R/feData.R

In rOpenGov/mpg: FuelEconomy.gov Data

feData <-
  function(type, year = NULL, ...) {
    # bulk pull all data
    if (!is.null(year)) {
      if (is.null(type) || type == "vehicles") {
        y <- substring(year, nchar(year) - 1, nchar(year))
        y2 <- as.numeric(y)
        if (y2 %in% c(84:97)) {
          u <- paste("http://www.fueleconomy.gov/feg/epadata/", y, "mfgui.zip", sep = "")
        } else if (y2 == 98) {
          u <- "http://www.fueleconomy.gov/feg/epadata/98guide6.zip"
        } else if (y2 == 99) {
          u <- "http://www.fueleconomy.gov/feg/epadata/99guide.zip"
        } else if (y2 %in% c(78:83) | (y2 > 0 && y2 < 78) | y == "00") {
          u <- paste("http://www.fueleconomy.gov/feg/epadata/", y, "data.zip", sep = "")
        } else {
          stop("Unrecognized year")
        }
      } else if (type == "greenguide") {
        y <- substring(year, nchar(year) - 1, nchar(year))
        u <- paste("http://www.fueleconomy.gov/feg/EPAGreenGuide/txt/all_alpha_", y, ".txt", sep = "")
      } else {
        stop("selected 'type' not supported")
      }
    } else if (type == "vehicles") {
      u <- "http://www.fueleconomy.gov/feg/epadata/vehicles.csv.zip"
    } else if (type == "emissions") {
      u <- "http://www.fueleconomy.gov/feg/epadata/emissions.csv.zip"
    }
    tmp <- tempfile()
    d <- download.file(u, tmp, mode = "wb")
    if (d) {
      stop("File download failed")
    }
    if (type == "greenguide") {
      # do something
      out <- read.table(u, fill = TRUE)
      names(out) <- as.character(unname(unlist(out[1, , drop = TRUE])))
      out <- out[-1, ]
    } else {
      f <- unzip(tmp, list = TRUE)
      ucon <- unz(file.path(tempdir(), tmp), filename = f$Name)
      ## These are actually xlsx files, not CSV...so that sucks ##
      ## out <- read.csv(ucon)
      close(ucon)
    }
    unlink(tmp)
  }