fix(smtp): better HTTP Multipart parsing; fix SMTP body ending detection

src/Traffic/Message/Multipart/Part.php

@@ -28,26 +28,23 @@ protected function __construct(
      */
     public static function create(array $headers): Part
     {
-        /**
-         * Check Content-Disposition header
-         *
-         * @var string $contentDisposition
-         */
-        $contentDisposition = self::findHeader($headers, 'Content-Disposition')[0]
-            ?? throw new \RuntimeException('Missing Content-Disposition header.');
-        if ($contentDisposition === '') {
-            throw new \RuntimeException('Missing Content-Disposition header, can\'t be empty');
-        }
+        $contentDisposition = self::findHeader($headers, 'Content-Disposition')[0] ?? null;
+
+        $name = $fileName = null;
+        if ((string) $contentDisposition !== '') {
+            // Get field name and file name
+            $name = \preg_match('/\bname=(?:(?<a>[^" ;,]++)|"(?<b>[^"]++)")/', $contentDisposition, $matches) === 1
+                ? ($matches['a'] ?: $matches['b'])
+                : null;
 
-        // Get field name and file name
-        $name = \preg_match('/\bname=(?:(?<a>[^" ;,]++)|"(?<b>[^"]++)")/', $contentDisposition, $matches) === 1
-            ? ($matches['a'] ?: $matches['b'])
-            : null;
+            // Decode file name
+            $fileName = \preg_match(
+                '/\bfilename=(?:(?<a>[^" ;,]++)|"(?<b>[^"]++)")/',
+                $contentDisposition,
+                $matches,
+            ) === 1 ? ($matches['a'] ?: $matches['b']) : null;
+        }
 
-        // Decode file name
-        $fileName = \preg_match('/\bfilename=(?:(?<a>[^" ;,]++)|"(?<b>[^"]++)")/', $contentDisposition, $matches) === 1
-            ? ($matches['a'] ?: $matches['b'])
-            : null;
         $fileName = $fileName !== null ? \html_entity_decode($fileName) : null;
         $isFile = (string) $fileName !== ''
             || \preg_match('/text\\/.++/', self::findHeader($headers, 'Content-Type')[0] ?? 'text/plain') !== 1;

src/Traffic/Parser/Http.php

@@ -224,7 +224,7 @@ private function parseBody(StreamClient $stream, ServerRequestInterface $request
         $contentType = $request->getHeaderLine('Content-Type');
         return match (true) {
             $contentType === 'application/x-www-form-urlencoded' => self::parseUrlEncodedBody($request),
-            \str_contains($contentType, 'multipart/form-data') => $this->processMultipartForm($request),
+            \str_contains($contentType, 'multipart/') => $this->processMultipartForm($request),
             default => $request,
         };
     }

src/Traffic/Parser/MultipartType.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Buggregator\Trap\Traffic\Parser;
+
+/**
+ * @internal
+ */
+enum MultipartType: string
+{
+    case Mixed = 'mixed';
+    case Alternative = 'alternative';
+    case Digest = 'digest';
+    case Parallel = 'parallel';
+    case FormData = 'form-data';
+    case Report = 'report';
+    case Signed = 'signed';
+    case Encrypted = 'encrypted';
+    case Related = 'related';
+    case Other = 'other';
+
+    public static function fromHeaderLine(string $headerLine): self
+    {
+        $type = \explode(';', $headerLine, 2)[0];
+        return match ($type) {
+            'multipart/mixed' => self::Mixed,
+            'multipart/alternative' => self::Alternative,
+            'multipart/digest' => self::Digest,
+            'multipart/parallel' => self::Parallel,
+            'multipart/form-data' => self::FormData,
+            'multipart/report' => self::Report,
+            'multipart/signed' => self::Signed,
+            'multipart/encrypted' => self::Encrypted,
+            'multipart/related' => self::Related,
+            default => self::Other,
+        };
+    }
+}

src/Traffic/Parser/Smtp.php

@@ -32,7 +32,7 @@ public function parseStream(array $protocol, StreamClient $stream): Message\Smtp
         $message = Message\Smtp::create($protocol, headers: $headers);
 
         // Defaults
-        $boundary = "\r\n.\r\n";
+        $endOfStream = ["\r\n.\r\n"];
         $isMultipart = false;
 
         // Check the message is multipart.
@@ -41,10 +41,11 @@ public function parseStream(array $protocol, StreamClient $stream): Message\Smtp
             && \preg_match('/boundary="?([^"\\s;]++)"?/', $contentType, $matches) === 1
         ) {
             $isMultipart = true;
-            $boundary = "\r\n--{$matches[1]}--\r\n\r\n";
+            $endOfStream = ["\r\n--{$matches[1]}--\r\n\r\n"];
+            $endOfStream[] = $endOfStream[0] . ".\r\n";
         }
 
-        $stored = $this->storeBody($fileStream, $stream, $boundary);
+        $stored = $this->storeBody($fileStream, $stream, $endOfStream);
         $message = $message->withBody($fileStream);
         // Message's body must be seeked to the beginning of the body.
         $fileStream->seek(-$stored, \SEEK_CUR);
@@ -62,16 +63,19 @@ public function parseStream(array $protocol, StreamClient $stream): Message\Smtp
      * Flush stream data into PSR stream.
      * Note: there can be read more data than {@see $limit} bytes but write only {@see $limit} bytes.
      *
-     * @return int Number of bytes written to the stream.
+     * @param non-empty-array<non-empty-string> $endings
+     *
+     * @return int<0, max> Number of bytes written to the stream.
      */
     private function storeBody(
         StreamInterface $fileStream,
         StreamClient $stream,
-        string $end = "\r\n.\r\n",
+        array $endings = ["\r\n.\r\n"],
     ): int {
         $written = 0;
-        $endLen = \strlen($end);
+        $endLen = \min(\array_map('\strlen', $endings));
 
+        /** @var string $chunk */
         foreach ($stream->getIterator() as $chunk) {
             // Write chunk to the file stream.
             $fileStream->write($chunk);
@@ -83,8 +87,11 @@ private function storeBody(
                     $fileStream->seek(-$endLen, \SEEK_CUR);
                     $chunk = $fileStream->read($endLen);
                 }
-                if (\str_ends_with($chunk, $end)) {
-                    return $written;
+
+                foreach ($endings as $end) {
+                    if (\str_ends_with($chunk, $end)) {
+                        return $written;
+                    }
                 }
             }
 

tests/Unit/Traffic/Parser/MultipartBodyParserTest.php

@@ -9,6 +9,7 @@
 use Buggregator\Trap\Traffic\Message\Multipart\File;
 use Buggregator\Trap\Traffic\Message\Multipart\Part;
 use Buggregator\Trap\Traffic\Parser;
+use Buggregator\Trap\Traffic\Parser\MultipartType;
 use Nyholm\Psr7\Stream;
 use PHPUnit\Framework\TestCase;
 use Psr\Http\Message\StreamInterface;
@@ -159,6 +160,51 @@ public function testBase64Encoded(): void
         self::assertSame($file2, $file->getStream()->__toString());
     }
 
+    /**
+     * Simple multipart/mixed message without nested parts.
+     */
+    public function testMultipartMixed(): void
+    {
+        $body = $this->makeStream(
+            <<<BODY
+                --40ugHb8e\r
+                Content-Type: text/plain; charset=utf-8\r
+                Content-Transfer-Encoding: quoted-printable\r
+                \r
+                Test Body\r
+                --40ugHb8e\r
+                Content-Type: text/plain; name=test.txt\r
+                Content-Transfer-Encoding: base64\r
+                Content-Disposition: attachment; name=test.txt; filename=test.txt\r
+                \r
+                c2RnCg==\r
+                --40ugHb8e--\r
+                \r
+                .\r
+
+                BODY,
+        );
+
+        $result = $this->parse($body, '40ugHb8e', MultipartType::Mixed);
+
+
+        self::assertCount(2, $result);
+        // Field
+        $file = $result[0];
+        self::assertInstanceOf(Field::class, $file);
+        self::assertNull($file->getName());
+        self::assertSame('Test Body', $file->getValue());
+
+        // Attached file
+        $file = $result[1];
+        self::assertInstanceOf(File::class, $file);
+        self::assertSame('test.txt', $file->getName());
+        self::assertSame('test.txt', $file->getClientFilename());
+        self::assertSame('text/plain', $file->getClientMediaType());
+        self::assertNull($file->getEmbeddingId());
+        self::assertSame("sdg\n", $file->getStream()->__toString());
+    }
+
     private function makeStream(string $body): StreamInterface
     {
         $stream = Stream::create($body);
@@ -171,8 +217,11 @@ private function makeStream(string $body): StreamInterface
      *
      * @return iterable<Part>
      */
-    private function parse(StreamInterface $body, string $boundary): iterable
-    {
+    private function parse(
+        StreamInterface $body,
+        string $boundary,
+        MultipartType $type = MultipartType::FormData,
+    ): iterable {
         return $this->runInFiber(static fn() => Parser\Http::parseMultipartBody($body, $boundary));
     }
 }