Initial commit

lib/util.js

@@ -0,0 +1,70 @@
+const crypto = require('crypto');
+
+module.exports = {
+    /**
+     * Port of Python's base64.urlsafe_b64encode: Returns a base64-encoded
+     * representation of s, made URL-safe by replacing + and / with - and _
+     * respectively. Additionally all trailing =s are stripped from the
+     * resulting value to mirror django.core.signing.b64_encode.
+     * @param  {string} s Input string.
+     * @return {string}   URL-safe encoded string.
+     */
+    b64Encode: function (s) {
+        // Validate
+        if (typeof s !== 'string') return;
+
+        // Convert from binary to Base64
+        var b64String = Buffer(s, 'binary').toString('base64');
+
+        // Replace special characters with URL-safe alternates
+        return b64String.replace(
+            /[+/]/g,
+            function (c) {
+                return {'+': '-', '/': '_'}[c];
+            }
+        ).replace(/=+$/, '');
+    },
+
+    /**
+     * Port of Python's base64.urlsafe_b64decode: Returns a base64-decoded
+     * representation of s, made URL-safe by replacing + and / with - and _
+     * respectively. Handles removal of trailing =s which are stripped from
+     * encoded values to mirror django.core.signing.b64_decode.
+     * @param  {string} s Base64 encoded string.
+     * @return {string}   Decoded string.
+     */
+    b64Decode: function (s) {
+        // Validate
+        if (typeof s !== 'string') return;
+
+        // Trim leading "dot" character
+        if (s[0] === '.') s = s.substring(1);
+
+        // Replace encoded special characters
+        s = s.replace(
+            /[-_]/g,
+            function (c) {
+                return {'-': '+', '_': '/'}[c];
+            }
+        );
+
+        // Convert from Base64 to binary
+        return new Buffer(s, 'base64').toString('binary');
+    },
+
+    /**
+     * Creates an MD5 hash from the specified input string.
+     * @param  {string} s Input string.
+     * @return {string}   Hash.
+     */
+    md5: function (s) {
+        // Validate
+        if (typeof s !== 'string') return;
+
+        // Create hash and return hex digest
+        return crypto
+            .createHash('md5')
+            .update(s)
+            .digest('hex');
+    }
+};