If you install Simon on an Apple Silicon (M1, M2, etc) based Mac, you may notice Web Page tests timing out.

That is because the Web Page service uses an embedded helper tool to load the HTML in a separate process, to improve performance and reduce the risk of crashing Simon. But currently this helper is Intel-only. Some other helpers, e.g. to send emails or upload reports to a remote server, are also Intel-only.

This is fine, but it means that you need to install Rosetta, Apple’s emulation layer to enable running Intel apps on Apple Silicon.

The main Simon app is universal, so launching it won’t prompt to install Rosetta, but you can override that by checking the “Open using Rosetta” option in the Finder’s Get Info window:

Just remember to uncheck that option after you’ve opened Simon, so subsequent launches use the universal code.

A customer sent a query, asking how to use Simon to monitor the subscriber counts on YouTube channels.

This is easy for Simon to do, by having Web Page tests for each YouTube channel, each with a filter to extract the subscriber count, and whatever notifier you wish.

The first step is to add a Web Page test for a YouTube channel, and look at the HTML output in the Preview pane, to find how the subscriber count appears.

For example, for my Sinclair Trails channel, the HTML includes:

    "subscriberCountText":{"accessibility":{"accessibilityData":{"label":"30 subscribers"}},"simpleText":"30 subscribers”},

Yes, I currently only have 30 subscribers… rather sad. Please subscribe to help me reach a more respectable number!

A sensible default choice for a filter is the Block one, though in this case a better choice would be the Find Regular Expression filter. But if you want to have several tests with the same notifier configuration, an even better choice is to create a new custom notifier, so you don’t have to configure the notifier for each test.

A regular expression to extract the subscriber count from that HTML could be:

    subscriberCountText.+?simpleText\":\"(.+?)\”\}

This will look for text starting with “subscriberCountText”, some more text, then “simpleText”:"” , then capture the desired text up until “”\}” .

In my case, that will result in:

    30 subscribers

To make a new filter for this, you can go to the Filters page in Simon, and add a new filter named “YouTube subscribers” (or whatever you prefer).

Then choose Find for the Filter Kind, and Regular Expression from the find options menu:

Then enter the expression as the find text, and choose Capture 1 as the output:

Click Done, then go back to your YouTube test, and choose this new filter on the Filters page:

This will output just the subscriber count:

You can see this output in the Activity log:

Or you can add a new Email notifier to email the filter output using the {FilterOutputText} variable:

And of course use that notifier in your test, along with whatever other notifiers you wish:

Then you can add more tests for other YouTube channels you want to monitor, specifying your YouTube subscribers filter for each. For example, CGP Grey has a few more subscribers than me:

I hope this helps!

Here’s a fun example of using Simon for a purpose that may not be entirely obvious.

My wife and I had a big trip to Yellowstone National Park coming up, so I was curious about what the traffic was like to get into the park.

Conveniently, Yellowstone has a number of webcams that watch the park, including the west entrance gate, where we’d be entering.

So I thought I could leverage Simon to help me watch it over time — rather than keeping the web page open and watching it throughout the day, I can have Simon capture the webcam images to a local folder, then review at my convenience.

To find the URL of the webcam image, I used Safari’s web inspector:

Then I added a custom service to Simon to download the webcam images to a folder:

That uses the curl command line tool to download the image and save to a local folder; the `date -v+1H +%Y%m%d%H%M%S` part of the path outputs the date and time in the format YYMMDDHHMMSS, adding one hour from my local time zone, since Yellowstone was an hour ahead of me at the time.

To schedule the captures, I added a test in Simon that checks once per minute, using that service. No filters or notifiers needed.

That results in a folder in the Finder with files like this:

I can arrow through them to quickly view them. And I can also do other things, like use the excellent Retrobatch app to convert them to a GIF:

Click to view an example of the resulting GIF, showing the traffic flow from 06:00 to 18:00 on one day (the GIF is 61 MB, despite being scaled, so might take a moment to load); each frame of the GIF represents one minute, six frames per second:

That seems typical; it gets really busy around 06:30, and eases off around 12:30 every day. So a tip for Yellowstone visitors; enter in the afternoon! Of course, that really only works if you’re staying in the park, since it takes ages to get anywhere in the park. It’s a big place.

If you’re curious, I did several posts about this Yellowstone trip on my Sinclair Trails blog. Check it out!

One of the major strengths of Simon, my website and server monitoring tool, is the flexibility it offers through the ability to write custom scripts in many scripting languages. Simon is plenty useful with the built-in services, filters, and notifiers, but the ability for customers to enhance it themselves makes it even better.

There are several script-based services, filters, and notifiers built in to the app, and others can be downloaded from the Simon Extras page.

One such example is the Show & Screenshot notifier script (click that link to download it). To install it, go to the Notifiers page in Simon, add a new notifier, choose Script for the notifier kind, click the Open Script… button, and choose the downloaded script.

This script simply opens the page in the default web browser, waits a few seconds for the page to render, then takes a screenshot of it. By default it’ll wait 10 seconds, and save to the Desktop, but you can customize those values; enter the path of a folder to save them to (the folder must already exist). Also specify how long to wait before performing the screenshot, in seconds:

And of course to use the notifier, specify it in the Notifiers page of a test:

Note that when this notifier is first used, macOS will ask for permission to capture the screen; until you grant that, it’ll capture an empty desktop.

Check out the Simon Extras page for other scripts. And if you create a useful script for Simon, please share it with others!