How to use an R script from GitHub?

Question

I am trying to use an R script hosted on GitHub plugin-draw.R. How should I use this plugin?

Answer 1

You can simply use source_url from package devtools :

library(devtools)
source_url("https://raw.github.com/tonybreyal/Blog-Reference-Functions/master/R/bingSearchXScraper/bingSearchXScraper.R")

Answer 2

You can use solution offered on R-Bloggers:

source_github <- function(u) {
  # load package
  require(RCurl)
 
  # read script lines from website
  script <- getURL(u, ssl.verifypeer = FALSE)
 
  # parase lines and evaluate in the global environment
  eval(parse(text = script))
}
 
source_github("https://raw.github.com/tonybreyal/Blog-Reference-Functions/master/R/bingSearchXScraper/bingSearchXScraper.R")

For the function to be evaluated in a global environment (I'm guessing that you will prefer this solution) you can use:

source_https <- function(u, unlink.tmp.certs = FALSE) {
  # load package
  require(RCurl)
 
  # read script lines from website using a security certificate
  if(!file.exists("cacert.pem")) download.file(url="http://curl.haxx.se/ca/cacert.pem", destfile = "cacert.pem")
  script <- getURL(u, followlocation = TRUE, cainfo = "cacert.pem")
  if(unlink.tmp.certs) unlink("cacert.pem")
 
  # parase lines and evealuate in the global environement
  eval(parse(text = script), envir= .GlobalEnv)
}
 
source_https("https://raw.github.com/tonybreyal/Blog-Reference-Functions/master/R/bingSearchXScraper/bingSearchXScraper.R")
source_https("https://raw.github.com/tonybreyal/Blog-Reference-Functions/master/R/htmlToText/htmlToText.R", unlink.tmp.certs = TRUE)

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As mentioned in the the original article by Tony Breyal, this discussion on SO should also be credited as it is relevant to the discussed question.