support CAS identity provider

Signed-off-by: hongming <talonwan@yunify.com>

vendor/gopkg.in/cas.v2/sanitise.go

@@ -0,0 +1,28 @@
+package cas
+
+import (
+	"net/url"
+)
+
+var (
+	urlCleanParameters = []string{"gateway", "renew", "service", "ticket"}
+)
+
+// sanitisedURL cleans a URL of CAS specific parameters
+func sanitisedURL(unclean *url.URL) *url.URL {
+	// Shouldn't be any errors parsing an existing *url.URL
+	u, _ := url.Parse(unclean.String())
+	q := u.Query()
+
+	for _, param := range urlCleanParameters {
+		q.Del(param)
+	}
+
+	u.RawQuery = q.Encode()
+	return u
+}
+
+// sanitisedURLString cleans a URL and returns its string value
+func sanitisedURLString(unclean *url.URL) string {
+	return sanitisedURL(unclean).String()
+}