Develop Logic Skill

1. The Architecture: Actions & Binding

In Simple Platform, logic is decoupled from execution triggers.

• •Logic (The Code): A pure function (WASM).
• •Trigger (The Event): A signal (DB change, Schedule, Webhook).
• •Binding (The Link): Connecting a Logic to a Trigger.

This allows one piece of Logic to be triggered by multiple events (e.g., "Send Email" triggered by "Signup" OR "Nightly Job").

[!CAUTION] Signature Mismatch Risk

• •Server Actions (simple.Handle) are NOT Record Behaviors.
• •Record Behaviors (export default ({$form})) are NOT Server Actions.
• •NEVER mix these signatures. See rules/logic-standards.md.

[!IMPORTANT] No Seeding in Code Do not use logic to create seed data. Use SCL instance blocks. See skills/data-seeding/SKILL.md.

2. Server Actions (The Code)

File: apps/<app>/actions/<name>/index.ts Command: simple new action <app> <name> --scope myorg --env server

import simple from '@simpleplatform/sdk'
simple.Handle(async (req) => {
  const { id } = req.parse<{ id: string }>()
  // ... implementation ...
})

3. The Registration Pattern (SCL)

You must register the components in apps/<app>/records/.

Step A: Define Logic (20_logic.scl)

set dev_simple_system.logic, action_process_order {
  name "process-order"
  display_name "Process Order"
  execution_environment server
  language go # or ts
}

Step B: Define Trigger (20_triggers.scl)

1. Database Event

• •operations: ["insert", "update", "delete"]
• •condition: jq expression (e.g., .record.status == "Active").
  • •Context: .record (new), .changes (diff), .operation.

2. Schedule (Cron)

• •time_schedule options:
  • •frequency: minutely|hourly|daily|weekly
  • •timezone: IANA string (e.g. America/New_York)
  • •weekdays: true

3. Webhook

• •method: post (default), get, put, delete
• •is_public: false (requires auth) or true (open)

Step C: Bind Them (30_links.scl)

This is the critical step that activates the logic.

set dev_simple_system.logic_trigger, bind_process_order {
  is_active true
  
  # Connect the dots
  logic_id `$var('meta') |> $jq('.logics[] | select(.name == "process-order") | .id')`
  trigger_id `$var('meta') |> $jq('.triggers[] | select(.name == "on-order-created") | .id')`
}

4. Client Record Behaviors

File: apps/<app>/scripts/record-behaviors/<table>.js

Events

• •load: Set defaults (Client+Server).
• •update: React to changes (Client only).
• •submit: Validate (Client+Server).

$form API

// Properties
$form.event              // 'load', 'update', 'submit'
$form.record()           // Get all values

// Field Methods
$form('status').value()        // Get
$form('status').set('Active')  // Set
$form('total').editable(false) // Read-only
$form('notes').visible(false)  // Hide
$form('email').required(true)  // Mandate
$form('age').error('Too young') // Block save

$db API (Read-Only)

const { product } = await $db.query(
  `query($id: ID!) { ... }`, 
  { id: 123 }
)