RMT Reference: Security and Policies

Executable language rules live in tools/rmt-language/vnext-security.js.

Security and hydration policies live in lifecycle operation policy blocks.

Syntax

Operator	Form	Allowed contexts	Parameters	Function	Diagnostics	Related operators
`trust boundary`	`trust boundary "xtend.security.sanitizing-boundary.v1"`	Lifecycle policy, remote surface	static string	Binds rendering or remote surface to a trust boundary.	Boundary must be a string.	`sanitize`
`hydration policy`	`hydration policy visible-only`	Lifecycle policy	policy identifier	Documents the hydration strategy.	Hydration must use `policy`, `mode` or `insular`.	`hydrate`
`hydration mode`	`hydration mode eager`	Lifecycle policy	mode identifier	Sets the hydration mode.	Wrong clause kind is reported.	`hydration policy`
`hydration insular`	`hydration insular true`	Lifecycle policy	boolean or identifier	Marks isolated hydration.	Value must be boolean or identifier.	`isolation boundary`
`isolation boundary`	`isolation boundary "docs.preview"`	Lifecycle policy	string or identifier	Sets an isolation boundary.	Isolation must use `boundary` or `mode`.	`trust boundary`
`isolation mode`	`isolation mode strict`	Lifecycle policy	mode identifier	Sets isolation mode.	Wrong clause kind is reported.	`sanitize`
`sanitize`	`sanitize html`	Lifecycle policy	format identifier	Requires sanitizing for rendered content.	Format must be an identifier.	`trust boundary`

Allowed contexts

These operators appear in the policy block after mount, hydrate, update, stream or other lifecycle operations. trust boundary also appears in remote surface.

Parameters

Trust boundaries are stable string identifiers. Hydration, isolation and sanitize values are static identifiers or booleans.

Description

Policies describe security and hydration boundaries without executing host code in the RMT source.

Examples

template reference.security {
  portal app.root root "#app" layer surface

  surface preview kind page component x-section {
    portal app.root
    lane visible weight 80 {
      mount preview.body from endpoint docs.preview {
        trust boundary "xtend.security.sanitizing-boundary.v1"
        hydration policy visible-only
        hydration mode eager
        hydration insular true
        isolation boundary "docs.preview"
        isolation mode strict
        sanitize html
      }
    }
  }
}

Diagnostics

Policy blocks allow only slots, event bindings, hydration, isolation and security policies. Other tokens are context errors.

mount, hydrate, stream, remote surface, origin, integrity sha256.

The RMT reference index distinguishes language-level policy records from host security policy. Related article

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