Add config field for lstu;

config.example.js

@@ -21,4 +21,7 @@ module.exports = {
 
     // Network interface on which to run the webhook server.
     hostname: '0.0.0.0',
+
+    // Instance of lstu to shorten links -- keep empty to not use.
+    lstu: 'https://lstu.fr'
 }

index.js

@@ -33,19 +33,27 @@ var app = express();
 app.use(bodyParser.json()); // for parsing application/json
 app.use(bodyParser.urlencoded({ extended: true })); // for parsing application/x-www-form-urlencoded
 
-function shortenURL(url, callback) {
-    request('https://lstu.fr/a', { method: 'POST', form: { lsturl: url, format: 'json' } }, function (err, res, body) {
-        try {
-            body = JSON.parse(body);
-        } catch(err) {
-            body = {err: 'cant parse JSON'};
-        }
-        if (err || !body.success) {
-            console.error("Error when shortening link: (status: " + res.statusCode + ")", '\nerror:', err, '\nfailure reason:', body.msg);
-        } else {
-            callback(body.short);
-        }
-    });
+var shortenURL = function(url, callback) { callback(url); };
+
+if (config.lstu) {
+    if (config.lstu[config.lstu.length - 1] !== '/') {
+        config.lstu += '/';
+    }
+
+    shortenURL = function shortenURL(url, callback) {
+        request(config.lstu + 'a', { method: 'POST', form: { lsturl: url, format: 'json' } }, function (err, res, body) {
+            try {
+                body = JSON.parse(body);
+            } catch(err) {
+                body = {err: 'cant parse JSON'};
+            }
+            if (err || !body.success) {
+                console.error("Error when shortening link: (status: " + res.statusCode + ")", '\nerror:', err, '\nfailure reason:', body.msg);
+            } else {
+                callback(body.short);
+            }
+        });
+    };
 }
 
 var handlers = {