Adds better error handling/checking around getting content of a document via Tika

Signed-off-by: Trenton Holmes <797416+stumpylog@users.noreply.github.com>

src/paperless_mail/parsers.py

@@ -13,6 +13,7 @@ from humanfriendly import format_size
 from imap_tools import MailAttachment
 from imap_tools import MailMessage
 from tika_client import TikaClient
+from tika_client.data_models import TikaKey
 
 from documents.parsers import DocumentParser
 from documents.parsers import ParseError
@@ -172,8 +173,12 @@ class MailDocumentParser(DocumentParser):
             with TikaClient(tika_url=self.tika_server) as client:
                 parsed = client.tika.as_text.from_buffer(html, "text/html")
 
-                if "X-TIKA:content" in parsed.data:
-                    return parsed.data["X-TIKA:content"].strip()
+                if hasattr(parsed, "content") and parsed.content is not None:
+                    return parsed.content.strip()
+                elif TikaKey.Content in parsed.data:
+                    # May not be a completely handled type, but
+                    # the Tika response may still include content
+                    return parsed.data[TikaKey.Content].strip()
                 return ""
         except Exception as err:
             raise ParseError(