dot-parallelRangedDownload: Download a file in parallel using HTTP Range requests
In reproducible: Enhance Reproducibility of R Code

.parallelRangedDownload

R Documentation

Download a file in parallel using HTTP Range requests

Description

Internal helper for the opt-in parallel download path (Feature A). Splits ⁠[0, size)⁠ into n contiguous byte ranges and fetches them concurrently with one curl handle per part (each carrying its own ⁠Range:⁠ header) via curl's multi interface. On success the parts are concatenated in order and the total size is verified to equal size, so the result is byte-identical to a single-stream download. Returns FALSE (rather than erroring) on any partial failure or size mismatch, so the caller can fall back to single-stream.

Usage

.parallelRangedDownload(
  url,
  destFile,
  size,
  n,
  verbose = getOption("reproducible.verbose", 1)
)

Arguments

`url`	The (already-resolved, range-capable) URL.
`destFile`	The destination file path to assemble into.
`size`	Total expected size in bytes (from `.probeRange()`).
`n`	Number of parallel streams (`reproducible.parallel.streams`).
`verbose`	Numeric verbosity level.