As you know, Simon is a website and server monitoring tool. This mouthful is to try to describe two of the levels at which Simon operates. At the very basic level, Simon is a very simple utility to watch web pages, and let you know when they change or go down. But Simon has much more depth to it — it enables you to monitor all sorts of internet servers and services, local applications, disk volumes, and more.

The Preview pane has this duality, too. When used with a web-based test (i.e. one using the Web Page service), it displays the rendered web page and graphics on the left (which can be interacted with like in a web browser), and the HTML source, web page headers, and filter output on the right:

This is really handy, both to quickly see the page while in Simon, without having to switch to a web browser (which is easy too, via the File ▸ Visit Site command), and when setting up the test in the first place.

The service and filter output are useful, too; you can see the HTML (or other) output, and the output of each filter.

The filters are one of Simon’s key features. This is a page of the test editor, where you can tell Simon to only look at the HTML source between two blocks of text, or find required text, or evaluate numbers, or reformat text, and much more. This enables you to focus on the part of the page you care about, and avoid dynamic portions like banner ads etc. You can easily set this up via the Preview window. With the test editor open, after entering the URL, show the Preview to display the preview of the page. Then search through the HTML source for interesting portions of the text (click in the HTML then press ⌘F to find text), select it, copy the relevant text, and paste into filter fields.

For example, here’s Apple’s RSS feed, with filters to extract and format the title and body text of the latest news:

As useful as this is, it’s not done yet. The Preview is also supported by many other services, in a slightly different way. For non-web services, the Preview looks much the same, but without the rendered content. Instead of the HTML source, it shows the output of the service. This is all plain text, since that’s what these services deal with.

For example, here’s the preview of a Ping test:

These services support the filters, too: just like with web pages, you can use filters to analyze the output and extract interesting nuggets.

I hope you’ll use the Preview to good advantage when configuring and using Simon.