Add invalid params error handling for Saml::Bindings::HTTPRedirect.receive_message

[soartec-lab]

Summary

Saml::Bindings::HTTPRedirect.receive_message decodes the request parameter SAMLRequest or SAMLResponse, but if neither exists, it becomes nil. Then, nil is specified in the argument of Saml :: Encoding.decode_64` method, and the following error occurs.

$ Saml::Encoding.decode_64(nil)
NoMethodError: undefined method `unpack1' for nil:NilClass
from /usr/local/lib/ruby/2.7.0/base64.rb:59:in `decode64'

This error isn't kind to the developer, so I've added a process to check that the input parameter has a SAMLRequest or SAMLResponse and raise an exception if it doesn't.

This is similar to the next PR. #176

[coveralls]

Coverage increased (+0.002%) to 99.85% when pulling 7d5c436 on soartec-lab:feature/add-invalid-params-error-in-http-redirect into ac82910 on digidentity:master.

[coveralls]

Coverage increased (+0.0002%) to 99.849% when pulling 7d5c436 on soartec-lab:feature/add-invalid-params-error-in-http-redirect into ac82910 on digidentity:master.

[jdongelmans]

Thanks again!

[jdongelmans]

Released as v3.9.3