Add geo information to prebid openrtb requests (#101)

Author: ChristianPavilonis

crates/common/src/geo.rs

@@ -11,6 +11,76 @@ use crate::constants::{
     HEADER_X_GEO_INFO_AVAILABLE, HEADER_X_GEO_METRO_CODE,
 };
 
+/// Geographic information extracted from a request.
+///
+/// Contains all available geographic data from Fastly's geolocation service,
+/// including city, country, continent, coordinates, and DMA/metro code.
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct GeoInfo {
+    /// City name
+    pub city: String,
+    /// Two-letter country code (e.g., "US", "GB")
+    pub country: String,
+    /// Continent name
+    pub continent: String,
+    /// Latitude coordinate
+    pub latitude: f64,
+    /// Longitude coordinate
+    pub longitude: f64,
+    /// DMA (Designated Market Area) / metro code
+    pub metro_code: i64,
+    /// Region code
+    pub region: Option<String>,
+}
+
+impl GeoInfo {
+    /// Creates a new `GeoInfo` from a request by performing a geo lookup.
+    ///
+    /// This constructor performs a geo lookup based on the client's IP address and returns
+    /// all available geographic data in a structured format. It does not modify the request
+    /// or set headers.
+    ///
+    /// # Arguments
+    ///
+    /// * `req` - The request to extract geographic information from
+    ///
+    /// # Returns
+    ///
+    /// `Some(GeoInfo)` if geo data is available, `None` otherwise
+    ///
+    /// # Example
+    ///
+    /// ```ignore
+    /// if let Some(geo_info) = GeoInfo::from_request(&req) {
+    ///     println!("User is in {} ({})", geo_info.city, geo_info.country);
+    ///     println!("Coordinates: {}", geo_info.coordinates_string());
+    /// }
+    /// ```
+    pub fn from_request(req: &Request) -> Option<Self> {
+        req.get_client_ip_addr()
+            .and_then(geo_lookup)
+            .map(|geo| GeoInfo {
+                city: geo.city().to_string(),
+                country: geo.country_code().to_string(),
+                continent: format!("{:?}", geo.continent()),
+                latitude: geo.latitude(),
+                longitude: geo.longitude(),
+                metro_code: geo.metro_code(),
+                region: geo.region().map(str::to_string),
+            })
+    }
+
+    /// Returns coordinates as a formatted string "latitude,longitude"
+    pub fn coordinates_string(&self) -> String {
+        format!("{},{}", self.latitude, self.longitude)
+    }
+
+    /// Checks if a valid metro code is available (non-zero)
+    pub fn has_metro_code(&self) -> bool {
+        self.metro_code > 0
+    }
+}
+
 /// Extracts the DMA (Designated Market Area) code from the request's geolocation data.
 ///
 /// This function:

crates/common/src/prebid_proxy.rs

@@ -12,6 +12,7 @@ use serde_json::{json, Value};
 use crate::backend::ensure_backend_from_url;
 use crate::constants::{HEADER_SYNTHETIC_FRESH, HEADER_SYNTHETIC_TRUSTED_SERVER};
 use crate::error::TrustedServerError;
+use crate::geo::GeoInfo;
 use crate::settings::Settings;
 use crate::synthetic::{generate_synthetic_id, get_or_generate_synthetic_id};
 
@@ -162,9 +163,19 @@ fn enhance_openrtb_request(
     }
 
     // Add geo information if available
-    // Note: get_dma_code requires a mutable reference, but we only have immutable
-    // For now, we'll skip DMA code in the enhancement
-    // TODO: Refactor get_dma_code to accept immutable reference
+    if let Some(geo_info) = GeoInfo::from_request(req) {
+        let geo_obj = json!({
+            "type": 2, // 2 = IP address location
+            "country": geo_info.country, // Note: OpenRTB expects ISO 3166-1 alpha-3, but Fastly provides alpha-2
+            "city": geo_info.city,
+            "region": geo_info.region,
+        });
+
+        if !request["device"].is_object() {
+            request["device"] = json!({});
+        }
+        request["device"]["geo"] = geo_obj.clone();
+    }
 
     // Add site information if missing
     if !request["site"].is_object() {