Bdtjtk

I was sure that when I do like this:

http = Net::HTTP.start uri.host, uri.port

request = Net::HTTP::Get.new uri

response = http.request request

I get some sort of established connection to the remote HTTP resource to be able to tell, for example, its Content-Type, while to really load the whole resource I then call the response.body.

But either I was always wrong or it is something with the server I access right now, the http.request loads the whole remote file that is unacceptable for me:

[Net::HTTP debug] opening connection to v.redd.it:80...  

[Net::HTTP debug] opened  

[Net::HTTP debug] <- "GET /6otzwem1c7721/DASH_9_6_M?source=fallback HTTP/1.1rnAccept-Encoding: gzip;q=1.0,deflate;q=0.6,identity;q=0.3rnAccept: */*rnUser-Agent: RubyrnHost: v.redd.itrnConnection: closernrn"  

[Net::HTTP debug] -> "HTTP/1.1 200 OKrn"  

[Net::HTTP debug] -> "Last-Modified: Sat, 29 Dec 2018 11:25:57 GMTrn"  

[Net::HTTP debug] -> "ETag: "662291aec20b252aaebcf54c3b1827af-42"rn"  

[Net::HTTP debug] -> "Content-Type: video/mp4rn"  

[Net::HTTP debug] -> "Cache-Control: public, max-age=604800, s-maxage=86400, must-revalidatern"  

[Net::HTTP debug] -> "Accept-Ranges: bytesrn"  

[Net::HTTP debug] -> "Content-Length: 218756120rn"  

[Net::HTTP debug] -> "Accept-Ranges: bytesrn"  

[Net::HTTP debug] -> "Date: Sun, 30 Dec 2018 13:44:21 GMTrn"  

[Net::HTTP debug] -> "Via: 1.1 varnishrn"  

[Net::HTTP debug] -> "Connection: closern"  

[Net::HTTP debug] -> "X-Served-By: cache-fra19120-FRArn"  

[Net::HTTP debug] -> "X-Cache: HITrn"  

[Net::HTTP debug] -> "X-Cache-Hits: 0rn"  

[Net::HTTP debug] -> "X-Timer: S1546177461.284280,VS0,VE0rn"  

[Net::HTTP debug] -> "Server: snooservrn"  

[Net::HTTP debug] -> "Vary: Originrn"  

[Net::HTTP debug] -> "rn"  

[Net::HTTP debug] reading 218756120 bytes... 

I went inside with byebug until found where it happens:

[159, 168] in /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http/response.rb

   159:   def reading_body(sock, reqmethodallowbody)  #:nodoc: internal use only

   160:     @socket = sock

   161:     @body_exist = reqmethodallowbody && self.class.body_permitted?

   162:     begin

   163:       yield

=> 164:       self.body   # ensure to read body

   165:     ensure

   166:       @socket = nil

   167:     end

   168:   end

(byebug) where

--> #0  Net::HTTPResponse.reading_body(sock#Net::BufferedIO, reqmethodallowbody#TrueClass) at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http/response.rb:164

    #1  Net::HTTP.transport_request(req#Net::HTTP::Get) at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http.rb:1445

    #2  Net::HTTP.request(req#Net::HTTP::Get, body#NilClass, &block#NilClass) at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http.rb:1407

    #3  block in Net::HTTP.block in request(req#Net::HTTP::Get, body#NilClass, &block#NilClass) at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http.rb:1400

    #4  Net::HTTP.start at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http.rb:853

    #5  Net::HTTP.request(req#Net::HTTP::Get, body#NilClass, &block#NilClass) at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/net/http.rb:1398

Is it server's fault? Ruby fault? Or should I use some another method if I want to get the header data without loading the whole resource?

P.S.: I do not need third-party fancy dependency, I need to use only the Net::HTTP.

Depending on what you actually want to accomplish:

Don't care about the body at all:

Use HEAD instead of GET:

uri = URI('http://example.com')

http = Net::HTTP.start uri.host, uri.port 

request = Net::HTTP::Head.new uri

response = http.request request

response.body

# => nil

Load the body conditionally

Using blocks with net/http will let you hook before the body is actually loaded:

uri = URI('http://example.com')

res = nil



Net::HTTP.start(uri.host, uri.port) do |http|

  request = Net::HTTP::Get.new uri



  http.request request do |response|

    res = response

    break

  end

end



res

# => #<Net::HTTPOK 200 OK readbody=false> 

res['Content-Type']

# => "text/html; charset=UTF-8"