util/sql.lua

   1
   2 local setmetatable, getmetatable = setmetatable, getmetatable;
   3 local ipairs, unpack, select = ipairs, unpack, select;
   4 local tonumber, tostring = tonumber, tostring;
   5 local assert, xpcall, debug_traceback = assert, xpcall, debug.traceback;
   6 local t_concat = table.concat;
   7 local s_char = string.char;
   8 local log = require "util.logger".init("sql");
   9
  10 local DBI = require "DBI";
  11 -- This loads all available drivers while globals are unlocked
  12 -- LuaDBI should be fixed to not set globals.
  13 DBI.Drivers();
  14 local build_url = require "socket.url".build;
  15
  16 module("sql")
  17
  18 local column_mt = {};
  19 local table_mt = {};
  20 local query_mt = {};
  21 --local op_mt = {};
  22 local index_mt = {};
  23
  24 function is_column(x) return getmetatable(x)==column_mt; end
  25 function is_index(x) return getmetatable(x)==index_mt; end
  26 function is_table(x) return getmetatable(x)==table_mt; end
  27 function is_query(x) return getmetatable(x)==query_mt; end
  28 function Integer(n) return "Integer()" end
  29 function String(n) return "String()" end
  30
  31 function Column(definition)
  32         return setmetatable(definition, column_mt);
  33 end
  34 function Table(definition)
  35         local c = {}
  36         for i,col in ipairs(definition) do
  37                 if is_column(col) then
  38                         c[i], c[col.name] = col, col;
  39                 elseif is_index(col) then
  40                         col.table = definition.name;
  41                 end
  42         end
  43         return setmetatable({ __table__ = definition, c = c, name = definition.name }, table_mt);
  44 end
  45 function Index(definition)
  46         return setmetatable(definition, index_mt);
  47 end
  48
  49 function table_mt:__tostring()
  50         local s = { 'name="'..self.__table__.name..'"' }
  51         for i,col in ipairs(self.__table__) do
  52                 s[#s+1] = tostring(col);
  53         end
  54         return 'Table{ '..t_concat(s, ", ")..' }'
  55 end
  56 table_mt.__index = {};
  57 function table_mt.__index:create(engine)
  58         return engine:_create_table(self);
  59 end
  60 function table_mt:__call(...)
  61         -- TODO
  62 end
  63 function column_mt:__tostring()
  64         return 'Column{ name="'..self.name..'", type="'..self.type..'" }'
  65 end
  66 function index_mt:__tostring()
  67         local s = 'Index{ name="'..self.name..'"';
  68         for i=1,#self do s = s..', "'..self[i]:gsub("[\\\"]", "\\%1")..'"'; end
  69         return s..' }';
  70 --      return 'Index{ name="'..self.name..'", type="'..self.type..'" }'
  71 end
  72
  73 local function urldecode(s) return s and (s:gsub("%%(%x%x)", function (c) return s_char(tonumber(c,16)); end)); end
  74 local function parse_url(url)
  75         local scheme, secondpart, database = url:match("^([%w%+]+)://([^/]*)/?(.*)");
  76         assert(scheme, "Invalid URL format");
  77         local username, password, host, port;
  78         local authpart, hostpart = secondpart:match("([^@]+)@([^@+])");
  79         if not authpart then hostpart = secondpart; end
  80         if authpart then
  81                 username, password = authpart:match("([^:]*):(.*)");
  82                 username = username or authpart;
  83                 password = password and urldecode(password);
  84         end
  85         if hostpart then
  86                 host, port = hostpart:match("([^:]*):(.*)");
  87                 host = host or hostpart;
  88                 port = port and assert(tonumber(port), "Invalid URL format");
  89         end
  90         return {
  91                 scheme = scheme:lower();
  92                 username = username; password = password;
  93                 host = host; port = port;
  94                 database = #database > 0 and database or nil;
  95         };
  96 end
  97
  98 local engine = {};
  99 function engine:connect()
 100         if self.conn then return true; end
 101
 102         local params = self.params;
 103         assert(params.driver, "no driver")
 104         local dbh, err = DBI.Connect(
 105                 params.driver, params.database,
 106                 params.username, params.password,
 107                 params.host, params.port
 108         );
 109         if not dbh then return nil, err; end
 110         dbh:autocommit(false); -- don't commit automatically
 111         self.conn = dbh;
 112         self.prepared = {};
 113         self:set_encoding();
 114         self:onconnect();
 115         return true;
 116 end
 117 function engine:onconnect()
 118         -- Override from create_engine()
 119 end
 120 function engine:execute(sql, ...)
 121         local success, err = self:connect();
 122         if not success then return success, err; end
 123         local prepared = self.prepared;
 124
 125         local stmt = prepared[sql];
 126         if not stmt then
 127                 local err;
 128                 stmt, err = self.conn:prepare(sql);
 129                 if not stmt then return stmt, err; end
 130                 prepared[sql] = stmt;
 131         end
 132
 133         local success, err = stmt:execute(...);
 134         if not success then return success, err; end
 135         return stmt;
 136 end
 137
 138 local result_mt = { __index = {
 139         affected = function(self) return self.__stmt:affected(); end;
 140         rowcount = function(self) return self.__stmt:rowcount(); end;
 141 } };
 142
 143 function engine:execute_query(sql, ...)
 144         if self.params.driver == "PostgreSQL" then
 145                 sql = sql:gsub("`", "\"");
 146         end
 147         local stmt = assert(self.conn:prepare(sql));
 148         assert(stmt:execute(...));
 149         return stmt:rows();
 150 end
 151 function engine:execute_update(sql, ...)
 152         if self.params.driver == "PostgreSQL" then
 153                 sql = sql:gsub("`", "\"");
 154         end
 155         local prepared = self.prepared;
 156         local stmt = prepared[sql];
 157         if not stmt then
 158                 stmt = assert(self.conn:prepare(sql));
 159                 prepared[sql] = stmt;
 160         end
 161         assert(stmt:execute(...));
 162         return setmetatable({ __stmt = stmt }, result_mt);
 163 end
 164 engine.insert = engine.execute_update;
 165 engine.select = engine.execute_query;
 166 engine.delete = engine.execute_update;
 167 engine.update = engine.execute_update;
 168 function engine:_transaction(func, ...)
 169         if not self.conn then
 170                 local ok, err = self:connect();
 171                 if not ok then return ok, err; end
 172         end
 173         --assert(not self.__transaction, "Recursive transactions not allowed");
 174         local args, n_args = {...}, select("#", ...);
 175         local function f() return func(unpack(args, 1, n_args)); end
 176         self.__transaction = true;
 177         local success, a, b, c = xpcall(f, debug_traceback);
 178         self.__transaction = nil;
 179         if success then
 180                 log("debug", "SQL transaction success [%s]", tostring(func));
 181                 local ok, err = self.conn:commit();
 182                 if not ok then return ok, err; end -- commit failed
 183                 return success, a, b, c;
 184         else
 185                 log("debug", "SQL transaction failure [%s]: %s", tostring(func), a);
 186                 if self.conn then self.conn:rollback(); end
 187                 return success, a;
 188         end
 189 end
 190 function engine:transaction(...)
 191         local ok, ret = self:_transaction(...);
 192         if not ok then
 193                 local conn = self.conn;
 194                 if not conn or not conn:ping() then
 195                         self.conn = nil;
 196                         ok, ret = self:_transaction(...);
 197                 end
 198         end
 199         return ok, ret;
 200 end
 201 function engine:_create_index(index)
 202         local sql = "CREATE INDEX `"..index.name.."` ON `"..index.table.."` (";
 203         for i=1,#index do
 204                 sql = sql.."`"..index[i].."`";
 205                 if i ~= #index then sql = sql..", "; end
 206         end
 207         sql = sql..");"
 208         if self.params.driver == "PostgreSQL" then
 209                 sql = sql:gsub("`", "\"");
 210         elseif self.params.driver == "MySQL" then
 211                 sql = sql:gsub("`([,)])", "`(20)%1");
 212         end
 213         if index.unique then
 214                 sql = sql:gsub("^CREATE", "CREATE UNIQUE");
 215         end
 216         --print(sql);
 217         return self:execute(sql);
 218 end
 219 function engine:_create_table(table)
 220         local sql = "CREATE TABLE `"..table.name.."` (";
 221         for i,col in ipairs(table.c) do
 222                 local col_type = col.type;
 223                 if col_type == "MEDIUMTEXT" and self.params.driver ~= "MySQL" then
 224                         col_type = "TEXT"; -- MEDIUMTEXT is MySQL-specific
 225                 end
 226                 if col.auto_increment == true and self.params.driver == "PostgreSQL" then
 227                         col_type = "BIGSERIAL";
 228                 end
 229                 sql = sql.."`"..col.name.."` "..col_type;
 230                 if col.nullable == false then sql = sql.." NOT NULL"; end
 231                 if col.primary_key == true then sql = sql.." PRIMARY KEY"; end
 232                 if col.auto_increment == true then
 233                         if self.params.driver == "MySQL" then
 234                                 sql = sql.." AUTO_INCREMENT";
 235                         elseif self.params.driver == "SQLite3" then
 236                                 sql = sql.." AUTOINCREMENT";
 237                         end
 238                 end
 239                 if i ~= #table.c then sql = sql..", "; end
 240         end
 241         sql = sql.. ");"
 242         if self.params.driver == "PostgreSQL" then
 243                 sql = sql:gsub("`", "\"");
 244         elseif self.params.driver == "MySQL" then
 245                 sql = sql:gsub(";$", " CHARACTER SET 'utf8' COLLATE 'utf8_bin';");
 246         end
 247         local success,err = self:execute(sql);
 248         if not success then return success,err; end
 249         for i,v in ipairs(table.__table__) do
 250                 if is_index(v) then
 251                         self:_create_index(v);
 252                 end
 253         end
 254         return success;
 255 end
 256 function engine:set_encoding() -- to UTF-8
 257         local driver = self.params.driver;
 258         if driver == "SQLite3" then
 259                 return self:transaction(function()
 260                         if self:select"PRAGMA encoding;"()[1] == "UTF-8" then
 261                                 self.charset = "utf8";
 262                         end
 263                 end);
 264         end
 265         local set_names_query = "SET NAMES '%s';"
 266         local charset = "utf8";
 267         if driver == "MySQL" then
 268                 set_names_query = set_names_query:gsub(";$", " COLLATE 'utf8_bin';");
 269                 local ok, charsets = self:transaction(function()
 270                         return self:select"SELECT `CHARACTER_SET_NAME` FROM `information_schema`.`CHARACTER_SETS` WHERE `CHARACTER_SET_NAME` LIKE 'utf8%' ORDER BY MAXLEN DESC LIMIT 1;";
 271                 end);
 272                 local row = ok and charsets();
 273                 charset = row and row[1] or charset;
 274         end
 275         self.charset = charset;
 276         return self:transaction(function() return self:execute(set_names_query:format(charset)); end);
 277 end
 278 local engine_mt = { __index = engine };
 279
 280 function db2uri(params)
 281         return build_url{
 282                 scheme = params.driver,
 283                 user = params.username,
 284                 password = params.password,
 285                 host = params.host,
 286                 port = params.port,
 287                 path = params.database,
 288         };
 289 end
 290
 291 function create_engine(self, params, onconnect)
 292         return setmetatable({ url = db2uri(params), params = params, onconnect = onconnect }, engine_mt);
 293 end
 294
 295 return _M;