diff --git a/.gitignore b/.gitignore
index 8eaf2fe..479a4e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
+.venv/
 maubot-htmlfile.zip
diff --git a/.nix/flake.nix b/.nix/flake.nix
index 01ebacd..ed596a8 100644
--- a/.nix/flake.nix
+++ b/.nix/flake.nix
@@ -7,13 +7,30 @@
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
+
+        python = pkgs.python3;
+        python-with-packages = python.withPackages (p: with p; [
+          python-lsp-server
+          rope
+          pyflakes
+          mccabe
+          pycodestyle
+          autopep8
+        ]);
       in
       {
         devShell = pkgs.mkShell {
           nativeBuildInputs = [ pkgs.bashInteractive ];
           buildInputs = with pkgs; [
+            python-with-packages
+            nodePackages.pyright
             zip
           ];
+          shellHook = ''
+            python -m venv .venv
+            source .venv/bin/activate
+            pip install --requirement requirements.txt
+          '';
         };
       }
     );
diff --git a/htmlfile.py b/htmlfile.py
index 27082e1..38a9810 100644
--- a/htmlfile.py
+++ b/htmlfile.py
@@ -1,5 +1,7 @@
-from mautrix.types import EventType, MessageType
-from mautrix.crypto import attachments
+# pyright: reportPrivateImportUsage=false
+
+from mautrix.types import EventType, MediaMessageEventContent, MessageType
+from mautrix.crypto.attachments import decrypt_attachment
 
 from maubot import Plugin, MessageEvent
 from maubot.handlers import event
@@ -8,18 +10,19 @@ from maubot.handlers import event
 class HtmlFile(Plugin):
     @event.on(EventType.ROOM_MESSAGE)
     async def event_handler(self, event: MessageEvent) -> None:
-
-        # self.log.debug(f"received: {event}")
-
         if not event.content.msgtype == MessageType.FILE:
             return
+        else:
+            content = MediaMessageEventContent.deserialize(event.content.serialize())
 
-        if event.content.info.mimetype == "text/html":
-            if event.content.url:
-                file_content = (await self.client.download_media(url = event.content.url)).decode("utf-8")
-            else:
-                enc_file = event.content.file
-                ciphertext = await self.client.download_media(url = enc_file.url)
-                file_content = attachments.decrypt_attachment(ciphertext, enc_file.key.key, enc_file.hashes["sha256"], enc_file.iv).decode("utf-8")
-
-            await event.reply(file_content, allow_html = True)
+        file_content: str = ""
+        if content.info and content.info.mimetype == "text/html":
+            if content.url:
+                file_content = (await self.client.download_media(url=content.url)).decode("utf-8")
+            elif content.file and content.file.url:
+                enc_file = content.file
+                ciphertext = await self.client.download_media(url=content.file.url)
+                file_content = decrypt_attachment(ciphertext, enc_file.key.key,
+                                                  enc_file.hashes["sha256"], enc_file.iv).decode("utf-8")
+            if file_content:
+                await event.reply(file_content, allow_html=True)
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..5860ace
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,30 @@
+aiohttp==3.8.3
+aiosignal==1.3.1
+aiosqlite==0.17.0
+async-timeout==4.0.2
+asyncpg==0.25.0
+attrs==22.1.0
+bcrypt==3.2.2
+cffi==1.15.1
+charset-normalizer==2.1.1
+click==8.1.3
+colorama==0.4.6
+commonmark==0.9.1
+frozenlist==1.3.3
+idna==3.4
+Jinja2==3.1.2
+MarkupSafe==2.1.1
+maubot==0.3.1
+mautrix==0.15.8
+multidict==6.0.2
+packaging==21.3
+prompt-toolkit==3.0.33
+pycparser==2.21
+pyparsing==3.0.9
+questionary==1.10.0
+ruamel.yaml==0.17.21
+ruamel.yaml.clib==0.2.7
+SQLAlchemy==1.3.24
+typing_extensions==4.4.0
+wcwidth==0.2.5
+yarl==1.8.1