Downloading large files with R/RCurl efficiently

Question

I see that many examples for downloading binary files with RCurl are like such:

library(\"RCurl\")
curl = getCurlHandle()
bfile=getBinaryURL (
        \"http         


        

Answer 1

um.. use mode = 'wb' :) ..run this and follow along w/ my comments.

# create a temporary file and a temporary directory on your local disk
tf <- tempfile()
td <- tempdir()

# run the download file function, download as binary..  save the result to the temporary file
download.file(
    "http://sourceforge.net/projects/peazip/files/4.8/peazip_portable-4.8.WINDOWS.zip/download",
    tf ,
    mode = 'wb' 
)

# unzip the files to the temporary directory
files <- unzip( tf , exdir = td )

# here are your files
files

Answer 2

This is the working example:

library(RCurl)
#
f = CFILE("bfile.zip", mode="wb")
curlPerform(url = "http://www.example.com/bfile.zip", writedata = f@ref)
close(f)

It will download straight to file. The returned value will be (instead of the downloaded data) the status of the request (0, if no errors occur).

Mention to CFILE is a bit terse on RCurl manual. Hopefully in the future it will include more details/examples.

For your convenience the same code is packaged as a function (and with a progress bar):

bdown=function(url, file){
    library('RCurl')
    f = CFILE(file, mode="wb")
    a = curlPerform(url = url, writedata = f@ref, noprogress=FALSE)
    close(f)
    return(a)
}

## ...and now just give remote and local paths     
ret = bdown("http://www.example.com/bfile.zip", "path/to/bfile.zip")