fix: test whether the storage proxy exists in storage.js

build/express-gateway/plugins/storage.js

@@ -47,25 +47,27 @@ module.exports = {
         const params = parseParams(req.params[0], pluginContext.settings.providers)
         if (params.provider && params.bucket && params.key) {
           const storageProxy = storageProxies[params.provider];
-          storageProxy.getObject({
-            Bucket: params.bucket,
-            Key: params.key,
-            Range: req.headers.range // Forward range requests
-          })
-          .on('httpHeaders', (statusCode, headers) => { 
-            // Avoid catching event raised by connection initialization
-            // https://stackoverflow.com/questions/35782434/streaming-file-from-s3-with-express-including-information-on-length-and-filetype
-            if (headers['content-length']) {
-              res.status(statusCode);
-              res.set(headers);
-            } else logger.debug('Invalid response with status ' + statusCode)
-          })
-          .createReadStream()
-          .on('error', (err) => {
-            logger.debug(err);
-            return res.status(404).send(err);
-          })
-          .pipe(res);
+          if (storageProxy) {
+            storageProxy.getObject({
+              Bucket: params.bucket,
+              Key: params.key,
+              Range: req.headers.range // Forward range requests
+            })
+            .on('httpHeaders', (statusCode, headers) => { 
+              // Avoid catching event raised by connection initialization
+              // https://stackoverflow.com/questions/35782434/streaming-file-from-s3-with-express-including-information-on-length-and-filetype
+              if (headers['content-length']) {
+                res.status(statusCode);
+                res.set(headers);
+              } else logger.debug('Invalid response with status ' + statusCode)
+            })
+            .createReadStream()
+            .on('error', (err) => {
+              logger.debug(err);
+              return res.status(404).send(err);
+            })
+            .pipe(res);
+          }
         }
       });
     });