Implement CSV output mode (#92)

This change implements a new output mode for CSV files.

The new command option `--output-csv=...` enables CSV output mode, and must be given the path to a directory. The output mode will create `.csv` files in the given directory, named according to the dumped tables.

This output format does not support output redirection from `stdout` as the default MySQL SQL format does.

CSV files will be created only for tables that contain data. In other words, `schema` type dumps will skip the table in question. Also, dumping views/triggers makes no sense for CSV files, they will be skipped as well.

How to best write binary (BLOB) data and/or NULL values in CSV files is probably highly controversial. For now, we'll just go with the [`0x...` hex literals supported by MySQL](https://dev.mysql.com/doc/refman/8.0/en/hexadecimal-literals.html). Maybe having binary data in CSV files is not a sane idea in the first place.

Co-authored-by: Matthias Pigulla <mp@webfactory.de>

Author: FabianSchmick

README.md

@@ -67,6 +67,16 @@ do this by using the cli-parameter `single-line-insert-statements`. This can spe
 Example:
 `slimdump --single-line-insert-statements {DSN} {config-file}`
 
+#### output-csv
+
+This option turns on the CSV (comma separated values) output mode. It must be given the path to a directory where `.csv` files will be created. The files are named according to tables, e. g. `my_table.csv`.
+
+CSV files contain only data. They are not created for views, triggers, or tables dumped with the `schema` dump mode. Also, no files will be created for empty tables.
+
+Since this output format needs to write to different files for different tables, redirecting `stdout` output (as can be done for the default MySQL SQL mode) is not possible.
+
+**Experimental Feature** CSV support is a new, [experimental feature](https://github.com/webfactory/slimdump/pull/92). The output formatting may change at any time.  
+
 ## Configuration
 Configuration is stored in XML format somewhere in your filesystem. As a benefit, you could add the configuration to your repository to share a quickstart to your database dump with your coworkers.
 
@@ -254,4 +264,4 @@ If you're a developer looking for new challenges, we'd like to hear from you! Ot
 - <https://www.webfactory.de>
 - <https://twitter.com/webfactory>
 
-Copyright 2014-2020 webfactory GmbH, Bonn. Code released under [the MIT license](LICENSE).
+Copyright 2014-2022 webfactory GmbH, Bonn. Code released under [the MIT license](LICENSE).

src/Webfactory/Slimdump/Database/CsvOutputFormatDriver.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace Webfactory\Slimdump\Database;
+
+use Doctrine\DBAL\Connection;
+use Doctrine\DBAL\Schema;
+use InvalidArgumentException;
+use Webfactory\Slimdump\Config\Table;
+
+class CsvOutputFormatDriver implements OutputFormatDriverInterface
+{
+    /**
+     * @var Connection
+     */
+    private $connection;
+
+    /**
+     * @var string
+     */
+    private $directory;
+
+    /**
+     * @var ?resource
+     */
+    private $outputFile = null;
+
+    /**
+     * @var bool
+     */
+    private $firstLine = true;
+
+    public function __construct(string $directory, Connection $connection)
+    {
+        if (!is_dir($directory) || !is_writable($directory)) {
+            throw new InvalidArgumentException(sprintf('The directoy "%s" does not exist or is not writeable', $directory));
+        }
+
+        $this->directory = $directory;
+        $this->connection = $connection;
+    }
+
+    public function beginDump(): void
+    {
+    }
+
+    public function endDump(): void
+    {
+    }
+
+    public function dumpViewDefinition(Schema\View $asset, Table $config): void
+    {
+    }
+
+    public function beginTableDataDump(Schema\Table $asset, Table $config): void
+    {
+        $this->firstLine = true;
+        $this->outputFile = fopen($this->directory.\DIRECTORY_SEPARATOR.$asset->getName().'.csv', 'w');
+    }
+
+    public function endTableDataDump(Schema\Table $asset, Table $config): void
+    {
+        fclose($this->outputFile);
+    }
+
+    public function dumpTableStructure(Schema\Table $asset, Table $config): void
+    {
+    }
+
+    public function dumpTableRow(array $row, Schema\Table $asset, Table $config): void
+    {
+        if ($this->firstLine) {
+            fputcsv($this->outputFile, array_keys($row));
+            $this->firstLine = false;
+        }
+
+        fputcsv($this->outputFile, $row);
+    }
+}

src/Webfactory/Slimdump/SlimdumpCommand.php

@@ -15,11 +15,14 @@
 use Symfony\Component\Console\Output\NullOutput;
 use Symfony\Component\Console\Output\OutputInterface;
 use Webfactory\Slimdump\Config\ConfigBuilder;
+use Webfactory\Slimdump\Database\CsvOutputFormatDriver;
 use Webfactory\Slimdump\Database\MysqlOutputFormatDriver;
 use Webfactory\Slimdump\Database\OutputFormatDriverInterface;
 
 final class SlimdumpCommand extends Command
 {
+    const OUTPUT_CSV = 'output-csv';
+
     protected function configure()
     {
         $this
@@ -35,6 +38,12 @@ protected function configure()
                 InputArgument::IS_ARRAY | InputArgument::REQUIRED,
                 'Configuration files (at least one).'
             )
+            ->addOption(
+                self::OUTPUT_CSV,
+                null,
+                InputOption::VALUE_REQUIRED,
+                'Output .csv files. Requires a directory path where files will be created (no stdout).'
+            )
             ->addOption(
                 'buffer-size',
                 'b',
@@ -62,13 +71,20 @@ protected function configure()
      */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
+        $progressOutput = $this->createProgressOutput($input, $output);
+
         $connection = $this->createConnection($input);
         $connection->getDatabasePlatform()->registerDoctrineTypeMapping('enum', 'string');
-        $this->setMaxExecutionTimeUnlimited($connection, $output);
+        $this->setMaxExecutionTimeUnlimited($connection, $progressOutput);
 
         $config = ConfigBuilder::createConfigurationFromConsecutiveFiles($input->getArgument('config'));
-        $outputFormatDriver = $this->createOutputDriverMysql($input, $output, $connection);
-        $progressOutput = $this->createProgressOutput($input, $output);
+
+        if ($dir = $input->getOption(self::OUTPUT_CSV)) {
+            $outputFormatDriver = $this->createOutputDriverCsv($dir, $connection);
+            $progressOutput->writeln('<comment>CSV output format is still experimental – format details may change at any time</comment>');
+        } else {
+            $outputFormatDriver = $this->createOutputDriverMysql($input, $output, $connection);
+        }
 
         $dumptask = new DumpTask($connection, $config, $outputFormatDriver, $progressOutput);
         $dumptask->dump();
@@ -84,6 +100,11 @@ private function createOutputDriverMysql(InputInterface $input, OutputInterface
         return new MysqlOutputFormatDriver($output, $connection, $bufferSize, $singleLineInsertStatements);
     }
 
+    private function createOutputDriverCsv(string $directory, Connection $connection): OutputFormatDriverInterface
+    {
+        return new CsvOutputFormatDriver($directory, $connection);
+    }
+
     private function parseBufferSize(?string $bufferSize): ?int
     {
         if (null === $bufferSize) {
@@ -117,9 +138,7 @@ private function setMaxExecutionTimeUnlimited(Connection $connection, OutputInte
 
         if ($maxExecutionTimeInfo && 0 != $maxExecutionTimeInfo['Value']) {
             $connection->executeQuery('SET SESSION max_execution_time = 0');
-            if ($output instanceof ConsoleOutputInterface) {
-                $output->getErrorOutput()->writeln('<info>The MySQL "max_execution_time" timeout setting has been disabled for the current database connection.</info>');
-            }
+            $output->writeln('<info>The MySQL "max_execution_time" timeout setting has been disabled for the current database connection.</info>');
         }
     }