In Django, SuspiciousFileOperation can be avoid by read the file from external dir and make a tmp file within the project media then save in the appropriate file filed as below
import tempfile
file_name="file_name.pdf"
EXT_FILE_PATH = "/home/somepath/"
file_path = EXT_FILE_PATH + file_name
if exists(file_path):
#create a named temporary file within the project base , here in media
lf = tempfile.NamedTemporaryFile(dir="media")
f = open(file_path, 'rb')
lf.write(f.read())
#doc object with file FileField.
doc.file.save(file_name, File(lf), save=True)
lf.close()