Got rid of proxy methods in MatrixBot, v0.6.0

- Updated README.md
- Updated examples
- `MatrixBot` does not redefine methods from classes it is composed of anymore

.gitignore

@@ -6,3 +6,4 @@ dist/
 *.egg-info/
 *.swp
 *.swo
+*.tmp

README.md

@@ -10,6 +10,7 @@ The library supports the following features:
 - **Completely `asyncio` based**
 - **Filter-based callback system**
 - **Downloading and transparently decrypting files**
+- **Sending files**
 - **Sending images**
 - **Sending videos with automatic thumbnail generation (requires `ffmpeg`)**
 
@@ -22,13 +23,13 @@ install the latest version of the library:
 
 ```bash
 apt install libmagic1-dev libolm-dev
-python -m pip install git+https://git.tyukalov.su/nikita/mab@v0.5.1
+python -m pip install git+https://git.tyukalov.su/nikita/mab@v0.6.0
 ```
 
 `libmagic1-dev` is needed for automatic file MIME type detection, `libolm-dev`
 is needed for E2EE to work.
 
-Please inspect [`examples/image_gen_bot.py`](examples/image_gen_bot.py),
+Please inspect [`examples/image_bot.py`](examples/image_bot.py),
 [`examples/echo_bot.py`](examples/echo_bot.py) or open [`examples/`](examples/)
 directory to find usage examples. Examples require that you set
 `MATRIX_HOMESERVER` and `MATRIX_USERNAME` environment variables. Examples create

examples/command_bot.py

@@ -29,18 +29,18 @@ async def on_help_command(ctx: EventContext) -> None:
         "<li><code>!args arg1 [arg2] ... [arg5]</code> - command that takes 1..5 arguments</li>"
         "</ul>"
     )
-    await ctx.bot.send_text(ctx.room, HELP_MESSAGE)
+    await ctx.bot.send.text(ctx.room, HELP_MESSAGE)
 
 async def on_time_command(ctx: EventContext) -> None:
     """!time"""
-    await ctx.bot.send_text(
+    await ctx.bot.send.text(
         ctx.room,
         f"Current UNIX timestamp is <strong>{int(time.time())}</strong>"
     )
 
 async def on_raise_command(ctx: EventContext) -> None:
     """!raise"""
-    await ctx.bot.send_text(
+    await ctx.bot.send.text(
         ctx.room,
         "<strong>Executing <code>raise RuntimeError()</code>...</strong>"
     )
@@ -48,7 +48,7 @@ async def on_raise_command(ctx: EventContext) -> None:
 
 async def on_assert_command(ctx: EventContext) -> None:
     """!assert"""
-    await ctx.bot.send_text(
+    await ctx.bot.send.text(
         ctx.room,
         "<strong>Executing <code>assert False</code>...</strong>"
     )
@@ -63,9 +63,9 @@ async def on_mul_command(ctx: EventContext) -> None:
             v *= n
         response = " * ".join(html.escape("%.2f" % n) for n in numbers)
         response += f" = <strong>{html.escape(str(v))}<strong>"
-        await ctx.bot.send_text(ctx.room, response)
+        await ctx.bot.send.text(ctx.room, response)
     except Exception as e:
-        await ctx.bot.send_text(ctx.room, f"Could not process the command: {e}")
+        await ctx.bot.send.text(ctx.room, f"Could not process the command: {e}")
 
 async def on_args_command(ctx: EventContext) -> None:
     """!args"""
@@ -79,19 +79,19 @@ async def on_args_command(ctx: EventContext) -> None:
         for arg in ctx[CTX_CMD_ARGS]:
             response += f"<li><code>{html.escape(arg)}</code></li>"
         response += "</ol>"
-        await ctx.bot.send_text(
+        await ctx.bot.send.text(
             ctx.room,
             response
         )
     except:
-        await ctx.bot.send_text(
+        await ctx.bot.send.text(
             ctx.room,
             f"Could not process the command: {traceback.format_exc()}"
         )
 
 async def invalid_usage(ctx: EventContext) -> None:
     """This callback is called when the bot used incorrectly."""
-    await ctx.bot.send_text(ctx.room, "Use <code>!help</code>")
+    await ctx.bot.send.text(ctx.room, "Use <code>!help</code>")
 
 
 async def main() -> None:

examples/echo_bot.py

@@ -15,7 +15,7 @@ from _environment import check_environment
 
 async def on_text_message(ctx: EventContext) -> None:
     """This callback is called when a text message arrives."""
-    await ctx.bot.send_text(ctx.room, ctx[CTX_BODY])
+    await ctx.bot.send.text(ctx.room, ctx[CTX_BODY])
 
 async def main() -> None:
     """Application entry point"""

examples/file_bot.py

@@ -0,0 +1,97 @@
+"""
+This example implements Matrix bot that calculates SHA256 for a file sent by
+user.
+
+It uses environment variables to specify authorization data. Use Ctrl+C to stop
+the bot.
+"""
+
+import asyncio
+import aiofiles
+import os
+import logging
+import hashlib
+
+from mab import *
+
+from _environment import check_environment
+
+async def on_text_message(ctx: EventContext) -> None:
+    """This callback is called when a text message arrives."""
+    await ctx.bot.send.text(ctx.room, "Please send a file/image/video")
+
+async def on_file_message(ctx: EventContext) -> None:
+    """This callback is called when a file arrives."""
+    sha = hashlib.sha256()
+    does_temp_exist = False
+    if ctx[CTX_FILE_SIZE] > 1_000_000:
+        await ctx.bot.send.text(
+            ctx.room,
+            "The file is larger than 1 MB, downloading to filesystem"
+        )
+        await ctx.bot.download.file(ctx, path="temp.tmp")
+        async with aiofiles.open("temp.tmp", "rb") as f:
+            while True:
+                data = await f.read(64 * 1024)
+                if not data:
+                    break
+                sha.update(data)
+        does_temp_exist = True
+    else:
+        await ctx.bot.send.text(
+            ctx.room,
+            "The file is smaller than 1 MB, downloading to RAM"
+        )
+        content = await ctx.bot.download.file(ctx, path=None)
+        sha.update(content)
+    # result
+    response = f"SHA256 for file `{ctx[CTX_FILE_NAME]}`"
+    response += f" ({ctx[CTX_FILE_SIZE]} bytes, {ctx[CTX_FILE_MIME]})"
+    await ctx.bot.send.file_bytes(
+        room=ctx.room,
+        data=sha.hexdigest().encode("utf-8"),
+        filename="hash of the file.txt",
+        mime_type="text/plain",
+        text=response
+    )
+    # resend the file to test uploading
+    if does_temp_exist:
+        await ctx.bot.send.file(
+            room=ctx.room,
+            path="temp.tmp",
+            filename=ctx[CTX_FILE_NAME],
+            text="This is the file you have sent, but it was reuploaded"
+        )
+        try:
+            os.unlink("temp.tmp")
+        except:
+            pass
+        
+
+async def main() -> None:
+    """Application entry point"""
+    logging.basicConfig(level=logging.INFO)
+    logging.getLogger("nio").setLevel(logging.CRITICAL+1)
+    check_environment()
+
+    config = MatrixBotConfig(
+        matrix_homeserver_url=os.environ["MATRIX_HOMESERVER"],
+        matrix_username_localpart=os.environ["MATRIX_USERNAME"],
+        storage_directory="session_storage"
+    )
+    bot = MatrixBot(config)
+    bot.add_callback(
+        ~SenderIsBotFilter() & BodyExistsFilter() & MessageTypeFilter(MessageType.TEXT),
+        on_text_message)
+    bot.add_callback(
+        ~SenderIsBotFilter() & MessageHasFile() & NewMessageFilter(),
+        on_file_message)
+
+    # run until Ctrl+C
+    try:
+        await bot.run()
+    except asyncio.CancelledError:
+        pass
+
+if __name__ == "__main__":
+    asyncio.run(main())

examples/image_bot.py

@@ -24,9 +24,9 @@ async def on_gen_command(data: EventContext) -> None:
     try:
         r, g, b = [float(v) for v in data[CTX_CMD_ARGS]]
     except:
-        await data.bot.send_text(data.room, "Invalid arguments")
+        await data.bot.send.text(data.room, "Invalid arguments")
         return
-    await data.bot.send_text(data.room, "Generating the noise...")
+    await data.bot.send.text(data.room, "Generating the noise...")
     # create the basic noise
     img = Image.new("RGB", (16, 16))
     for x in range(img.width):
@@ -44,17 +44,14 @@ async def on_gen_command(data: EventContext) -> None:
     buf.seek(0)
     buf = buf.read()
     # send
-    await data.bot.send_image_bytes(data.room, buf, "noise.png")
+    await data.bot.send.image_bytes(data.room, buf, "noise.png")
 
 async def on_image(ctx: EventContext) -> None:
     """This callback is called when an image is received."""
     # download
     s = time.time()
-    data = await ctx.bot.download_file(ctx)
+    data = await ctx.bot.download.file(ctx)
     took_time = time.time() - s
-    if not isinstance(data, bytes):
-        await ctx.bot.send_text(ctx.room, "😧")
-        return
     # convert to Image
     with BytesIO(data) as buf:
         img = Image.open(buf)
@@ -69,7 +66,7 @@ async def on_image(ctx: EventContext) -> None:
     buf.seek(0)
     buf = buf.read()
     # send
-    await ctx.bot.send_image_bytes(
+    await ctx.bot.send.image_bytes(
         ctx.room,
         buf,
         "blurred.png",
@@ -78,7 +75,7 @@ async def on_image(ctx: EventContext) -> None:
 
 async def on_wrong_message(data: EventContext) -> None:
     """This callback is called when a wrong message is received."""
-    await data.bot.send_text(
+    await data.bot.send.text(
         data.room,
         "Text me something like <code>!gen 0.1 0.7 1.0</code> or send an image to blur"
     )

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "mab"
-version = "0.5.1"
+version = "0.6.0"
 authors = [
     { name = "Tyukalov Nikita", email = "nikita@tyukalov.su" }
 ]

src/mab/__init__.py

@@ -27,6 +27,9 @@ __all__ = [
     "CTX_CMD_PREFIX",
     "CTX_CMD_VERB",
     "CTX_CMD_ARGS",
+    "CTX_FILE_SIZE",
+    "CTX_FILE_MIME",
+    "CTX_FILE_NAME",
 
     # .bot
     "MatrixBot",
@@ -50,4 +53,5 @@ __all__ = [
     "RedactedMessageFilter",
     "SenderIsFilter",
     "SenderIsBotFilter",
+    "MessageHasFile",
 ]

src/mab/bot/_client_downloader.py

@@ -2,10 +2,9 @@ import asyncio
 import aiofiles
 import logging
 import os
-import time
+from typing import overload
 import threading
-import traceback
-import random
+from uuid import uuid4
 from pathlib import Path
 
 import hashlib
@@ -36,7 +35,7 @@ class ClientDownloader:
                     config: MatrixBotConfig,
                     client: AsyncClient) -> None:
         """
-        Setup the sender.
+        Setup the downloader.
 
         Args:
             - config - config to use
@@ -151,7 +150,19 @@ class ClientDownloader:
             cancel.set()
             raise
 
-    async def download_file(self,
+    @overload
+    async def file(self,
+                            source: EventContext | Event,
+                            *,
+                            path: str | Path) -> Path: ...
+    
+    @overload
+    async def file(self,
+                            source: EventContext | Event,
+                            *,
+                            path: None = None) -> bytes: ...
+    
+    async def file(self,
                             source: EventContext | Event,
                             *,
                             path: str | Path | None = None) -> Path | bytes:
@@ -218,14 +229,12 @@ class ClientDownloader:
             if key is not None and iv is not None and sha256 is not None:
                 # on disk
                 if isinstance(result, Path):
-                    r = unpaddedbase64.encode_base64(random.randbytes(8))
                     temp_path = result.with_name(
-                        f".{result.name}.{int(time.time())}{r}.tmp"
+                        f".{result.name}.{uuid4().hex}.tmp"
                     )
                     await self._decrypt_file(
                         result, temp_path, key, iv, sha256
                     )
-                    result.unlink()
                     temp_path.replace(result)
                     temp_path = None
                 # in memory

src/mab/bot/_client_sender.py

@@ -98,9 +98,9 @@ class ClientSender:
         self._client = client
         self._uploader = uploader
 
-    async def send_content(self,
-                           room: MatrixRoom | str,
-                           content: dict) -> RoomSendResponse:
+    async def content(self,
+                      room: MatrixRoom | str,
+                      content: dict) -> RoomSendResponse:
         """
         Send raw `content` JSON to `room`.
 
@@ -124,7 +124,7 @@ class ClientSender:
             if self._config.auto_verify_all_known_devices:
                 if not Utils.verify_all_known_devices(self._client):
                     raise
-                return await self.send_content(room, content)
+                return await self.content(room, content)
             else:
                 raise
         if type(result) is RoomSendResponse:
@@ -134,11 +134,11 @@ class ClientSender:
         else:
             raise RuntimeError("Unknown error has occured", result)
 
-    async def send_text(self,
-                        room: MatrixRoom | str,
-                        text: str,
-                        *,
-                        is_html: bool | None = None) -> str:
+    async def text(self,
+                   room: MatrixRoom | str,
+                   text: str,
+                   *,
+                   is_html: bool | None = None) -> str:
         """
         Send text message to `room`.
 
@@ -156,15 +156,15 @@ class ClientSender:
             "msgtype": "m.text",
             **text_data
         }
-        return (await self.send_content(room, content)).event_id
+        return (await self.content(room, content)).event_id
 
-    async def send_image(self,
-                         room: MatrixRoom | str,
-                         path: Path | str, *,
-                         text: str | None = None,
-                         is_html: bool | None = None,
-                         filename: str | None = None,
-                         timeout: float | None = 60 * 60) -> str:
+    async def image(self,
+                    room: MatrixRoom | str,
+                    path: Path | str, *,
+                    text: str | None = None,
+                    is_html: bool | None = None,
+                    filename: str | None = None,
+                    timeout: float | None = 60 * 60) -> str:
         """
         Send the image to `room`. Please note that formatted text is displayed
         incorrectly in some clients as of September 8th, 2026
@@ -213,16 +213,16 @@ class ClientSender:
                 "h": height
             }
         }
-        return (await self.send_content(room, content)).event_id
+        return (await self.content(room, content)).event_id
 
-    async def send_image_bytes(self,
-                               room: MatrixRoom | str,
-                               data: bytes,
-                               filename: str,
-                               *,
-                               text: str | None = None,
-                               is_html: bool | None = None,
-                               timeout: float | None = 60 * 60) -> str:
+    async def image_bytes(self,
+                          room: MatrixRoom | str,
+                          data: bytes,
+                          filename: str,
+                          *,
+                          text: str | None = None,
+                          is_html: bool | None = None,
+                          timeout: float | None = 60 * 60) -> str:
         """
         Send the image to `room`. Please note that formatted text is displayed
         incorrectly in some clients as of September 8th, 2026
@@ -276,16 +276,16 @@ class ClientSender:
                 "h": height
             }
         }
-        return (await self.send_content(room, content)).event_id
+        return (await self.content(room, content)).event_id
 
-    async def send_video(self,
-                         room: MatrixRoom | str,
-                         path: Path | str,
-                         *,
-                         props: VideoFileProperties | None = None,
-                         text: str | None = None,
-                         is_html: bool | None = None,
-                         timeout: float | None = 60 * 60) -> str:
+    async def video(self,
+                    room: MatrixRoom | str,
+                    path: Path | str,
+                    *,
+                    props: VideoFileProperties | None = None,
+                    text: str | None = None,
+                    is_html: bool | None = None,
+                    timeout: float | None = 60 * 60) -> str:
         """
         Send the video to `room`. Please note that formatted text is displayed
         incorrectly in some clients as of September 8th, 2026. Unknown video
@@ -361,4 +361,123 @@ class ClientSender:
             }
         }
         # send
-        return (await self.send_content(room, content)).event_id
+        return (await self.content(room, content)).event_id
+
+    async def file(self,
+                   room: MatrixRoom | str,
+                   path: Path | str,
+                   *,
+                   filename: str | None = None,
+                   mime_type: str | None = None,
+                   text: str | None = None,
+                   is_html: bool | None = None,
+                   timeout: float | None = 60 * 60):
+        """
+        Send the file to `room`. Please note that formatted text is displayed
+        incorrectly in some clients as of September 8th, 2026.
+
+        Args:
+            - room - the room to send the file to
+            - path - path to the file
+            - filename - filename to use for upload (`None` to use basename from
+              `path`)
+            - mime_type - mime type to use (`None` for autodetect using content
+              of `path`)
+            - text - caption to use (`None` to disable)
+            - is_html - whether the text is HTML-formatted (`None` for auto)
+            - timeout - upload timeout in seconds (`None` to disable)
+        
+        Returns:
+            - `event_id` of sent message on success
+            - Raises an exception on error
+        """
+        if self._client is None or self._config is None:
+            raise RuntimeError("ClientSender is not set up")
+        # get filename if not set
+        if not filename:
+            filename = os.path.basename(path)
+        # caption must not actually be empty
+        if text is None or not text.strip():
+            text = filename
+            is_html = False
+        # get the mime type if not specified
+        if mime_type is None:
+            mime_type = magic.from_file(path, mime=True)
+        # upload
+        async with asyncio.timeout(timeout):
+            upload_result = await self._uploader.upload_file(
+                path, mime_type=mime_type, filename=filename)
+        # send
+        content = {
+            "msgtype": "m.file",
+            "filename": filename,
+            **self._process_html_text(text, is_html),
+            "file": {
+                "url": upload_result.response.content_uri,
+                "mimetype": mime_type,
+                **upload_result.keys
+            },
+            "info": {
+                "mimetype": mime_type,
+                "size": upload_result.filesize
+            }
+        }
+        return (await self.content(room, content)).event_id
+    
+    async def file_bytes(self,
+                         room: MatrixRoom | str,
+                         data: bytes,
+                         filename: str,
+                         *,
+                         mime_type: str | None = None,
+                         text: str | None = None,
+                         is_html: bool | None = None,
+                         timeout: float | None = 60 * 60) -> str:
+        """
+        Send the file to `room`.
+
+        Args:
+            - room - the room to send the file to
+            - data - the content of the file to send
+            - filename - filename to use for the file
+            - mime_type - mime type to use (`None` for autodetect using `data`
+              content)
+            - text - caption to use (`None` to disable)
+            - is_html - whether the text is HTML-formatted (`None` for auto)
+            - timeout - upload timeout in seconds (`None` to disable)
+        
+        Returns:
+            - `event_id` of sent message on success
+            - Raises an exception on error
+        """
+        # caption must not actually be empty
+        if text is None or not text.strip():
+            text = filename
+            is_html = False
+        # check if the file is image
+        if not mime_type:
+            mime_type = magic.from_buffer(data, mime=True)
+        # upload
+        buffer = BytesIO(data)
+        async with asyncio.timeout(timeout):
+            upload_result = await self._uploader.upload_using_provider(
+                provider=buffer,
+                mime_type=mime_type,
+                filename=filename,
+                filesize=len(data))
+        # prepare the content and send
+        content = {
+            "msgtype": "m.file",
+            "filename": filename,
+            **self._process_html_text(text, is_html),
+            "file": {
+                "url": upload_result.response.content_uri,
+                "mimetype": mime_type,
+                **upload_result.keys
+            },
+            "info": {
+                "mimetype": mime_type,
+                "size": upload_result.filesize
+            }
+        }
+        return (await self.content(room, content)).event_id

src/mab/bot/bot.py

@@ -1,7 +1,7 @@
 import asyncio
 import logging
 
-from typing import Callable, Coroutine, Any
+from typing import Callable, Coroutine, Any, overload
 
 from nio import AsyncClient, MatrixRoom, Event
 
@@ -119,7 +119,8 @@ class MatrixBot:
         finally:
             await self.stop()
 
-    def get_client(self) -> AsyncClient:
+    @property
+    def client(self) -> AsyncClient:
         """
         Get AsyncClient.
 
@@ -129,148 +130,12 @@ class MatrixBot:
         """
         return self._client_manager.get_client()
 
-    async def send_text(self,
-                        room: MatrixRoom | str,
-                        text: str,
-                        *,
-                        is_html: bool | None = None) -> str:
-        """
-        Send text message to `room`.
+    @property
+    def send(self) -> ClientSender:
+        """Get ClientSender that you should use to send messages."""
+        return self._client_sender
 
-        Args:
-            - room - the room to send the text to
-            - text - the text to send to the room
-            - is_html - whether the text is HTML-formatted. Use `None` for auto
-        
-        Returns:
-            - `event_id` of sent message on success
-            - Raises an exception on error
-        """
-        return await self._client_sender.send_text(
-            room=room,
-            text=text,
-            is_html=is_html
-        )
-
-    async def send_image(self,
-                         room: MatrixRoom | str,
-                         path: Path | str, *,
-                         text: str | None = None,
-                         is_html: bool | None = None,
-                         filename: str | None = None,
-                         timeout: float | None = 60 * 60) -> str:
-        """
-        Send the image to `room`. Please note that formatted text is displayed
-        incorrectly in some clients as of September 8th, 2026
-
-        Args:
-            - room - the room to send the text to
-            - path - path to the image file
-            - text - image caption to use (`None` to disable)
-            - is_html - whether the text is HTML-formatted (`None` for auto)
-            - filename - filename to use for the file (`None` for auto)
-            - timeout - upload timeout in seconds (`None` to disable)
-        
-        Returns:
-            - `event_id` of sent message on success
-            - Raises an exception on error
-        """
-        return await self._client_sender.send_image(
-            room=room,
-            path=path,
-            text=text,
-            is_html=is_html,
-            filename=filename,
-            timeout=timeout
-        )
-
-    async def send_image_bytes(self,
-                               room: MatrixRoom | str,
-                               data: bytes,
-                               filename: str,
-                               *,
-                               text: str | None = None,
-                               is_html: bool | None = None,
-                               timeout: float | None = 60 * 60) -> str:
-        """
-        Send the image to `room`. Please note that formatted text is displayed
-        incorrectly in some clients as of September 8th, 2026
-
-        Args:
-            - room - the room to send the text to
-            - bytes - the image to send
-            - filename - filename to use for the file
-            - text - image caption to use (`None` to disable)
-            - is_html - whether the text is HTML-formatted (`None` for auto)
-            - timeout - upload timeout in seconds (`None` to disable)
-        
-        Returns:
-            - `event_id` of sent message on success
-            - Raises an exception on error
-        """
-        return await self._client_sender.send_image_bytes(
-            room=room,
-            data=data,
-            filename=filename,
-            text=text,
-            is_html=is_html,
-            timeout=timeout
-        )
-
-    async def send_video(self,
-                         room: MatrixRoom | str,
-                         path: Path | str,
-                         *,
-                         props: VideoFileProperties | None = None,
-                         text: str | None = None,
-                         is_html: bool | None = None,
-                         timeout: float | None = 60 * 60) -> str:
-        """
-        Send the video to `room`. Please note that formatted text is displayed
-        incorrectly in some clients as of September 8th, 2026. Unknown video
-        properties will be automatically deduced as configured in
-        `MatrixBotConfig`.
-
-        Args:
-            - room - the room to send the text to
-            - path - path to the video file
-            - props - video properties (`None` for auto, if the feature is ON)
-            - text - video caption to use (`None` to disable)
-            - is_html - whether the text is HTML-formatted (`None` for auto)
-            - timeout - upload timeout in seconds (`None` to disable)
-        
-        Returns:
-            - `event_id` of sent message on success
-            - Raises an exception on error
-        """
-        return await self._client_sender.send_video(
-            room=room,
-            path=path,
-            props=props,
-            text=text,
-            is_html=is_html,
-            timeout=timeout
-        )
-    
-    async def download_file(self,
-                            source: EventContext | Event,
-                            *,
-                            path: str | Path | None = None) -> Path | bytes:
-        """
-        Download the file from the event. Automatically dechiphers encrypted
-        media.
-
-        Args:
-            - source - event that has a file in its `content`
-            - path - where to save the file to. Use `None` to store the file in
-                     memory. Use path to specify file download path.
-        
-        Returns:
-            - Returns `Path` to the file on success (if `path` isn't `None`)
-            - Returns `bytes` of the file on success (if `path` is `None`)
-            - Raises an exception on error
-        """
-        return await self._client_downloader.download_file(
-            source=source,
-            path=path
-        )
+    @property
+    def download(self) -> ClientDownloader:
+        """Get ClientDownloader that you should use to download files."""
+        return self._client_downloader

src/mab/context.py

@@ -34,6 +34,15 @@ CTX_CMD_ARGS = ContextDataKey[list[str]]("CTX_CMD_ARGS")
 CTX_ROOM_ENCRYPTED = ContextDataKey[bool]("CTX_ROOM_ENCRYPTED")
 """True if the room is encrypted"""
 
+CTX_FILE_SIZE = ContextDataKey[int]("CTX_FILE_SIZE")
+"""Size of the file attached to the message (bytes)"""
+
+CTX_FILE_MIME = ContextDataKey[str]("CTX_FILE_MIME")
+"""Mime type of the file attached to the message"""
+
+CTX_FILE_NAME = ContextDataKey[str]("CTX_FILE_NAME")
+"""Name of the file attached to the message"""
+
 
 #
 # EventContext implementation

src/mab/filters/message.py

@@ -1,7 +1,12 @@
 import traceback
 from .base import BaseEventFilter, EventTypeFilter
 from ..types import MessageType
-from ..context import EventContext, CTX_MESSAGE_TYPE, CTX_SENDER
+from ..context import (EventContext,
+                       CTX_MESSAGE_TYPE,
+                       CTX_SENDER,
+                       CTX_FILE_SIZE,
+                       CTX_FILE_MIME,
+                       CTX_FILE_NAME)
 
 from nio import AsyncClient
 from nio import MatrixRoom, Event
@@ -118,4 +123,29 @@ class SenderIsBotFilter(BaseEventFilter):
     async def __call__(self, context: EventContext) -> bool:
         if not await super().__call__(context):
             return False
-        return context.bot.get_client().user_id == context.event.sender
+        return context.bot.client.user_id == context.event.sender
+
+class MessageHasFile(BaseEventFilter):
+    """
+    This filter returns True if the message contains file that can be
+    downloaded.
+
+    This filter sets `CTX_FILE_NAME`, `CTX_FILE_SIZE` and `CTX_FILE_MIME`
+    variables in the context (if they are present in the).
+    """
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
+            return False
+        content: dict | None = context.event.source.get("content")
+        if content is None:
+            return False
+        # `file` if encrypted, `url` if not encrypted
+        if "file" not in content and "url" not in content:
+            return False
+        context[CTX_FILE_NAME] = content.get("filename") or content.get("body")
+        context[CTX_FILE_SIZE] = content["info"].get("size")
+        context[CTX_FILE_MIME] = content["info"].get("mimetype")
+        return True