trust-tasks-rs 0.1.0

//! Ties a Rust struct to the *Trust Task specification* it represents.
//!
//! [`Payload`] is the integration seam between the framework crate and per-
//! spec types (whether generated by `trust-tasks-codegen` or hand-written).
//! Once a type implements [`Payload`], callers can build documents without
//! restating the Type URI:
//!
//! ```rust,ignore
//! use trust_tasks_rs::{Payload, TrustTask};
//!
//! let req = TrustTask::for_payload("req-1", AclGrant { ... });
//! assert_eq!(req.type_uri, AclGrant::type_uri());
//! ```
//!
//! The generated code emits one impl per request payload and, where the
//! specification defines a success response, a second impl on the response
//! type with the `#response` fragment in [`Payload::TYPE_URI`].

use serde::de::DeserializeOwned;
use serde::Serialize;

use crate::type_uri::TypeUri;

/// A Rust type that corresponds to one variant (request or response) of a
/// versioned *Trust Task specification*.
///
/// The generated code emits one impl per (slug, version, variant). Hand-
/// written impls are equally valid; the only requirement is that
/// [`TYPE_URI`](Self::TYPE_URI) parses as a [`TypeUri`].
pub trait Payload: Serialize + DeserializeOwned {
    /// The canonical Type URI this payload targets, including the `#response`
    /// fragment for success-response payloads (SPEC.md §4.4.1).
    const TYPE_URI: &'static str;

    /// Whether the originating *Trust Task specification* is a *bearer
    /// specification* per SPEC.md §4.8.3 — that is, opts out of the §4.8.2
    /// audience-binding rule.
    ///
    /// Defaults to `false` (non-bearer). The codegen emits an explicit
    /// `const IS_BEARER: bool = true;` override only when the spec's front
    /// matter declares `bearer: true`.
    ///
    /// Consumers consult this constant via
    /// [`crate::TrustTask::enforce_audience_binding`] to apply SPEC.md §7.2
    /// item 8 without consulting the registry at runtime.
    const IS_BEARER: bool = false;

    /// Parsed form of [`TYPE_URI`](Self::TYPE_URI).
    ///
    /// The default implementation calls [`str::parse`] and panics on a
    /// malformed value — which can only happen if a `Payload` impl supplies
    /// an invalid `TYPE_URI`, i.e. a static-string bug worth surfacing
    /// loudly.
    fn type_uri() -> TypeUri {
        Self::TYPE_URI
            .parse()
            .expect("TYPE_URI constant must be a valid Type URI")
    }
}