R/parse-url.R

In pkgcache: Cache 'CRAN'-Like Metadata and R Packages

parse_url <- function(url) {
  re_url <- paste0(
    "^(?<protocol>[a-zA-Z0-9]+)://",
    "(?:(?<username>[^@/:]+)(?::(?<password>[^@/]+))?@)?",
    "(?<host>[^/]+)",
    "(?<path>.*)$"            # don't worry about query params here...
  )

  mch <- re_match(url, re_url)
  mch[, setdiff(colnames(mch), c(".match", ".text")), drop = FALSE]
}

re_match <- function(text, pattern, perl = TRUE, ...) {

  stopifnot(is.character(pattern), length(pattern) == 1, !is.na(pattern))
  text <- as.character(text)

  match <- regexpr(pattern, text, perl = perl, ...)
  match <- regexpr(pattern, text, perl = perl, ...)

  start  <- as.vector(match)
  length <- attr(match, "match.length")
  end    <- start + length - 1L

  matchstr <- substring(text, start, end)
  matchstr[ start == -1 ] <- NA_character_

  res <- data.frame(
    stringsAsFactors = FALSE,
    .text = text,
    .match = matchstr
  )

  if (!is.null(attr(match, "capture.start"))) {

    gstart  <- attr(match, "capture.start")
    glength <- attr(match, "capture.length")
    gend    <- gstart + glength - 1L

    groupstr <- substring(text, gstart, gend)
    groupstr[ gstart == -1 ] <- NA_character_
    dim(groupstr) <- dim(gstart)

    res <- cbind(groupstr, res, stringsAsFactors = FALSE)
  }

  names(res) <- c(attr(match, "capture.names"), ".text", ".match")
  res
}