Saml_IDP gem not pulling metadata or acceptable_hosts - ruby-on-rails

Question

I'm trying to implement SSO via SAML and using my application as both the IdP (routes are based off localhost:3000) and SP (routes based off lvh.me:3000). I used the saml_idp gem to set up the IdP and the omniauth-saml gem for the SP side.
I can get a request sent to the IdP and a response sent back if I bypass the validate_saml_request method in the SamlIdpController in the gem. The response I get returns the user's email and first/last name per what I configured in the config/saml_idp.rb file.
I really don't want to bypass the validate_saml_request. When I looked to see why my request is not being validated, I see that the logs return '[] compare to lvh.me' and 'No acceptable AssertionConsumerServiceURL, either configure them via config.service_provider.response_hosts or match to your metadata_url_host'.
For SPs, my config/saml_idp.rb file looks like:
service_providers = {
"my-application" => {
fingerprint: ENV['SAML_CERT_FINGERPRINT'],
metadata_url: "http://lvh.me:3000/auth/saml/metadata",
response_hosts: ["lvh.me:3000"]
},
}
I confirmed that the metadata does exist at that metadata_url as well. Not really sure why it's not pulling anything via the metadata_url or response_hosts via the config.
On my SP side, the config/omniauth.rb file looks like:
Rails.application.config.middleware.use OmniAuth::Builder do
provider :saml,
:assertion_consumer_service_url => "http://lvh.me:3000/auth/saml/callback",
:issuer => "portal",
:idp_sso_target_url => "http://localhost:3000/saml/auth",
:idp_sso_target_url_runtime_params => {:original_request_param => :mapped_idp_param},
:idp_cert => ENV['SAML_CERT'],
:idp_cert_fingerprint => ENV['SAML_CERT_FINGERPRINT'],
:idp_cert_fingerprint_validator => lambda { |fingerprint| fingerprint },
:name_identifier_format => "urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"
end

Answer 1

While I was unable to get it working using this piece of configuration in the config/saml_idp.rb file, I only needed to have the IdP interact with one SP and was able to get it working by adjusting what I passed to response_hosts and using another part of the code given in the config file (example below):
config.service_provider.finder = ->(issuer_or_entity_id) do
{
fingerprint: ENV['SAML_CERT_FINGERPRINT'],
metadata_url: "http://lvh.me:3000/saml/metadata",
response_hosts: ["lvh.me"]
}
end