fix: fix attachment file size check differences between FE and BE

[sebastianwzq]

Problem

We received Invalid answer: AttachmentValidator: File size more than limit on the backend. Given that attachment size is checked on the frontend, this shouldn't happen in normal cases.

The validation condition on frontend and backend is different.

Frontend

       if (
          !IMAGE_UPLOAD_TYPES_TO_COMPRESS.includes(file.type) &&
          maxSize &&
          file.size > maxSize
        ) {
          return {
            code: 'file-too-large',
            message: `You have exceeded the limit, please upload a file below ${readableMaxSize}`,
          }
        }

backend

const makeAttachmentSizeValidator: AttachmentValidatorConstructor =
  (attachmentField) => (response) => {
    const { attachmentSize } = attachmentField
    const byteSizeLimit = parseInt(attachmentSize) * MB
    return response.content.byteLength < byteSizeLimit
      ? right(response)
      : left(`AttachmentValidator:\t File size more than limit`)
  }

Given that limit = 1MB and uploaded file size = 1MB, frontend will allow the upload to go true while backend will reject the upload, resulting in users experiencing 400 errors.

Closes FRM-1571

Solution

Standardised validation conditions across frontend and backend

Breaking Changes

• Yes - this PR contains breaking changes
  • Details ...
• No - this PR is backwards compatible

Features:

• Details ...

Improvements:

• Details ...

Bug Fixes:

• Details ...

Before & After Screenshots

BEFORE:

AFTER:

Tests

• create email mode form with attachment field of 1mb limit
• run mkfile 1000000 test.txt to create a 1mb file (note that formsg uses 1mb = 1000000 instead of 1024*1024)
• upload attachment, you should not encounter any errors

Deploy Notes

New environment variables:

• env var : env var details

New scripts:

• script : script details

New dependencies:

• dependency : dependency details

New dev dependencies:

• dependency : dependency details

[linear]

FRM-1571 fix attachment file size check differences between FE and BE

[justynoh]

lgtm