Method to_json

nodedb/src/engine/graph/algo/result.rs:168–195

Serialize the result batch as JSON (for pgwire/REST response). Returns a JSON array of objects: `[{"node_id": "alice", "rank": 0.42}, ...]`. Used by tests; production code uses `to_msgpack()` + `decode_payload_to_json()`.

(&self)

    /// Returns a JSON array of objects: `[{"node_id": "alice", "rank": 0.42}, ...]`.
    /// Used by tests; production code uses `to_msgpack()` + `decode_payload_to_json()`.
    pub fn to_json(&self) -> Result<Vec<u8>, crate::Error> {
        let schema = self.algorithm.result_schema();
        let mut rows = Vec::with_capacity(self.row_count);

        for row_idx in 0..self.row_count {
            let mut obj = serde_json::Map::new();
            for (col_idx, &(col_name, _col_type)) in schema.iter().enumerate() {
                let (col_type, vec_idx) = self.column_map[col_idx];
                let val = match col_type {
                    AlgoColumnType::Text => {
                        serde_json::Value::String(self.text_columns[vec_idx][row_idx].clone())
                    }
                    AlgoColumnType::Float64 => {
                        serde_json::json!(self.f64_columns[vec_idx][row_idx])
                    }
                    AlgoColumnType::Int64 => {
                        serde_json::json!(self.i64_columns[vec_idx][row_idx])
                    }
                };
                obj.insert(col_name.to_string(), val);
            }
            rows.push(serde_json::Value::Object(obj));
        }

        sonic_rs::to_vec(&rows).map_err(|e| crate::Error::Internal {
            detail: format!("json serialization: {e}"),
        })
    }
}

impl zerompk::ToMessagePack for AlgoResultBatch {