Ruby XMLRPC localhost Runtime Error : Wrong Size

I am trying to connect to the XMLRPC API of a dokuwiki website.

I am successfully doing that from my own laptop, with a SSL connection, however, when I try to do it from my production server (which hosts both the wiki and the rails app from which the ruby code is executed), I run into a

Runtime Error

Wrong size. Was 163, should be 113

Here's how I initialize the connection :

    @wiki = ::XMLRPC::Client.new3( 
        host: "wiki.example.com",
        path: "/lib/exe/xmlrpc.php",
        use_ssl: true)
      # Temp Hack because SSL Fails
      @wiki.instance_variable_get(:@http).instance_variable_set(:@verify_mode, OpenSSL::SSL::VERIFY_NONE)
    end
    @authenticated = false
    authenticate!
  end

  def authenticate!
    # Fails at below line :
    @authenticated = @wiki.call("dokuwiki.login", ENV['WIKI_USER'], ENV['WIKI_PASSWORD'])
    Rails.logger.info (@authenticated ? "Authenticated on Wiki !" : "Authentication failed on wiki !")
  end

I've read many posts saying that there is a bug in the XMLRPC lib of Ruby. I was running ruby 2.1.5pxx on my laptop and ruby 1.9.xx at my server so I did a rvm install 2.1.5, yet the problem is still here

(btw, I assumed it was enough to do a rvm use 2.1.5 and then touch restart to restart my rails server, but how can I check which version of ruby it's using ?)

What is wrong ?

EDIT

On my laptop, I am running ruby 2.1.5p273 (2014-11-13 revision 48405) [x64-mingw32]

On my production server, I am running ruby-2.1.5 [ i686 ]

I tried another library, libxml-xmlrpc, and I get the following error when running the same command:

Net::HTTPBadResponse: wrong status line: "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">"

But again, the same code is running fine with the default ruby xmlrpc client on my Windows + rubyx64 2.1.5, so I really don't get it!

Edit2 : I tried adding

@wiki.http_header_extra = { "accept-encoding" => "identity" }

But then I get a

Authorization failed. HTTP-Error: 401 Unauthorized

The first call @wiki.call("dokuwiki.login", "myUsr", "myPwd") worked, but apparently it failed to authenticate me (Of course I am still using the same login information that should work)

EDIT 3

After investigation, a successful login from any other computer than localhost will set a cookie like

@cookie="DokuWiki=[small string] ; [very big string]

Whereas if I do it on localhost : I will write [...] for random strings

@cookie="[small string 2]=deleted; DokuWiki=[small string]; [very big string]"

So I have an extra variable info stored in my cookie, which is "[small string 2]=deleted;

I believe this is what makes my authentication fails. Anyone knows what this is ???

Solution

So this localhost connection was messing up with the cookie. Apparently, even the ruby library doesn't know why, and the "Wrong size" comes from this unexpected string [random string]=deleted added at the beginning of the cookie.

Unless someone can explain WHY such a string is added, I will accept my solution of simply adding

@wiki.http_header_extra = { "accept-encoding" => "identity" }

which removes the "Wrong size" error, then

if /deleted/.match(@wiki.cookie)
  @wiki.cookie = @wiki.cookie.gsub(/.*deleted; /, '')
end

To remove the beginning of the cookie