Usage

```ruby require ‘facebook-signed-request’

# The secret can be set globally
Facebook::SignedRequest.secret = "dkhsdfhjsd123d2ed3q1wd222qd2"
request = Facebook::SignedRequest.new( params[:signed_request] )

# or as an optional parameter for individual calls
request = Facebook::SignedRequest.new( params[:signed_request], secret )

request.valid?
# => true / false

request.errors
# => [
#  "Invalid Format. See http://developers.facebook.com/docs/authentication/signed_request/",
#  "Invalid Base64 encoding for signature",
#  "Invalid Base64 Encoding for data",
#  "Invalid JSON object",
#  "Invalid Algorithm. Expected: HMAC-SHA256",
#  "Signatures do not match. #{expected} but was #{computed}"
#]

request.data
# => {
#      :Algorithm   => "HMAC-SHA256",
#      :expires     => 1308988800,
#      :issued_at   => 1308985018,
#      :oauth_token => "114998258593813|2.AQBAttRlLVnwqNPZ.3600.1308988800…",
#      :user => {
#        :country => "de",
#        :locale  => "en_US",
#        :age     => {"min"=>21}
#      },
#      :user_id => "100000656666199"
#    }


Facebook::SignedRequest.encode_and_sign { :foo => bar }
# => g_eE3hoQDPKFusHcc_Tj7k2xxo3mCKsOEXKMViq0pAY=.eyJmb28iOiJiYXIifQ==

```

Run the tests with rake test:units