support additional run options, including result table and chunk limit (#14)

* result table

* db, schema, & result tbl chunk limit

* support schema, change db to search path; also errors_as_json

* add comment about appender connection

src/http_server.cpp

@@ -13,6 +13,8 @@
 #include <duckdb/common/serializer/binary_serializer.hpp>
 #include <duckdb/common/serializer/memory_stream.hpp>
 #include <duckdb/main/attached_database.hpp>
+#include <duckdb/main/client_data.hpp>
+#include <duckdb/parser/parsed_data/create_table_info.hpp>
 #include <duckdb/parser/parser.hpp>
 
 namespace duckdb {
@@ -364,8 +366,10 @@ void HttpServer::DoHandleRun(const httplib::Request &req,
 
   auto connection_name = req.get_header_value("X-DuckDB-UI-Connection-Name");
 
-  auto database_name =
+  auto database_name_option =
       DecodeBase64(req.get_header_value("X-DuckDB-UI-Database-Name"));
+  auto schema_name_option =
+      DecodeBase64(req.get_header_value("X-DuckDB-UI-Schema-Name"));
 
   std::vector<std::string> parameter_values;
   auto parameter_count_string =
@@ -379,6 +383,35 @@ void HttpServer::DoHandleRun(const httplib::Request &req,
     }
   }
 
+  // default to effectively no limit
+  auto result_chunk_limit = INT_MAX;
+  auto result_chunk_limit_string =
+      req.get_header_value("X-DuckDB-UI-Result-Chunk-Limit");
+  if (!result_chunk_limit_string.empty()) {
+    result_chunk_limit = std::stoi(result_chunk_limit_string);
+  }
+
+  auto result_database_name_option =
+      DecodeBase64(req.get_header_value("X-DuckDB-UI-Result-Database-Name"));
+  auto result_schema_name_option =
+      DecodeBase64(req.get_header_value("X-DuckDB-UI-Result-Schema-Name"));
+  auto result_table_name =
+      DecodeBase64(req.get_header_value("X-DuckDB-UI-Result-Table-Name"));
+
+  // If no result table is specified, then the result table chunk limit is zero.
+  // Otherwise, default to effectively no limit.
+  auto result_table_chunk_limit = result_table_name.empty() ? 0 : INT_MAX;
+  auto result_table_chunk_limit_string =
+      req.get_header_value("X-DuckDB-UI-Result-Table-Chunk-Limit");
+  // Only set the result table chunk limit if a result table name is specified.
+  if (!result_table_name.empty() && !result_table_chunk_limit_string.empty()) {
+    result_table_chunk_limit = std::stoi(result_table_chunk_limit_string);
+  }
+
+  auto errors_as_json_string =
+      req.get_header_value("X-DuckDB-UI-Errors-As-JSON");
+  auto errors_as_json = errors_as_json_string == "true";
+
   std::string content = ReadContent(content_reader);
 
   auto db = ddb_instance.lock();
@@ -391,13 +424,21 @@ void HttpServer::DoHandleRun(const httplib::Request &req,
   auto connection =
       UIStorageExtensionInfo::GetState(*db).FindOrCreateConnection(
           *db, connection_name);
-
-  // Set current database if optional header is provided.
-  if (!database_name.empty()) {
   auto &context = *connection->context;
+  auto &config = ClientConfig::GetConfig(context);
+
+  // Set errors_as_json
+  config.errors_as_json = errors_as_json;
+
+  // Set current database & schema
+  if (!database_name_option.empty() || !schema_name_option.empty()) {
+    // It's fine if the database name is empty, but we need a valid schema name.
+    auto schema_name =
+        schema_name_option.empty() ? DEFAULT_SCHEMA : schema_name_option;
     context.RunFunctionInTransaction([&] {
-      auto &manager = context.db->GetDatabaseManager();
+      duckdb::ClientData::Get(context).catalog_search_path->Set(
-      manager.SetDefaultDatabase(context, database_name);
+          {database_name_option, schema_name},
+          duckdb::CatalogSetPathType::SET_SCHEMA);
     });
   }
 
@@ -414,7 +455,7 @@ void HttpServer::DoHandleRun(const httplib::Request &req,
   // If there's more than one statement, run all but the last.
   if (statement_count > 1) {
     for (auto i = 0; i < statement_count - 1; ++i) {
-      auto pending = connection->PendingQuery(std::move(statements[i]));
+      auto pending = connection->PendingQuery(std::move(statements[i]), true);
       // Return any error found before execution.
       if (pending->HasError()) {
         SetResponseErrorResult(res, pending->GetError());
@@ -499,17 +540,67 @@ void HttpServer::DoHandleRun(const httplib::Request &req,
     // Get the result. This should be quick because it's ready.
     auto result = pending->Execute();
 
+    // We use a separate connection for the appender, including creating the
+    // result table, because we still need to fetch chunks from the pending
+    // query on the user's connection.
+    unique_ptr<duckdb::Connection> appender_connection;
+    unique_ptr<duckdb::Appender> appender;
+
+    if (!result_table_name.empty()) {
+      auto result_database_name = result_database_name_option.empty()
+                                      ? "memory"
+                                      : result_database_name_option;
+      auto result_schema_name = result_schema_name_option.empty()
+                                    ? "main"
+                                    : result_schema_name_option;
+
+      auto result_table_info = make_uniq<duckdb::CreateTableInfo>(
+          result_database_name, result_schema_name, result_table_name);
+      for (idx_t i = 0; i < result->names.size(); i++) {
+        result_table_info->columns.AddColumn(
+            ColumnDefinition(result->names[i], result->types[i]));
+      }
+
+      appender_connection = make_uniq<duckdb::Connection>(*db);
+      auto appender_context = appender_connection->context;
+      appender_context->RunFunctionInTransaction([&] {
+        auto &catalog = duckdb::Catalog::GetCatalog(*appender_context,
+                                                    result_database_name);
+        MetaTransaction::Get(*appender_context)
+            .ModifyDatabase(catalog.GetAttached());
+        catalog.CreateTable(*appender_context, std::move(result_table_info));
+      });
+
+      appender = make_uniq<duckdb::Appender>(
+          *appender_connection, result_database_name, result_schema_name,
+          result_table_name);
+    }
+
     // Fetch the chunks and serialize the result.
     SuccessResult success_result;
     success_result.column_names_and_types = {std::move(result->names),
                                              std::move(result->types)};
 
-    // TODO: support limiting the number of chunks fetched
+    auto chunk_limit = std::max(result_chunk_limit, result_table_chunk_limit);
-    auto chunk = result->Fetch();
+    auto chunks_fetched = 0;
-    while (chunk) {
+    unique_ptr<duckdb::DataChunk> chunk;
+    while (chunks_fetched < chunk_limit) {
+      chunk = result->Fetch();
+      if (!chunk) {
+        break;
+      }
+      ++chunks_fetched;
+      if (appender && chunks_fetched <= result_table_chunk_limit) {
+        appender->AppendDataChunk(*chunk);
+      }
+      if (chunks_fetched <= result_chunk_limit) {
         success_result.chunks.push_back(
             {static_cast<uint16_t>(chunk->size()), std::move(chunk->data)});
-      chunk = result->Fetch();
+      }
+    }
+
+    if (appender) {
+      appender->Close();
     }
 
     MemoryStream success_response_content;