fix(rust): fix update, open_table, fts search in remote client (#1785)

* `open_table` uses `POST` not `GET`
* `update` uses `predicate` key not `only_if`
* For FTS search, vector cannot be omitted. It must be passed as empty.
* Added logging of JSON request bodies to debug level logging.

rust/lancedb/src/remote/client.rs

@@ -341,7 +341,22 @@ impl<S: HttpSend> RestfulLanceDbClient<S> {
             request_id
         };
 
-        debug!("Sending request_id={}: {:?}", request_id, &request);
+        if log::log_enabled!(log::Level::Debug) {
+            let content_type = request
+                .headers()
+                .get("content-type")
+                .map(|v| v.to_str().unwrap());
+            if content_type == Some("application/json") {
+                let body = request.body().as_ref().unwrap().as_bytes().unwrap();
+                let body = String::from_utf8_lossy(body);
+                debug!(
+                    "Sending request_id={}: {:?} with body {}",
+                    request_id, request, body
+                );
+            } else {
+                debug!("Sending request_id={}: {:?}", request_id, request);
+            }
+        }
 
         if with_retry {
             self.send_with_retry_impl(client, request, request_id).await

rust/lancedb/src/remote/db.rs

@@ -161,7 +161,7 @@ impl<S: HttpSend> ConnectionInternal for RemoteDatabase<S> {
         if self.table_cache.get(&options.name).is_none() {
             let req = self
                 .client
-                .get(&format!("/v1/table/{}/describe/", options.name));
+                .post(&format!("/v1/table/{}/describe/", options.name));
             let (request_id, resp) = self.client.send(req, true).await?;
             if resp.status() == StatusCode::NOT_FOUND {
                 return Err(crate::Error::TableNotFound { name: options.name });
@@ -301,7 +301,7 @@ mod tests {
     #[tokio::test]
     async fn test_open_table() {
         let conn = Connection::new_with_handler(|request| {
-            assert_eq!(request.method(), &reqwest::Method::GET);
+            assert_eq!(request.method(), &reqwest::Method::POST);
             assert_eq!(request.url().path(), "/v1/table/table1/describe/");
             assert_eq!(request.url().query(), None);
 

rust/lancedb/src/remote/table.rs

@@ -310,8 +310,8 @@ impl<S: HttpSend> TableInternal for RemoteTable<S> {
         body["nprobes"] = query.nprobes.into();
         body["refine_factor"] = query.refine_factor.into();
 
-        if let Some(vector) = query.query_vector.as_ref() {
-            let vector: Vec<f32> = match vector.data_type() {
+        let vector: Vec<f32> = if let Some(vector) = query.query_vector.as_ref() {
+            match vector.data_type() {
                 DataType::Float32 => vector
                     .as_any()
                     .downcast_ref::<arrow_array::Float32Array>()
@@ -325,9 +325,12 @@ impl<S: HttpSend> TableInternal for RemoteTable<S> {
                         message: "VectorQuery vector must be of type Float32".into(),
                     })
                 }
-            };
-            body["vector"] = serde_json::json!(vector);
-        }
+            }
+        } else {
+            // Server takes empty vector, not null or undefined.
+            Vec::new()
+        };
+        body["vector"] = serde_json::json!(vector);
 
         if let Some(vector_column) = query.column.as_ref() {
             body["vector_column"] = serde_json::Value::String(vector_column.clone());
@@ -358,6 +361,8 @@ impl<S: HttpSend> TableInternal for RemoteTable<S> {
 
         let mut body = serde_json::Value::Object(Default::default());
         Self::apply_query_params(&mut body, query)?;
+        // Empty vector can be passed if no vector search is performed.
+        body["vector"] = serde_json::Value::Array(Vec::new());
 
         let request = request.json(&body);
 
@@ -379,7 +384,7 @@ impl<S: HttpSend> TableInternal for RemoteTable<S> {
 
         let request = request.json(&serde_json::json!({
             "updates": updates,
-            "only_if": update.filter,
+            "predicate": update.filter,
         }));
 
         let (request_id, response) = self.client.send(request, false).await?;
@@ -933,7 +938,7 @@ mod tests {
                 assert_eq!(col_name, "b");
                 assert_eq!(expression, "b - 1");
 
-                let only_if = value.get("only_if").unwrap().as_str().unwrap();
+                let only_if = value.get("predicate").unwrap().as_str().unwrap();
                 assert_eq!(only_if, "b > 10");
             }
 
@@ -1167,6 +1172,7 @@ mod tests {
                     "query": "hello world",
                 },
                 "k": 10,
+                "vector": [],
             });
             assert_eq!(body, expected_body);