Add App::terminate() stream support

demos/_unit-test/stream.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Atk4\Ui\Demos;
+
+use Atk4\Ui\Button;
+use Nyholm\Psr7\Factory\Psr17Factory;
+
+/** @var \Atk4\Ui\App $app */
+require_once __DIR__ . '/../init-app.php';
+
+/**
+ * Size in Mb of generated download file.
+ * This can also be passed as GET['size_mb'] parameter.
+ *
+ * @var int
+ */
+$size_mb = (int) ($_GET['size_mb'] ?? 64);
+
+$button = Button::addTo($app, ['Download', 'class.atk-test' => true]);
+$button->on('click', function () use ($app, $size_mb) {
+    // Generate big data and write it to a temporary file
+    $pattern = str_repeat('0123456789ABCDEF', 65536); // 1Mb
+    $total_size = strlen($pattern) * $size_mb;
+    $tempFile = tempnam(sys_get_temp_dir(), 'test.txt');
+
+    $fh = fopen($tempFile, 'w');
+    for ($i = 0; $i < $size_mb; ++$i) {
+        fwrite($fh, $pattern);
+    }
+    fclose($fh);
+
+    // Send the data using a file stream response
+    $factory = new Psr17Factory();
+    $stream = $factory->createStreamFromFile($tempFile);
+    $app->setResponseHeader('Content-Type', 'text/plain');
+    $app->setResponseHeader('Content-Disposition', 'attachment; filename="test.txt"');
+    $app->setResponseHeader('Content-Length', (string) $total_size);
+    $app->terminate($stream);
+});

src/App.php

@@ -25,6 +25,7 @@
 use Nyholm\Psr7Server\ServerRequestCreator;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Message\StreamInterface;
 use Psr\Log\LoggerInterface;
 
 class App
@@ -394,7 +395,7 @@ public function setResponseHeader(string $name, string $value): self
      * directly, instead call it form Callback, JsCallback or similar
      * other classes.
      *
-     * @param string|array $output Array type is supported only for JSON response
+     * @param string|StreamInterface|array $output Array type is supported only for JSON response
      *
      * @return never
      */
@@ -405,7 +406,10 @@ public function terminate($output = ''): void
             throw new Exception('Content type must be always set');
         }
 
-        if ($type === 'application/json') {
+        if ($output instanceof StreamInterface) {
+            $this->response = $this->response->withBody($output);
+            $this->outputResponse('');
+        } elseif ($type === 'application/json') {
             if (is_string($output)) {
                 $output = $this->decodeJson($output);
             }
@@ -1128,7 +1132,11 @@ protected function outputResponse(string $data): void
             return;
         }
 
-        $this->response->getBody()->write($data);
+        $stream = $this->response->getBody();
+        if ($data !== '' /* && $stream->isWritable() */) {
+            $stream->write($data);
+        }
+
         $this->emitResponse();
     }
 

tests/DemosTest.php

@@ -368,6 +368,19 @@ public function testWizard(): void
         static::assertMatchesRegularExpression($this->regexHtml, $response->getBody()->getContents());
     }
 
+    public function testDownloadAsStream(): void
+    {
+        $btn = 'atk_layout_maestro_button_click';
+        $response = $this->getResponseFromRequest(
+            '_unit-test/stream.php?' . Callback::URL_QUERY_TRIGGER_PREFIX . $btn . '=ajax&' . Callback::URL_QUERY_TARGET . '=' . $btn,
+            [
+                'size_mb' => 64, // 128Mb will give out of memory error
+            ]
+        );
+        static::assertSame(200, $response->getStatusCode());
+        static::assertSame(16 * 65536 * 64, strlen($response->getBody()->getContents())); // 64Mb
+    }
+
     /**
      * Test reload and loader callback.
      */