send permutive segments to adserver

crates/common/src/auction/context.rs

@@ -0,0 +1,249 @@
+//! Context query-parameter forwarding for auction providers.
+//!
+//! Provides a config-driven mechanism for ad-server / mediator providers to
+//! forward integration-supplied data (e.g. audience segments) as URL query
+//! parameters without hard-coding integration-specific knowledge.
+
+use serde::{Deserialize, Serialize};
+use std::collections::{BTreeMap, HashMap};
+
+/// A strongly-typed context value forwarded from the JS client payload.
+///
+/// Replaces raw `serde_json::Value` so that consumers get compile-time
+/// exhaustiveness checks. The `#[serde(untagged)]` attribute preserves
+/// wire-format compatibility — the JS client sends plain JSON arrays, strings,
+/// or numbers which serde maps to the matching variant in declaration order.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(untagged)]
+pub enum ContextValue {
+    /// A list of string values (e.g. audience segment IDs).
+    StringList(Vec<String>),
+    /// A single string value.
+    Text(String),
+    /// A numeric value.
+    Number(f64),
+}
+
+/// Mapping from auction-request context keys to query-parameter names.
+///
+/// Used by ad-server / mediator providers to forward integration-supplied data
+/// (e.g. audience segments) as URL query parameters without hard-coding
+/// integration-specific knowledge.
+///
+/// ```toml
+/// [integrations.adserver_mock.context_query_params]
+/// permutive_segments = "permutive"
+/// lockr_ids          = "lockr"
+/// ```
+pub type ContextQueryParams = BTreeMap<String, String>;
+
+/// Build a URL by appending context values as query parameters according to the
+/// provided mapping.
+///
+/// For each entry in `mapping`, if the corresponding key exists in `context`:
+/// - **Arrays** are serialised as a comma-separated string.
+/// - **Strings / numbers** are serialised as-is.
+/// - Other JSON types are skipped.
+///
+/// The [`url::Url`] crate is used for construction so all values are
+/// percent-encoded, preventing query-parameter injection.
+///
+/// Returns the original `base_url` unchanged when no parameters are appended.
+#[must_use]
+pub fn build_url_with_context_params(
+    base_url: &str,
+    context: &HashMap<String, ContextValue>,
+    mapping: &ContextQueryParams,
+) -> String {
+    let Ok(mut url) = url::Url::parse(base_url) else {
+        log::warn!("build_url_with_context_params: failed to parse base URL, returning as-is");
+        return base_url.to_string();
+    };
+
+    let mut appended = 0usize;
+
+    for (context_key, param_name) in mapping {
+        if let Some(value) = context.get(context_key) {
+            let serialized = serialize_context_value(value);
+            if !serialized.is_empty() {
+                url.query_pairs_mut().append_pair(param_name, &serialized);
+                appended += 1;
+            }
+        }
+    }
+
+    if appended > 0 {
+        log::info!(
+            "build_url_with_context_params: appended {} context query params",
+            appended
+        );
+    }
+
+    url.to_string()
+}
+
+/// Serialise a single [`ContextValue`] into a string suitable for a query
+/// parameter value.  String lists are joined with commas; strings and numbers
+/// are returned directly.
+fn serialize_context_value(value: &ContextValue) -> String {
+    match value {
+        ContextValue::StringList(items) => items.join(","),
+        ContextValue::Text(s) => s.clone(),
+        ContextValue::Number(n) => n.to_string(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_build_url_with_context_params_appends_array() {
+        let context = HashMap::from([(
+            "permutive_segments".to_string(),
+            ContextValue::StringList(vec!["10000001".into(), "10000003".into(), "adv".into()]),
+        )]);
+        let mapping = BTreeMap::from([("permutive_segments".to_string(), "permutive".to_string())]);
+
+        let url = build_url_with_context_params(
+            "http://localhost:6767/adserver/mediate",
+            &context,
+            &mapping,
+        );
+        assert_eq!(
+            url,
+            "http://localhost:6767/adserver/mediate?permutive=10000001%2C10000003%2Cadv"
+        );
+    }
+
+    #[test]
+    fn test_build_url_with_context_params_preserves_existing_query() {
+        let context = HashMap::from([(
+            "permutive_segments".to_string(),
+            ContextValue::StringList(vec!["123".into(), "adv".into()]),
+        )]);
+        let mapping = BTreeMap::from([("permutive_segments".to_string(), "permutive".to_string())]);
+
+        let url = build_url_with_context_params(
+            "http://localhost:6767/adserver/mediate?debug=true",
+            &context,
+            &mapping,
+        );
+        assert_eq!(
+            url,
+            "http://localhost:6767/adserver/mediate?debug=true&permutive=123%2Cadv"
+        );
+    }
+
+    #[test]
+    fn test_build_url_with_context_params_no_matching_keys() {
+        let context = HashMap::new();
+        let mapping = BTreeMap::from([("permutive_segments".to_string(), "permutive".to_string())]);
+
+        let url = build_url_with_context_params(
+            "http://localhost:6767/adserver/mediate",
+            &context,
+            &mapping,
+        );
+        assert_eq!(url, "http://localhost:6767/adserver/mediate");
+    }
+
+    #[test]
+    fn test_build_url_with_context_params_empty_array_skipped() {
+        let context = HashMap::from([(
+            "permutive_segments".to_string(),
+            ContextValue::StringList(vec![]),
+        )]);
+        let mapping = BTreeMap::from([("permutive_segments".to_string(), "permutive".to_string())]);
+
+        let url = build_url_with_context_params(
+            "http://localhost:6767/adserver/mediate",
+            &context,
+            &mapping,
+        );
+        assert!(!url.contains("permutive="));
+    }
+
+    #[test]
+    fn test_build_url_with_context_params_multiple_mappings() {
+        let context = HashMap::from([
+            (
+                "permutive_segments".to_string(),
+                ContextValue::StringList(vec!["seg1".into()]),
+            ),
+            (
+                "lockr_ids".to_string(),
+                ContextValue::Text("lockr-abc-123".into()),
+            ),
+        ]);
+        let mapping = BTreeMap::from([
+            ("lockr_ids".to_string(), "lockr".to_string()),
+            ("permutive_segments".to_string(), "permutive".to_string()),
+        ]);
+
+        let url = build_url_with_context_params(
+            "http://localhost:6767/adserver/mediate",
+            &context,
+            &mapping,
+        );
+        assert!(url.contains("permutive=seg1"));
+        assert!(url.contains("lockr=lockr-abc-123"));
+    }
+
+    #[test]
+    fn test_build_url_with_context_params_scalar_number() {
+        let context = HashMap::from([("count".to_string(), ContextValue::Number(42.0))]);
+        let mapping = BTreeMap::from([("count".to_string(), "n".to_string())]);
+
+        let url = build_url_with_context_params(
+            "http://localhost:6767/adserver/mediate",
+            &context,
+            &mapping,
+        );
+        assert_eq!(url, "http://localhost:6767/adserver/mediate?n=42");
+    }
+
+    #[test]
+    fn test_serialize_context_value_string_list() {
+        assert_eq!(
+            serialize_context_value(&ContextValue::StringList(vec![
+                "a".into(),
+                "b".into(),
+                "3".into()
+            ])),
+            "a,b,3"
+        );
+    }
+
+    #[test]
+    fn test_serialize_context_value_text() {
+        assert_eq!(
+            serialize_context_value(&ContextValue::Text("hello".into())),
+            "hello"
+        );
+    }
+
+    #[test]
+    fn test_serialize_context_value_number() {
+        assert_eq!(serialize_context_value(&ContextValue::Number(99.0)), "99");
+    }
+
+    #[test]
+    fn test_context_value_deserialize_array() {
+        let v: ContextValue =
+            serde_json::from_str(r#"["a","b"]"#).expect("should deserialize string list");
+        assert_eq!(v, ContextValue::StringList(vec!["a".into(), "b".into()]));
+    }
+
+    #[test]
+    fn test_context_value_deserialize_string() {
+        let v: ContextValue = serde_json::from_str(r#""hello""#).expect("should deserialize text");
+        assert_eq!(v, ContextValue::Text("hello".into()));
+    }
+
+    #[test]
+    fn test_context_value_deserialize_number() {
+        let v: ContextValue = serde_json::from_str("42").expect("should deserialize number");
+        assert_eq!(v, ContextValue::Number(42.0));
+    }
+}

crates/common/src/auction/formats.rs

@@ -12,6 +12,7 @@ use serde_json::Value as JsonValue;
 use std::collections::HashMap;
 use uuid::Uuid;
 
+use crate::auction::context::ContextValue;
 use crate::creative;
 use crate::error::TrustedServerError;
 use crate::geo::GeoInfo;
@@ -30,7 +31,6 @@ use super::types::{
 #[serde(rename_all = "camelCase")]
 pub struct AdRequest {
     pub ad_units: Vec<AdUnit>,
-    #[allow(dead_code)]
     pub config: Option<JsonValue>,
 }
 
@@ -135,6 +135,40 @@ pub fn convert_tsjs_to_auction_request(
         geo: GeoInfo::from_request(req),
     });
 
+    // Forward allowed config entries from the JS request into the context map.
+    // Only keys listed in `auction.allowed_context_keys` are accepted;
+    // unrecognised keys are silently dropped to prevent injection of
+    // arbitrary data by a malicious client payload.
+    let mut context = HashMap::new();
+    if let Some(ref config) = body.config {
+        if let Some(obj) = config.as_object() {
+            for (key, value) in obj {
+                if settings.auction.allowed_context_keys.contains(key) {
+                    match serde_json::from_value::<ContextValue>(value.clone()) {
+                        Ok(cv) => {
+                            context.insert(key.clone(), cv);
+                        }
+                        Err(_) => {
+                            log::debug!(
+                                "Auction context: dropping key '{}' with unsupported type",
+                                key
+                            );
+                        }
+                    }
+                } else {
+                    log::debug!("Auction context: dropping disallowed key '{}'", key);
+                }
+            }
+            if !context.is_empty() {
+                log::debug!(
+                    "Auction request context: {} entries ({})",
+                    context.len(),
+                    context.keys().cloned().collect::<Vec<_>>().join(", ")
+                );
+            }
+        }
+    }
+
     Ok(AuctionRequest {
         id: Uuid::new_v4().to_string(),
         slots,
@@ -152,7 +186,7 @@ pub fn convert_tsjs_to_auction_request(
             domain: settings.publisher.domain.clone(),
             page: format!("https://{}", settings.publisher.domain),
         }),
-        context: HashMap::new(),
+        context,
     })
 }
 

crates/common/src/auction/mod.rs

@@ -11,13 +11,15 @@ use crate::settings::Settings;
 use std::sync::Arc;
 
 pub mod config;
+pub mod context;
 pub mod endpoints;
 pub mod formats;
 pub mod orchestrator;
 pub mod provider;
 pub mod types;
 
 pub use config::AuctionConfig;
+pub use context::{build_url_with_context_params, ContextQueryParams, ContextValue};
 pub use orchestrator::AuctionOrchestrator;
 pub use provider::AuctionProvider;
 pub use types::{

crates/common/src/auction/orchestrator.rs

@@ -509,7 +509,7 @@ mod tests {
     };
     use crate::test_support::tests::crate_test_settings_str;
     use fastly::Request;
-    use std::collections::HashMap;
+    use std::collections::{HashMap, HashSet};
 
     use super::AuctionOrchestrator;
 
@@ -645,6 +645,7 @@ mod tests {
             mediator: None,
             timeout_ms: 2000,
             creative_store: "creative_store".to_string(),
+            allowed_context_keys: HashSet::from(["permutive_segments".to_string()]),
         };
 
         let orchestrator = AuctionOrchestrator::new(config);

crates/common/src/auction/types.rs

@@ -4,6 +4,7 @@ use fastly::Request;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 
+use crate::auction::context::ContextValue;
 use crate::geo::GeoInfo;
 use crate::settings::Settings;
 
@@ -22,8 +23,8 @@ pub struct AuctionRequest {
     pub device: Option<DeviceInfo>,
     /// Site information
     pub site: Option<SiteInfo>,
-    /// Additional context
-    pub context: HashMap<String, serde_json::Value>,
+    /// Additional context forwarded from the JS client payload.
+    pub context: HashMap<String, ContextValue>,
 }
 
 /// Represents a single ad slot/impression.