Effects

Last updated: 18 Jul 2024

What is an Effect?

Effects are sent from plugins back to Canvas in order to perform an action. Effects can be used to react to events that are received in plugins and then send Canvas instructions to ‘do something’.

Why should I use them?

Effects are useful because they can perform pre-determined actions in the Canvas EMR. This makes it possible to define workflows that, for example, create elements, show notifications or modify search results.

How do I use them?

Effects can be returned as a list from the compute method of a plugin that inherits from BaseProtocol. For example:

import json

from canvas_sdk.events import EventType
from canvas_sdk.effects import Effect, EffectType
from canvas_sdk.protocols import BaseProtocol

class Protocol(BaseProtocol):
    RESPONDS_TO = EventType.Name(EventType.MEDICATION_STATEMENT__MEDICATION__POST_SEARCH)

    def compute(self):
        results = self.context.get("results")

        post_processed_results = []
        ## custom results modifying code here
        ...

        return [
            Effect(
                type=EffectType.AUTOCOMPLETE_SEARCH_RESULTS,
                payload=json.dumps(post_processed_results),
            )
        ]

For more information on writing plugins, see the guide here.

Effect Types #

The following effects are available to be applied in Canvas.

Effect	Description
AUTOCOMPLETE_SEARCH_RESULTS	Can be used to modify search results by re-ordering or adding text annotations to individual result records. To see how you can put this to use, check out this guide.
ADD_BANNER_ALERT	Can be used to add a banner alert to a patient’s chart.
REMOVE_BANNER_ALERT	Can be used to remove a banner alert from a patient’s chart.
ORIGINATE_ASSESS_COMMAND	Can be used to originate an assess command in a note.
ORIGINATE_DIAGNOSE_COMMAND	Can be used to originate a diagnose command in a note.
ORIGINATE_GOAL_COMMAND	Can be used to originate a goal command in a note.
ORIGINATE_HPI_COMMAND	Can be used to originate a history of present illness command in a note.
ORIGINATE_MEDICATION_STATEMENT_COMMAND	Can be used to originate a medication statement command in a note.
ORIGINATE_PLAN_COMMAND	Can be used to originate a plan command in a note.
ORIGINATE_PRESCRIBE_COMMAND	Can be used to originate a prescribe command in a note.
ORIGINATE_QUESTIONNAIRE_COMMAND	Can be used to originate a questionnaire command in a note.
ORIGINATE_REASON_FOR_VISIT_COMMAND	Can be used to originate a reason for visit command in a note.
ORIGINATE_STOP_MEDICATION_COMMAND	Can be used to originate a stop medication command in a note.
ORIGINATE_UPDATE_GOAL_COMMAND	Can be used to originate an update goal command in a note.
CREATE_TASK	Cause a task you define in a plugin to be created. Use the Task class in the data module.
UPDATE_TASK	Cause a task to be updated. Use the Task class in the data module.
CREATE_TASK_COMMENT	Add a comment to an existing task. Use the Task class in the data module.