Add sharedfile voting support

components/sharedfiles.js

@@ -55,6 +55,48 @@ SteamCommunity.prototype.postSharedfileComment = function(userID, sid, message,
             return;
         }
 
+        callback(null || err);
+    }, "steamcommunity");
+};
+
+/**
+ * Downvotes a sharedfile
+ * @param {String} sid - ID of the sharedfile
+ * @param {function} callback - Takes only an Error object/null as the first argument
+ */
+SteamCommunity.prototype.voteDownSharedfile = function(sid, callback) {
+    this.httpRequestPost({
+        "uri": "https://steamcommunity.com/sharedfiles/votedown",
+        "form": {
+            "id": sid,
+            "sessionid": this.getSessionID()
+        }
+    }, function(err, response, body) {
+        if (!callback) {
+            return;
+        }
+
+        callback(null || err);
+    }, "steamcommunity");
+};
+
+/**
+ * Upvotes a sharedfile
+ * @param {String} sid - ID of the sharedfile
+ * @param {function} callback - Takes only an Error object/null as the first argument
+ */
+SteamCommunity.prototype.voteUpSharedfile = function(sid, callback) {
+    this.httpRequestPost({
+        "uri": "https://steamcommunity.com/sharedfiles/voteup",
+        "form": {
+            "id": sid,
+            "sessionid": this.getSessionID()
+        }
+    }, function(err, response, body) {
+        if (!callback) {
+            return;
+        }
+
         callback(null || err);
     }, "steamcommunity");
 };