/**
* This action is for importing a single CSV file into a single database table.
* It guides the user through the four stages of importing:
* uploading, field matching, previewing, and doing the actual import.
* All of the actual work is done in the CSV class.
*
* 1. In the first stage, a CSV file is **uploaded**, validated, and moved to a temporary directory.
* The file is then accessed from this location in the subsequent stages of importing,
* and only deleted upon either successful import or the user cancelling the process.
* (The 'id' parameter of this action is the identifier for the uploaded file.)
* 2. Once a valid CSV file has been uploaded,
* its colums are presented to the user to be **matched** to those in the database table.
* The columns from the database are presented first and the CSV columns are matched to these,
* rather than vice versa,
* because this way the user sees immediately what columns are available to be imported into.
* 3. The column matches are then used to produce a **preview** of what will be added to and/or changed in the database.
* All columns from the database are shown (regardless of whether they were in the import) and all rows of the import.
* If a column is not present in the import the database will (obviously) use the default value if there is one;
* this will be shown in the preview.
* 4. When the user accepts the preview, the actual **import** of data is carried out.
* Rows are saved to the database using the usual `Table::save()` method
* and a message presented to the user to indicate successful completion.
*
* @return void
*/
public function import($args)
{
$template = new Template('import.html');
// Set up the progress bar.
$template->stages = array('choose_file', 'match_fields', 'preview', 'complete_import');
$template->stage = 'choose_file';
// First make sure the user is allowed to import data into this table.
$table = $this->getTable($args['table']);
$template->record = $table->getDefaultRecord();
$template->action = 'import';
$template->table = $table;
$template->maxsize = \Tabulate\File::maxUploadSize();
if (!$table->getDatabase()->checkGrant(Grants::IMPORT, $table->getName())) {
$template->addNotice('error', 'You do not have permission to import data into this table.');
return $template->render();
}
/*
* Stage 1 of 4: Uploading.
*/
$template->form_action = $table->getUrl('import');
try {
$hash = isset($_GET['hash']) ? $_GET['hash'] : false;
$uploaded = isset($_FILES['file']) ? $_FILES['file'] : false;
$csvFile = new \Tabulate\CSV($hash, $uploaded);
} catch (\Exception $e) {
$template->addNotice('error', $e->getMessage());
return $template->render();
}
/*
* Stage 2 of 4: Matching fields
*/
if ($csvFile->loaded()) {
$template->file = $csvFile;
$template->stage = $template->stages[1];
$template->form_action .= "&hash=" . $csvFile->hash;
}
/*
* Stage 3 of 4: Previewing
*/
if ($csvFile->loaded() and isset($_POST['preview'])) {
$template->stage = $template->stages[2];
$template->columns = serialize($_POST['columns']);
$errors = array();
// Make sure all required columns are selected
foreach ($table->getColumns() as $col) {
// Handle missing columns separately; other column errors are
// done in the CSV class. Missing columns don't matter if importing
// existing records.
$missing = empty($_POST['columns'][$col->getName()]);
$pkPresent = isset($_POST['columns'][$table->getPkColumn()->getName()]);
if (!$pkPresent && $col->isRequired() && $missing) {
$errors[] = array('column_name' => '', 'column_number' => '', 'field_name' => $col->getName(), 'row_number' => 'N/A', 'messages' => array('Column required, but not found in CSV'));
}
}
$template->errors = empty($errors) ? $csvFile->matchFields($table, wp_unslash($_POST['columns'])) : $errors;
}
/*
* Stage 4 of 4: Import
*/
if ($csvFile->loaded() && isset($_POST['import'])) {
$template->stage = $template->stages[3];
$this->wpdb->query('BEGIN');
$result = $csvFile->importData($table, unserialize($_POST['columns']));
$this->wpdb->query('COMMIT');
$template->addNotice('updated', 'Import complete; ' . $result . ' rows imported.');
}
return $template->render();
}