Separate uploaded file validation logic from the model "Attachments"

models/attachments.js

@@ -1,15 +1,12 @@
 import { Meteor } from 'meteor/meteor';
 import { FilesCollection } from 'meteor/ostrio:files';
-import { exec } from 'node:child_process';
-import { promisify } from 'node:util';
+import { isFileValid } from './fileValidation';
 import { createBucket } from './lib/grid/createBucket';
 import fs from 'fs';
-import FileType from 'file-type';
 import path from 'path';
 import { AttachmentStoreStrategyFilesystem, AttachmentStoreStrategyGridFs} from '/models/lib/attachmentStoreStrategy';
 import FileStoreStrategyFactory, {moveToStorage, rename, STORAGE_NAME_FILESYSTEM, STORAGE_NAME_GRIDFS} from '/models/lib/fileStoreStrategy';
 
-let asyncExec;
 let attachmentUploadExternalProgram;
 let attachmentUploadMimeTypes = [];
 let attachmentUploadSize = 0;
@@ -17,7 +14,6 @@ let attachmentBucket;
 let storagePath;
 
 if (Meteor.isServer) {
-  asyncExec = promisify(exec);
   attachmentBucket = createBucket('attachments');
 
   if (process.env.ATTACHMENTS_UPLOAD_MIME_TYPES) {
@@ -155,34 +151,7 @@ if (Meteor.isServer) {
       check(fileObjId, String);
 
       const fileObj = Attachments.findOne({_id: fileObjId});
-      let isValid = true;
-
-      if (attachmentUploadMimeTypes.length) {
-        const mimeTypeResult = Promise.await(FileType.fromFile(fileObj.path));
-
-        const mimeType = (mimeTypeResult ? mimeTypeResult.mime : fileObj.type);
-        const baseMimeType = mimeType.split('/', 1)[0];
-
-        isValid = attachmentUploadMimeTypes.includes(mimeType) || attachmentUploadMimeTypes.includes(baseMimeType + '/*') || attachmentUploadMimeTypes.includes('*');
-
-        if (!isValid) {
-          console.log("Validation of uploaded file failed: file " + fileObj.path + " - mimetype " + mimeType);
-        }
-      }
-
-      if (attachmentUploadSize && fileObj.size > attachmentUploadSize) {
-        console.log("Validation of uploaded file failed: file " + fileObj.path + " - size " + fileObj.size);
-        isValid = false;
-      }
-
-      if (isValid && attachmentUploadExternalProgram) {
-        Promise.await(asyncExec(attachmentUploadExternalProgram.replace("{file}", '"' + fileObj.path + '"')));
-        isValid = fs.existsSync(fileObj.path);
-
-        if (!isValid) {
-          console.log("Validation of uploaded file failed: file " + fileObj.path + " has been deleted externally");
-        }
-      }
+      const isValid = Promise.await(isFileValid(fileObj, attachmentUploadMimeTypes, attachmentUploadSize, attachmentUploadExternalProgram));
 
       if (!isValid) {
         Attachments.remove(fileObjId);
@@ -192,12 +161,11 @@ if (Meteor.isServer) {
       check(fileObjId, String);
       check(storageDestination, String);
 
-      Meteor.defer(() => Meteor.call('validateAttachment', fileObjId));
+      Meteor.call('validateAttachment', fileObjId);
 
       const fileObj = Attachments.findOne({_id: fileObjId});
 
       if (fileObj) {
-        console.debug("Validation of uploaded file completed: file " + fileObj.path + " - storage destination " + storageDestination);
         Meteor.defer(() => Meteor.call('moveAttachmentToStorage', fileObjId, storageDestination));
       }
     },

models/fileValidation.js

@@ -0,0 +1,48 @@
+import { Meteor } from 'meteor/meteor';
+import { exec } from 'node:child_process';
+import { promisify } from 'node:util';
+import fs from 'fs';
+import FileType from 'file-type';
+
+let asyncExec;
+
+if (Meteor.isServer) {
+  asyncExec = promisify(exec);
+}
+
+export async function isFileValid(fileObj, mimeTypesAllowed, sizeAllowed, externalCommandLine) {
+  let isValid = true;
+
+  if (mimeTypesAllowed.length) {
+    const mimeTypeResult = await FileType.fromFile(fileObj.path);
+
+    const mimeType = (mimeTypeResult ? mimeTypeResult.mime : fileObj.type);
+    const baseMimeType = mimeType.split('/', 1)[0];
+
+    isValid = mimeTypesAllowed.includes(mimeType) || mimeTypesAllowed.includes(baseMimeType + '/*') || mimeTypesAllowed.includes('*');
+
+    if (!isValid) {
+      console.log("Validation of uploaded file failed: file " + fileObj.path + " - mimetype " + mimeType);
+    }
+  }
+
+  if (isValid && sizeAllowed && fileObj.size > sizeAllowed) {
+    console.log("Validation of uploaded file failed: file " + fileObj.path + " - size " + fileObj.size);
+    isValid = false;
+  }
+
+  if (isValid && externalCommandLine) {
+    await asyncExec(externalCommandLine.replace("{file}", '"' + fileObj.path + '"'));
+    isValid = fs.existsSync(fileObj.path);
+
+    if (!isValid) {
+      console.log("Validation of uploaded file failed: file " + fileObj.path + " has been deleted externally");
+    }
+  }
+
+  if (isValid) {
+    console.debug("Validation of uploaded file successful: file " + fileObj.path);
+  }
+
+  return isValid;
+}