parlov-elicit 0.3.0

//! `EmgStateConflict` -- POST state conflict body differential.
//!
//! Sends a POST with the body template to both baseline and probe URLs.
//! Per RFC 9110 S15.5.10, 409 Conflict SHOULD include enough information
//! for the user to recognize the source of the conflict. When the server
//! returns different error bodies for existing (conflicting) vs nonexistent
//! resources, existence is revealed through body content.

use http::Method;
use parlov_core::{NormativeStrength, OracleClass, Technique, Vector};

use crate::context::ScanContext;
use crate::strategy::Strategy;
use crate::types::{ProbeSpec, RiskLevel, StrategyMetadata};
use crate::util::{build_pair, clone_headers_with};

fn metadata() -> StrategyMetadata {
    StrategyMetadata {
        strategy_id: "emg-state-conflict",
        strategy_name: "EMG: POST State Conflict",
        risk: RiskLevel::MethodDestructive,
    }
}

fn technique() -> Technique {
    Technique {
        id: "emg-state-conflict",
        name: "POST state conflict body differential",
        oracle_class: OracleClass::Existence,
        vector: Vector::ErrorMessageGranularity,
        strength: NormativeStrength::Should,
    }
}

/// Elicits existence differentials via POST state conflict body content differences.
pub struct EmgStateConflict;

impl Strategy for EmgStateConflict {
    fn id(&self) -> &'static str {
        "emg-state-conflict"
    }

    fn name(&self) -> &'static str {
        "EMG: POST State Conflict"
    }

    fn risk(&self) -> RiskLevel {
        RiskLevel::MethodDestructive
    }

    fn methods(&self) -> &[Method] {
        &[Method::POST]
    }

    fn is_applicable(&self, ctx: &ScanContext) -> bool {
        ctx.body_template.is_some()
    }

    fn generate(&self, ctx: &ScanContext) -> Vec<ProbeSpec> {
        let headers = clone_headers_with(&ctx.headers, "content-type", "application/json");
        let pair = build_pair(
            ctx,
            Method::POST,
            headers.clone(),
            headers,
            None,
            metadata(),
            technique(),
        );
        vec![ProbeSpec::Pair(pair)]
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use http::HeaderMap;

    fn make_ctx() -> ScanContext {
        ScanContext {
            target: "https://api.example.com/documents/{id}/comments".to_string(),
            baseline_id: "1001".to_string(),
            probe_id: "9999".to_string(),
            headers: HeaderMap::new(),
            max_risk: RiskLevel::MethodDestructive,
            known_duplicate: None,
            state_field: None,
            alt_credential: None,
            body_template: Some(r#"{"text":"test comment"}"#.to_string()),
        }
    }

    fn make_ctx_no_body() -> ScanContext {
        ScanContext {
            body_template: None,
            ..make_ctx()
        }
    }

    #[test]
    fn generates_correct_technique_vector() {
        let specs = EmgStateConflict.generate(&make_ctx());
        assert_eq!(specs[0].technique().vector, Vector::ErrorMessageGranularity);
    }

    #[test]
    fn generates_correct_technique_strength() {
        let specs = EmgStateConflict.generate(&make_ctx());
        assert_eq!(specs[0].technique().strength, NormativeStrength::Should);
    }

    #[test]
    fn is_applicable_with_body_template() {
        assert!(EmgStateConflict.is_applicable(&make_ctx()));
    }

    #[test]
    fn not_applicable_without_body_template() {
        assert!(!EmgStateConflict.is_applicable(&make_ctx_no_body()));
    }

    #[test]
    fn risk_is_method_destructive() {
        assert_eq!(EmgStateConflict.risk(), RiskLevel::MethodDestructive);
    }

    #[test]
    fn generates_post_method() {
        let specs = EmgStateConflict.generate(&make_ctx());
        let ProbeSpec::Pair(pair) = &specs[0] else {
            panic!("expected Pair variant")
        };
        assert_eq!(pair.baseline.method, Method::POST);
        assert_eq!(pair.probe.method, Method::POST);
    }
}