Problem with decoding a compressed string

ruby-talk
1

I am writing an app in Ruby on Rails that I want to use for
authenticating Google Apps users.

I am having difficulty decoding the SAMLRequest. My code looks like
this:

    string = CGI::unescape(params[:SAMLRequest])
    doc = Base64.decode64(string)
    zstream = Zlib::Inflate.new
    buf = zstream.inflate(string)

The data from the SAMLRequest looks like this:

fVLJTsMwEL0j8Q
%2BW71kakEBWE1SoKiqxRG3gwM04Q2Li2MbjNPD3pGmrwgFu1vjNW2ZmevXZKrIBh9LolE7CmBLQwpRSVyl9KhbBJb3KTk
%2BmyFtl2azztV7BRwfoydCpkY0fKe2cZoajRKZ5C8i8YOvZ
%2FR1LwphZZ7wRRlGynKe0rQAaqKtXDlVTN6C0svbdciHqdzu8TakrsLqh5PlgK9naWiJ2sNToufZDKY4vgkkSxEkRn7MkZvHZCyX5Xula6l2C
%2F2y97kDIbosiD%2FLHdTESbGQJ7mFAp7QyplIQCtNSMkME5wc7N0Zj14Jbg9tIAU
%2Bru5TW3ltkUdT3fXhsingkfW9cg%2BdhhxEXuE2Rc0S5Gdi964Bm42TZGM79GOn
%2F1vnBDM2OctPoB1W239g2yHKeGyXFF5kpZfobB9wf5MnCuJb7v9Um4WSsyDJ4G6Gs02hByDcJJSVRtlP9fRrDwXwD

I get this error: "Zlib::DataError: incorrect header check"

I have tried every combination of unescape, decode and inflate that I
can think of, but no joy.

I will really appreciate any help.

Thanks in anticipation,

Keith

2

I've no idea the format of SAMLRequest, but if you're going to feed
that data (which I assume is the contents of the "string" variable?)
to #decode64, I think you need to remove the newlines and unescape
it...

string = string.gsub("\n", "")
string = string.gsub(/%[0-9A-Fa-f]{2}/) { | h |
  h[1..-1].hex.chr
}

Also, what is the point of "doc" since you're just passing "string" to
#inflate?

Sorry I can't be of more help.
Jordan

···

On Dec 2, 5:05 am, keith_g <kpgar...@gmail.com> wrote:

I am writing an app in Ruby on Rails that I want to use for
authenticating Google Apps users.

I am having difficulty decoding the SAMLRequest. My code looks like
this:

                string = CGI::unescape(params[:SAMLRequest])
                doc = Base64.decode64(string)
                zstream = Zlib::Inflate.new
                buf = zstream.inflate(string)

The data from the SAMLRequest looks like this:

fVLJTsMwEL0j8Q
%2BW71kakEBWE1SoKiqxRG3gwM04Q2Li2MbjNPD3pGmrwgFu1vjNW2ZmevXZKrIBh9LolE7CmBLQwpRSVyl9KhbBJb3KTk
%2BmyFtl2azztV7BRwfoydCpkY0fKe2cZoajRKZ5C8i8YOvZ
%2FR1LwphZZ7wRRlGynKe0rQAaqKtXDlVTN6C0svbdciHqdzu8TakrsLqh5PlgK9naWiJ2sNToufZDKY4vgkkSxEkRn7MkZvHZCyX5Xula6l2C
%2F2y97kDIbosiD%2FLHdTESbGQJ7mFAp7QyplIQCtNSMkME5wc7N0Zj14Jbg9tIAU
%2Bru5TW3ltkUdT3fXhsingkfW9cg%2BdhhxEXuE2Rc0S5Gdi964Bm42TZGM79GOn
%2F1vnBDM2OctPoB1W239g2yHKeGyXFF5kpZfobB9wf5MnCuJb7v9Um4WSsyDJ4G6Gs02hByDcJJSVRtlP9fRrDwXwD

I get this error: "Zlib::DataError: incorrect header check"

I have tried every combination of unescape, decode and inflate that I
can think of, but no joy.

I will really appreciate any help.

Thanks in anticipation,

Keith