## File: url.exists.Rd

package info (click to toggle)
r-cran-rcurl 1.95-4.8-2
 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152 \name{url.exists} \alias{url.exists} \title{Check if URL exists} \description{ This functions is analogous to \code{\link[base]{file.exists}} and determines whether a request for a specific URL responds without error. We make the request but ask the server not to return the body. We just process the header. } \usage{ url.exists(url, ..., .opts = list(...), curl = getCurlHandle(.opts = .opts), .header = FALSE) } \arguments{ \item{url}{the URL whose existence we are to test} \item{\dots}{name = value pairs of Curl options.} \item{.opts}{a list of name = value pairs of Curl options.} \item{curl}{a Curl handle that the caller can specify if she wants to reuse an existing handle, e.g. with different options already specified or that has previously established a connection to the Web server} \item{.header}{a logical value that if \code{TRUE} causes the header information to be returned. } } \details{ This makes an HTTP request but with the nobody option set to \code{FALSE} so that we don't actually retrieve the contents of the URL. } \value{ If \code{.header} is \code{FALSE}, this returns \code{TRUE} or \code{FALSE} indicating whether the request was successful (had a status with a value in the 200 range). If \code{.header} is \code{TRUE} } \references{ HTTP specification } \author{ Duncan Temple Lang } \seealso{ \code{\link{curlPerform}} } \examples{ url.exists("http://www.omegahat.net/RCurl") try(url.exists("http://www.omegahat.net/RCurl-xxx")) }