refactor, create base64url.js

Author: psteniusubi

docs/base64url.js

@@ -0,0 +1,36 @@
+/*
+ * Base64 decode url safe
+ * https://tools.ietf.org/html/rfc7515#appendix-C
+ * https://tools.ietf.org/html/rfc4648#section-5
+ */
+function atobUrlSafe(text) {
+    if (text == null) {
+        return null;
+    }
+    text = text
+        .replace(/\s+/g, "") // removes whitespace such as linefeeds from input encoded string
+        .replace(/-/g, "+") // replace '-' with '+'
+        .replace(/_/g, "/"); // replace '_' with '/'
+    switch(text.length % 4) {
+        case 2: text += "=="; break; 
+        case 3: text += "="; break; 
+        default: break; // if padding is wrong then eventually the atob call below fails
+    }
+    return atob(text);
+}
+
+/*
+ * Base64 encode url safe
+ * https://tools.ietf.org/html/rfc7515#appendix-C
+ * https://tools.ietf.org/html/rfc4648#section-5
+ */
+function btoaUrlSafe(text) {
+    if (text == null) {
+        return null;
+    }
+    text = btoa(text)
+        .replace(/\+/g, "-") // replace '+' with '-'
+        .replace(/\//g, "_") // replace '/' with '_'
+        .replace(/=+$/, ""); // remove trailing padding characters
+    return text;
+}

docs/id_token.html

@@ -1,6 +1,7 @@
 <!DOCTYPE html>
 
-<script type="text/javascript" src="//code.jquery.com/jquery-3.3.1.js"></script>
+<script type="text/javascript" src="https://code.jquery.com/jquery-3.3.1.js"></script>
+<script type="text/javascript" src="base64url.js"></script>
 <script type="text/javascript">
 
     var issuer = "https://login.example.ubidemo.com/uas";
@@ -22,21 +23,6 @@
             });
     }
 
-    function atobUrlSafe(text) {
-        if (text == null) {
-            return null;
-        }
-        text = text
-            .replace(/\s+/g, "")
-            .replace(/_/g, "/")
-            .replace(/-/g, "+");
-        if (text.length === 0) {
-            return "";
-        }
-        text += "==".substr(0, text.length % 4);
-        return atob(text);
-    }
-
     function decodeJWT(jwks, jwt) {
 
         var jws = jwt.split(".");

docs/spa.html

@@ -3,6 +3,7 @@
 <head>
     <meta name="viewport" content="initial-scale=1"></meta>
     <script type="text/javascript" src="//code.jquery.com/jquery-3.3.1.js"></script>
+    <script type="text/javascript" src="base64url.js"></script>
     <script type="text/javascript">
 
         var issuer = "https://login.example.ubidemo.com/uas";
@@ -33,21 +34,6 @@
                 );
         }
 
-        function atobUrlSafe(text) {
-            if (text == null) {
-                return null;
-            }
-            text = text
-                .replace(/\s+/g, "")
-                .replace(/_/g, "/")
-                .replace(/-/g, "+");
-            if (text.length === 0) {
-                return "";
-            }
-            text += "==".substr(0, (4 - text.length % 4) % 4);
-            return atob(text);
-        }
-
         function matchParam(qs, name, mapper = null) {
             return new Promise(resolve => {
                 if (qs.startsWith("?")) {