1 files changed, 32 insertions, 0 deletions
diff --git a/browser/extensions/screenshots/domainFromUrl.js b/browser/extensions/screenshots/domainFromUrl.js
new file mode 100644
index 0000000000..b610007a34
--- /dev/null
+++ b/browser/extensions/screenshots/domainFromUrl.js
@@ -0,0 +1,32 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/** Returns the domain of a URL, but safely and in ASCII; URLs without domains
+    (such as about:blank) return the scheme, Unicode domains get stripped down
+    to ASCII */
+
+"use strict";
+
+this.domainFromUrl = (function () {
+  return function urlDomainForId(location) {
+    // eslint-disable-line no-unused-vars
+    let domain = location.hostname;
+    if (!domain) {
+      domain = location.origin.split(":")[0];
+      if (!domain) {
+        domain = "unknown";
+      }
+    }
+    if (domain.search(/^[a-z0-9._-]{1,1000}$/i) === -1) {
+      // Probably a unicode domain; we could use punycode but it wouldn't decode
+      // well in the URL anyway.  Instead we'll punt.
+      domain = domain.replace(/[^a-z0-9._-]/gi, "");
+      if (!domain) {
+        domain = "site";
+      }
+    }
+    return domain;
+  };
+})();
+null;