R/source_github.R

In achubaty/amc: Alex's Miscellaneous Code

#' Source a file hosted in a pubic or private GitHub repo
#'
#' @param repo   Name of the GitHub repository in the form \code{"user/repo"}.
#'
#' @param branch Branch from which to source the file (default master).
#'
#' @param file   Filename to source, including relative path.
#'
#' @param auth   Personal Access Token to use for authorization.
#'               Required to access files in private repositories.
#'               By default, checks for \code{GITHUB_PAT} environment variable.
#' See \url{https://help.github.com/articles/creating-an-access-token-for-command-line-use/}.
#'
#' @author Alex Chubaty
#' @importFrom base64enc base64decode
#' @importFrom httr add_headers content GET stop_for_status
#' @importFrom magrittr %>%
#' @export
#' @rdname source_github
#'
#' @examples
#' \dontrun{
#' repo = "PredictiveEcology/SpaDES"
#' branch = "development"
#' file = "_ignore/thinSpatialPolygons.R"
#' auth = "" ## your Personal Access Token
#'
#' source_github(repo, branch, file, auth)
#' }
source_github <- function(repo, branch = "master", file, # nolint
                          auth = Sys.getenv("GITHUB_PAT")) {
  stopifnot(
    all(sapply(c(repo, branch, file), is.character)),
    all(sapply(c(repo, branch, file), length) == 1)
  )

  header_accept <- "application/vnd.github.v3.raw"  # nolint
  header_auth <- if (is.null(auth)) {  # nolint
    NULL
  } else {
    paste0("auth")
  }

  tmpfile <- tempfile()
  on.exit(unlink(tmpfile))

  url <- paste0("https://api.github.com/repos/", repo, "/contents/", file,
                "?ref=", branch)

  r <- httr::GET(url, config = list(
    add_headers(Accept = header_accept, Authorization = header_auth)
  ))
  httr::stop_for_status(r)

  httr::content(r)$content %>%
    base64enc::base64decode %>%
    writeBin(tmpfile)

  source(tmpfile)
}