Build Advanced Automations with Home APIs on Android

Understanding Home API Automations

• 💡 Automations are defined as a set of "if this, then that" statements to control device states based on selected factors.
• 🧩 They are composed of three node types: starters (initial conditions to activate), conditions (constraints to evaluate after triggering), and actions (commands or state updates to perform).
• ⚙️ Nodes can be evaluated in sequential (starter, condition, action) or parallel (multiple actions simultaneously) flows.
• 📝 Developers use a domain-specific language (DSL) to provide these nodes to the automation engine.

Creating an Automation Editor

• 🛠️ An automation editor empowers users to configure devices, commands, and parameters themselves.
• 🔌 Starters are configured by selecting a device, trait, operation, and value, with the app handling preset operations and trait mappings.
• 💡 Actions are defined similarly, specifying device, trait, command, and any necessary parameter values (e.g., brightness level).
• 📝 Automation drafts are prepared in a DraftViewModel, structuring the automation graph using starter and action variables.

Automation Creation and Validation

• 🚀 The Automation APIs are used to create, delete, and query smart home automations.
• ✅ Automations are validated upon creation; an is_valid field indicates success, with validation_issues providing details for invalid automations.
• ⚡ Automations can be executed via a starter event or a manual execution API call.

Leveraging the Discovery API

• 🔍 The Discovery API allows querying devices to identify supported attributes and commands.
• 🧩 Discovered candidates (commands, events, trait attributes) can be used to create automation nodes.
• 📱 The app can present discovered actions to the user, pre-populating action nodes in the automation draft based on their selection.

Advanced Automation Examples

• ⏰ Beyond device traits, time-based starters can be used to schedule automations.
• 📢 The Assistant Broadcast trait can be used as an action to announce messages.
• ⏳ Advanced operators like delayFor (delays commands) and suppressFor (prevents repeated triggering) enhance automation logic.
• 📍 AreaPresenceState can detect if someone is home, enabling automations like locking doors after a certain time.