less json overhead

backend/src/routes/routing.rs

@@ -83,7 +83,7 @@ pub async fn route(
     }
 
     // Call OSRM
-    let json = osrm
+    let (body, osrm_code) = osrm
         .route(
             &profile,
             &coordinates,
@@ -95,7 +95,7 @@ pub async fn route(
         .await?;
 
     // Check OSRM response code
-    if let Some(code) = json.get("code").and_then(|c| c.as_str()) {
+    if let Some(code) = osrm_code.as_deref() {
         match map_osrm_code(code) {
             OsrmCodeMapping::Ok => {} // Success, continue
             OsrmCodeMapping::NoRoute => {
@@ -119,9 +119,6 @@ pub async fn route(
         }
     }
 
-    let body = serde_json::to_string(&json)
-        .map_err(|e| AppError::InternalError(format!("JSON serialization failed: {e}")))?;
-
     // Cache for 30 minutes
     cache.set_json(&cache_key, &body, 1800).await;
 

backend/src/routes/search.rs

@@ -88,13 +88,10 @@ pub async fn search(
     }
 
     // Call Photon
-    let json = photon
+    let body = photon
         .search(&q_clean, query.lat, query.lon, limit, lang, query.bbox.as_deref())
         .await?;
 
-    let body = serde_json::to_string(&json)
-        .map_err(|e| AppError::InternalError(format!("JSON serialization failed: {e}")))?;
-
     // Cache the result
     cache.set_json(&cache_key, &body, 3600).await;
 
@@ -165,9 +162,7 @@ pub async fn reverse(
             .body(cached));
     }
 
-    let json = photon.reverse(lat, lon, limit, lang).await?;
-    let body = serde_json::to_string(&json)
-        .map_err(|e| AppError::InternalError(format!("JSON serialization failed: {e}")))?;
+    let body = photon.reverse(lat, lon, limit, lang).await?;
 
     cache.set_json(&cache_key, &body, 3600).await;
 

backend/src/services/osrm.rs

@@ -32,7 +32,7 @@ impl OsrmService {
     }
 
     /// Request a route from the appropriate OSRM instance.
-    /// Returns raw JSON from OSRM.
+    /// Returns the raw JSON body and the OSRM `code` field for error mapping.
     pub async fn route(
         &self,
         profile: &str,
@@ -41,7 +41,7 @@ impl OsrmService {
         steps: bool,
         geometries: &str,
         overview: &str,
-    ) -> Result<serde_json::Value, AppError> {
+    ) -> Result<(String, Option<String>), AppError> {
         let base = self.base_url_for_profile(profile).ok_or_else(|| {
             AppError::InvalidParameter(format!("Invalid profile: {profile}"))
         })?;
@@ -64,12 +64,17 @@ impl OsrmService {
             )));
         }
 
-        let json: serde_json::Value = resp.json().await.map_err(|e| {
-            tracing::error!(error = %e, "Failed to parse OSRM response");
-            AppError::UpstreamError("Failed to parse routing response".into())
+        let body = resp.text().await.map_err(|e| {
+            tracing::error!(error = %e, "Failed to read OSRM response");
+            AppError::UpstreamError("Failed to read routing response".into())
         })?;
 
-        Ok(json)
+        // Extract only the `code` field to avoid a full parse.
+        #[derive(serde::Deserialize)]
+        struct OsrmCode { code: Option<String> }
+        let code = serde_json::from_str::<OsrmCode>(&body).ok().and_then(|r| r.code);
+
+        Ok((body, code))
     }
 
     /// Health probe for a specific OSRM profile.

backend/src/services/photon.rs

@@ -18,7 +18,7 @@ impl PhotonService {
         }
     }
 
-    /// Forward geocoding search. Returns raw JSON from Photon.
+    /// Forward geocoding search. Returns the raw JSON body from Photon.
     pub async fn search(
         &self,
         q: &str,
@@ -27,7 +27,7 @@ impl PhotonService {
         limit: u32,
         lang: &str,
         bbox: Option<&str>,
-    ) -> Result<serde_json::Value, AppError> {
+    ) -> Result<String, AppError> {
         let mut url = format!("{}/api?q={}&limit={}&lang={}", self.base_url, urlencod(q), limit, lang);
 
         if let (Some(lat), Some(lon)) = (lat, lon) {
@@ -50,22 +50,20 @@ impl PhotonService {
             )));
         }
 
-        let json: serde_json::Value = resp.json().await.map_err(|e| {
-            tracing::error!(error = %e, "Failed to parse Photon response");
-            AppError::UpstreamError("Failed to parse search response".into())
-        })?;
-
-        Ok(json)
+        resp.text().await.map_err(|e| {
+            tracing::error!(error = %e, "Failed to read Photon response");
+            AppError::UpstreamError("Failed to read search response".into())
+        })
     }
 
-    /// Reverse geocoding. Returns raw JSON from Photon.
+    /// Reverse geocoding. Returns the raw JSON body from Photon.
     pub async fn reverse(
         &self,
         lat: f64,
         lon: f64,
         limit: u32,
         lang: &str,
-    ) -> Result<serde_json::Value, AppError> {
+    ) -> Result<String, AppError> {
         let url = format!(
             "{}/reverse?lat={lat}&lon={lon}&limit={limit}&lang={lang}",
             self.base_url
@@ -83,12 +81,10 @@ impl PhotonService {
             )));
         }
 
-        let json: serde_json::Value = resp.json().await.map_err(|e| {
-            tracing::error!(error = %e, "Failed to parse Photon reverse response");
-            AppError::UpstreamError("Failed to parse reverse geocoding response".into())
-        })?;
-
-        Ok(json)
+        resp.text().await.map_err(|e| {
+            tracing::error!(error = %e, "Failed to read Photon reverse response");
+            AppError::UpstreamError("Failed to read reverse geocoding response".into())
+        })
     }
 
     /// Health probe.