Add test that check that compression is enabled

If the Compression parameter is set to 1, then the content encoding should be
set to `zstd` otherwise it should be empty

Author: slabko

driver/api/impl/impl.cpp

@@ -505,12 +505,8 @@ SQLRETURN GetStmtAttr(
             CASE_NUM(SQL_ATTR_RETRIEVE_DATA, SQLULEN, SQL_RD_ON);
             CASE_NUM(SQL_ATTR_USE_BOOKMARKS, SQLULEN, SQL_UB_OFF);
 
-            case SQL_CH_STMT_ATTR_LAST_QUERY_ID: {
-                auto & query_id = statement.getQueryId();
-                if (query_id.empty())
-                    throw SqlException("Invalid cursor state", "24000");
-
-                return fillOutputString<PTChar>(query_id, out_value, out_value_max_length, out_value_length, true);
+            case SQL_CH_STMT_ATTR_NATIVE_STATEMENT_ATTR: {
+                return fillOutputPOD<void*>(&statement, out_value, out_value_length);
             }
 
             case SQL_ATTR_FETCH_BOOKMARK_PTR:

driver/platform/platform.h

@@ -120,4 +120,4 @@
 // User range is between SQL_DRIVER_STMT_ATTR_BASE (0x00004000) and 0x00007FFF, see
 // https://learn.microsoft.com/en-us/sql/odbc/reference/develop-app/driver-specific-data-types-descriptor-information-diagnostic
 #define SQL_CH_STMT_ATTR_BASE (SQL_DRIVER_STMT_ATTR_BASE + 1)
-#define SQL_CH_STMT_ATTR_LAST_QUERY_ID (SQL_CH_STMT_ATTR_BASE + 1)
+#define SQL_CH_STMT_ATTR_NATIVE_STATEMENT_ATTR (SQL_CH_STMT_ATTR_BASE + 1)

driver/statement.cpp

@@ -173,8 +173,9 @@ void Statement::requestNextPackOfResultSets(std::unique_ptr<ResultMutator> && mu
     // and so we cannot pass an rvalue to it (e.g.`std::string()`),
     // it will be deleted when the function returns.
     // We use a static variable that will never be deleted.
-    static const std::string empty_query_id{};
-    query_id = response->get("X-ClickHouse-Query-Id", empty_query_id);
+    static const std::string empty_string{};
+    query_id = response->get("X-ClickHouse-Query-Id", empty_string);
+    content_encoding = response->get("Content-Encoding", empty_string);
 
     Poco::Net::HTTPResponse::HTTPStatus status = response->getStatus();
     if (status != Poco::Net::HTTPResponse::HTTP_OK) {
@@ -370,6 +371,10 @@ const std::string & Statement::getQueryId() const {
     return query_id;
 }
 
+const std::string & Statement::getContentEncoding() const {
+    return content_encoding;
+}
+
 bool Statement::advanceToNextResultSet() {
     if (!is_executed)
         return false;

driver/statement.h

@@ -50,6 +50,9 @@ class Statement
     /// Get the current query id, or an empty string if query id is not applicable or not available.
     const std::string & getQueryId() const;
 
+    /// Get the current content encoding, or an empty string if content encoding was not defined
+    const std::string & getContentEncoding() const;
+
     /// Make the next result set current, if any.
     bool advanceToNextResultSet();
 
@@ -117,5 +120,6 @@ class Statement
     std::istream* in = nullptr;
     std::unique_ptr<ResultReader> result_reader;
     std::string query_id;
+    std::string content_encoding;
     std::size_t next_param_set_idx = 0;
 };

driver/test/client_test_base.h

@@ -47,33 +47,11 @@ class ClientTestBaseMixin
         ODBC_CALL_ON_DBC_THROW(hdbc, SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt));
     }
 
-    std::string getQueryId()
+    Statement & getStatement()
     {
-        char query_id_data[74] = {};
-        SQLINTEGER query_id_len{};
-        SQLGetStmtAttr(hstmt, SQL_CH_STMT_ATTR_LAST_QUERY_ID, query_id_data, std::size(query_id_data), &query_id_len);
-
-#ifdef _win_
-        return toUTF8(reinterpret_cast<PTChar*>(query_id_data));
-#else
-        // unixODBC usually converts all strings from the driver encoding to the application encoding,
-        // similar to how Windows behaves. However, `SQLGetStmtAttr` appears to be an exception in unixODBC,
-        // as it passes the result in the driver encoding unchanged.
-        // See: https://github.com/lurcher/unixODBC/issues/22
-        //
-        // To solve this issue and ensure the result reaches the application in the correct encoding,
-        // we would need to implement both `SQLGetStmtAttr` and `SQLGetStmtAttrW` in the driver.
-        // This would introduce a number of workarounds and non-uniform solutions.
-        // Currently, there is only one string attribute, `SQL_CH_STMT_ATTR_LAST_QUERY_ID`, which is internal,
-        // so this added complexity in the driver is not currently justified.
-        //
-        // Since we know that the Query ID is 36 bytes long, we can infer the encoding of the result
-        // and re-encode it accordingly here in the test.
-        if (query_id_len == 36)
-            return toUTF8(query_id_data);
-        else
-            return toUTF8(reinterpret_cast<char16_t*>(query_id_data));
-#endif
+        Statement * statement = nullptr;
+        SQLGetStmtAttr(hstmt, SQL_CH_STMT_ATTR_NATIVE_STATEMENT_ATTR, &statement, SQL_IS_POINTER, nullptr);
+        return *statement;
     }
 
 protected:

driver/test/error_handling_it.cpp

@@ -1,3 +1,4 @@
+#include "driver/statement.h"
 #include "driver/test/client_utils.h"
 #include "driver/test/client_test_base.h"
 #include "driver/test/result_set_reader.hpp"
@@ -21,7 +22,7 @@ TEST_F(ErrorHandlingTest, ServerExceptionInBeginning)
     ODBC_CALL_ON_STMT_THROW(hstmt, SQLPrepare(hstmt, ptcharCast(query.data()), SQL_NTS));
     ASSERT_EQ(SQLExecute(hstmt), SQL_ERROR);
     auto error_message = extract_diagnostics(hstmt, SQL_HANDLE_STMT);
-    auto query_id = getQueryId();
+    auto query_id = getStatement().getQueryId();
 
     auto expect_error_message = "1:[HY000][1]Error while processing query " + query_id + ": HTTP status code: 400";
     ASSERT_EQ(error_message.substr(0, expect_error_message.size()), expect_error_message);
@@ -53,7 +54,7 @@ TEST_F(ErrorHandlingTest, ServerExceptionInMiddleOfStream)
             error_message = extract_diagnostics(hstmt, SQL_HANDLE_STMT);
     }
 
-    auto query_id = getQueryId();
+    auto query_id = getStatement().getQueryId();
     auto expect_error_message =
         "1:[HY000][1]Error while processing query " + query_id + ": "
         "ClickHouse exception: Code: 395. DB::Exception: Value passed to 'throwIf'";

driver/test/misc_it.cpp

@@ -1,3 +1,4 @@
+#include "driver/statement.h"
 #include "driver/platform/platform.h"
 #include "driver/test/client_utils.h"
 #include "driver/test/client_test_base.h"
@@ -150,6 +151,31 @@ TEST_F(MiscellaneousTest, NullableNothing) {
     EXPECT_EQ(nullable, SQL_NULLABLE);
 }
 
+TEST_F(MiscellaneousTest, CompressionMatchesConfiguration) {
+    // Get version directly by calling `select version()`
+    auto query = fromUTF8<PTChar>("select version()");
+    ODBC_CALL_ON_STMT_THROW(hstmt, SQLExecDirect(hstmt, ptcharCast(query.data()), SQL_NTS));
+    ODBC_CALL_ON_STMT_THROW(hstmt, SQLFetch(hstmt));
+    std::basic_string<PTChar> query_version(256, '\0');
+    SQLLEN query_version_len = 0;
+    ODBC_CALL_ON_STMT_THROW(hstmt, SQLGetData(
+        hstmt,
+        1,
+        getCTypeFor<SQLTCHAR*>(),
+        query_version.data(),
+        query_version.size(),
+        &query_version_len
+    ));
+
+    Statement & statement = getStatement();
+    Connection & connection = statement.getParent();
+
+    if (connection.enable_http_compression)
+        EXPECT_EQ(statement.getContentEncoding(), "zstd");
+    else
+        EXPECT_TRUE(statement.getContentEncoding().empty());
+}
+
 enum class FailOn {
     Connect,
     Execute,
@@ -369,7 +395,7 @@ TEST_P(CustomClientName, UserAgentTest) {
     SQLLEN sql_type = SQL_TYPE_NULL;
     ODBC_CALL_ON_STMT_THROW(hstmt, SQLColAttribute(hstmt, 1, SQL_DESC_TYPE, NULL, 0, NULL, &sql_type));
 
-    const auto query_id = getQueryId();
+    const auto query_id = getStatement().getQueryId();
 
     ResultSetReader reader{hstmt};
     while (reader.fetch())