Access Physical Folder through Applications

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I have new requiremtn for custom application that genrerate physcial files on DB directory .then link to user allow to hime to download this files.

DB dircectory created . but how can allow access to user for this files though Application .

there is one idea create folder under http://erp:8000/OA_HTML/ . but eveyone can access it to >>>

any idea >>>