download.file() issue, corrupted file

[johan809]

I am trying to create a package to download, import and clean data from the Dominican Republic Central Bank web page. I have done all the coding in Rstudio.cloud and everything works just fine, but when I try the functions in my local machine they do not work.

After digging a bit on each function, I realized that the problem was the downloaded file, it is corrupt.

I am including the first steps of a function just to illustrate my issue.

file url

# Packages
library(readxl)

# file url. 
url <- paste0("https://cdn.bancentral.gov.do/documents/",
              "estadisticas/precios/documents/",
              "ipc_base_2010.xls?v=1570116997757")

# termporary path
file_path <- tempfile(pattern = "", fileext = ".xls")

# downloading 
download.file(url, file_path, quiet = TRUE)

# reading the file
ipc_general <- readxl::read_excel(
            file_path,
            sheet = 1,
            col_names = FALSE,
            skip = 7
        )

Error: 
  filepath: C:\Users\Johan Rosa\AppData\Local\Temp\RtmpQ1rOT3\2a74778a1a64.xls
  libxls error: Unable to open file

I am using temporary but that is not the problem, you can try to download the file in your working directory and the problem persist.

I want to konw:

1. Why this code works in rstudio.clowd and not local?
2. What can I do to get the job done? (alternative approach, packages, functions)

[andresrcs]

@johan809

Why this code works in rstudio.clowd and not local?

RStudio Cloud runs on Linux servers, but for Windows, you need to make some adjustments to the download.file() command.

download.file(url, file_path, quiet = TRUE, mode = "wb")

[johan809]

Excellent, it works. Thanks!!

Now I have to think a way to detect if the function is running on Linux or Windows, to set that argument accordingly.

I can write a new download file function using if else calls on .Platform$OS.type result.

Or, can I set mode = "wb" for all download.file() calls?

Do you have any recommendations?

[andresrcs]

@johan809

I can write a new download file function using if else calls on .Platform$OS.type result.

I don't know if this is the best way to handle this multi-OS situation but I use a very similar approach, I use this function to get the OS and perform some tasks accordingly, obviously, this is not a general solution since it only works for the operating systems that I use, but it can give you an idea.

get_os <- function(){
    sysinf <- Sys.info()
    os <- sysinf['sysname']
    if (os == 'Darwin'){
        os <- "osx"
    } else {
        os <- .Platform$OS.type
        if (grepl("^darwin", R.version$os))
            os <- "osx"
        if (grepl("linux-gnu", R.version$os))
            os <- "linux"
        if (grepl("linux-gnueabihf", R.version$os))
            os <- "raspbian"
    }
    tolower(os)
}

@johan809

Or, can I set mode = "wb" for all download.file() calls?

This is supposed to be Windows-only but I have tested it on Ubuntu and it works normally so I would say, give it a try.

[jlacko]

When I was facing your situation (lots of foul language was involved) I ended up sidestepping the issue and downloading via curl::curl_download().

It has other benefits in addition to being platform neutral, and it is imported by httr which in turn is used by just about everyone, so I did not feel so bad about creating a package dependency.

[johan809]

I will try that function. Thanks, I did not know about curl::curl_download().