Optional Enable Table Data Storage as JSON

Nice.

I guess that at some point a conditional is needed to detect if the used database type and version supports the JSON Data Type.

  // Get the connection object for the specified database key and target.
  $conn = Database::getConnection();

  switch ($conn->databaseType()) {
  case 'mysql':
    if (version_compare(mysql_get_client_info(), '5.7', '>=')) {
      print 'JSON Data Type available with ';
    }
    print 'mysql  ' . mysql_get_client_info();
    break;

  case 'pgsql':
    $v = pg_version();
    if (version_compare( $v['client'], '9.2', '>=')) {
      print 'JSON Data Type available with ';
    }
    print 'pgsql  ' . $v['client'];
    break;

  default:
    print $conn->databaseType();
    break;
  }

PHP Fatal error: Maximum function nesting level of '256' reached, aborting! in /sites/all/modules/contrib/tablefield/tablefield.module on line 2439

This seems to happen when using xdebug because of the recursive use of the function tablefield_unserialize().

Furthermore it gives an undefined index error because the field setting initially does not exist. This can probably be avoided in the same function with:

  $storage = isset($field['settings']['backend_storage_format']) ? $field['settings']['backend_storage_format'] : 'serialize';
  switch ($storage) {

Also on https://simplytest.me/project/tablefield/7.x-3.x?patch[]=https://www.dru... we get a 500 Internal Server Error. Unsure if this has the same cause.

Cool. I had to change the conditional to:

  case 'mysql':
    if ((function_exists('mysql_get_client_info') && version_compare(mysql_get_client_info(), '5.7', '>=')) || !function_exists('mysql_get_client_info')) {
..}

because the function is dropped in PHP 7 (see http://php.net/manual/en/function.mysql-get-client-info.php). In the case the function does not exists we can be pretty sure we're dealing with PHP 7.

EDIT:
We should find an alternative for mysql_get_client_info in PHP 7 to determine the MySQL version.

Uff!! Looks like it can be as simple as:

/**
 * Provides list of storage format options based on database capability.
 */
function tablefield_field_backend_storage_options() {
  // Only provide PHP serialize if the database does not provide JSON column type.
  $backend_options = array(
    'serialize' => 'Serialized (PHP)',
  );
  // Get the connection object for the specified database key and target.
  $conn = Database::getConnection();
  $v = $conn->version();
  switch ($conn->databaseType()) {
  case 'mysql':
    if (version_compare($v, '5.7', '>=')) {
      $backend_options = array(
        'serialize' => 'Serialized (PHP)',
        'json' => 'JSON',
      );
    }
    break;

  case 'pgsql':
    if (version_compare( $v, '9.2', '>=')) {
      $backend_options = array(
        'serialize' => 'Serialized (PHP)',
        'json' => 'JSON',
      );
    }
    break;
  }
  return $backend_options;
}

That should work for both PHP 5 and 7.

Furthermore:
Warning: Missing argument 2 for watchdog(), called in /home/martin/www/yellow/sites/all/modules/contrib/tablefield/tablefield.module on line 2512.

See https://api.drupal.org/api/drupal/includes%21bootstrap.inc/function/watc....

Also:
Notice: Undefined index: backend_storage_format in tablefield_unserialize() (line 2489 of /home/martin/www/yellow/sites/all/modules/contrib/tablefield/tablefield.module).

This could be solved by using an update hook in the .install file giving a field settings value to all existing table fields. You can use the existing update hooks as examples.

Alternatively use the code below that assigns a value if no field settings have been set.

/**
 * Helper function to unserialize data for storage.
 */
function tablefield_unserialize($field, $data) {
  $backend_storage_format = isset($field['settings']['backend_storage_format']) ? $field['settings']['backend_storage_format'] : 'serialize';
  switch ($backend_storage_format) {
    case 'json':
    $unserialized = json_decode($data, TRUE);
    break;

    case 'serialize':
    default:
    $unserialized = unserialize($data);
    break;
  }
  return $unserialized;
}

Rolled suggestions of #14 and #16 into a new patch.

What is the status with this?

@lollypopgr:
Nice to see interest in this awesome new feature built by @robertwb.

Feel free to test. Keep in mind your MySQL version should be 5.7+ or PostgreSQL 9.2+.

If this goes in it will likely be a new 7.x-4.x branch if it would have big implications for an upgrade on existing sites. To analyse that as well.