HTTP Request

Last updated: 16 Apr 2026

The HttpRequest effect enables plugins to make HTTP requests to external services. Use on_success and on_failure to chain additional effects based on the response status.

Making an HTTP Request #

To make an HTTP request, import the HttpRequest class and create an instance with the request details.

Attribute		Type	Description
url	required	string	The URL to send the request to. Must be included in the plugin’s url_permissions.
method	optional	string	The HTTP method: GET, POST, PUT, PATCH, or DELETE. Defaults to GET.
headers	optional	dict	HTTP headers to include with the request.
body	optional	string	The request body. For JSON payloads, use json.dumps() to serialize.
on_success	optional	list[Effect]	Effects to execute when the response status is 2xx.
on_failure	optional	list[Effect]	Effects to execute when the response status is non-2xx or the request fails with an error.

import json

from canvas_sdk.effects.http_request import HttpRequest
from canvas_sdk.events import EventType
from canvas_sdk.handlers import BaseHandler


class MyHandler(BaseHandler):
    RESPONDS_TO = EventType.Name(EventType.CLAIM_CREATED)

    def compute(self):
        http_effect = HttpRequest(
            url="https://api.example.com/notify",
            method="POST",
            headers={
                "Authorization": "Bearer my-api-token",
                "Content-Type": "application/json",
            },
            body=json.dumps({"claim_id": self.target}),
        )

        return [http_effect.apply()]

URL Permissions #

The URL must be included in your plugin’s url_permissions in CANVAS_MANIFEST.json. If the URL is not permitted, the effect will fail.

{
  "sdk_version": "0.1.4",
  "plugin_version": "0.0.1",
  "name": "my_plugin",
  "description": "My plugin description",
  "url_permissions": [
    "https://api.example.com/*"
  ]
}

Effect Chaining #

Use on_success to chain effects that run when the response status is 2xx, and on_failure for effects that run when the response fails (non-2xx status or network error).

import json

from canvas_sdk.effects.http_request import HttpRequest
from canvas_sdk.effects.claim import AddClaimComment, MoveClaimToQueue
from canvas_sdk.events import EventType
from canvas_sdk.handlers import BaseHandler


class MyHandler(BaseHandler):
    RESPONDS_TO = EventType.Name(EventType.CLAIM_CREATED)

    def compute(self):
        claim_id = self.target

        http_effect = HttpRequest(
            url="https://api.example.com/submit-claim",
            method="POST",
            headers={"Authorization": "Bearer token"},
            body=json.dumps({"claim_id": claim_id}),
            on_success=[
                MoveClaimToQueue(claim_id=claim_id, queue="Filed").apply(),
            ],
            on_failure=[
                AddClaimComment(claim_id=claim_id, comment="External submission failed").apply(),
            ],
        )

        return [http_effect.apply()]

Chained Effects with Delays #

Chained effects preserve delay_seconds values, letting you schedule follow-up actions after a delay:

http_effect = HttpRequest(
    url="https://api.example.com/submit",
    method="POST",
    body=json.dumps({"data": "value"}),
    on_success=[
        # This effect will run 5 minutes after the HTTP request succeeds
        AddTask(
            title="Review submission result",
            patient_id=patient_id,
        ).apply(delay_seconds=300),
    ],
)

Supported HTTP Methods #

Method	Description
GET	Retrieve data from the server (default)
POST	Submit data to create a new resource
PUT	Replace an existing resource entirely
PATCH	Partially update an existing resource
DELETE	Remove a resource from the server