omniauth-saml nil values in info hash - ruby-on-rails

Question

I'm working with devise and omniauth-saml, following the instructions from https://github.com/PracticallyGreen/omniauth-saml and the omniauth Facebook example https://github.com/plataformatec/devise/wiki/OmniAuth:-Overview
I have a simplesamlphp server running, using the metadata provided by omniauth, and everything seems to be connecting properly, but the response from the simplesaml server has nil values for email, first_name, last_name and name. The weird thing is that it is returning the email and name values, just not in a useful part of the response (see below - super#man.com is the email, Clark Kent is the name)
The weird thing is that I get these nil values with both omniauth-saml and devise-saml-authenticatable gems, but I think my simplesamlphp server is configured properly.
The response from omniauth looks like this:
#<OmniAuth::AuthHash credentials=#<OmniAuth::AuthHash> extra=#<OmniAuth::AuthHash raw_info=#<OneLogin::RubySaml::Attributes:0x007fc695850148 #attributes={"urn:oid:0.9.2342.19200300.100.1.1"=>["super#man.com"], "urn:oid:2.16.840.1.113730.3.1.241"=>["Clark Kent"], "fingerprint"=>"FINGERPRINT REMOVED"}>> info=#<OmniAuth::AuthHash::InfoHash email=nil first_name=nil last_name=nil name=nil> provider="saml" uid="_ca76f49ccb6ccce7827111ae1ff0563f534f0a4d1a">
The simplesamlphp config looks like this:
$metadata['http://localhost:3000/saml/users/auth/saml/metadata'] = array(
'AssertionConsumerService' => 'http://localhost:3000/saml/users/auth/saml/callback',
'NameIDFormat' => 'urn:oasis:names:tc:SAML:2.0:nameid-format:email',
'simplesaml.nameidattribute' => 'email',
);
I am sure that there are good values for the user in the database, and when I test authentication on the IDP itself, everything works as expected.

Answer 1

I solved this. The problem was that I was trying to use values that didn't use the ldap attribute names.
I changed my sp metadata as follows (after modifying my model to use first_name and last_name instead of just name)
$metadata['http://localhost:3000/saml/users/auth/saml/metadata'] = array(
'AssertionConsumerService' => 'http://localhost:3000/saml/users/auth/saml/callback',
'NameIDFormat' => 'urn:oasis:names:tc:SAML:2.0:nameid-format:email',
'authproc' => array(
95 => array(
'class' => 'core:AttributeMap',
'givenName' => 'first_name',
'sn' => 'last_name',
'mail' => 'email',
),
96 => array(
'class' => 'core:AttributeLimit',
'email', 'first_name', 'last_name'
),
),
'simplesaml.nameidattribute' => 'email',
);