[Fix] Multi Doc support in prompt studio (#1078)

* changed read length to full length

* added todo

* code refactor

---------

Co-authored-by: Gayathri <[email protected]>

backend/utils/FileValidator.py

@@ -8,6 +8,7 @@
 from django.template.defaultfilters import filesizeformat
 from django.utils.translation import gettext_lazy as _
 from typing_extensions import NotRequired, Unpack
+from unstract.sdk.file_storage.constants import FileOperationParams
 
 
 class FileValidationParam(TypedDict):
@@ -69,7 +70,10 @@ def _check_file_extension(self, file: InMemoryUploadedFile) -> None:
             raise ValidationError(message)
 
     def _check_file_mime_type(self, file: InMemoryUploadedFile) -> None:
-        mimetype = magic.from_buffer(file.read(2048), mime=True)
+        # TODO: Need to optimise, istead of reading entire file.
+        mimetype = magic.from_buffer(
+            file.read(FileOperationParams.READ_ENTIRE_LENGTH), mime=True
+        )
         file.seek(0)  # Reset the file pointer to the start
 
         if self.allowed_mimetypes and mimetype not in self.allowed_mimetypes: