Comparison

plugins/storage/sqlbasic.lib.lua @ 2678:c5882e2e12b5

mod_storage, plus a bit of SQL and XML.
author Waqas Hussain <waqas20@gmail.com>
date Fri, 19 Feb 2010 22:32:28 +0500
child 5021:85b2689dbcfe
comparison
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2677:467568f1117d 2678:c5882e2e12b5
1
2 -- Basic SQL driver
3 -- This driver stores data as simple key-values
4
5 local ser = require "util.serialization".serialize;
6 local deser = function(data)
7 module:log("debug", "deser: %s", tostring(data));
8 if not data then return nil; end
9 local f = loadstring("return "..data);
10 if not f then return nil; end
11 setfenv(f, {});
12 local s, d = pcall(f);
13 if not s then return nil; end
14 return d;
15 end;
16
17 local driver = {};
18 driver.__index = driver;
19
20 driver.item_table = "item";
21 driver.list_table = "list";
22
23 function driver:prepare(sql)
24 module:log("debug", "query: %s", sql);
25 local err;
26 if not self.sqlcache then self.sqlcache = {}; end
27 local r = self.sqlcache[sql];
28 if r then return r; end
29 r, err = self.connection:prepare(sql);
30 if not r then error("Unable to prepare SQL statement: "..err); end
31 self.sqlcache[sql] = r;
32 return r;
33 end
34
35 function driver:load(username, host, datastore)
36 local select = self:prepare("select data from "..self.item_table.." where username=? and host=? and datastore=?");
37 select:execute(username, host, datastore);
38 local row = select:fetch();
39 return row and deser(row[1]) or nil;
40 end
41
42 function driver:store(username, host, datastore, data)
43 if not data or next(data) == nil then
44 local delete = self:prepare("delete from "..self.item_table.." where username=? and host=? and datastore=?");
45 delete:execute(username, host, datastore);
46 return true;
47 else
48 local d = self:load(username, host, datastore);
49 if d then -- update
50 local update = self:prepare("update "..self.item_table.." set data=? where username=? and host=? and datastore=?");
51 return update:execute(ser(data), username, host, datastore);
52 else -- insert
53 local insert = self:prepare("insert into "..self.item_table.." values (?, ?, ?, ?)");
54 return insert:execute(username, host, datastore, ser(data));
55 end
56 end
57 end
58
59 function driver:list_append(username, host, datastore, data)
60 if not data then return; end
61 local insert = self:prepare("insert into "..self.list_table.." values (?, ?, ?, ?)");
62 return insert:execute(username, host, datastore, ser(data));
63 end
64
65 function driver:list_store(username, host, datastore, data)
66 -- remove existing data
67 local delete = self:prepare("delete from "..self.list_table.." where username=? and host=? and datastore=?");
68 delete:execute(username, host, datastore);
69 if data and next(data) ~= nil then
70 -- add data
71 for _, d in ipairs(data) do
72 self:list_append(username, host, datastore, ser(d));
73 end
74 end
75 return true;
76 end
77
78 function driver:list_load(username, host, datastore)
79 local select = self:prepare("select data from "..self.list_table.." where username=? and host=? and datastore=?");
80 select:execute(username, host, datastore);
81 local r = {};
82 for row in select:rows() do
83 table.insert(r, deser(row[1]));
84 end
85 return r;
86 end
87
88 local _M = {};
89 function _M.new(dbtype, dbname, ...)
90 local d = {};
91 setmetatable(d, driver);
92 local dbh = get_database(dbtype, dbname, ...);
93 --d:set_connection(dbh);
94 d.connection = dbh;
95 return d;
96 end
97 return _M;