Added file uploading support, v0.5.2

- Added example `file_bot.py`
- Added *.tmp to .gitignore
- Added CTX_FILE_SIZE, CTX_FILE_MIME and CTX_FILE_NAME
- Added MessageHasFile filter
- Added `send_file` and `send_file_bytes` for ClientSender and Bot

.gitignore

@@ -5,4 +5,5 @@ session_storage/
 dist/
 *.egg-info/
 *.swp
-*.swo
+*.swo
+*.tmp

README.md

@@ -9,10 +9,11 @@ there, but it aims to be convenient and usable for relatively serious projects.
 The library supports the following features:
 - **Completely `asyncio` based**
 - **Filter-based callback system**
+- **Downloading and transparently decrypting files**
 - **Sending images**
 - **Sending videos with automatic thumbnail generation (requires `ffmpeg`)**
 
-## 🚀 Usage
+## 📦 Installation
 
 Use `apt` to install required system packages and `pip` to install the package.
 You may need to use `root` privileges to use `apt`. It's highly recommended you
@@ -21,18 +22,78 @@ 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@v0.4.0
+python -m pip install git+https://git.tyukalov.su/nikita/mab@v0.5.1
 ```
 
 `libmagic1-dev` is needed for automatic file MIME type detection, `libolm-dev`
 is needed for E2EE to work.
 
-Please inspect [`examples/shell_bot.py`](examples/shell_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
 `session_storage` directory in working directory.
 
+## 🚀 Usage
+
+If you use `mab`, your application will *most likely* be using **callbacks** to
+react to user actions. `mab` uses filter-based callback system to avoid exposing
+raw `nio-matrix` event objects.
+
+This is the workflow you will most likely follow:
+1. **Define the callback as `async` function that take 1 argument of type
+   `EventContext`.** For example, this callback would print the caption of the
+   message:
+   ```python
+   from mab import *
+
+   async def on_media_with_body(ctx: EventContext):
+       """To be called when a message with image/video and caption is received."""
+       print(ctx[CTX_BODY])
+   ```
+2. **Define the conditions your callback must be called on.** For example, you
+   may want your callback to be called when `the sender is not the bot` and
+   `the message contains textual body` and (`the message is an image` or
+   `the message is a video`).
+3. **Define the conditions as `filters`.** Most of them are pretty
+   straightforward. For example, if you want to use the conditions from above:
+   ```python
+   from mab import *
+
+   filters = (
+       ~SenderIsBotFilter()
+       & MessageTypeFilter([MessageType.IMAGE, MessageType.VIDEO])
+       & BodyExistsFilter()
+   )
+   ```
+4. **Add the callback to your `MatrixBot` instance.** For example, if you would
+   have used everything from above, then your code would look something like
+   this:
+   ```python
+   from mab import *
+
+   # let's assume you create your MatrixBot as `bot` variable here
+
+   async def on_media_with_body(ctx: EventContext):
+       """To be called when a message with image/video and caption is received."""
+       print(ctx[CTX_BODY])
+   
+   filters = (
+       ~SenderIsBotFilter()
+       & MessageTypeFilter([MessageType.IMAGE, MessageType.VIDEO])
+       & BodyExistsFilter()
+   )
+   bot.add_callback(filters, on_media_with_body)
+
+   ...
+   ```
+
+Filters support bitwise operators to implement complex matching logic. Some
+filters set context variables which can be accessed by
+`context[CTX_KEY_NAME]`-like syntax. Possible variables are defined in
+[this file](src/mab/context.py). Filters are implemented in
+[files of this directory](src/mab/filters/).
+
 ## 🏷️ Versioning
 
 Releases are tagged in this repository using the `vX.Y.Z` format. If the commit

examples/command_bot.py

@@ -0,0 +1,130 @@
+"""
+This example implements Matrix bot that can execute some commands.
+
+It uses environment variables to specify authorization data. Use Ctrl+C to stop
+the bot.
+"""
+
+import asyncio
+import time
+import html
+import os
+import traceback
+import logging
+
+from mab import *
+
+from _environment import check_environment
+
+async def on_help_command(ctx: EventContext) -> None:
+    """!help"""
+    HELP_MESSAGE = (
+        "<strong>Here is the list of the commands:</strong><br>"
+        "<ul>"
+        "<li><code>!help</code> - this help message</li>"
+        "<li><code>!time</code> - get UNIX timestamp</li>"
+        "<li><code>!raise</code> - raise <code>RuntimeError()</code></li>"
+        "<li><code>!assert</code> - perform <code>assert</code> that will fail</li>"
+        "<li><code>!mul A B [C] [D]...</code> - multiply A, B... and so on</li>"
+        "<li><code>!args arg1 [arg2] ... [arg5]</code> - command that takes 1..5 arguments</li>"
+        "</ul>"
+    )
+    await ctx.bot.send_text(ctx.room, HELP_MESSAGE)
+
+async def on_time_command(ctx: EventContext) -> None:
+    """!time"""
+    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(
+        ctx.room,
+        "<strong>Executing <code>raise RuntimeError()</code>...</strong>"
+    )
+    raise RuntimeError()
+
+async def on_assert_command(ctx: EventContext) -> None:
+    """!assert"""
+    await ctx.bot.send_text(
+        ctx.room,
+        "<strong>Executing <code>assert False</code>...</strong>"
+    )
+    assert False
+
+async def on_mul_command(ctx: EventContext) -> None:
+    """!mul"""
+    try:
+        numbers = [float(v) for v in ctx[CTX_CMD_ARGS]]
+        v = numbers[0]
+        for n in numbers[1:]:
+            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)
+    except Exception as e:
+        await ctx.bot.send_text(ctx.room, f"Could not process the command: {e}")
+
+async def on_args_command(ctx: EventContext) -> None:
+    """!args"""
+    try:
+        response = (
+            f"Prefix: <code>{ctx[CTX_CMD_PREFIX]}</code><br>"
+            f"Verb: <code>{ctx[CTX_CMD_VERB]}</code><br>"
+            f"Arguments: <code>{len(ctx[CTX_CMD_ARGS])}</code><br>"
+            f"Arguments are:<br><ol>"
+        )
+        for arg in ctx[CTX_CMD_ARGS]:
+            response += f"<li><code>{html.escape(arg)}</code></li>"
+        response += "</ol>"
+        await ctx.bot.send_text(
+            ctx.room,
+            response
+        )
+    except:
+        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>")
+
+
+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)
+
+    COMMANDS = {
+        on_help_command: BodyCommandFilter(["help", "?"]),
+        on_time_command: BodyCommandFilter("time"),
+        on_raise_command: BodyCommandFilter("raise"),
+        on_assert_command: BodyCommandFilter("assert"),
+        on_mul_command: BodyCommandFilter("mul", min_args=2),
+        on_args_command: BodyCommandFilter("args", min_args=1, max_args=5),
+    }
+    for callback, filter in COMMANDS.items():
+        f = ~SenderIsBotFilter() & filter
+        bot.add_callback(f, callback)
+    bot.add_callback(~SenderIsBotFilter() & NewMessageFilter(), invalid_usage)
+
+    # run until Ctrl+C
+    try:
+        await bot.run()
+    except asyncio.CancelledError:
+        pass
+
+if __name__ == "__main__":
+    asyncio.run(main())

examples/echo_bot.py

@@ -9,21 +9,13 @@ import asyncio
 import os
 import logging
 
-from mab import (
-    MatrixBot,
-    MatrixBotConfig,
-    RoomEventData,
-    BodyExistsFilter,
-    MessageTypeFilter,
-    SenderIsBotFilter,
-    MessageType
-)
+from mab import *
 
 from _environment import check_environment
 
-async def on_text_message(data: RoomEventData) -> None:
+async def on_text_message(ctx: EventContext) -> None:
     """This callback is called when a text message arrives."""
-    await data.bot.send_text(data.room, data.event.body) # type: ignore
+    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

@@ -9,27 +9,20 @@ the bot.
 import asyncio
 from io import BytesIO
 import os
+import time
 import logging
 import random
-from PIL import Image
+from PIL import Image, ImageFilter
 
-from mab import (
-    MatrixBot,
-    MatrixBotConfig,
-    RoomEventData,
-    MessageTypeFilter,
-    BodyCommandFilter,
-    SenderIsBotFilter,
-    MessageType
-)
+from mab import *
 
 from _environment import check_environment
 
-async def on_gen_command(data: RoomEventData) -> None:
+async def on_gen_command(data: EventContext) -> None:
     """This callback is called when `!gen R G B` command is received."""
     # convert R, G and B to floats
     try:
-        r, g, b = [float(v) for v in data.event.command_args] # type: ignore
+        r, g, b = [float(v) for v in data[CTX_CMD_ARGS]]
     except:
         await data.bot.send_text(data.room, "Invalid arguments")
         return
@@ -53,11 +46,38 @@ async def on_gen_command(data: RoomEventData) -> None:
     # send
     await data.bot.send_image_bytes(data.room, buf, "noise.png")
 
-async def on_wrong_message(data: RoomEventData) -> None:
+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)
+    took_time = time.time() - s
+    # convert to Image
+    with BytesIO(data) as buf:
+        img = Image.open(buf)
+        # apply effects
+        blur = ImageFilter.GaussianBlur(
+            radius=min(img.size[0] // 10, 5)
+        )
+        img = img.filter(blur)
+    # save to buffer
+    buf = BytesIO()
+    img.save(buf, format="PNG")
+    buf.seek(0)
+    buf = buf.read()
+    # send
+    await ctx.bot.send_image_bytes(
+        ctx.room,
+        buf,
+        "blurred.png",
+        text="Download and decryption took %.4f seconds" % took_time
+    )
+
+async def on_wrong_message(data: EventContext) -> None:
     """This callback is called when a wrong message is received."""
     await data.bot.send_text(
         data.room,
-        "Text me something like <code>!gen 0.1 0.7 1.0</code>"
+        "Text me something like <code>!gen 0.1 0.7 1.0</code> or send an image to blur"
     )
 
 async def main() -> None:
@@ -84,12 +104,18 @@ async def main() -> None:
     bot.add_callback(
         ~SenderIsBotFilter() & command_filter,
         on_gen_command)
+
+    # callback for new image message
+    bot.add_callback(
+        ~SenderIsBotFilter() & MessageTypeFilter(MessageType.IMAGE) & NewMessageFilter(),
+        on_image
+    )
     
     # callback for message that
     # 1. are sent not by this bot
-    # 2. do NOT match the command filter
+    # 2. are new messages (not edits)
     bot.add_callback(
-        ~SenderIsBotFilter() & ~command_filter,
+        ~SenderIsBotFilter() & BodyExistsFilter() & NewMessageFilter(),
         on_wrong_message
     )
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "mab"
-version = "0.4.0"
+version = "0.5.2"
 authors = [
     { name = "Tyukalov Nikita", email = "nikita@tyukalov.su" }
 ]

src/mab/__init__.py

@@ -1,7 +1,8 @@
 from . import bot
 from . import types
 
-from .types import MatrixBotConfig, RoomEventData, MessageType
+from .types import MatrixBotConfig, MessageType
+from .context import *
 
 from .bot import MatrixBot
 
@@ -16,9 +17,20 @@ __all__ = [
 
     # .types
     "MatrixBotConfig",
-    "RoomEventData",
     "MessageType",
 
+    # .context
+    "EventContext",
+    "CTX_BODY",
+    "CTX_MESSAGE_TYPE",
+    "CTX_SENDER",
+    "CTX_CMD_PREFIX",
+    "CTX_CMD_VERB",
+    "CTX_CMD_ARGS",
+    "CTX_FILE_SIZE",
+    "CTX_FILE_MIME",
+    "CTX_FILE_NAME",
+
     # .bot
     "MatrixBot",
 
@@ -41,4 +53,5 @@ __all__ = [
     "RedactedMessageFilter",
     "SenderIsFilter",
     "SenderIsBotFilter",
+    "MessageHasFile",
 ]

src/mab/bot/_callbacks.py

@@ -10,7 +10,8 @@ from nio import MatrixInvitedRoom, InviteMemberEvent, JoinResponse
 from nio.events.room_events import Event as RoomEvent
 
 from ._storage import Storage
-from ..types import MatrixBotConfig, RoomEventData
+from ..types import MatrixBotConfig
+from ..context import EventContext
 from ..filters.base import BaseEventFilter
 
 if TYPE_CHECKING:
@@ -31,7 +32,7 @@ class Callbacks:
         filter: BaseEventFilter
         """Filter to use for matching"""
 
-        callback: Callable[[RoomEventData], Coroutine[Any, Any, None]] | None
+        callback: Callable[[EventContext], Coroutine[Any, Any, None]] | None
         """Callback that will be called if the filter matches"""
 
         stop_matching: bool
@@ -51,20 +52,19 @@ class Callbacks:
         for callback_info in self._filters:
             if not isinstance(callback_info, self._FilterBasedCallback):
                 continue
+            event_data = EventContext(
+                room=room,
+                event=event,
+                bot=self._matrix_bot
+            )
             try:
-                if not await callback_info.filter(room, event, self._client):
+                if not await callback_info.filter(event_data):
                     continue
             except asyncio.CancelledError:
                 raise
             except:
                 self._logger.error(traceback.format_exc())
                 continue
-            event_data = RoomEventData(
-                room=room,
-                event=event,
-                filter=callback_info.filter,
-                bot=self._matrix_bot
-            )
             try:
                 # dump argument types
                 if callback_info.callback is None:
@@ -144,7 +144,7 @@ class Callbacks:
     def add_room_event_callback(
             self,
             filter: BaseEventFilter,
-            callback: Callable[[RoomEventData], Coroutine[Any, Any, None]] | None,
+            callback: Callable[[EventContext], Coroutine[Any, Any, None]] | None,
             *,
             stop_matching: bool = True) -> None:
         """

src/mab/bot/_client_downloader.py

@@ -0,0 +1,237 @@
+import asyncio
+import aiofiles
+import logging
+import os
+import threading
+from uuid import uuid4
+from pathlib import Path
+
+import hashlib
+import hmac
+import unpaddedbase64
+from Crypto.Cipher import AES
+from Crypto.Util import Counter
+
+from nio import (
+    AsyncClient,
+    Event,
+    DiskDownloadResponse,
+    MemoryDownloadResponse
+)
+
+from ..types import MatrixBotConfig
+from ..context import EventContext
+
+class ClientDownloader:
+    """This class downloads files"""
+
+    def __init__(self):
+        self._logger = logging.getLogger("ClientSender")
+        self._config: MatrixBotConfig | None = None
+        self._client: AsyncClient | None = None
+
+    async def setup(self,
+                    config: MatrixBotConfig,
+                    client: AsyncClient) -> None:
+        """
+        Setup the downloader.
+
+        Args:
+            - config - config to use
+            - client - client to use
+        """
+        self._config = config
+        self._client = client
+
+    async def _decrypt_file(self,
+                            src: Path,
+                            dst: Path,
+                            key: str,
+                            iv: str,
+                            sha256: str) -> None:
+        """
+        Decrypts `src` and saves it as `dst` asynchronously.
+        
+        Args:
+            - src - path to the source (encrypted) file
+            - dst - path where the resulting (decrypted) file will be saved
+            - key - key, from event["content"]["file"]["key"]["k"]
+            - iv - initialization vector, from event["content"]["file"]["iv"]
+            - sha256 - SHA-256 digest, from
+                       event["content"]["file"]["hashes"]["sha256"]
+        
+        Returns:
+            - Returns nothing on success
+            - Raises an exception on error
+        """
+        async with aiofiles.open(src, "rb") as reader:
+            # check file hash
+            expected = unpaddedbase64.decode_base64(sha256)
+            digest = hashlib.sha256()
+            while chunk := await reader.read(16 * 1024):
+                digest.update(chunk)
+            if not hmac.compare_digest(digest.digest(), expected):
+                raise RuntimeError("SHA256 mismatch")
+            await reader.seek(0)
+            # decrypt
+            decoded_key = unpaddedbase64.decode_base64(key)
+            decoded_iv = unpaddedbase64.decode_base64(iv)
+            cipher = AES.new(
+                decoded_key,
+                AES.MODE_CTR,
+                counter=Counter.new(
+                    nbits=64,
+                    prefix=decoded_iv[:8],
+                    initial_value=int.from_bytes(decoded_iv[8:], "big")
+                )
+            )
+            async with aiofiles.open(dst, "wb") as writer:
+                while chunk := await reader.read(16 * 1024):
+                    await writer.write(cipher.decrypt(chunk))
+
+    async def _decrypt_bytes(self,
+                             data: bytes,
+                             key: str,
+                             iv: str,
+                             sha256: str) -> bytes:
+        """
+        Decrypts `data`. It starts subthread that performs decryption.
+        
+        Args:
+            - data - data that needs to be decrypted
+            - key - key, from event["content"]["file"]["key"]["k"]
+            - iv - initialization vector, from event["content"]["file"]["iv"]
+            - sha265 - SHA-256 digest, from
+                       event["content"]["file"]["hashes"]["sha256"]
+        
+        Returns:
+            - Returns decrypted data on success
+            - Raises an exception on error
+        """
+        cancel = threading.Event()
+        # subfunction that will run in another thread
+        def decrypt() -> bytes:
+            chunk_size = 64 * 1024
+            view = memoryview(data)
+            expected = unpaddedbase64.decode_base64(sha256)
+            digest = hashlib.sha256()
+            for offset in range(0, len(view), chunk_size):
+                if cancel.is_set():
+                    return b""
+                digest.update(view[offset:offset + chunk_size])
+            if not hmac.compare_digest(digest.digest(), expected):
+                raise RuntimeError("SHA-256 mismatch")
+            # prepare AES-CTR
+            decoded_key = unpaddedbase64.decode_base64(key)
+            decoded_iv = unpaddedbase64.decode_base64(iv)
+            cipher = AES.new(
+                decoded_key,
+                AES.MODE_CTR,
+                counter=Counter.new(
+                    nbits=64,
+                    prefix=decoded_iv[:8],
+                    initial_value=int.from_bytes(decoded_iv[8:], "big"),
+                ),
+            )
+            # decrypt
+            result = bytearray()
+            for offset in range(0, len(view), chunk_size):
+                if cancel.is_set():
+                    return b""
+                result.extend(
+                    cipher.decrypt(view[offset:offset + chunk_size])
+                )
+            return bytes(result)
+        # decrypt in thread
+        try:
+            return await asyncio.to_thread(decrypt)
+        except asyncio.CancelledError:
+            cancel.set()
+            raise
+
+    async def download_file(self,
+                            source: EventContext | Event,
+                            *,
+                            path: str | Path | None = None) -> Path | bytes:
+        """
+        Download the file from the event. Automatically deciphers 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
+        """
+        if self._client is None:
+            raise RuntimeError("ClientDownloader is not set up")
+        # prepare the args
+        if isinstance(source, EventContext):
+            source = source.event
+        content: dict = source.source["content"]
+        f = content.get("file")
+        # encypted
+        if f:
+            if not isinstance(f["url"], str):
+                raise RuntimeError("`source` does not contain file URL")
+            mxc = f["url"]
+            if f["key"]["alg"].upper() != "A256CTR":
+                raise NotImplementedError(
+                    f"Unsupported encryption algorithm `{f['key']['alg']}`"
+                )
+            key: str | None = f["key"]["k"]
+            iv: str | None = f["iv"]
+            sha256: str | None = f["hashes"]["sha256"]
+        # not encrypted
+        else:
+            mxc = content["url"]
+            key = None
+            iv = None
+            sha256 = None
+        # prepare path
+        if isinstance(path, str):
+            path = Path(path)
+        filename: str | None = \
+            os.path.basename(path) if isinstance(path, Path) else None
+        # download
+        result = await self._client.download(
+            mxc,
+            filename=filename,
+            save_to=path
+        )
+        # check the response
+        if isinstance(result, DiskDownloadResponse):
+            result = Path(result.body)
+        elif isinstance(result, MemoryDownloadResponse):
+            result = result.body
+        else:
+            raise RuntimeError(result)
+        # decrypt if needed
+        temp_path: Path | None = None
+        try:
+            if key is not None and iv is not None and sha256 is not None:
+                # on disk
+                if isinstance(result, Path):
+                    temp_path = result.with_name(
+                        f".{result.name}.{uuid4().hex}.tmp"
+                    )
+                    await self._decrypt_file(
+                        result, temp_path, key, iv, sha256
+                    )
+                    temp_path.replace(result)
+                    temp_path = None
+                # in memory
+                else:
+                    result = await self._decrypt_bytes(
+                        result, key, iv, sha256
+                    )
+        finally:
+            if isinstance(temp_path, Path) and isinstance(result, Path):
+                result.unlink(missing_ok=True)
+                temp_path.unlink(missing_ok=True)
+        # return the result
+        return result

src/mab/bot/_client_sender.py

@@ -361,4 +361,123 @@ class ClientSender:
             }
         }
         # send
+        return (await self.send_content(room, content)).event_id
+
+    async def send_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.send_content(room, content)).event_id
+    
+    async def send_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.send_content(room, content)).event_id

src/mab/bot/bot.py

@@ -1,16 +1,18 @@
 import asyncio
 import logging
 
-from typing import Callable, Coroutine, Any
+from typing import Callable, Coroutine, Any, overload
 
-from nio import AsyncClient
+from nio import AsyncClient, MatrixRoom, Event
 
 from ..filters.base import BaseEventFilter
 from ..types import *
+from ..context import EventContext
 
 from ._validation import Validator
 from ._storage import Storage
 from ._client_auth import ClientAuth
+from ._client_downloader import ClientDownloader
 from ._client_manager import ClientManager
 from ._client_uploader import ClientUploader
 from ._client_sender import ClientSender
@@ -32,6 +34,7 @@ class MatrixBot:
         self._client_auth = ClientAuth(self._storage)
         self._client_manager = ClientManager(self._client_auth, self._storage)
         self._client_uploader = ClientUploader(self._storage)
+        self._client_downloader = ClientDownloader()
         self._client_sender = ClientSender()
         self._callbacks = Callbacks(self._storage, self)
         # validate the config and save it
@@ -44,7 +47,7 @@ class MatrixBot:
 
     def add_callback(self,
                            filter: BaseEventFilter,
-                           callback: Callable[[RoomEventData], Coroutine[Any, Any, None]] | None,
+                           callback: Callable[[EventContext], Coroutine[Any, Any, None]] | None,
                            *,
                            stop_matching: bool = True) -> None:
         """
@@ -79,6 +82,10 @@ class MatrixBot:
             self._config,
             self._client_manager.get_client()
         )
+        await self._client_downloader.setup(
+            self._config,
+            self._client_manager.get_client()
+        )
         await self._client_sender.setup(
             self._config,
             self._client_manager.get_client(),
@@ -243,4 +250,110 @@ class MatrixBot:
             text=text,
             is_html=is_html,
             timeout=timeout
+        )
+
+    async def send_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 auto)
+            - 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
+        """
+        return await self._client_sender.send_file(
+            room=room,
+            path=path,
+            filename=filename,
+            mime_type=mime_type,
+            text=text,
+            is_html=is_html,
+            timeout=timeout
+        )
+
+    async def send_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
+            - 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
+        """
+        return await self._client_sender.send_file_bytes(
+            room=room,
+            data=data,
+            filename=filename,
+            mime_type=mime_type,
+            text=text,
+            is_html=is_html,
+            timeout=timeout
+        )
+
+    @overload
+    async def download_file(self,
+                            source: EventContext | Event,
+                            *,
+                            path: str | Path) -> Path: ...
+    
+    @overload
+    async def download_file(self,
+                            source: EventContext | Event,
+                            *,
+                            path: None = None) -> bytes: ...
+    
+    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
         )

src/mab/context.py

@@ -0,0 +1,88 @@
+"""This module implements logic for event context"""
+
+from dataclasses import dataclass
+from typing import Any, TYPE_CHECKING
+
+from .types import ContextDataKey, MessageType
+
+from nio import MatrixRoom, Event
+
+if TYPE_CHECKING:
+    from .bot import MatrixBot
+
+#
+# Possible context variables
+#
+CTX_BODY = ContextDataKey[str]("CTX_BODY")
+"""Value of `event.body`"""
+
+CTX_MESSAGE_TYPE = ContextDataKey[MessageType]("CTX_MESSAGE_TYPE")
+"""Value of `msgtype` for the event"""
+
+CTX_SENDER = ContextDataKey[str]("CTX_SENDER")
+"""Value of `event.sender`"""
+
+CTX_CMD_PREFIX = ContextDataKey[str]("CTX_CMD_PREFIX")
+"""Command prefix that was used when matching"""
+
+CTX_CMD_VERB = ContextDataKey[str]("CTX_CMD_VERB")
+"""The verb that was used to execute the command"""
+
+CTX_CMD_ARGS = ContextDataKey[list[str]]("CTX_CMD_ARGS")
+"""Arguments that were passed with the command"""
+
+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
+#
+@dataclass
+class EventContext:
+    """The class holding information about an event that happened in the room"""
+
+    room: MatrixRoom
+    """The room the event has happened in"""
+
+    event: Event
+    """The event that has happened in the room"""
+
+    bot: "MatrixBot"
+    """The bot that is the source of the event"""
+
+    def __setitem__[T](self, key: ContextDataKey[T], value: T | None) -> None:
+        """Set a value inside the context data storage. `None` removes it"""
+        if not hasattr(self, "_datastore"):
+            self._datastore: dict[ContextDataKey, Any] = {}
+        if value is None:
+            del self._datastore[key]
+        else:
+            self._datastore[key] = value
+
+    def __getitem__[T](self, key: ContextDataKey[T]) -> T:
+        """
+        Get a value inside the context data storage.
+        
+        Raises RuntimeError if the value is not present.
+        """
+        if not hasattr(self, "_datastore") or key not in self._datastore:
+            raise RuntimeError(f"Context does not contain {repr(key)}")
+        return self._datastore[key]
+
+    def __contains__[T](self, key: ContextDataKey[T]) -> bool:
+        """Check if context data storage contains the value"""
+        if not hasattr(self, "_datastore"):
+            return False
+        if key not in self._datastore:
+            return False
+        return True

src/mab/filters/base.py

@@ -5,6 +5,8 @@ from typing import Any, Type
 from nio import AsyncClient
 from nio import MatrixRoom, Event
 
+from ..context import EventContext
+
 class BaseEventFilter(ABC):
     """Base class for all message filters"""
     _logger = logging.Logger("EventFilter")
@@ -35,7 +37,7 @@ class BaseEventFilter(ABC):
         )
 
     def __ror__(self, other):
-        return self.__ror__(other)
+        return self.__or__(other)
 
     # XOR
     def __xor__(self, other):
@@ -64,7 +66,7 @@ class BaseEventFilter(ABC):
         """
         return str(self.__class__.__name__)
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
+    async def __call__(self, context: EventContext) -> bool:
         """
         This abstract method must be redefined in derived classes so that the
         filter operates according to its description. This method must not raise
@@ -72,9 +74,9 @@ class BaseEventFilter(ABC):
         and return False
         
         Args:
-            - room - room the event has happened in
-            - event - the event to check againts this filter
-            - client - the client
+            - context - event context; your derived classes may add variables
+                        to it (see `message.MessageTypeFilter` implementation
+                        for reference)
         
         Returns:
             - True if the event satisfies this filter
@@ -88,8 +90,10 @@ class EventTypeFilter(BaseEventFilter):
         super().__init__(**kwargs)
         self._type = type
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        return isinstance(event, self._type)
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
+            return False
+        return isinstance(context.event, self._type)
 
 class CompoundEventFilter(BaseEventFilter):
     """Event filter that consists of multiple filters"""
@@ -140,8 +144,10 @@ class CompoundEventFilter(BaseEventFilter):
             expression = f"~{reprs[0]}"
         return f"({expression})"
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        evaluated = [await arg(room, event, client) for arg in self._arguments]
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
+            return False
+        evaluated = [await arg(context) for arg in self._arguments]
         if self._operator == self.OPERATOR_AND:
             return all(evaluated)
         elif self._operator == self.OPERATOR_OR:

src/mab/filters/body.py

@@ -1,6 +1,13 @@
 import re
 import traceback
 from .message import NewMessageFilter
+from ..context import EventContext
+from ..context import (
+    CTX_BODY,
+    CTX_CMD_PREFIX,
+    CTX_CMD_VERB,
+    CTX_CMD_ARGS
+)
 
 from nio import AsyncClient
 from nio import MatrixRoom, Event
@@ -21,24 +28,27 @@ class BodyExistsFilter(NewMessageFilter):
 
     This filter will match any message that has `body` in it, including images,
     videos, files, etc.
+
+    This filter sets `CTX_BODY` context variable.
     """
     def __init__(self, *, ignore_filename_in_body: bool = True, **kwargs):
         super().__init__(**kwargs)
         self._ignore_filename_in_body = ignore_filename_in_body
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        if not hasattr(event, "body"):
+        if not hasattr(context.event, "body"):
             return False
-        if not isinstance(event.body, str): # type: ignore
+        if not isinstance(context.event.body, str): # type: ignore
             return False
-        if not event.body.strip(): # type: ignore
+        if not context.event.body.strip(): # type: ignore
             return False
         if self._ignore_filename_in_body:
-            content = event.source["content"]
-            if "filename" in content and content["filename"] == event.body: # type: ignore
+            content = context.event.source["content"]
+            if "filename" in content and content["filename"] == context.event.body: # type: ignore
                 return False
+        context[CTX_BODY] = context.event.body # type: ignore
         return True
 
 class BodyContainsFilter(BodyExistsFilter):
@@ -61,10 +71,10 @@ class BodyContainsFilter(BodyExistsFilter):
         self._any_case = any_case
         self._needle = needle
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        body = event.body.lower() if self._any_case else event.body # type: ignore
+        body = context.event.body.lower() if self._any_case else context.event.body # type: ignore
         for n in self._needle:
             if n in body:
                 return True
@@ -90,10 +100,10 @@ class BodyStartsWithFilter(BodyExistsFilter):
         self._any_case = any_case
         self._substring = substring
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        body = event.body.lower() if self._any_case else event.body # type: ignore
+        body = context.event.body.lower() if self._any_case else context.event.body # type: ignore
         for s in self._substring:
             if body.startswith(s):
                 return True
@@ -119,10 +129,10 @@ class BodyEndsWithFilter(BodyExistsFilter):
         self._any_case = any_case
         self._substring = substring
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        body = event.body.lower() if self._any_case else event.body # type: ignore
+        body = context.event.body.lower() if self._any_case else context.event.body # type: ignore
         for s in self._substring:
             if body.endswith(s):
                 return True
@@ -145,9 +155,10 @@ class BodyCommandFilter(BodyExistsFilter):
     store all verbs in lower case. This filter will not match any verbs that
     use mixed case of upper case.
 
-    If this filter is matched, then it will set a new attribute for the event:
-    `event.command_args: list[str]`. You may use this attribute in your callback
-    for this event.
+    This filter sets the following context variables:
+    - `CTX_CMD_PREFIX` - prefix that was used
+    - `CTX_CMD_VERB` - verb that was used
+    - `CTX_CMD_ARGS` - arguments that were passed
     """
     def __init__(self, verbs: str | list[str], min_args: int = 0, max_args: int | None = None, prefix: str = "!", **kwargs):
         super().__init__(**kwargs)
@@ -158,10 +169,10 @@ class BodyCommandFilter(BodyExistsFilter):
         self._max_args = max_args
         self._prefix = prefix
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        parts = [p.strip() for p in event.body.split() if p.strip()] # type: ignore
+        parts = [p.strip() for p in context.event.body.split() if p.strip()] # type: ignore
         args_count = len(parts) - 1
         if args_count < self._min_args:
             return False
@@ -172,7 +183,9 @@ class BodyCommandFilter(BodyExistsFilter):
         cmd = parts[0][len(self._prefix):].lower()
         for verb in self._verbs:
             if cmd == verb:
-                setattr(event, "command_args", parts[1:])
+                context[CTX_CMD_PREFIX] = self._prefix
+                context[CTX_CMD_VERB] = verb
+                context[CTX_CMD_ARGS] = parts[1:]
                 return True
         return False
 
@@ -186,11 +199,11 @@ class BodyRegexFilter(BodyExistsFilter):
             regex = re.compile(regex)
         self._regex = regex
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
         try:
-            return self._regex.match(event.body) # type: ignore
+            return self._regex.match(context.event.body) is not None # type: ignore
         except:
             self._logger.error(traceback.format_exc())
             return False

src/mab/filters/message.py

@@ -1,6 +1,12 @@
 import traceback
 from .base import BaseEventFilter, EventTypeFilter
 from ..types import MessageType
+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
@@ -15,6 +21,8 @@ class MessageTypeFilter(BaseEventFilter):
 
     `types` list is stored by reference so you may modify the behavior of this
     filter dynamically.
+
+    This filter sets `CTX_MESSAGE_TYPE` variable in the context.
     """
     def __init__(self, types: list[MessageType] | MessageType, **kwargs):
         super().__init__(**kwargs)
@@ -22,14 +30,16 @@ class MessageTypeFilter(BaseEventFilter):
             types = [types]
         self._types = types
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        if "msgtype" not in event.source["content"]:
+        if "msgtype" not in context.event.source["content"]:
             return False
-        return (
-            event.source["content"]["msgtype"] in [t.value for t in self._types]
-        )
+        msgtype = context.event.source["content"]["msgtype"]
+        if not msgtype in [t.value for t in self._types]:
+            return False
+        context[CTX_MESSAGE_TYPE] = MessageType(msgtype)
+        return True
 
 class NewMessageFilter(BaseEventFilter):
     """
@@ -40,10 +50,10 @@ class NewMessageFilter(BaseEventFilter):
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        return "m.new_content" not in event.source["content"]
+        return "m.new_content" not in context.event.source["content"]
 
 class EditedMessageFilter(BaseEventFilter):
     """
@@ -53,10 +63,10 @@ class EditedMessageFilter(BaseEventFilter):
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        return "m.new_content" in event.source["content"]
+        return "m.new_content" in context.event.source["content"]
 
 class RedactedMessageFilter(EventTypeFilter):
     """
@@ -64,9 +74,10 @@ class RedactedMessageFilter(EventTypeFilter):
     """
     def __init__(self, **kwargs):
         super().__init__(RedactionEvent, **kwargs)
+        raise NotImplementedError()
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        return await super().__call__(room, event, client)
+    async def __call__(self, context: EventContext) -> bool:
+        raise NotImplementedError()
 
 class SenderIsFilter(BaseEventFilter):
     """
@@ -77,6 +88,8 @@ class SenderIsFilter(BaseEventFilter):
 
     `senders` list is stored by reference so you can modify behavior of this
     filter dynamically.
+
+    This filter sets `CTX_SENDER` variable in the context.
     """
     def __init__(self, sender: list[str] | str, *, any_case: bool = True, **kwargs):
         super().__init__(**kwargs)
@@ -85,12 +98,13 @@ class SenderIsFilter(BaseEventFilter):
         self._sender = sender
         self._any_case = any_case
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        sender = event.sender.lower() if self._any_case else event.sender
+        sender = context.event.sender.lower() if self._any_case else context.event.sender
         for s in self._sender:
             if sender == s:
+                context[CTX_SENDER] = sender
                 return True
         return False
 
@@ -106,7 +120,32 @@ class SenderIsBotFilter(BaseEventFilter):
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
-        if not await super().__call__(room, event, client):
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
             return False
-        return client.user_id == event.sender
+        return context.bot.get_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

src/mab/filters/room.py

@@ -1,7 +1,6 @@
 from .base import BaseEventFilter
 
-from nio import AsyncClient
-from nio import MatrixRoom, Event
+from ..context import EventContext, CTX_ROOM_ENCRYPTED
 
 class RoomEncryptedFilter(BaseEventFilter):
     """
@@ -10,8 +9,11 @@ class RoomEncryptedFilter(BaseEventFilter):
     def __init__(self):
         super().__init__()
 
-    async def __call__(self, room: MatrixRoom, event: Event, client: AsyncClient) -> bool:
+    async def __call__(self, context: EventContext) -> bool:
+        if not await super().__call__(context):
+            return False
         try:
-            return room.encrypted
+            context[CTX_ROOM_ENCRYPTED] = context.room.encrypted
+            return context.room.encrypted
         except:
             return False

src/mab/types.py

@@ -4,15 +4,8 @@ from pathlib import Path
 from dataclasses import dataclass
 from enum import Enum
 
-from nio import MatrixRoom, Event
 from nio import UploadResponse
 
-from .filters.base import BaseEventFilter
-
-from typing import TYPE_CHECKING
-if TYPE_CHECKING:
-    from .bot import MatrixBot
-
 @dataclass
 class MatrixBotConfig:
     """Configuration for MatrixBot"""
@@ -68,22 +61,6 @@ class VideoFileProperties:
     thumbnail: Path | str | bytes | None = None
     """Path to the thumbnail or the raw JPEG thumbnail data"""
 
-@dataclass
-class RoomEventData:
-    """Dataclass that hold information about event that happened in the room"""
-
-    room: MatrixRoom
-    """The room the event has happened in"""
-
-    event: Event
-    """The event that has happened in the room"""
-
-    filter: BaseEventFilter
-    """The filter that invoked this event"""
-
-    bot: "MatrixBot"
-    """The bot that is the source of the event"""
-
 @dataclass
 class UploadResult:
     """Result of data upload"""
@@ -108,4 +85,21 @@ class MessageType(Enum):
     FILE = "m.file"
     AUDIO = "m.audio"
     LOCATION = "m.location"
-    VIDEO = "m.video"
+    VIDEO = "m.video"
+
+class ContextDataKey[T]:
+    """
+    Instances of this class represent a single possible data key that can be
+    stored inside EventContext.
+    """
+    def __init__(self, name: str) -> None:
+        """
+        Initialize a ContextDataKey
+        
+        Args:
+            - name - name that will be used internally
+        """
+        self._name = name
+
+    def __repr__(self) -> str:
+        return f"ContextDataKey[{type(T)}]({repr(self._name)})"