Update AuthnReq signature generation

• Using spec recommendation for Canonicalization Method
• Fixed AuthReqn marshaling issue

Custom time format XML marshalling.

Being compatible with Azure IdP when marshalling IssueInstant for AuthnRequests

Rename to github.com/pressly/saml

We renamed github.com/goware/saml to github.com/pressly/saml.

This is a breaking API change. But that's fine, since we haven't released v1.0 yet.

Signed SAML HTTP-POST AuthnRequests

Merge pull request #17 from goware/signed_saml_requests

Signing SAML HTTP-POST requests.

HTTP-POST Binding

This is an API breaking release.

It adds SP support for generating a HTTP-POST binding AuthnRequest.

Eg;

serviceProvider := &saml.ServiceProvider{}

// Parse IdP metadata
//
// from URL
serviceProvider.IdPMetadataURL = "http://idp.example.com/metadata.xml"
// or from XML file
serviceProvider.IdPMetadataXML = []byte("<xml>")
idpMetadata, _ := serviceProvider.ParseIdPMetadata()

// Get SSOService element for the selected binding
//
ssoService := idpMetadata.SSOService(saml.HTTPPostBinding)
serviceProvider.IdPSSOServiceBinding = ssoService.Binding
serviceProvider.IdPSSOServiceURL = ssoService.Location

// or set information from a different source
serviceProvider.IdPSSOServiceBinding = "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST",
serviceProvider.IdPSSOServiceURL = "https://idp.example.com/sso",

// Generate SAML Response for HTTP-POST binding
samlReq, _ := serviceProvider.NewPostSAMLRequest()

Removes ServeSSO handler wrapper and introduces an explicit function to generate a SAML Response for a given AuthnRequest.

Removes http.Request dependency from IdPAuthnRequest

Makes IdP metadata parsing explicit

API breaking release

Drop magical HTTP handlers and middleware.

Instead, provide simple ServiceProvider methods, ie. to parse SAML response and get the assertion, serve Metadata XML and generate AuthnRequest URL.

Drop the custom logger, since we return explicit errors to the caller now instead of logging them.