Example Chart Application

An example custom UI Application for the patient chart. This particular application loads the active staff user and displays some attributes about them (ex: their name), and it also loads templated HTML and JavaScript to make a REST call to a user-defined endpoint, right in the Canvas EMR.

SDK Features #

Configuration #

These SimpleAPI endpoints use the StaffSessionAuthMixin

The CANVAS_MANIFEST.json file defines attributes specific to the Application, including scope (patient_specific) and icon image.

Structure #

example_chart_app/
├── applications/
│   ├── __init__.py
│   ├── my_application.py     # Defines API endpoints and Application
├── assets
|   ├──rx.png                 # Image file
├── templates/
│   └── custom_ui.html        # HTML template for visualization UI
├── CANVAS_MANIFEST.json      # Plugin configuration
└── README.md                 # Documentation

CANVAS_MANIFEST.json #

{
    "sdk_version": "0.1.4",
    "plugin_version": "0.0.1",
    "name": "example_chart_app",
    "description": "Used to test various canvas plugins functionality",
    "url_permissions": [],
    "components": {
        "protocols": [
            {
                "class": "example_chart_app.applications.my_application:MyApi",
                "description": "Provides api for the application",
                "data_access": {
                    "event": "",
                    "read": [],
                    "write": []
                }
            }
        ],
        "applications": [
            {
                "class": "example_chart_app.applications.my_application:MyChartApplication",
                "name": "Example Chart App",
                "description": "Show a custom, interactive UI in the chart",
                "scope": "patient_specific",
                "icon": "assets/rx.png"
            }
        ],
        "commands": [],
        "content": [],
        "effects": [],
        "views": []
    },
    "secrets": [],
    "tags": {},
    "references": [],
    "license": "",
    "diagram": false,
    "readme": "./README.md"
}

templates/ #

custom-ui.html #

This is the html template called by the render_to_string function with a logged_in_staff object. It contains styling and custom Javascript to call the user-defined POST endpoint when a specific element is clicked.

applications/ #

my_application.py #

This file defines an application plugin for Canvas Medical using the Canvas SDK. It includes a custom application (MyChartApplication) and an API (MyApi) for rendering a modal user interface pane and handling related actions, such as adding tasks.

MyChartApplication Class

  • Subclasses the Application class from the Canvas SDK.
  • The on_open method is triggered when the application is opened. It retrieves the current patient’s ID from self.context.
  • It returns a LaunchModalEffect, which opens a custom modal UI in the right chart pane. The URL for this modal includes the patient ID as a query parameter.

MyApi Class

  • Subclasses both StaffSessionAuthMixin and SimpleAPI, enabling API definition with authentication.
  • Defines two endpoints using the @api decorator: a GET and a POST.

GET /custom-ui

  • Endpoint: /custom-ui
  • Retrieves the logged-in staff user via the header "canvas-logged-in-user-id" and the Canvas SDK Staff data model (but it could retrieve any data!)
  • Renders a template (templates/custom-ui.html) with context including the logged-in staff and the selected patient ID.
  • Returns the rendered HTML as an HTMLResponse with HTTP 200 (OK) status.

POST /add-task

  • Endpoint: /add-task
  • Creates a new task for the specified patient (using patient_id from the posted JSON payload).
  • Sets the task to be due in 5 days from the current UTC time and sets its status to open.
  • Returns two responses:
    • The effect to add a task (which also triggers any related UI updates).
    • A JSON response with a success message and HTTP 202 (Accepted) status.

Miscellaneous

  • Imports various components and utilities from the Canvas SDK, such as effects for UI actions, response types, authentication mixins, and template rendering.
  • Uses the arrow library for time/date handling.

Summary

The code provides a Canvas plugin that opens a modal UI displaying custom content for a selected patient. It can also create a new patient-related task when a specific endpoint is called, handling user authentication and returning appropriate UI and API responses. The flow is tailored to staff users interacting with patient charts.

import arrow

from http import HTTPStatus

from canvas_sdk.effects import Effect
from canvas_sdk.effects.launch_modal import LaunchModalEffect
from canvas_sdk.effects.simple_api import Response, JSONResponse, HTMLResponse
from canvas_sdk.effects.task import AddTask, TaskStatus

from canvas_sdk.handlers.application import Application
from canvas_sdk.handlers.simple_api import StaffSessionAuthMixin, SimpleAPI, api

from canvas_sdk.templates import render_to_string

from canvas_sdk.v1.data.staff import Staff


class MyChartApplication(Application):
    def on_open(self) -> Effect:
        patient_id = self.context['patient']['id']
        return LaunchModalEffect(
            url=f"/plugin-io/api/example_chart_app/custom-ui?patient={patient_id}",
            target=LaunchModalEffect.TargetType.RIGHT_CHART_PANE,
        ).apply()


class MyApi(StaffSessionAuthMixin, SimpleAPI):
    @api.get("/custom-ui")
    def custom_ui(self) -> list[Response | Effect]:
        logged_in_staff = Staff.objects.get(id=self.request.headers["canvas-logged-in-user-id"])

        context = {
            "logged_in_staff": logged_in_staff,
            "patient_id": self.request.query_params["patient"],
        }
        return [
            HTMLResponse(
                render_to_string("templates/custom-ui.html", context),
                status_code=HTTPStatus.OK,
            )
        ]

    @api.post("/add-task")
    def add_task(self) -> list[Response | Effect]:
        add_task = AddTask(
            title="This came from the custom patient ui.",
            patient_id=self.request.json()["patient_id"],
            due=arrow.utcnow().shift(days=5).datetime,
            status=TaskStatus.OPEN,
        )
        return [
            add_task.apply(),
            JSONResponse(
                {"message": "Task will be created"},
                status_code=HTTPStatus.ACCEPTED
            )
        ]

assets/ #

rx.png #

This is an image file used as the Application icon within the Canvas UI.




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