improvements

src/Message.php

@@ -44,7 +44,20 @@ public function getHeaders(): array
 
     public function getHeader(string $header, $default = null): ?string
     {
-        return $this->headers[$header] ?? $default;
+        $header = strtolower($header);
+
+        foreach ($this->headers as $key => $value) {
+            if (strtolower($key) === $header) {
+                return $value;
+            }
+        }
+
+        return $default;
+    }
+
+    public function getContentType(): string
+    {
+        return $this->getHeader('Content-Type', '');
     }
 
     public function getId(): string
@@ -169,7 +182,6 @@ protected function parse()
 
             if (isset($this->boundary) && $line === '--'.$this->boundary.'--') {
                 // We've reached the end of the message
-                $this->addPart($currentBody, $currentBodyHeaders);
                 break;
             }
 
@@ -208,6 +220,21 @@ protected function parse()
             }
 
             if (preg_match('/^(?<key>[A-Za-z\-0-9]+): (?<value>.*)$/', $line, $matches)) {
+                if (strtolower($matches['key']) === 'content-type' && !isset($this->boundary)) {
+                    // this might be a single-part message. Let's start collecting the body.
+                    $collectingBody = true;
+                    $currentBody = '';
+                    $currentBodyHeaders = [
+                        $matches['key'] => $matches['value'],
+                    ];
+
+                    if (str_ends_with($currentBodyHeaders[$matches['key']], ';')) {
+                        $currentBodyHeaderInProgress = $matches['key'];
+                    }
+
+                    continue;
+                }
+
                 $this->headers[$matches['key']] = $matches['value'];
 
                 // if the last character is a semicolon, then the header is continued on the next line
@@ -221,6 +248,19 @@ protected function parse()
             // The line is not part of the email message. Let's remove it altogether.
             $this->message = ltrim(substr($this->message, strlen($line)));
         }
+
+        if (!empty($currentBody) || !empty($currentBodyHeaders)) {
+            $this->addPart($currentBody, $currentBodyHeaders);
+        }
+
+        if (! $this->getContentType() && ($part = $this->getParts()[0] ?? null)) {
+            foreach ($part->getHeaders() as $key => $value) {
+                if (strtolower($key) === 'content-type') {
+                    $this->headers[$key] = $value;
+                    break;
+                }
+            }
+        }
     }
 
     protected function addPart(string $currentBody, array $currentBodyHeaders): void

tests/Unit/MessageTest.php

@@ -5,6 +5,64 @@
 use Opcodes\MailParser\Message;
 
 it('can parse a simple mail message', function () {
+    $messageString = <<<EOF
+From: Sender <[email protected]>
+To: Receiver <[email protected]>
+Subject: Test Subject
+Message-ID: <[email protected]>
+MIME-Version: 1.0
+Date: Fri, 25 Aug 2023 15:36:13 +0200
+Content-Type: text/html; charset=utf-8
+Content-Transfer-Encoding: quoted-printable
+
+Email content goes here.
+EOF;
+
+    $message = Message::fromString($messageString);
+
+    expect($message->getFrom())->toBe('Sender <[email protected]>')
+        ->and($message->getTo())->toBe('Receiver <[email protected]>')
+        ->and($message->getSubject())->toBe('Test Subject')
+        ->and($message->getId())->toBe('[email protected]')
+        ->and($message->getDate()?->format('Y-m-d H:i:s'))->toBe('2023-08-25 15:36:13')
+        ->and($message->getContentType())->toBe('text/html; charset=utf-8')
+        ->and($message->getHtmlPart()?->getContent())->toBe('Email content goes here.')
+        ->and($message->getHtmlPart()?->getHeaders())->toBe([
+            'Content-Type' => 'text/html; charset=utf-8',
+            'Content-Transfer-Encoding' => 'quoted-printable',
+        ]);
+});
+
+it('can parse lowercase headers', function () {
+    $messageString = <<<EOF
+from: Sender <[email protected]>
+to: Receiver <[email protected]>
+subject: Test Subject
+message-id: <[email protected]>
+mime-version: 1.0
+date: Fri, 25 Aug 2023 15:36:13 +0200
+content-type: text/html; charset=utf-8
+content-transfer-encoding: quoted-printable
+
+Email content goes here.
+EOF;
+
+    $message = Message::fromString($messageString);
+
+    expect($message->getHeaders())->toBe([
+        'from' => 'Sender <[email protected]>',
+        'to' => 'Receiver <[email protected]>',
+        'subject' => 'Test Subject',
+        'message-id' => '<[email protected]>',
+        'mime-version' => '1.0',
+        'date' => 'Fri, 25 Aug 2023 15:36:13 +0200',
+        'content-type' => 'text/html; charset=utf-8',
+    ])
+        ->and($message->getFrom())->toBe('Sender <[email protected]>')
+        ->and($message->getHeader('Content-Type'))->toBe('text/html; charset=utf-8');
+});
+
+it('can parse a mail message with boundaries', function () {
     date_default_timezone_set('UTC');
     $messageString = <<<EOF
 From: [email protected]
@@ -177,7 +235,7 @@
 </body>
 </html>
 
-------=_Part_1_1234567890-- 
+------=_Part_1_1234567890--
 EOF;
 
     $message = Message::fromString($messageString);