Refactor the CsvResponse to support sending a downloadable response

This change update the CsvResponse to be able to either send a plain CSV
text response, or to send the response as a downloadable file instead.

Author: settermjd

src/Response/CsvResponse.php

@@ -1,79 +1,105 @@
-<?php
-/**
- * @see       https://github.com/zendframework/zend-diactoros for the canonical source repository
- * @copyright Copyright (c) 2015-2018 Zend Technologies USA Inc. (https://www.zend.com)
- * @license   https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
- */
-
-declare(strict_types=1);
-
-namespace Zend\Diactoros\Response;
-
-use Psr\Http\Message\StreamInterface;
-use Zend\Diactoros\Exception;
-use Zend\Diactoros\Response;
-use Zend\Diactoros\Stream;
-
-use function get_class;
-use function gettype;
-use function is_object;
-use function is_string;
-use function sprintf;
-
-/**
- * CSV response.
- *
- * Allows creating a CSV response by passing a string to the constructor;
- * by default, sets a status code of 200 and sets the Content-Type header to
- * text/csv.
- */
-class CsvResponse extends Response
-{
-    use InjectContentTypeTrait;
-
-    /**
-     * Create a CSV response.
-     *
-     * Produces a CSV response with a Content-Type of text/csv and a default
-     * status of 200.
-     *
-     * @param string|StreamInterface $text String or stream for the message body.
-     * @param int $status Integer status code for the response; 200 by default.
-     * @param array $headers Array of headers to use at initialization.
-     * @throws Exception\InvalidArgumentException if $text is neither a string or stream.
-     */
-    public function __construct($text, int $status = 200, array $headers = [])
-    {
-        parent::__construct(
-            $this->createBody($text),
-            $status,
-            $this->injectContentType('text/csv; charset=utf-8', $headers)
-        );
-    }
-
-    /**
-     * Create the CSV message body.
-     *
-     * @param string|StreamInterface $text
-     * @throws Exception\InvalidArgumentException if $text is neither a string or stream.
-     */
-    private function createBody($text) : StreamInterface
-    {
-        if ($text instanceof StreamInterface) {
-            return $text;
-        }
-
-        if (! is_string($text)) {
-            throw new Exception\InvalidArgumentException(sprintf(
-                'Invalid CSV content (%s) provided to %s',
-                (is_object($text) ? get_class($text) : gettype($text)),
-                __CLASS__
-            ));
-        }
-
-        $body = new Stream('php://temp', 'wb+');
-        $body->write($text);
-        $body->rewind();
-        return $body;
-    }
-}
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-diactoros for the canonical source repository
+ * @copyright Copyright (c) 2015-2018 Zend Technologies USA Inc. (https://www.zend.com)
+ * @license   https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace Zend\Diactoros\Response;
+
+use Psr\Http\Message\StreamInterface;
+use Zend\Diactoros\Exception;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\Stream;
+
+use function get_class;
+use function gettype;
+use function is_object;
+use function is_string;
+use function sprintf;
+
+/**
+ * CSV response.
+ *
+ * Allows creating a CSV response by passing a string to the constructor;
+ * by default, sets a status code of 200 and sets the Content-Type header to
+ * text/csv.
+ */
+class CsvResponse extends Response
+{
+    use DownloadResponseTrait;
+    use InjectContentTypeTrait;
+
+    /**
+     * Create a CSV response.
+     *
+     * Produces a CSV response with a Content-Type of text/csv and a default
+     * status of 200.
+     *
+     * @param string|StreamInterface $text String or stream for the message body.
+     * @param int $status Integer status code for the response; 200 by default.
+     * @param string $filename
+     * @param array $headers Array of headers to use at initialization.
+     */
+    public function __construct($text, int $status = 200, string $filename = '', array $headers = [])
+    {
+        if (is_string($filename) && $filename !== '') {
+            $headers = $this->prepareDownloadHeaders($filename, $headers);
+        }
+
+        parent::__construct(
+            $this->createBody($text),
+            $status,
+            $this->injectContentType('text/csv; charset=utf-8', $headers)
+        );
+    }
+
+    /**
+     * Create the CSV message body.
+     *
+     * @param string|StreamInterface $text
+     * @return StreamInterface
+     * @throws Exception\InvalidArgumentException if $text is neither a string or stream.
+     */
+    private function createBody($text) : StreamInterface
+    {
+        if ($text instanceof StreamInterface) {
+            return $text;
+        }
+
+        if (! is_string($text)) {
+            throw new Exception\InvalidArgumentException(sprintf(
+                'Invalid CSV content (%s) provided to %s',
+                (is_object($text) ? get_class($text) : gettype($text)),
+                __CLASS__
+            ));
+        }
+
+        $body = new Stream('php://temp', 'wb+');
+        $body->write($text);
+        $body->rewind();
+        return $body;
+    }
+
+    /**
+     * Get download headers
+     *
+     * @param string $filename
+     * @return array
+     */
+    private function getDownloadHeaders(string $filename): array
+    {
+        $headers = [];
+        $headers['cache-control'] = ['must-revalidate'];
+        $headers['content-description'] = ['File Transfer'];
+        $headers['content-disposition'] = [sprintf('attachment; filename=%s', $filename)];
+        $headers['content-transfer-encoding'] = ['Binary'];
+        $headers['content-type'] = ['text/csv; charset=utf-8'];
+        $headers['expires'] = ['0'];
+        $headers['pragma'] = ['Public'];
+
+        return $headers;
+    }
+}