SIP-28: Background Events

SIPS/sip-28.md

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+---
+sip: 28
+title: Background Events
+status: Draft
+author: Olaf Tomalka (@ritave)
+created: 2024-10-09
+---
+
+## Abstract
+
+This SIP introduces a way to schedule non-recurring events in the future.
+
+## Motivation
+
+Scheduled recurring events are already supported in the Snaps platform via the Cronjobs feature. By introducing non-recurring events we will allow novel use-cases for Snap developers, such as allowing a snap that sets a reminder for ENS domain expiration date.
+
+## Specification
+
+> Indented sections like this are considered non-normative.
+
+### Language
+
+The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
+"OPTIONAL" written in uppercase in this document are to be interpreted as described in [RFC 2119](https://www.ietf.org/rfc/rfc2119.txt)
+
+### Snap Manifest
+
+This SIP doesn't introduce any new permissions, but rather extends `endowment:cronjob` with new capabilities through two new RPC methods.
+
+### RPC Methods
+
+#### `snap_scheduleBackgroundEvent`
+
+This method allows a Snap to schedule a one-off callback to `onCronjob` handler in the future with a JSON-RPC request object as a parameter.
+
+```typescript
+type ScheduleBackgroundEventParams = {
+  date: string;
+  request: JsonRpcRequest;
+};
+
+type ScheduleBackgroundEventResult = string;
+```
+
+The RPC method takes two parameters:
+
+- `date` - An [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) date and time and optional timezone offset.
+  - The time's precision SHALL be truncated on the extension side to minutes.
+  - If no timezone is provided, the time SHALL be understood to be local-time.
+    > Use ISO's `Z` identifier if you want to use UTC time.
+- `request` - A JSON object that will provided as-is to `onCronjob` handler as parameter.
+
+An example of usage is given below.
+
+```typescript
+snap.request({
+  method: "snap_scheduleBackgroundEvent",
+  params: {
+    date: "2024-10-09T09:59",
+    request: {
+      method: "foobar",
+      params: {
+        foo: "bar",
+      },
+    },
+  },
+});
+```
+
+The RPC method call returns a `string` that is a unique ID representing that specific background event, allowing it to be cancelled.
+
+#### `snap_cancelBackgroundEvent`
+
+This method allows to cancel an already scheduled background event using the unique ID returned from `snap_backgroundEventSchedule`
+
+```typescript
+type CancelBackgroundEventParams = { id: string };
+```
+
+This RPC method takes one argument:
+
+- `id` - The id that was returned during schedule.
+
+An example of usage is given below.
+
+```typescript
+snap.request({
+  method: "snap_cancelBackgroundEvent",
+  params: {
+    id: myReturnedId,
+  },
+});
+```
+
+### `onCronjob` handler
+
+This SIP doesn't modify `onCronjob` handler in any way.
+
+## Copyright
+
+Copyright and related rights waived via [CC0](../LICENSE).