downloadWithRetries {argoFloats}

Download and Cache a Dataset

Description

General function for downloading and caching a dataset.

Usage

downloadWithRetries(
  url,
  destdir,
  destfile,
  quiet = FALSE,
  age = argoDefaultProfileAge(),
  retries = 3,
  async = FALSE,
  debug = 0
)

Arguments

url

character value giving the full URL of a file to be downloaded.

destdir

character value indicating the directory in which to store downloaded files. The default value is to compute this using argoDefaultDestdir(), which returns ⁠~/data/argo⁠ by default, although it also provides ways to set other values using options(). Set destdir=NULL if destfile is a filename with full path information. File clutter is reduced by creating a top-level directory called data, with subdirectories for various file types; see “Examples”.

destfile

either character value indicating the name of the file or NULL (the default), in which case the file name is constructed from the other parameters of the function call, so that subsequent calls with the same parameters will yield the same result; this is useful for caching.

quiet

logical value; use FALSE to show more verbose information when downloading files. (Even if quiet is TRUE, problems will still be reported.)

age

a numerical value indicating a time interval, in days. If the file to be downloaded from the server already exists locally, and was created is less than age days in the past, it will not be downloaded. The default, argoDefaultProfileAge(), is one year. Setting age=0 will force a download.

retries

integer telling how many times to retry a download, if the first attempt fails.

async

Use TRUE to perform requests asynchronously. This is much faster for many small files (e.g., Argo profile NetCDF files).

debug

integer value indicating level of debugging. If this is less than 1, no debugging is done. Otherwise, some functions will print debugging information. If a function call fails, the first step should be to rerun the function with debug=1, to see if the output suggests a problem in the call.

Value

A character value indicating the full pathname to the downloaded file, or NA, if there was a problem with the download.

Author(s)

Dan Kelley