needsTimestampOld: Determine whether an item should fetch a timestamp or not

In USGS-VIZLAB/vizlab: Utilities for building online data visualizations

Description

Looks in the dependency scripts and on the current search path (plus vizlab) to determine whether the fetchTimestamp method for this fetcher is actually available somewhere. DOESN'T currently look in any packages loaded via library within the sourced scripts (to avoid altering the current environment without the user's permission), which means we'll get confused if some other package implements, say, fetchTimestamp.yadayada. That's an unlikely situation, so if we need it, we can implement it then (or the user can call library() on that package before calling createMakefiles()).

Usage

needsTimestampOld(item.info)

Details

Looks at the fetchTimestamp argument in this item's viz.yaml info to see what the user expects.

Value

logical: TRUE if timestamp is needed (== a fetchTimestamp.fetcherforthisvizitem method is available), FALSE otherwise. Also produces an error if there's a mismatch between what's declared in the viz.yaml and whether a fetchTimestamp method appears to be available for this fetcher.

USGS-VIZLAB/vizlab documentation built on July 10, 2019, 12:08 a.m.