+function engine:set_encoding() -- to UTF-8
+ local driver = self.params.driver;
+ if driver == "SQLite3" then
+ return self:transaction(function()
+ for encoding in self:select"PRAGMA encoding;" do
+ if encoding[1] == "UTF-8" then
+ self.charset = "utf8";
+ end
+ end
+ end);
+ end
+ local set_names_query = "SET NAMES '%s';"
+ local charset = "utf8";
+ if driver == "MySQL" then
+ self:transaction(function()
+ for row in self:select"SELECT `CHARACTER_SET_NAME` FROM `information_schema`.`CHARACTER_SETS` WHERE `CHARACTER_SET_NAME` LIKE 'utf8%' ORDER BY MAXLEN DESC LIMIT 1;" do
+ charset = row and row[1] or charset;
+ end
+ end);
+ set_names_query = set_names_query:gsub(";$", (" COLLATE '%s';"):format(charset.."_bin"));
+ end
+ self.charset = charset;
+ log("debug", "Using encoding '%s' for database connection", charset);
+ local ok, err = self:transaction(function() return self:execute(set_names_query:format(charset)); end);
+ if not ok then
+ return ok, err;
+ end
+
+ if driver == "MySQL" then
+ local ok, actual_charset = self:transaction(function ()
+ return self:select"SHOW SESSION VARIABLES LIKE 'character_set_client'";
+ end);
+ local charset_ok = true;
+ for row in actual_charset do
+ if row[2] ~= charset then
+ log("error", "MySQL %s is actually %q (expected %q)", row[1], row[2], charset);
+ charset_ok = false;
+ end
+ end
+ if not charset_ok then
+ return false, "Failed to set connection encoding";
+ end
+ end
+
+ return true;
+end