SDUI Protocol

The Server-Driven UI Architecture. How ObjectStack treats "Interface as Data" to deliver infinite customization.

ObjectUI is the View Layer specification. It is built on the principle of Server-Driven UI (SDUI).

In a traditional frontend, the layout is hardcoded in React/Vue components (<CustomerForm />). In ObjectStack, the frontend is a generic Renderer. It downloads a JSON layout definition from the server and paints it on the fly.

The UI Pipeline

1. The Layout Request

The client asks: "Give me the form for editing Invoice #1024".

GET /api/v4/ui/layouts/invoice/edit

2. The Resolution Engine

The server provides the layout, merging three layers of customization:

1. Base Protocol: The default fields defined in invoice.object.yml.
2. Admin Config: Custom sections and fields added via the Page Builder.
3. User Preference: Column widths and hidden fields personalized by the user.

3. The Layout JSON (The Response)

The server responds with a component tree description, not HTML.

{
  "type": "page",
  "layout": "two_column",
  "regions": {
    "main": [
      { "type": "field_group", "label": "Basics", "children": ["name", "date"] },
      { "type": "related_list", "object": "invoice_line", "label": "Line Items" }
    ],
    "sidebar": [
      { "type": "widget", "component": "approval_history" }
    ]
  }
}

4. The Renderer (The Client)

The generic PageRenderer component traverses this JSON and instantiates the mapped components (FieldGroup, RelatedList, Widget).

Why SDUI?

1. Instant Updates: Change a field label or move a section in the Schema, and every user (Web, Mobile, External Portal) sees it instantly without an app update.
2. Platform Native: The same JSON can be rendered as DOM nodes in React, native Views in SwiftUI/Kotlin, or command lines in a TUI.
3. Personalization: Because the layout is generated per-request, we can hide entire sections based on the user's role or the record's status (e.g., Hide "Approve" button if status is "Draft").