Added DataStream builder to symfony http foundation bridge

documentation/components/bridges/symfony-http-foundation-bridge.md

@@ -32,22 +32,28 @@ declare(strict_types=1);
 
 namespace Symfony\Application\Controller;
 
-use Flow\Bridge\Symfony\HttpFoundation\FlowStreamedResponse;
+use Flow\Bridge\Symfony\HttpFoundation\DataStream;
 use Flow\Bridge\Symfony\HttpFoundation\Output\CSVOutput;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Attribute\Route;
 use function Flow\ETL\Adapter\Parquet\ParquetEtractor;
+use Flow\Bridge\Symfony\HttpFoundation\Transformation\MaskColumns;
+use Flow\Bridge\Symfony\HttpFoundation\Transformation\AddRowIndex;
 
 final class ReportsController extends AbstractController
 {
     #[Route('/stream/report', name: 'stream-report')]
     public function streamReport() : Response
     {
-        return new FlowStreamedResponse(
-            new ParquetEtractor(__DIR__ . '/reports/orders.parquet'),
-            new CSVOutput(withHeader: true)
-        );
+        return DataStream()
+            ::open(from_parquet(__DIR__ . '/reports/orders.parquet'))
+            ->underFilename('orders.csv')
+            ->transform(
+                 new MaskColumns(['email', 'address']),
+                 new AddRowIndex()
+            )
+            ->to(new CSVOutput(withHeader: true));
     }
 }
 ```

src/bridge/symfony/http-foundation/src/Flow/Bridge/Symfony/HttpFoundation/DataStream.php

@@ -0,0 +1,122 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\Bridge\Symfony\HttpFoundation;
+
+use Flow\ETL\{Extractor, Transformation, Transformations};
+use Symfony\Component\HttpFoundation\{HeaderUtils, Response};
+
+/**
+ * FlowStreamedResponse builder.
+ */
+final class DataStream
+{
+    /**
+     * @var array<string, string>
+     */
+    private array $headers = [
+        'Cache-Control' => 'no-store, no-cache, must-revalidate, private',
+        'X-Accel-Buffering' => 'no', // provides support for Nginx
+        'Pragma' => 'no-cache', // Backward compatibility for HTTP/1.0
+    ];
+
+    private ?Output $output = null;
+
+    private int $status = Response::HTTP_OK;
+
+    /**
+     * @var array<Transformation>
+     */
+    private array $transformations = [];
+
+    public function __construct(private readonly Extractor $extractor)
+    {
+    }
+
+    public static function open(Extractor $extractor) : self
+    {
+        return new self($extractor);
+    }
+
+    /**
+     * Send the data stream to the output.
+     */
+    public function sendTo(Output $output) : FlowStreamedResponse
+    {
+        $this->output = $output;
+
+        $this->headers['Content-Type'] = $this->output->type()->toContentTypeHeader();
+
+        return new FlowStreamedResponse(
+            $this->extractor,
+            $this->output,
+            \count($this->transformations) ? new Transformations(...$this->transformations) : new Transformations(),
+            $this->status,
+            $this->headers
+        );
+    }
+
+    /**
+     * Apply transformations to the data stream.
+     * Transformations are applied in the order they are passed.
+     * Transformations are applied on the fly, while streaming the data, this means
+     * that any resource expensive transformations like for example aggregations or sorting
+     * might significantly slow down the streaming process or even cause out of memory errors.
+     */
+    public function transform(Transformation ...$transformations) : self
+    {
+        $this->transformations = $transformations;
+
+        return $this;
+    }
+
+    /**
+     * Set the filename for the response.
+     * If the attachment flag is set to true, the response will be treated as an attachment meaning that
+     * the browser will prompt the user to download the file.
+     */
+    public function underFilename(string $name, bool $attachment = true) : self
+    {
+        $this->headers['Content-Disposition'] = HeaderUtils::makeDisposition(
+            $attachment ? HeaderUtils::DISPOSITION_ATTACHMENT : HeaderUtils::DISPOSITION_INLINE,
+            $name
+        );
+
+        return $this;
+    }
+
+    /**
+     * Set additional headers.
+     * Headers are merged with the default headers.
+     */
+    public function withHeaders(array $headers) : self
+    {
+        $this->headers = array_merge($this->headers, $headers);
+
+        return $this;
+    }
+
+    /**
+     * Remove a specific header if it exists.
+     * If the header does not exist, nothing happens.
+     */
+    public function withoutHeader(string $name) : self
+    {
+        if (\array_key_exists($name, $this->headers)) {
+            unset($this->headers[$name]);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Set the HTTP status code. Default is 200.
+     */
+    public function withStatus(int $status) : self
+    {
+        $this->status = $status;
+
+        return $this;
+    }
+}

src/bridge/symfony/http-foundation/src/Flow/Bridge/Symfony/HttpFoundation/FlowStreamedResponse.php

@@ -5,8 +5,8 @@
 namespace Flow\Bridge\Symfony\HttpFoundation;
 
 use function Flow\ETL\DSL\df;
-use Flow\Bridge\Symfony\HttpFoundation\Transformation\{Transformations};
 use Flow\ETL\{Config, Extractor, Transformation};
+use Flow\ETL\{Transformations};
 use Symfony\Component\HttpFoundation\StreamedResponse;
 
 class FlowStreamedResponse extends StreamedResponse

src/bridge/symfony/http-foundation/src/Flow/Bridge/Symfony/HttpFoundation/Transformation/AddRowIndex.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\Bridge\Symfony\HttpFoundation\Transformation;
+
+use function Flow\ETL\DSL\int_entry;
+use Flow\Bridge\Symfony\HttpFoundation\Transformation\AddRowIndex\StartFrom;
+use Flow\ETL\{DataFrame, Row, Transformation};
+
+final readonly class AddRowIndex implements Transformation
+{
+    public function __construct(private string $indexColumn = 'index', private StartFrom $startFrom = StartFrom::ZERO)
+    {
+    }
+
+    public function transform(DataFrame $dataFrame) : DataFrame
+    {
+        $index = $this->startFrom === StartFrom::ZERO ? 0 : 1;
+
+        return $dataFrame->map(function (Row $row) use (&$index) {
+            $row = $row->add(int_entry($this->indexColumn, $index));
+            $index++;
+
+            return $row;
+        });
+    }
+}

src/bridge/symfony/http-foundation/src/Flow/Bridge/Symfony/HttpFoundation/Transformation/AddRowIndex/StartFrom.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\Bridge\Symfony\HttpFoundation\Transformation\AddRowIndex;
+
+enum StartFrom
+{
+    case ONE;
+    case ZERO;
+}

src/bridge/symfony/http-foundation/src/Flow/Bridge/Symfony/HttpFoundation/Transformation/BatchSize.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\Bridge\Symfony\HttpFoundation\Transformation;
+
+use Flow\ETL\{DataFrame, Transformation};
+use Flow\Filesystem\Exception\InvalidArgumentException;
+
+/**
+ * Sets batch size for DataFrame.
+ * Small batch size can be useful when processing large data sets since only one row is processed at a time.
+ * This means that while processing large data sets, memory usage is kept low.
+ *
+ * Normally flow allows to use batch size -1 (which means no batches) but it defeats the purpose of using this transformation on
+ * Data Streams.
+ */
+final readonly class BatchSize implements Transformation
+{
+    /**
+     * @param int<1, max> $size
+     */
+    public function __construct(private int $size)
+    {
+        if ($size < 1) {
+            throw new InvalidArgumentException('Batch size must be greater than 0');
+        }
+    }
+
+    public function transform(DataFrame $dataFrame) : DataFrame
+    {
+        return $dataFrame->batchSize($this->size);
+    }
+}

src/bridge/symfony/http-foundation/src/Flow/Bridge/Symfony/HttpFoundation/Transformation/MaskColumns.php

@@ -7,6 +7,10 @@
 use function Flow\ETL\DSL\lit;
 use Flow\ETL\{DataFrame, Transformation};
 
+/**
+ * Mask columns in DataFrame by replacing their values with a mask.
+ * If column does not exist in DataFrame, it will be added with a mask value.
+ */
 final readonly class MaskColumns implements Transformation
 {
     public function __construct(private array $columns = [], private string $mask = '******')

src/bridge/symfony/http-foundation/tests/Flow/Bridge/Symfony/HttpFoundation/Tests/Integration/FlowStreamedResponseTest.php

@@ -6,7 +6,8 @@
 
 use function Flow\ETL\Adapter\JSON\from_json;
 use function Flow\ETL\DSL\from_array;
-use Flow\Bridge\Symfony\HttpFoundation\{FlowStreamedResponse,
+use Flow\Bridge\Symfony\HttpFoundation\{DataStream,
+    FlowStreamedResponse,
     Output\CSVOutput,
     Output\JsonOutput,
     Output\XMLOutput};
@@ -37,14 +38,14 @@ public function test_streaming_array_response_to_csv() : void
 
     public function test_streaming_array_response_to_json() : void
     {
-        $response = new FlowStreamedResponse(
-            from_array([
-                ['id' => 1, 'size' => 'XL', 'color' => 'red', 'ean' => '1234567890123'],
-                ['id' => 2, 'size' => 'M', 'color' => 'blue', 'ean' => '1234567890124'],
-                ['id' => 3, 'size' => 'S', 'color' => 'green', 'ean' => '1234567890125'],
-            ]),
-            new JsonOutput()
-        );
+        $extractor = from_array([
+            ['id' => 1, 'size' => 'XL', 'color' => 'red', 'ean' => '1234567890123'],
+            ['id' => 2, 'size' => 'M', 'color' => 'blue', 'ean' => '1234567890124'],
+            ['id' => 3, 'size' => 'S', 'color' => 'green', 'ean' => '1234567890125'],
+        ]);
+
+        $response = DataStream::open($extractor)
+            ->sendTo(new JsonOutput());
 
         self::assertEquals(<<<'JSON'
 [{"id":1,"size":"XL","color":"red","ean":"1234567890123"},{"id":2,"size":"M","color":"blue","ean":"1234567890124"},{"id":3,"size":"S","color":"green","ean":"1234567890125"}]
@@ -100,6 +101,21 @@ public function test_streaming_partitioned_dataset() : void
             , $this->sendResponse($response));
     }
 
+    public function test_streaming_with_disposition() : void
+    {
+        $response = DataStream::open(
+            from_array([
+                ['id' => 1, 'size' => 'XL', 'color' => 'red', 'ean' => '1234567890123'],
+                ['id' => 2, 'size' => 'M', 'color' => 'blue', 'ean' => '1234567890124'],
+                ['id' => 3, 'size' => 'S', 'color' => 'green', 'ean' => '1234567890125'],
+            ])
+        )
+            ->underFilename('products.csv')
+            ->sendTo(new CSVOutput());
+
+        self::assertEquals('attachment; filename=products.csv', $response->headers->get('Content-Disposition'));
+    }
+
     private function sendResponse(FlowStreamedResponse $response) : string
     {
         ob_start();

src/bridge/symfony/http-foundation/tests/Flow/Bridge/Symfony/HttpFoundation/Tests/Unit/Transformation/AddRowIndexTest.php

@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\Bridge\Symfony\HttpFoundation\Tests\Unit\Transformation;
+
+use function Flow\ETL\DSL\{df, from_array};
+use Flow\Bridge\Symfony\HttpFoundation\Transformation\AddRowIndex;
+use Flow\Bridge\Symfony\HttpFoundation\Transformation\AddRowIndex\StartFrom;
+use Flow\ETL\Tests\FlowTestCase;
+
+final class AddRowIndexTest extends FlowTestCase
+{
+    public function test_adding_row_index_to_each_row() : void
+    {
+        $rows = df()
+            ->read(from_array(
+                [
+                    ['id' => 1, 'name' => 'John Doe', 'salary' => 7000, 'currency' => 'USD'],
+                    ['id' => 2, 'name' => 'Jane Doe', 'salary' => 8000, 'currency' => 'USD'],
+                    ['id' => 3, 'name' => 'John Smith', 'salary' => 9000, 'currency' => 'USD'],
+                    ['id' => 4, 'name' => 'Jane Smith', 'salary' => 10000, 'currency' => 'USD'],
+                ]
+            ))
+            ->with(new AddRowIndex())
+            ->fetch()
+            ->toArray();
+
+        self::assertEquals(
+            [
+                ['index' => 0, 'id' => 1, 'name' => 'John Doe', 'salary' => 7000, 'currency' => 'USD'],
+                ['index' => 1, 'id' => 2, 'name' => 'Jane Doe', 'salary' => 8000, 'currency' => 'USD'],
+                ['index' => 2, 'id' => 3, 'name' => 'John Smith', 'salary' => 9000, 'currency' => 'USD'],
+                ['index' => 3, 'id' => 4, 'name' => 'Jane Smith', 'salary' => 10000, 'currency' => 'USD'],
+            ],
+            $rows
+        );
+    }
+
+    public function test_adding_row_index_to_each_row_starting_from_1() : void
+    {
+        $rows = df()
+            ->read(from_array(
+                [
+                    ['id' => 1, 'name' => 'John Doe', 'salary' => 7000, 'currency' => 'USD'],
+                    ['id' => 2, 'name' => 'Jane Doe', 'salary' => 8000, 'currency' => 'USD'],
+                    ['id' => 3, 'name' => 'John Smith', 'salary' => 9000, 'currency' => 'USD'],
+                    ['id' => 4, 'name' => 'Jane Smith', 'salary' => 10000, 'currency' => 'USD'],
+                ]
+            ))
+            ->with(new AddRowIndex(startFrom: StartFrom::ONE))
+            ->fetch()
+            ->toArray();
+
+        self::assertEquals(
+            [
+                ['index' => 1, 'id' => 1, 'name' => 'John Doe', 'salary' => 7000, 'currency' => 'USD'],
+                ['index' => 2, 'id' => 2, 'name' => 'Jane Doe', 'salary' => 8000, 'currency' => 'USD'],
+                ['index' => 3, 'id' => 3, 'name' => 'John Smith', 'salary' => 9000, 'currency' => 'USD'],
+                ['index' => 4, 'id' => 4, 'name' => 'Jane Smith', 'salary' => 10000, 'currency' => 'USD'],
+            ],
+            $rows
+        );
+    }
+}