microsoft-webui-protocol 0.0.5

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT license.

syntax = "proto3";

package webui;

// Root protocol containing all fragment records.
// Per-component metadata keyed by tag name.
message ComponentData {
  // Client-side template string for hydration.
  // Populated by the active parser plugin at build time.
  // Used by servers to send templates to the client during navigation.
  string template = 1;
  // Component CSS content for the Module strategy.
  // Contains the full CSS content when CssStrategy::Module is active.
  // Empty for Link and Style strategies (CSS is handled via <link> tags
  // or inline <style> tags baked into raw fragments by the parser).
  string css = 2;
  // External stylesheet href for the Link CSS strategy.
  // Set to e.g. "/my-card.css" when CssStrategy::Link is active and the
  // component has a CSS file. Empty for Style/Module strategies and for
  // components without CSS. The handler emits a <link> tag only when
  // this field is non-empty.
  string css_href = 3;
}

message WebUIProtocol {
  map<string, FragmentList> fragments = 1;
  // Sorted, deduplicated CSS custom property names used across all components
  // and entry page styles (e.g., "colorBrandBackground", "spacingMedium").
  // Only usage via var(--name) is included; local definitions are excluded.
  repeated string tokens = 2;
  // Per-component data keyed by tag name (f-template + CSS).
  map<string, ComponentData> components = 3;
}

// A list of fragments (needed because protobuf maps cannot have repeated values directly).
message FragmentList {
  repeated WebUIFragment fragments = 1;
}

// A single fragment — one of several types.
message WebUIFragment {
  oneof fragment {
    WebUIFragmentRaw raw = 1;
    WebUIFragmentComponent component = 2;
    WebUIFragmentFor for_loop = 3;
    WebUIFragmentSignal signal = 4;
    WebUIFragmentIf if_cond = 5;
    WebUIFragmentAttribute attribute = 6;
    WebUIFragmentPlugin plugin = 7;
    WebUIFragmentRoute route = 8;
    WebUIFragmentOutlet outlet = 9;
  }
}

// Declarative route definition linking a URL path template to a component.
// Nested routes are expressed via repeated children.
message WebUIFragmentRoute {
  string path = 1;
  string fragment_id = 2;
  bool exact = 3;
  // Nested child routes rendered at the component's <outlet />.
  repeated WebUIFragmentRoute children = 4;
}

// Outlet placeholder — marks where matched child route content renders.
// Components use this to indicate where nested route children are rendered.
message WebUIFragmentOutlet {}

// Opaque plugin-specific data passed from parser plugin to handler plugin.
// WebUI framework does not interpret this data — it is a pass-through conduit.
// Each parser/handler plugin pair defines its own binary contract for the data field.
message WebUIFragmentPlugin {
  bytes data = 1;
}

// Static text or HTML content.
message WebUIFragmentRaw {
  string value = 1;
}

// Reference to a reusable component fragment.
message WebUIFragmentComponent {
  string fragment_id = 1;
}

// Loop directive iterating over a collection.
message WebUIFragmentFor {
  string item = 1;
  string collection = 2;
  string fragment_id = 3;
}

// Dynamic data binding via signal.
message WebUIFragmentSignal {
  string value = 1;
  bool raw = 2;
}

// Conditional rendering fragment.
message WebUIFragmentIf {
  ConditionExpr condition = 1;
  string fragment_id = 2;
}

// Dynamic attribute binding.
message WebUIFragmentAttribute {
  string name = 1;
  // For simple dynamic attrs, the signal name.
  string value = 2;
  // For mixed (template) attrs, the sub-stream ID.
  string template = 3;
  // True for :-prefixed complex attributes.
  bool complex = 4;
  // True for the first dynamic attribute on a component element.
  bool attr_start = 5;
  // True for skipped attributes (class, style, role, data-*, aria-*).
  bool attr_skip = 6;
  // True for static attribute values on components.
  bool raw_value = 7;
  // For ?-prefixed boolean attributes, the condition tree.
  ConditionExpr condition_tree = 8;
}

// A condition expression tree.
message ConditionExpr {
  oneof expr {
    Predicate predicate = 1;
    NotCondition not = 2;
    CompoundCondition compound = 3;
    IdentifierCondition identifier = 4;
  }
}

// Simple comparison predicate.
message Predicate {
  string left = 1;
  ComparisonOperator operator = 2;
  string right = 3;
}

// Negation wrapper.
message NotCondition {
  ConditionExpr condition = 1;
}

// Two conditions joined by a logical operator.
message CompoundCondition {
  ConditionExpr left = 1;
  LogicalOperator op = 2;
  ConditionExpr right = 3;
}

// Single identifier (variable name).
message IdentifierCondition {
  string value = 1;
}

enum LogicalOperator {
  LOGICAL_OPERATOR_UNSPECIFIED = 0;
  AND = 1;
  OR = 2;
}

enum ComparisonOperator {
  COMPARISON_OPERATOR_UNSPECIFIED = 0;
  GREATER_THAN = 1;
  LESS_THAN = 2;
  EQUAL = 3;
  NOT_EQUAL = 4;
  GREATER_THAN_OR_EQUAL = 5;
  LESS_THAN_OR_EQUAL = 6;
}