add `/<uuid> route + backend handling

src/model/client.rs

@@ -0,0 +1,29 @@
+use crate::Backend;
+use serde::{Deserialize, Serialize};
+use sqlx::FromRow;
+use uuid::Uuid;
+
+#[derive(FromRow, Debug, Serialize, Deserialize)]
+pub struct Client {
+    pub uuid: String,
+    pub name: Option<String>,
+}
+
+impl Backend {
+    pub(crate) async fn get_client(&self, uuid: &Uuid) -> Client {
+        let uuid = uuid.to_string();
+
+        match self {
+            Backend::Sqlite(db) => {
+                sqlx::query!("INSERT OR IGNORE INTO client (uuid) VALUES (?);", uuid)
+                    .execute(db)
+                    .await
+                    .unwrap();
+                sqlx::query_as!(Client, "SELECT uuid, name FROM client WHERE uuid = ?", uuid)
+                    .fetch_one(db)
+                    .await
+                    .expect("we assured that uuid exists in previous query")
+            }
+        }
+    }
+}