Ruby - Validate and update URL

Question

I've been trying to modify this method from redirecting and returning the contents of the url to returning new valid url instead.

After reading up on the Net::HTTP object, I'm still not sure how exactly the get_response method works. Is this what's downloading the page? is there another method I could call that would just ping the url instead of downloading it?

require 'net/http'

def validate(url)
    uri = URI.parse(url)
    response = Net::HTTP.get_response(uri)

    case response
    when Net::HTTPSuccess
        return response
    when Net::HTTPRedirection
        return validate(response['location'])
    else
        return nill
    end
end


puts validate('http://somesite.com/somedir/mypage.html')

Answer 1

Do you mean, by 'ping the url', you want to know whether the url request returns an HTTP 200 response?

I haven't looked at the implementation of get_response, but I think it just sends out an HTTP GET request, by the looks of it.

If you want to check for the HTTP 200 response, I guess you could just keep doing get_response until you get HTTPSuccess && HTTPOK.

Answer 2

You are correct that get_response sends an HTTP GET request to the server, which requests the whole page.

You want to use a HEAD request instead of GET. This requests the same HTTP response header that a GET request would get, including the status code (200, 404, etc.), but without downloading the whole page.

See the request_head and head methods of Net::HTTP. For example

url = URI.parse('http://www.ruby-doc.org/stdlib/libdoc/net/http/rdoc/index.html')
res = Net::HTTP.start(url.host, url.port) {|http|
    http.head(url.path)
}
puts res.class