在提交事务之前显示日志文件。 仅在用户确认后提交

Question

When I update records in the data I want to show the user the update log BEFORE the transaction is committed and give the option to continue or roll back.

The code that commits the updates to the database follows this format:-

<?php
include 'submitLogger.php';

// Begin logging
ini_set( "error_log", $logFile );
ini_set( "log_errors", "On" );
ini_set( "display_errors", "Off" );
error_log( "Log file '" . $logFile . "' created" );

// Open the database
.
.

error_log( "Connect OK" );
.
.

error_log( "Transaction started (autocommit OFF)\n" ); 
.
.

error_log( "Processing " . count( $deletes ) . " item(s) marked for deletion..." ); 
.
.


// commit changes
error_log( "Committing changes..." ); 
if ( mysqli_commit( $link ) === false ) {
  mysqli_rollback( $link );
  error_log( "Commit failed. Transaction rolled back." ); 
  $response['error'] = "Could not commit changes. Transaction rolled back.";
} else {
  error_log( "Commit successful!" ); 
  $response['success'] = "Success!";
}

// close DB connection
.
.

// Return result
.
.

This is the code that loads the update code above and then displays the logfile, but AFTER the transaction has been committed:-

<script type="text/javascript">

$(document).ready( function() {


  // send AJAX request to perform the updates and begin logging
  $.post(
    '../lib/updateMenu.php', 
    sendData,
    function( response ) {
      // was it successful?
      if ( typeof response.success === 'undefined' ) {
        // no - show alert
        if ( response.error ) {
          alert( response.error );
        }
        console.error( "Amend not successful" );
        console.error( response );
        return;
      }

      // delete the AmendmenuAmendselected program window to force a reload on next click
      $( "#programWindowAmendmenuAmendselected" ).remove();
    },
    "json"
  ).error(function(jqXHR, textStatus, errorThrown) {
    alert( 'Unexpected error: ' + textStatus + ' ' + errorThrown );
    console.error( 'Unexpected error during amend: ' + textStatus + ' ' + errorThrown );
    console.error(jqXHR);
  }).complete(function() {
    // once a reply is received, stop the logging
    ajaxLogtail.stopTail();      
  });

  // begin querying log file
  var ajaxLogtail = new AjaxLogtail( '../lib/ajaxLogtail.php?logfile=' + logFile, "programWindowAmendmenuSubmit" );  
  ajaxLogtail.startTail();
});

</script>

I cannot figure out how to split this so that I can display the logfile and then, if there weren't any update errors, commit the transaction.

Does anyone have a neat idea to help, please?

Answer 1

As long as i know you cannot do it. At least not with php. Php is a server side, script code runned. It runs from the first line to the last line, stop.

You however can run a select and tell how many records will be at example deleted, give those data to the ajax and then on confirm do the real delete operation (and commit the change).

However you can (if your web app is used by a lot of people) have a situation where your ajax find 25 element to be deleted and the real delete query will delete 26 or more. For that better re-think your logic a little and produce a log after the delete query.