Normalize an optional integer param. Accepts a number or a numeric string. Rejects non-integers rather than rounding: a page of 1.5 is a caller mistake, and silently reading page 1 would return plausible wrong data.
Optional
Normalize an optional integer param. Accepts a number or a numeric string. Rejects non-integers rather than rounding: a page of 1.5 is a caller mistake, and silently reading page 1 would return plausible wrong data.