parlov-elicit 0.1.0

//! `RateLimitBurstElicitation` — collects burst samples to detect rate-limit differentials.
//!
//! Sends `burst_count` requests to the baseline URL then `burst_count` to the probe URL
//! with `ctx.headers` unmodified and no body. Differences in rate-limit response behavior
//! across a burst reveal whether the server applies per-resource or per-session rate limits,
//! leaking existence or authorization state through volume-sensitive header changes.

use http::Method;

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

/// Number of requests to send per side for rate-limit burst analysis.
const BURST_COUNT: usize = 100;

fn metadata() -> StrategyMetadata {
    StrategyMetadata {
        strategy_id: "rate-limit-burst-elicit",
        strategy_name: "Rate Limit Burst Elicitation",
        risk: RiskLevel::OperationDestructive,
    }
}

/// Elicits rate-limit state differentials by sending burst-volume requests to baseline and probe.
pub struct RateLimitBurstElicitation;

impl Strategy for RateLimitBurstElicitation {
    fn id(&self) -> &'static str {
        "rate-limit-burst-elicit"
    }

    fn name(&self) -> &'static str {
        "Rate Limit Burst Elicitation"
    }

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

    fn methods(&self) -> &[Method] {
        &[Method::GET, Method::HEAD]
    }

    fn is_applicable(&self, _ctx: &ScanContext) -> bool {
        true
    }

    fn generate(&self, ctx: &ScanContext) -> Vec<ProbeSpec> {
        let mut specs = Vec::with_capacity(2);
        for method in [Method::GET, Method::HEAD] {
            let pair = build_pair(
                ctx,
                method,
                ctx.headers.clone(),
                ctx.headers.clone(),
                None,
                metadata(),
            );
            specs.push(ProbeSpec::Burst(BurstSpec {
                baseline: pair.baseline,
                probe: pair.probe,
                burst_count: BURST_COUNT,
                metadata: pair.metadata,
            }));
        }
        specs
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::util::substitute_url;
    use http::{HeaderMap, Method};

    fn make_ctx() -> ScanContext {
        ScanContext {
            target: "https://api.example.com/users/{id}".to_string(),
            baseline_id: "1001".to_string(),
            probe_id: "9999".to_string(),
            headers: HeaderMap::new(),
            max_risk: RiskLevel::OperationDestructive,
            known_duplicate: None,
            state_field: None,
            alt_credential: None,
        }
    }

    #[test]
    fn risk_is_operation_destructive() {
        assert_eq!(
            RateLimitBurstElicitation.risk(),
            RiskLevel::OperationDestructive
        );
    }

    #[test]
    fn methods_contains_get_and_head() {
        let methods = RateLimitBurstElicitation.methods();
        assert_eq!(methods.len(), 2);
        assert!(methods.contains(&Method::GET));
        assert!(methods.contains(&Method::HEAD));
    }

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

    #[test]
    fn generate_returns_two_items() {
        assert_eq!(RateLimitBurstElicitation.generate(&make_ctx()).len(), 2);
    }

    #[test]
    fn all_items_are_burst_variants() {
        for spec in &RateLimitBurstElicitation.generate(&make_ctx()) {
            assert!(matches!(spec, ProbeSpec::Burst(_)));
        }
    }

    #[test]
    fn burst_count_is_100() {
        let specs = RateLimitBurstElicitation.generate(&make_ctx());
        for spec in &specs {
            let ProbeSpec::Burst(burst) = spec else { panic!("expected Burst") };
            assert_eq!(burst.burst_count, 100);
        }
    }

    #[test]
    fn baseline_url_uses_baseline_id() {
        let ctx = make_ctx();
        let specs = RateLimitBurstElicitation.generate(&ctx);
        let ProbeSpec::Burst(burst) = &specs[0] else { panic!("expected Burst") };
        assert_eq!(
            burst.baseline.url,
            substitute_url(&ctx.target, &ctx.baseline_id)
        );
    }

    #[test]
    fn probe_url_uses_probe_id() {
        let ctx = make_ctx();
        let specs = RateLimitBurstElicitation.generate(&ctx);
        let ProbeSpec::Burst(burst) = &specs[0] else { panic!("expected Burst") };
        assert_eq!(
            burst.probe.url,
            substitute_url(&ctx.target, &ctx.probe_id)
        );
    }
}