CLS Context is lost after using multer middleware (#695)

related issue: expressjs/multer#814
Used the solution described in the above link to fix the issue

Co-authored-by: Alan Wang <[email protected]>

Author: yidongw

src/middlewares/openapi.multipart.ts

@@ -20,51 +20,58 @@ export function multipart(
 ): OpenApiRequestHandler {
   const mult = multer(options.multerOpts);
   const Ajv = createRequestAjv(apiDoc, { ...options.ajvOpts });
-  return (req, res, next) => {
+  return async (req, res, next) => {
     // TODO check that format: binary (for upload) else do not use multer.any()
     // use multer.none() if no binary parameters exist
     if (shouldHandle(Ajv, req)) {
-      mult.any()(req, res, (err) => {
-        if (err) {
-          next(error(req, err));
-        } else {
-          // TODO:
-          // If a form parameter 'file' is defined to take file value, but the user provides a string value instead
-          // req.files will be empty and req.body.file will be populated with a string
-          // This will incorrectly PASS validation.
-          // Instead, we should return a 400 with an invalid type e.g. file expects a file, but found string.
-          //
-          // In order to support this, we likely need to inspect the schema directly to find the type.
-          // For example, if param with type: 'string', format: 'binary' is defined, we expect to see it in
-          // req.files. If it's not present we should throw a 400
-          //
-          // This is a bit complex because the schema may be defined inline (easy) or via a $ref (complex) in which
-          // case we must follow the $ref to check the type.
-
-          if (req.files) {
-            // to handle single and multiple file upload at the same time, let us this initialize this count variable
-            // for example { "files": 5 }
-            const count_by_fieldname = (<Express.Multer.File[]>req.files)
-              .map((file) => file.fieldname)
-              .reduce((acc, curr) => {
-                acc[curr] = (acc[curr] || 0) + 1;
-                return acc;
-              }, {});
-
-            // add file(s) to body
-            Object.entries(count_by_fieldname).forEach(
-              ([fieldname, count]: [string, number]) => {
-                // TODO maybe also check in the api doc if it is a single upload or multiple
-                const is_multiple = count > 1;
-                req.body[fieldname] = is_multiple
-                  ? new Array(count).fill('')
-                  : '';
-              },
-            );
-          }
-          next();
-        }
-      });
+      try {
+        await new Promise<void>((resolve, reject) => {
+          mult.any()(req, res, (err) => {
+            if (err) {
+              reject(error(req, err));
+            } else {
+              // TODO:
+              // If a form parameter 'file' is defined to take file value, but the user provides a string value instead
+              // req.files will be empty and req.body.file will be populated with a string
+              // This will incorrectly PASS validation.
+              // Instead, we should return a 400 with an invalid type e.g. file expects a file, but found string.
+              //
+              // In order to support this, we likely need to inspect the schema directly to find the type.
+              // For example, if param with type: 'string', format: 'binary' is defined, we expect to see it in
+              // req.files. If it's not present we should throw a 400
+              //
+              // This is a bit complex because the schema may be defined inline (easy) or via a $ref (complex) in which
+              // case we must follow the $ref to check the type.
+    
+              if (req.files) {
+                // to handle single and multiple file upload at the same time, let us this initialize this count variable
+                // for example { "files": 5 }
+                const count_by_fieldname = (<Express.Multer.File[]>req.files)
+                  .map((file) => file.fieldname)
+                  .reduce((acc, curr) => {
+                    acc[curr] = (acc[curr] || 0) + 1;
+                    return acc;
+                  }, {});
+    
+                // add file(s) to body
+                Object.entries(count_by_fieldname).forEach(
+                  ([fieldname, count]: [string, number]) => {
+                    // TODO maybe also check in the api doc if it is a single upload or multiple
+                    const is_multiple = count > 1;
+                    req.body[fieldname] = is_multiple
+                      ? new Array(count).fill('')
+                      : '';
+                  },
+                );
+              }
+              resolve();
+            }
+          });
+        });
+        next()
+      } catch (error) {
+        next(error);
+      }
     } else {
       next();
     }