Use binary buffers for hash; safe64 encode results. Addresses #1056

1 files changed, 24 insertions, 5 deletions

diff --git a/lib/utils.js b/lib/utils.js
index 037d3236c..c76d31500 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -108,19 +108,38 @@ exports.anonymizeIp = function anonymizeIp(ip) {
     }
 };
 
+function objectToHashableString(object) {
+    // See https://stackoverflow.com/questions/899574/which-is-best-to-use-typeof-or-instanceof/6625960#6625960
+    return (typeof(object) === 'string') ? object : JSON.stringify(object);
+}
+
+const DefaultHash = 'Compiler Explorer Default Version 1';
+
+/***
+ * Gets the hash (as a binary buffer) of the given object
+ *
+ * Limitation: object shall not have circular references
+ * @param object {*} Object to get hash from
+ * @param HashVersion {String} Hash "version"
+ * @returns {Buffer} Hash of object
+ */
+exports.getBinaryHash = function getHash(object, HashVersion = DefaultHash) {
+    return crypto.createHmac('sha256', HashVersion)
+        .update(objectToHashableString(object))
+        .digest('buffer');
+};
+
 /***
- * Gets the hash of the given object
+ * Gets the hash (as a hex string) of the given object
  *
  * Limitation: object shall not have circular references
  * @param object {*} Object to get hash from
  * @param HashVersion {String} Hash "version"
  * @returns {String} Hash of object
  */
-exports.getHash = function getHash(object, HashVersion = 'Compiler Explorer Default Version 1') {
-    // See https://stackoverflow.com/questions/899574/which-is-best-to-use-typeof-or-instanceof/6625960#6625960
-    const asString = (typeof(object) === 'string') ? object : JSON.stringify(object);
+exports.getHash = function getHash(object, HashVersion = DefaultHash) {
     return crypto.createHmac('sha256', HashVersion)
-        .update(asString)
+        .update(objectToHashableString(object))
         .digest('hex');
 };