gistfile1.py

def download_attachments(self, cr, uid, ids, context = None):
        
        cache_buster = randint(10000000000,90000000000)
        config_obj = self.pool.get('ir.config_parameter')
        attachment_obj = self.pool.get('ir.attachment')
        filestore_path = os.path.join(attachment_obj._filestore(cr, uid), '')
        print "filestore path..............",filestore_path
        attachment_dir = filestore_path + 'attachments'
        #create directory and remove its content
        if not os.path.exists(attachment_dir):
            os.makedirs(attachment_dir)
        else:
            shutil.rmtree(attachment_dir)
            os.makedirs(attachment_dir)
        file_name = 'files'
        if isinstance(ids, int):
            ids = [ids]
        wzrd_obj = self.browse(cr, uid, ids[0])
        config_ids = config_obj.search(cr, uid, [('key','=','web.base.url')])
        if len(config_ids):
            value = config_obj.browse(cr, uid, config_ids[0]).value
            active_model = 'ir.attachment'#wzrd_obj.active_model
            active_id = wzrd_obj.active_id
            #tar_dir = attachment_dir + '/' + file_name
            tar_dir = os.path.join(attachment_dir, file_name)
            tFile = tarfile.open(tar_dir, 'w')
            if value and active_model and active_id:
                #change working directory otherwise file is tared with all its parent directories
                original_dir = os.getcwd()
                
                if not wzrd_obj.attachment_ids:
                    raise Warning(_("No attachment to download"))
                
                for attachment in wzrd_obj.attachment_ids:
                    #to get full path of file
                    full_path = attachment_obj._full_path(cr, uid, attachment.store_fname)
                    new_file = os.path.join(attachment_dir, attachment.name)
                    #copying in a new directory with a new name
                    shutil.copy2(full_path,  new_file)
                    head, tail = ntpath.split(new_file)
                    #change working directory otherwise it tars all parent directory
                    os.chdir(head) 
                    tFile.add(tail)
                    print "added file ...................................",tail
                os.chdir(original_dir)
                
                
                attachment_id = self.pool.get('ir.attachment').create(cr, uid, 
                                                      {
                                                       'name' : file_name+'.tar', 
                                                       'res_model' : 'download.attachments',
                                                       'res_id' : ids[0],
                                                       'res_name' : 'test....',
                                                       'type': 'binary',
                                                       'store_fname' : 'attachments/files',
                                                       })
                
                
                active_id = attachment_id
                
                url = '%s/web/binary/saveas?model=%s&field=datas&filename_field=name&id=%s&t=%s"'%(value , active_model ,active_id, cache_buster)
                print "url................",url
                return {
                 'type': 'ir.actions.act_url',
                'url':url,
                'nodestroy': False,
                }