Page logic

• Define page logic as the entry point for one page request.
• Position it as thin coordination code rather than the home of all business rules.

How logic pairs with a view

• Explain filename pairing with the page view.
• Explain what happens when there is no logic file.

Logic hooks

go functions

• Introduce the go function.
• The functions should not output anything directly - any output from echo or debug code will be sent to the browser's developer console.

do functions

• Introduce do functions.
• Explain the role of do_* methods for user actions.

Order of execution

• Introduce go_before, `go_after.
• Explain the order in which they all run.
• Explain how nested _common logic will run in a particular order (from nested out, or the other way around, whatever it actually is).

What to do in page logic

• Read input.
• Call application classes or services.
• Bind data to the document.
• Set headers or response state.

What NOT to do in page logic

• Large business rules.
• Raw SQL manipulation code.
• HTML in strings construction.
• Reiterate that any output from echo or debug code will be sent to the browser's developer console.

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Now the pages can have dynamic content, let's learn about dynamic URLs.