rest: add cookie_from_header helper

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

proxmox-rest-server/src/lib.rs

@@ -201,6 +201,16 @@ pub fn extract_cookie(cookie: &str, cookie_name: &str) -> Option<String> {
     None
 }
 
+/// Extract a specific cookie from a HeaderMap's "COOKIE" entry.
+/// We assume cookie_name is already url encoded.
+pub fn cookie_from_header(headers: &http::HeaderMap, cookie_name: &str) -> Option<String> {
+    if let Some(Ok(cookie)) = headers.get("COOKIE").map(|v| v.to_str()) {
+        extract_cookie(&cookie, cookie_name)
+    } else {
+        None
+    }
+}
+
 /// normalize uri path
 ///
 /// Do not allow ".", "..", or hidden files ".XXXX"