How to download CSV file from function in WordPress plugin?

4 comments

1. /**
   * Query For Top Title Row
   */

   $results = $wpdb->get_results("SHOW COLUMNS FROM $table" );
   if(count($results) > 0){
       foreach($results as $result){
           $csv_output .= str_replace('_',' ',$result->Field).", "; // , or ;      
       }
   }
   $csv_output .= "n";
   

   /**
   * Query For All Required Data
   */

   $results = $wpdb->get_results("SELECT * FROM $table",ARRAY_A );
   if(count($results) > 0){
       foreach($results as $result){
           $result = array_values($result);
           $result = implode(", ", $result);
           $csv_output .= $result."n"; 
       }
   }
   

   /**
   * Prepare Filename And CSV File to export
   */

   $filename = $file."_".date("Y-m-d_H-i",time());
   header("Content-type: application/vnd.ms-excel");
   header("Content-disposition: csv" . date("Y-m-d") . ".csv");
   header( "Content-disposition: filename=".$filename.".csv");
   print $csv_output;
   exit;
   

   Putting this all in a function should do the trick

2. Try this:

   <?php
   
   class CSVExport
   {
   /**
    * Constructor
    */
   public function __construct()
   {
       if(isset($_GET['download_report']))
       {
           $csv = $this->generate_csv();
   
           header("Pragma: public");
           header("Expires: 0");
           header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
           header("Cache-Control: private", false);
           header("Content-Type: application/octet-stream");
           header("Content-Disposition: attachment; filename="report.csv";" );
           header("Content-Transfer-Encoding: binary");
   
           echo $csv;
           exit;
       }
   
       // Add extra menu items for admins
       add_action('admin_menu', array($this, 'admin_menu'));
   
       // Create end-points
       add_filter('query_vars', array($this, 'query_vars'));
       add_action('parse_request', array($this, 'parse_request'));
   }
   
   /**
    * Add extra menu items for admins
    */
   public function admin_menu()
   {
       add_menu_page('Download Report', 'Download Report', 'manage_options', 'download_report', array($this, 'download_report'));
   }
   
   /**
    * Allow for custom query variables
    */
   public function query_vars($query_vars)
   {
       $query_vars[] = 'download_report';
       return $query_vars;
   }
   
   /**
    * Parse the request
    */
   public function parse_request(&$wp)
   {
       if(array_key_exists('download_report', $wp->query_vars))
       {
           $this->download_report();
           exit;
       }
   }
   
   /**
    * Download report
    */
   public function download_report()
   {
       echo '<div class="wrap">';
       echo '<div id="icon-tools" class="icon32"></div>';
       echo '<h2>Download Report</h2>';
       //$url = site_url();
   
       echo '<p><a href="site_url()/wp-admin/admin.php?page=download_report&download_report">Export the Subscribers</a>';
   }
   
   /**
    * Converting data to CSV
    */
   public function generate_csv()
   {
       $csv_output = '';
       $table = 'users';
   
       $result = mysql_query("SHOW COLUMNS FROM ".$table."");
   
       $i = 0;
       if (mysql_num_rows($result) > 0) {
           while ($row = mysql_fetch_assoc($result)) {
               $csv_output = $csv_output . $row['Field'].",";
               $i++;
           }
       }
       $csv_output .= "n";
   
       $values = mysql_query("SELECT * FROM ".$table."");
       while ($rowr = mysql_fetch_row($values)) {
           for ($j=0;$j<$i;$j++) {
               $csv_output .= $rowr[$j].",";
           }
           $csv_output .= "n";
       }
   
       return $csv_output;
   }
   }
   
   // Instantiate a singleton of this plugin
   $csvExport = new CSVExport();
   

3. You’ll need to change some header information

   header('Content-Type: text/csv');
   header('Content-Disposition: attachment;filename="report.csv"');
   header('Cache-Control: max-age=0');
   // If you're serving to IE 9, then the following may be needed
   header('Cache-Control: max-age=1');
   // If you're serving to IE over SSL, then the following may be needed
   header ('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); // Date in the past
   header ('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT'); // always modified
   header ('Cache-Control: cache, must-revalidate'); // HTTP/1.1
   header ('Pragma: public'); // HTTP/1.0
   

   After that make use of php://output for providing the data directly to the browser, this will prevent the blank page.

   for example:

   $outstream = fopen("php://output", "w");
   
   foreach($result as $result)
   {
       fputcsv($outstream, $result);
   }
   
   fclose($outstream);
   exit();
   

   php://output is a read only stream that allows you provide data directly to the requester.

   EDIT: Also you should make use of $wpdb

4. Here is the solution I found, after having tons of trouble with the code outputting HTML code, when used on the front side of the site. The key is to exchange exit for ‘die’. This is the code I am using on my own sites.

   
   header('Content-Type: text/csv');
   $FileName = 'Content-Disposition: attachment; filename="'. 'Report.csv"';
   header($FileName);
   
   $fp = fopen('php://output', 'w');
       
   $header_row = array(
           0 => 'data1',
           1 => 'data2',
           2 => 'data3',
       );
   fputcsv($fp, $header_row); 
   
   $rows = GetDataBaseData();
   if(!empty($rows)) 
     {
      foreach($rows as $Record)
        {      
       // where data1, data2, data3 are the database column names 
       $OutputRecord = array($Record['data1'], $Record['data1'], $Record['data1']);
       fputcsv($fp, $OutputRecord);         
       }
       unset($rows);
     }
   
   fclose( $fp );
       
   die;   <===== key point.  Use DIE not Exit.  Exit will only work on the back end. Die will work on both.
   ```
   
   Works on the front and backend of wordpress.    
   

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