Add a client implementation.

bkapi-client/src/lib.rs

@@ -111,6 +111,77 @@ impl InjectContext for reqwest::RequestBuilder {
     }
 }
 
+/// The BKApi client, operating over NATS instead of HTTP.
+#[derive(Clone)]
+pub struct BKApiNatsClient {
+    client: async_nats::Client,
+}
+
+/// A hash and distance.
+#[derive(serde::Serialize, serde::Deserialize)]
+pub struct HashDistance {
+    hash: i64,
+    distance: u32,
+}
+
+impl BKApiNatsClient {
+    const NATS_SUBJECT: &str = "bkapi.search";
+
+    /// Create a new client with a given NATS client.
+    pub fn new(client: async_nats::Client) -> Self {
+        Self { client }
+    }
+
+    /// Search for a single hash.
+    pub async fn search(
+        &self,
+        hash: i64,
+        distance: i32,
+    ) -> Result<SearchResults, async_nats::Error> {
+        let hashes = [HashDistance {
+            hash,
+            distance: distance as u32,
+        }];
+
+        self.search_many(&hashes)
+            .await
+            .map(|mut results| results.remove(0))
+    }
+
+    /// Search many hashes at once.
+    pub async fn search_many(
+        &self,
+        hashes: &[HashDistance],
+    ) -> Result<Vec<SearchResults>, async_nats::Error> {
+        let payload = serde_json::to_vec(hashes).unwrap();
+
+        let message = self
+            .client
+            .request(Self::NATS_SUBJECT.to_string(), payload.into())
+            .await?;
+
+        let results: Vec<Vec<HashDistance>> = serde_json::from_slice(&message.payload).unwrap();
+
+        let results = results
+            .into_iter()
+            .zip(hashes)
+            .map(|(results, search)| SearchResults {
+                hash: search.hash,
+                distance: search.distance as u64,
+                hashes: results
+                    .into_iter()
+                    .map(|result| SearchResult {
+                        hash: result.hash,
+                        distance: result.distance as u64,
+                    })
+                    .collect(),
+            })
+            .collect();
+
+        Ok(results)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     fn get_test_endpoint() -> String {