Simplify folder structure

lib/api/middlewares/vector-error.js

@@ -0,0 +1,35 @@
+'use strict';
+
+const fs = require('fs');
+const timeoutErrorVectorTile = fs.readFileSync(__dirname + '/../../../assets/render-timeout-fallback.mvt');
+
+module.exports = function vectorError() {
+    return function vectorErrorMiddleware(err, req, res, next) {
+        if(req.params.format === 'mvt') {
+
+            if (isTimeoutError(err) || isRateLimitError(err)) {
+                res.set('Content-Type', 'application/x-protobuf');
+                return res.status(429).send(timeoutErrorVectorTile);
+            }
+        }
+
+        next(err);
+    };
+};
+
+
+function isRenderTimeoutError (err) {
+    return err.message === 'Render timed out';
+}
+
+function isDatasourceTimeoutError (err) {
+    return err.message && err.message.match(/canceling statement due to statement timeout/i);
+}
+
+function isTimeoutError (err) {
+    return isRenderTimeoutError(err) || isDatasourceTimeoutError(err);
+}
+
+function isRateLimitError (err) {
+    return err.type === 'limit' && err.subtype === 'rate-limit';
+}