    # File lib/ramaze/helper/httpdigest.rb, line 66
          def httpdigest(uid, realm, &block)
            session[SESSION_OPAQUE] ||= {}
            session[SESSION_OPAQUE][realm] ||= {}

            http_authorization = httpdigest_http_authorization(uid, realm)

            httpdigest_failure unless session_nonce = session[SESSION_NONCE]
            httpdigest_failure unless session_opaque = session[SESSION_OPAQUE][realm][uid]

            auth_type, auth_raw = http_authorization.split(' ', 2)
            httpdigest_failure unless auth_type == 'Digest'

            authorization = Rack::Auth::Digest::Params.parse(auth_raw)

            digest_response, username, nonce, nc, cnonce, qop, opaque =
              authorization.values_at(*%w[response username nonce nc cnonce qop opaque])

            httpdigest_failure unless nonce == session_nonce and opaque == session_opaque

            ha1 = httpdigest_lookup(username, realm, &block)
            a2 = [request.request_method,request.request_uri]
            a2 << Digest::MD5.hexdigest(request.body.read) if qop == "auth-int"
            ha2 = Digest::MD5.hexdigest( a2.join(':') )
            md5 = Digest::MD5.hexdigest([ha1, nonce, nc, cnonce, qop, ha2].join(':'))

            httpdigest_failure unless digest_response == md5

            return username
          end