menu bar 1
end tell

Limitations and Improvements

There is one big limitation to this tool. You may have already guessed it. The tool, as it exists here, doesn’t work when the computer is locked. So I resorted to turning off “Require Password” in System Preferences on my home iMac. Which sounds like a huge security risk not worth taking for the benefit it provides but, frankly, if an untrustworthy person is sitting at my desk in my home office, I have bigger problems than whether or not there’s a password on my iMac.

This does, however, preclude me from using this particular solution for the reverse procedure of connecting to my work iMac from home. Turning off my system password definitely isn’t going to fly with our IT department. So, at the moment, this is at best half a solution.

Another thing I’ll probably change in the next iteration of the tool is to remove Hazel from the process entirely. Recently, in the process of debugging a Hazel rule, I recreated it from scratch inside Keyboard Maestro. KM’s ability to watch a folder and act on files that appear inside worked well enough for me to consider migrating more “watch folder” actions over there in the future. Its debugging tools are better, too.

Something else that could use improving is the speed of some of the actions. Currently, depending on how long it takes for me to accept the screen sharing session from my work iMac, the screen sharing menu bar icon may not be available in time for the AppleScript action to find it and grant me “Control” access. My current workaround is to just run the whole process again while I’m in “Observe” mode. It only takes a few second and it works fine.

Speaking of the AppleScript step, there’s also an odd delay of a few seconds between opening the menu bar app and selecting the “Allow Dan to Control” item. In my conversation with Dr. Drang, he pointed me to this post on Stack Overflow which both explained and solved the issue, so that seems like an easy fix for the next version.

By the way, it would seem (to me) that none of this would need to exist if there was some mechanism by which iMessage could tell that the Screen Sharing request was coming from my Apple ID, sent to my Apple ID, and allow me to automatically authenticate those interactions. Hell, prompt me for my iCloud password if you want to keep it safe. Seems like a reasonable request to me, but what do I know. I’m just some idiot with a blog.