Merge bitly#424 (x-auth-request access-token)

rebased+squashed version of bitly PR 424

Author: ploxiln

README.md

@@ -409,6 +409,10 @@ server {
     proxy_set_header X-User  $user;
     proxy_set_header X-Email $email;
 
+    # if you enabled --pass-access-token, this will pass the token to the backend
+    auth_request_set $token  $upstream_http_x_auth_request_access_token;
+    proxy_set_header X-Token $token;
+
     # if you enabled --cookie-refresh, this is needed for it to work with auth_request
     auth_request_set $auth_cookie $upstream_http_set_cookie;
     add_header Set-Cookie $auth_cookie;

oauthproxy.go

@@ -694,6 +694,9 @@ func (p *OAuthProxy) Authenticate(rw http.ResponseWriter, req *http.Request) int
 		if session.Email != "" {
 			rw.Header().Set("X-Auth-Request-Email", session.Email)
 		}
+		if p.PassAccessToken && session.AccessToken != "" {
+			rw.Header().Set("X-Auth-Request-Access-Token", session.AccessToken)
+		}
 	}
 	if p.PassAccessToken && session.AccessToken != "" {
 		req.Header["X-Forwarded-Access-Token"] = []string{session.AccessToken}