R/cranmirrors.R

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## cranmirrors
## @include crandb.R


#' @title CRAN archive (CRAN-archive.html + archivedb)
#' @description
#' \code{cranmirrors_down} downloads the csv file of CRAN mirrors, modifies the
#' "Maintainer" and "Host" columns, eventually saves the modified data.frame on
#' the disk, loads this data.frame in .GlobalEnv and prints in the console a
#' subset of the data.frame made of the selected columns.
#'
#' @param   filename   character. The path to file "CRAN-mirrors1.csv" (or equivalent).
#' @param   dir        character. The directory where \code{filename} is saved.
#'                     Default value \code{"."} is the current directory.
#' @param   columns    a vector of integers or a vector of names.
#'                     The column numbers or the column names. Allowed numbers
#'                     are within 1:9. Allowed names are: "Name", "Country",
#'                     "City", "URL", "Host", "Maintainer", "OK", "CountryCode"
#'                     and "Comment".
#' @param   save       logical. Save the file. If \code{FALSE}, the default, the
#'                     file is just loaded in .GlobalEnv and a subset is printed
#'                     in the console.
#' @param   url        character. The url address of the CRAN csv file.
#'
#' @examples
#' cranmirrors_down(dir = file.path(tempdir(), "cranmirrors"), save = TRUE)
#'
#' @export
#' @name cranmirrors_down
cranmirrors_down <- function(filename = "CRAN-mirrors1.csv", dir = ".",
                        columns = c(1,2,3,7), save = FALSE,
                        url = "https://cran.r-project.org/CRAN_mirrors.csv") {
    dest <- tempfile()
    trdl <- trydownloadurl(url, dest)
    if (trdl != 0) {
        message(paste("URL does not exist:", url))
        return(invisible(NULL))
    }
    cranmirrors <- utils::read.csv(dest, stringsAsFactors = FALSE, encoding = "UTF-8")
    dfr2 <- gsub(" # ", "@", cranmirrors[,"Maintainer"])
    dfr2 <- gsub(">|<", "", dfr2)
    lst  <- sapply(dfr2, strsplit, split = " ", fixed = TRUE, USE.NAMES = FALSE)
    vec  <- sapply(lst, function(x) x[length(x)])
    cranmirrors[, "Maintainer"] <- vec
    vec2 <- sapply(cranmirrors[, "Host"], function(x) substring(
                   x, 1, 76), USE.NAMES = FALSE)
    cranmirrors[, "Host"] <- vec2
    if (save) {
        if (!dir.exists(dir)) dir.create(dir, recursive = TRUE)
        destfile <- file.path(dir, filename)
        utils::write.csv(cranmirrors, file = destfile, row.names = FALSE,
                         fileEncoding = "UTF-8")
    }
    cranmirrors <<- cranmirrors
    if (is.null(columns)) columns <- 0
    message(paste0("Modified cranmirrors loaded in .GlobalEnv."))
    message(paste0(nrow(cranmirrors), " servers. Columns printed: ",
                   paste0(columns, collapse = ", ")))
    cranmir <- if (columns[1] == 0) cranmirrors else cranmirrors[,columns]
if ("OK" %in% colnames(cranmir)) cranmir[order(cranmir$OK),] else cranmir
}