implement cell magic

closes #2

jupyterpost/__init__.py

 """Jupyterpost: Jupyterhub service for posting to Mattermost."""
 
-__version__ = "0.0.1"
+__version__ = "0.0.2"
 
-from .jupyterpost import (
-    configure_jupyterhub, hub_post_message, main, post
-)
+from .jupyterpost import configure_jupyterhub, hub_post_message, main
+from .client import post, load_ipython_extension
+
+
+__all__ = [
+    "configure_jupyterhub",
+    "hub_post_message",
+    "main",
+    "post",
+    "load_ipython_extension",
+]

jupyterpost/client.py

+from io import BytesIO
+import os
+from base64 import b64decode
+
+import httpx
+from IPython.core.magic import Magics, magics_class, line_cell_magic
+from IPython.core import magic_arguments
+from IPython import get_ipython
+from IPython.utils.capture import capture_output
+
+
+def post(message, channel, attachment=None, service_url=None, token=None):
+    """Post a message to Mattermost using the JupyterHub service.
+
+    Parameters
+    ----------
+    message : str
+        The message to post.
+    channel : str
+        The channel to post to. If it starts with '@', it is assumed to be a
+        direct message to the user with that username.
+    attachment : bytes or matplotlib figure, optional
+        A png file to upload. If given, will be attached to the message.
+    service_url : str, optional
+        The URL of the JupyterHub service. If not given, will be taken from the
+        JUPYTERPOST_URL environment variable.
+    token : str, optional
+        The API token to use. If not given, will be taken from the
+        JPY_API_TOKEN environment variable.
+    """
+    service_url = service_url or os.getenv("JUPYTERPOST_URL")
+    token = token or os.getenv("JPY_API_TOKEN")
+    if not service_url:
+        raise ValueError("No service URL given")
+    if not token:
+        raise ValueError("No API token given")
+    if attachment and not isinstance(attachment, bytes):
+        data = BytesIO()
+        try:
+            attachment.savefig(data, format="png")
+        except AttributeError:
+            raise TypeError("attachment must be a bytes object or matplotlib figure")
+        attachment = data.getvalue()
+
+    response = httpx.post(
+        service_url,
+        headers={"Authorization": f"token {token}"},
+        data={"message": message, "channel": channel},
+        files={"file": attachment} if attachment else None,
+    )
+    if response.is_error:
+        raise ValueError(response.text)
+
+
+@magics_class
+class JupyterpostMagics(Magics):
+    @magic_arguments.magic_arguments()
+    @magic_arguments.argument(
+        "channel",
+        type=str,
+        help=(
+            "The channel to post to. If it starts with '@', "
+            "it is assumed to be a direct message to the user with that username."
+        ),
+    )
+    @magic_arguments.argument(
+        "message",
+        nargs="*",
+        default="",
+        type=str,
+        help="The message to post.",
+    )
+    @magic_arguments.argument(
+        "-i",
+        "--input",
+        action="store_true",
+        help="Add formatted cell source to the message.",
+    )
+    @magic_arguments.argument(
+        "-r",
+        "--raw",
+        action="store_true",
+        help=(
+            "Post the cell source as raw text to keep formatting."
+            "Does not execute the cell."
+        ),
+    )
+    @magic_arguments.argument(
+        "--url",
+        type=str,
+        help=(
+            "The URL of the JupyterHub service. "
+            "Not required if running in configured JupyterHub."
+        ),
+    )
+    @magic_arguments.argument(
+        "--token",
+        type=str,
+        help="The API token to use. Not required if running in configured JupyterHub.",
+    )
+    @line_cell_magic
+    def post(self, line, cell=None):
+        """Post a message to Mattermost using the JupyterHub service."""
+        args = magic_arguments.parse_argstring(self.post, line)
+        message = [" ".join(args.message)]
+        if cell is None:
+            if not message[0]:
+                raise ValueError("No message given")
+            post(message[0], args.channel, service_url=args.url, token=args.token)
+            return
+        if args.raw:
+            message = "\n".join((message[0], cell))
+            post(message, args.channel, service_url=args.url, token=args.token)
+            return
+
+        if args.input:
+            message.append(f"```python{cell}```")
+
+        # Execute the cell
+        with capture_output() as captured:
+            self.shell.run_cell(cell)
+
+        captured.show()
+        message += captured.stdout
+        attachments = []
+        for output in captured.outputs:
+            for mime_type in [
+                "image/png",
+                # TODO: support other images
+                # "image/jpeg", "image/svg+xml",
+                "text/markdown",
+                "text/latex",
+                "text/plain",
+            ]:
+                if mime_type not in output.data:
+                    continue
+                if mime_type.startswith("image"):
+                    attachments.append(output.data[mime_type])
+                    break
+                elif mime_type == "text/plain":
+                    # Treat as preformatted text
+                    message.append(f"```\n{output.data[mime_type]}\n```")
+                else:
+                    message.append(output.data[mime_type])
+                    break
+
+        message = "\n".join(message)
+        if not message and not attachments:
+            raise ValueError("No message or attachments given")
+        # TODO: support multiple attachments
+        post(
+            message,
+            args.channel,
+            b64decode(attachments[0]) if attachments else None,
+            service_url=args.url,
+            token=args.token,
+        )
+
+
+def load_ipython_extension(ipython):
+    ipython.register_magics(JupyterpostMagics)
+
+
+# Try and initialize the magics on import
+try:
+    get_ipython().register_magics(JupyterpostMagics)
+except AttributeError:
+    pass

jupyterpost/jupyterpost.py

@@ -17,6 +17,11 @@ from jupyterhub.services.auth import HubAuthenticated
 from jupyterhub.roles import get_default_roles
 from jupyterhub.app import JupyterHub
 
+from IPython.core import magic_arguments
+from IPython.core.magic import register_cell_magic
+from IPython.display import display
+from IPython.utils.capture import capture_output
+
 logger = logging.getLogger("jupyterpost")
 logger.setLevel(logging.INFO)
 
@@ -201,49 +206,6 @@ def configure_jupyterhub(
     }
 
 
-def post(message, channel, attachment=None, service_url=None, token=None):
-    """Post a message to Mattermost using the JupyterHub service.
-
-    Parameters
-    ----------
-    message : str
-        The message to post.
-    channel : str
-        The channel to post to. If it starts with '@', it is assumed to be a
-        direct message to the user with that username.
-    attachment : bytes or matplotlib figure, optional
-        A png file to upload. If given, will be attached to the message.
-    service_url : str, optional
-        The URL of the JupyterHub service. If not given, will be taken from the
-        JUPYTERPOST_URL environment variable.
-    token : str, optional
-        The API token to use. If not given, will be taken from the
-        JPY_API_TOKEN environment variable.
-    """
-    service_url = service_url or os.getenv("JUPYTERPOST_URL")
-    token = token or os.getenv("JPY_API_TOKEN")
-    if not service_url:
-        raise ValueError("No service URL given")
-    if not token:
-        raise ValueError("No API token given")
-    if attachment and not isinstance(attachment, bytes):
-        data = BytesIO()
-        try:
-            attachment.savefig(data, format="png")
-        except AttributeError:
-            raise TypeError("attachment must be a bytes object or matplotlib figure")
-        attachment = data.getvalue()
-
-    response = httpx.post(
-        service_url,
-        headers={"Authorization": f"token {token}"},
-        data={"message": message, "channel": channel},
-        files={"file": attachment} if attachment else None,
-    )
-    if response.is_error:
-        raise ValueError(response.text)
-
-
 def main():
     app = Application(
         [