Show progress of code executed on form submit

Question

I have a form in my site (custom module) where the user chooses some options and depending on those options, some code is executed.

The code basically executes shell commands on a remote server and at the moment, all the drupal_set_message commands are only shown after all commands are executed.

Is there any way that I can show those messages as soon as each part of the code is executed?

function mymodule_connect() {
    $host = '<my ip address>';
    $username = '<my username>';
    $password = '<my password>';

    $connection = ssh2_connect($host, 22);
    ssh2_auth_password($connection, $username, $password);

    return $connection;
}

function mymodule_form_submit(&$form, &$form_state) {

    $delete_load = $form_state['values']['delete_load'];
    $change_load = $form_state['values']['change_load'];
    $load_number = $form_state['values']['check_load'];


    if($change_load == 1) {
        # DELETE
        # perform some command

        # LOAD
        # perform other command

        drupal_set_message('Deleting. Please wait...', 'error');
        drupal_set_message('Changing load. Please wait...', 'warning');
    } elseif ($delete_load == 1 && $change_load == 0) {
        # DELETE    
        drupal_set_message('Deleting. Please wait...', 'error');

        $command = "<some shell script command to send>";

        $connection = mymodule_connect();

        $stream = ssh2_exec($connection, $command);
        stream_set_blocking($stream, true);
        $output = stream_get_contents($stream);
        dpm($output);

        ssh2_exec($connection, 'exit');
        unset($connection);

    } else {
        # do nothing
    }

    # OTHER DIFFERENT SET OF COMMANDS TO SEND
    drupal_set_message('Configuring. Please wait...', 'status');

    $commands = array(
        "<some shell script command to send>",
        "<some shell script command to send>",
        "<some shell script command to send>",
    );

    $connection = mymodule_connect();

    foreach ($commands as $command) {
        $stream = ssh2_exec($connection, $command);
        stream_set_blocking($stream, true);
        $output = stream_get_contents($stream);
        dpm($output);
    };

    ssh2_exec($connection, 'exit');
    unset($connection);

    return t('Success');
}

Answer 1

As Mohammed Gomma mentioned you need to use Batch API to achieve the same. The implementation of batch api may look something like code given below:

1. Create Batch array
2. Create function to execute commands and call them using batch operation
3. set context message in the function created

4. create finish callback

   function mymodule_form_submit(&$form, &$form_state) {

         $delete_load = $form_state['values']['delete_load'];
         $change_load = $form_state['values']['change_load'];
         $load_number = $form_state['values']['check_load'];
   
   
         if ($change_load == 1) {
           # DELETE
           # perform some command
           # LOAD
           # perform other command
   
           drupal_set_message('Deleting. Please wait...', 'error');
           drupal_set_message('Changing load. Please wait...', 'warning');
         }
         elseif ($delete_load == 1 && $change_load == 0) {
           # DELETE    
           drupal_set_message('Deleting. Please wait...', 'error');
   
           $command = "<some shell script command to send>";
   
   
   
           $stream = ssh2_exec($connection, $command);
           stream_set_blocking($stream, true);
           $output = stream_get_contents($stream);
           dpm($output);
   
           ssh2_exec($connection, 'exit');
           unset($connection);
         }
         else {
           # do nothing
         }
   
         # OTHER DIFFERENT SET OF COMMANDS TO SEND
         drupal_set_message('Configuring. Please wait...', 'status');
   
         $commands = array(
           "<some shell script command to send>",
           "<some shell script command to send>",
           "<some shell script command to send>",
         );
   
         $batch = array(
           'finished' => 'batch_example_finished',
           'title' => t('Processing Example Batch'),
           'init_message' => t('Example Batch is starting.'),
           'progress_message' => t('Processed @current out of @total.'),
           'error_message' => t('Example Batch has encountered an error.'),
         );
         foreach ($commands as $command) {
           $batch['operations'][] = array('_batch_execute_command', array($command));
         };
   
         batch_set($batch);
   
   
   
         return t('Success');
       }
   
       function _batch_execute_command($command, &$context) {
         $connection = mymodule_connect();
         $stream = ssh2_exec($connection, $command);
         stream_set_blocking($stream, true);
         $output = stream_get_contents($stream);
         dpm($output);
         ssh2_exec($connection, 'exit');              
         unset($connection);
         $context['message'] = t('Now processing %command', array('%command' => $command));
         if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
           $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
         }
       }
   
       /**
        * Batch 'finished' callback
        */
       function batch_example_finished($success, $results, $operations) {
         if ($success) {
           // Here we do something meaningful with the results.
           $message = t('@count items successfully processed:', array('@count' => count($results)));
           // $message .= theme('item_list', $results);  // D6 syntax
           $message .= theme('item_list', array('items' => $results));
           drupal_set_message($message);
         }
         else {
           // An error occurred.
           // $operations contains the operations that remained unprocessed.
           $error_operation = reset($operations);
           $message = t('An error occurred while processing %error_operation with arguments: @arguments', array('%error_operation' => $error_operation[0], '@arguments' => print_r($error_operation[1], TRUE)));
           drupal_set_message($message, 'error');
         }
       }
   

Nested batch example:

function gamify_batch_form($form, $form_state) {
  return array(
    'submit' => array(
      '#type' => 'submit',
      '#title' => 'submit',
      '#value' => 'submit',
    ),
  );
}

function gamify_batch_form_submit($form, $form_state) {
  $batch = array(
    'finished' => 'batch_example_finished',
    'title' => t('Processing Example Batch'),
    'init_message' => t('Example Batch is starting.'),
    'progress_message' => t('Processed @current out of @total.'),
    'error_message' => t('Example Batch has encountered an error.'),
  );
  $commands = array(
    'hi',
    'hello',
    'world',
    'dear',
    'world',
  );
  foreach ($commands as $command) {
    $batch['operations'][] = array('_batch_execute_command', array($command));
  };

  batch_set($batch);
}

function _batch_execute_command($command, &$context) {
  file_get_contents("https://drupal.stackexchange.com/questions/246767/show-progress-of-code-executed-on-form-submit/247718?noredirect=1#comment303466_247718");
  if($command == 'world'){
    $batch = array(
      'finished' => 'batch_example_finished',
      'title' => t('Processing Example Batch'),
      'init_message' => t('Example Batch is starting.'),
      'progress_message' => t('Processed @current out of @total.'),
      'error_message' => t('Example Batch has encountered an error.'),
    );
    $commands = array(
      'hi 1',
      'hello 2',
      'dear 3',
    );
    foreach ($commands as $innercommand) {
      $batch['operations'][] = array('_batch_execute_command', array($innercommand));
    };

    batch_set($batch);
  }
  $context['message'] = t('Now processing %command', array('%command' => $command));
  if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
    $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
  }
}

/**
 * Batch 'finished' callback
 */
function batch_example_finished($success, $results, $operations) {
  if ($success) {
    // Here we do something meaningful with the results.
    $message = t('@count items successfully processed:', array('@count' => count($results)));
    // $message .= theme('item_list', $results);  // D6 syntax
    $message .= theme('item_list', array('items' => $results));
    drupal_set_message($message);
  }
  else {
    // An error occurred.
    // $operations contains the operations that remained unprocessed.
    $error_operation = reset($operations);
    $message = t('An error occurred while processing %error_operation with arguments: @arguments', array('%error_operation' => $error_operation[0], '@arguments' => print_r($error_operation[1], TRUE)));
    drupal_set_message($message, 'error');
  }
}

Answer 2

Surely you need to implement Batch API to achieve what you need, and keep the user notified for what's happening in the background.

Very similar question that will help you more. Read it carefully.

These modules will help you:

1. Progerss This is an attempt to implement a generic framework for keeping track of any progress
2. Background progress takes over the existing Batch API and runs batch jobs in a background process