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\name{source_url}
\alias{source_url}
\title{Download an R file from a URL and source it}
\usage{
source_url(url, sha = NULL, ..., prompt = TRUE,
quiet = FALSE)
}
\arguments{
\item{url}{The URL to download.}
\item{sha}{A SHA-1 hash of the file at the URL.}
\item{prompt}{Prompt the user if no value for \code{sha}
is provided.}
\item{quiet}{If \code{FALSE} (the default), print out
status messages about checking SHA.}
\item{...}{Other arguments that are passed to
\code{\link{source}()}.}
}
\description{
This will download a file and source it. Because it uses
the \code{\link{download}()} function, it can handle
https URLs.
}
\details{
By default, \code{source_url()} checks the SHA-1 hash of
the file. If it differs from the expected value, it will
throw an error. The default expectation is that a hash is
provided; if not, \code{source_url()} will prompt the
user, asking if they are sure they want to continue,
unless \code{prompt=FALSE} is used. In other words, if
you use \code{prompt=FALSE}, it will run the remote code
without checking the hash, and without asking the user.
The purpose of checking the hash is to ensure that the
file has not changed. If a \code{source_url} command with
a hash is posted in a public forum, then others who
source the URL (with the hash) are guaranteed to run the
same code every time. This means that the author doesn't
need to worry about the security of the server hosting
the file. It also means that the users don't have to
worry about the file being replaced with a damaged or
maliciously-modified version.
To find the hash of a local file, use
\code{\link{digest}()}. For a simple way to find the hash
of a remote file, use \code{\link{sha_url}()}.
}
\examples{
\dontrun{
# Source the a sample file
downloader::source_url("https://gist.github.com/wch/dae7c106ee99fe1fdfe7/raw/db0c9bfe0de85d15c60b0b9bf22403c0f5e1fb15/test.r",
sha="9b8ff5213e32a871d6cb95cce0bed35c53307f61")
}
}
\seealso{
\code{\link{source}()} for more information on the
arguments that can be used with this function.
}
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