I have created a Module to make blob file available for Download in Drupal 7 .
Below my code for .module file
<?php  function blobfile_block_info() {   $blocks = array();   $blocks['blobfile_block'] = array(     'info' => t('Blob Files Download'),   );    return $blocks; }  function blobfile_block_view($delta) {            $query = db_select('health_policy_document_upload_dtl', h)->fields('h');       $result = $query->execute();        $content ='';       while($record = $result->fetchAssoc()) {            $filename = $record['Document_Name'];           $file     = $record['Document'];           $type     = $record['Document_Type'];           $size     = filesize($file);             header("Content-length: $size");           header("Content-type: $type");                     header("Content-Disposition: attachment; filename=$filename");            $content .= "<a href='#'>".$filename."</a>";           $content .= "<br>";       }      return array(       'subject' => t('Bids'),       'content' => $content     );     } 
Please guide me where I went wrong.