1 files changed, 36 insertions, 2 deletions
diff --git a/src/handlers.rs b/src/handlers.rs
index 5d31600..7067f3a 100644
--- a/src/handlers.rs
+++ b/src/handlers.rs
@@ -21,6 +21,40 @@ pub async fn list_measurements(
     State(pool): State<PgPool>,
     AppQuery(query): AppQuery<ListQuery>,
 ) -> Result<Json<Vec<MeasurementView>>, AppError> {
+    Ok(Json(fetch_measurements(&pool, &query).await?))
+}
+
+pub async fn export_measurements(
+    State(pool): State<PgPool>,
+    AppQuery(query): AppQuery<ListQuery>,
+) -> Result<([(HeaderName, &'static str); 2], Vec<u8>), AppError> {
+    let rows = fetch_measurements(&pool, &query).await?;
+    let mut writer = csv::WriterBuilder::new()
+        .has_headers(false)
+        .from_writer(Vec::new());
+    writer.write_record(["id", "measured_at", "metric_type", "value", "unit"])?;
+    for row in &rows {
+        writer.serialize(row)?;
+    }
+    let csv = writer
+        .into_inner()
+        .map_err(|e| csv::Error::from(e.into_error()))?;
+    Ok((
+        [
+            (header::CONTENT_TYPE, "text/csv; charset=utf-8"),
+            (
+                header::CONTENT_DISPOSITION,
+                "attachment; filename=\"measurements.csv\"",
+            ),
+        ],
+        csv,
+    ))
+}
+
+async fn fetch_measurements(
+    pool: &PgPool,
+    query: &ListQuery,
+) -> Result<Vec<MeasurementView>, AppError> {
     let limit = match query.limit {
         Some(x) if (x > 0) => Some(x),
         None => None,
@@ -52,9 +86,9 @@ pub async fn list_measurements(
         matches!(query.order, Order::Desc),
         query.metric_type
     )
-    .fetch_all(&pool)
+    .fetch_all(pool)
     .await?;
-    Ok(Json(rows))
+    Ok(rows)
 }
 
 pub async fn create_measurement(