root: initial merging of outpost and main project

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

internal/outpost/proxy/claims.go

@@ -0,0 +1,30 @@
+package proxy
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+)
+
+type Claims struct {
+	Proxy struct {
+		UserAttributes map[string]interface{} `json:"user_attributes"`
+	} `json:"ak_proxy"`
+}
+
+func (c *Claims) FromIDToken(idToken string) error {
+	// id_token is a base64 encode ID token payload
+	// https://developers.google.com/accounts/docs/OAuth2Login#obtainuserinfo
+	jwt := strings.Split(idToken, ".")
+	jwtData := strings.TrimSuffix(jwt[1], "=")
+	b, err := base64.RawURLEncoding.DecodeString(jwtData)
+	if err != nil {
+		return err
+	}
+
+	err = json.Unmarshal(b, c)
+	if err != nil {
+		return err
+	}
+	return nil
+}