I would like to create a script in R that pings a given website. I haven't found any information about this specific for R.
To start 开发者_如何转开发with, all I need is the information on whether the website responses to the ping or not.
Does anyone have information about existing scripts or which package best to use to start with?
We can use a system2 call to get the return status of the ping command in the shell. On Windows (and probably linux) following will work :
ping <- function(x, stderr = FALSE, stdout = FALSE, ...){
pingvec <- system2("ping", x,
stderr = FALSE,
stdout = FALSE,...)
if (pingvec == 0) TRUE else FALSE
}
# example
> ping("google.com")
[1] FALSE
> ping("ugent.be")
[1] TRUE
If you want to capture the output of ping, you can either set stdout = "", or use a system call:
> X <- system("ping ugent.be", intern = TRUE)
> X
[1] "" "Pinging ugent.be [157.193.43.50] with 32 bytes of data:"
[3] "Reply from 157.193.43.50: bytes=32 time<1ms TTL=62" "Reply from 157.193.43.50: bytes=32 time<1ms TTL=62"
[5] "Reply from 157.193.43.50: bytes=32 time<1ms TTL=62" "Reply from 157.193.43.50: bytes=32 time<1ms TTL=62"
[7] "" "Ping statistics for 157.193.43.50:"
[9] " Packets: Sent = 4, Received = 4, Lost = 0 (0% loss)," "Approximate round trip times in milli-seconds:"
[11] " Minimum = 0ms, Maximum = 0ms, Average = 0ms"
using the option intern = TRUE makes it possible to save the output in a vector. I leave it to the reader as an exercise to rearrange this in order to get some decent output.
RCurl::url.exists works for localhost (where ping doesn't always) and is faster than RCurl::getURL.
> library(RCurl)
> url.exists("google.com")
[1] TRUE
> url.exists("localhost:8888")
[1] TRUE
> url.exists("localhost:8012")
[1] FALSE
Note that it is possible to set the timeout (which by default is rather long)
> url.exists("google.com", timeout = 5) # timeout in seconds
[1] TRUE
If you want to see if a website is responding to HTTP requests, you can test an URL in R with the RCurl library, which is an R interface to the curl HTTP client library.
Example:
> library(RCurl);
> getURL("http://www.google.com")
[1] "<!doctype html><ht....
If you want to examine the response code (for 200, 404, etc.) you will need to write a custom function to pass as the "header" option to getURL().
To get the status code
library(httr)
b <- GET("http://www.google.com")
b$status_code
[1] 200
There is a package for this ... {pingr} Link to CRAN.
library(pingr)
# check if domain can be reached via port 80
is_up(destination = "example.com")
## [1] TRUE
# check how domain name is resolved to ip adress
nsl("example.com")
## $answer
## name class type ttl data
## 1 example.com 1 1 85619 93.184.216.34
##
## $flags
## aa tc rd ra ad cd
## NA NA NA NA NA NA
# check HTTP port
pingr::ping_port("example.com", 80)
# check HTTPS port
pingr::ping_port("example.com", 443)
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