Making Head Request in Ruby

Making HEAD request in Ruby

I don't think that passing in a string to :start is enough; in the docs it looks like it requires a URI object's host and port for a correct address:

uri = URI('http://example.com/some_path?query=string')

Net::HTTP.start(uri.host, uri.port) do |http|
  request = Net::HTTP::Get.new uri

  response = http.request request # Net::HTTPResponse object
end

You can try this:

require 'net/http'

url = URI('yoururl.com')

Net::HTTP.start(url.host, url.port){|http|
   response = http.head('/file.xml')
   puts response
}

One thing I noticed - your puts response needs to be inside the block! Otherwise, the variable response is not in scope.

Edit: You can also treat the response as a hash to get the values of the headers:

response.each_value { |value| puts value }

How to make an HTTP head request with headers in ruby?

Try this:

require 'net/http'

url = 'http://...'
myusename = '...'
mykey = '...'

request = Net::HTTP.new(url, 80)
request.request_head('/', 'x-auth-user' => myusername, 'x-auth-key' => my_key)

Making HTTP HEAD request with timeout in Ruby

Try this snippet:

require 'net/http'

Net::HTTP.start('www.some_site.com') do |http|
  http.open_timeout = 2
  http.read_timeout = 2
  req = Net::HTTP::Head.new('/')
  http.request(req).each { |k, v| puts "#{k}: #{v}" }
end

Hope this is what you're looking for.

UPDATE

Because there is head method that looks like

def head(path, initheader = nil)
  request(Head.new(path, initheader))
end

You can also use this snippet:

require 'net/http'

Net::HTTP.start('www.rubyinside.com') do |http|
  http.open_timeout = 2
  http.read_timeout = 2
  http.head('/').each { |k, v| puts "#{k}: #{v}" }
end

Ruby NET::HTTP Read the header BEFORE the body (without HEAD request)?

net/http supports streaming, you can use this to read the header before the body.

Code example,

url = URI('http://stackoverflow.com/questions/41306082/ruby-nethttp-read-the-header-before-the-body-without-head-request')

Net::HTTP.start(url.host, url.port) do |http|
  request = Net::HTTP::Get.new(url)
  http.request(request) do |response|

    # check headers here, body has not yet been read
    # then call read_body or just body to read the body

    if true  
      response.read_body do |chunk|
        # process body chunks here
      end
    end
  end
end

Net::HTTP failing on a head request

If you follow the documentation properly, it works just fine. The library implementation probably has some assumptions on the usage when it determines whether to read the payload.

response = nil
Net::HTTP.start('github.com', :use_ssl => true) do |http|
  response = http.head('/rails/rails')
end

response.each { |k, v| [k, v] }

How can I perform a Head request using mechanize in Ruby

Just like get but it's head instead:

page = agent.head 'http://www.google.com/'
page.body.length
#=> 0
page.header.keys
#=> ["date", "expires", "cache-control", "content-type", "set-cookie", "p3p", "server", "x-xss-protection", "x-frame-options", "transfer-encoding"]

Ruby - Send GET request with headers

Using net/http as suggested by the question.

References:

Net::HTTP https://ruby-doc.org/stdlib-2.4.1/libdoc/net/http/rdoc/Net/HTTP.html
Net::HTTP::get https://ruby-doc.org/stdlib-2.4.1/libdoc/net/http/rdoc/Net/HTTP.html#method-c-get
Setting headers: https://ruby-doc.org/stdlib-2.4.1/libdoc/net/http/rdoc/Net/HTTP.html#class-Net::HTTP-label-Setting+Headers
Net::HTTP::Get https://ruby-doc.org/stdlib-2.4.1/libdoc/net/http/rdoc/Net/HTTP/Get.html
Net::HTTPGenericRequest https://ruby-doc.org/stdlib-2.4.1/libdoc/net/http/rdoc/Net/HTTPGenericRequest.html and Net::HTTPHeader https://ruby-doc.org/stdlib-2.4.1/libdoc/net/http/rdoc/Net/HTTPHeader.html (for methods that you can call on Net::HTTP::Get)

So, for example:

require 'net/http'    

uri = URI("http://www.ruby-lang.org")
req = Net::HTTP::Get.new(uri)
req['some_header'] = "some_val"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: uri.scheme == 'https') { |http|
  http.request(req)
}

puts res.body # <!DOCTYPE html> ... </html> => nil

Note: if your response has HTTP result state 301 (Moved permanently), see Ruby Net::HTTP - following 301 redirects

Making Head Request in Ruby