Description

New decorators to permit the creation of custom endpoints:

from cat.mad_hatter.decorators import endpoint

@endpoint.get
@endpoint.post
@endpoint.endpoint (for all the other HTTP verbs)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• Automatic tests implemented

Simple example of use inside a plugin

from cat.mad_hatter.decorators import endpoint

@endpoint.get(path="/hello")
def hello_world():
    return {"Hello":"world"}

Consume with:
curl http://localhost:1865/custom/hello

More complex example

from cat.mad_hatter.decorators import endpoint
from pydantic import BaseModel

class Item(BaseModel):
    name: str
    description: str

@endpoint.post(path="/hello", prefix="/example", tags=["Custom Tag"])
def my_post_endpoint(item: Item, stray=Depends(HTTPAuth(AuthResource.PLUGINS, AuthPermission.LIST))):
    return {"Hello": item.name, "Description": item.description, "Stray user": stray.user_id}

Consume with:

curl --request POST \
  --url http://localhost:1865/example/hello \
  --header 'Content-Type: application/json' \
  --data '{
  "name": "the Cat",
  "description": "is magic!"
}'

Internals

The decorators wrap the function as a FastAPI path operation, all the FastAPI path operation parameters can be used.
The default prefix is custom and default tag is Custom Endpoints

The new decorators are managed as other decorators (approach was: searched everywhere for hook and adapted for endpoint).

Activation and deactivation of plugins

• During activation we have to do just a trick to flush the openapi schema cache for /docs
• During deactivate we have to remove the FastAPI route manually, seems there is no official method to remove them, see Easy way to enable/disable endpoint fastapi/fastapi#8088, we have also to flush the openapi schema cache for /docs too

Change to startup process

Note, there is a change in the CheshireCat startup process, now the CheshireCat needs the FastAPI app instance, why?

The endpoint decorator creates a new FastAPI router for each new custom endpoint and then includes the router in the FastAPI app, CheshireCat activate the decorator injecting the FastAPI app.

Flows

Startup process

• CheshireCat starts MadHatter initialization
• MadHatter finds and loads all the plugins
• MadHatter activate all the plugins however at this steps the endpoints decorators are not "activated", the custom routers are not included in FastAPI app yet
• MadHatter.find_plugins() calls the CheshireCat callback on_finish_plugins_sync_callback
• In the callback CheshireCat all the endpoints of active plugins get activated
• The callback calls Endpoint.activate() for each custom endpoint
• Endpoint.activate() add the route to the FastAPI routes and clear the /docs cache

Plugin installation process

• User installs a plugin
• MadHatter install the plugin
• MadHatter calls toggle_plugin()
• toggle_plugin() activates the plugin (however the endpoints are not really active, are not yet included in FastAPI app)
• toggle_plugin() calls the CheshireCat callback on_finish_plugins_sync_callback
• The callback calls Endpoint.activate() for each custom endpoint
• Endpoint.activate() add the route to the FastAPI routes and clear the /docs cache

Plugin activation process

• User activates a plugin
• toggle_plugin() activates the plugin (however the endpoints are not really active, are not yet included in FastAPI app)
• toggle_plugin() calls the CheshireCat callback on_finish_plugins_sync_callback
• The callback calls Endpoint.activate() for each custom endpoint
• Endpoint.activate() add the route to the FastAPI routes and clear the /docs cache

Plugin deactivation process

• User activates a plugin
• toggle_plugin() deactivate the plugin
• Plugin.deactivate() calls Endpoint.deactivate() for each custom endpoint related to the plugin
• Endpoint.deactivate() removes the route from the FastAPI routes and clear the /docs cache
• toggle_plugin() calls the CheshireCat callback on_finish_plugins_sync_callback
• The callback do nothing about endpoint decorator

Plugins API

The endpoints are already exposed by the /plugins/ API (can be shown in the admin portal).
This is an example of the returned payload with the new endpoints node:

{
   "installed": [
            "id": "cc-dot-commands",
            "name": "Dot Commands",
            "description": "Handy utility designed to simplify and speed up your plugin development process. Install it, activate it, and send a message with just a period '.' in the chat",
            "author_name": "[email protected]",
            "hooks": [...],
            "tools": [...],
            "endpoints": [
                {
                    "name": "/example/hello",
                    "tags": [
                        "Dot Commands"
                    ]
                }
            ]
        }
]

Automatic tests

test_endpoints.py tests the new decorators.