Changeset

--- a/tools/migration/config.lua	Wed Feb 23 07:26:54 2011 +0500
+++ b/tools/migration/config.lua	Wed Feb 23 18:31:48 2011 +0000
@@ -1,26 +1,26 @@
-input {
-	type = "prosody_sql";
-	driver = "SQLite3";
-	database = "out.sqlite";
-}
-output {
-	type = "prosody_files";
-	path = "out";
-}
-
---[[
-
-input {
-	path = "../../data";
-	type = "prosody_files";
-	driver = "SQLite3";
-	database = "../../prosody.sqlite";
-}
-output {
-	type = "prosody_sql";
-	driver = "SQLite3";
-	database = "out.sqlite";
-	path = "out";
-}
-
-]]
+input {
+	type = "prosody_sql";
+	driver = "SQLite3";
+	database = "out.sqlite";
+}
+output {
+	type = "prosody_files";
+	path = "out";
+}
+
+--[[
+
+input {
+	path = "../../data";
+	type = "prosody_files";
+	driver = "SQLite3";
+	database = "../../prosody.sqlite";
+}
+output {
+	type = "prosody_sql";
+	driver = "SQLite3";
+	database = "out.sqlite";
+	path = "out";
+}
+
+]]

--- a/tools/migration/main.lua	Wed Feb 23 07:26:54 2011 +0500
+++ b/tools/migration/main.lua	Wed Feb 23 18:31:48 2011 +0000
@@ -1,27 +1,27 @@
-
-
-
-local function loadfilein(file, env) return loadin and loadin(env, io.open(file):read("*a")) or setfenv(loadfile(file), env); end
-config = {};
-local config_env = setmetatable({}, { __index = function(t, k) return function(tbl) config[k] = tbl; end; end });
-loadfilein("config.lua", config_env)();
-
-package.path = "../../?.lua;"..package.path
-package.cpath = "../../?.dll;"..package.cpath
-
-
-assert(config.input, "no input specified")
-assert(config.output, "no output specified")
-local itype = assert(config.input.type, "no input.type specified");
-local otype = assert(config.output.type, "no output.type specified");
-local reader = require(itype).reader(config.input);
-local writer = require(otype).writer(config.output);
-
-local json = require "util.json";
-
-for x in reader do
-	--print(json.encode(x))
-	writer(x);
-end
-writer(nil); -- close
-
+
+
+
+local function loadfilein(file, env) return loadin and loadin(env, io.open(file):read("*a")) or setfenv(loadfile(file), env); end
+config = {};
+local config_env = setmetatable({}, { __index = function(t, k) return function(tbl) config[k] = tbl; end; end });
+loadfilein("config.lua", config_env)();
+
+package.path = "../../?.lua;"..package.path
+package.cpath = "../../?.dll;"..package.cpath
+
+
+assert(config.input, "no input specified")
+assert(config.output, "no output specified")
+local itype = assert(config.input.type, "no input.type specified");
+local otype = assert(config.output.type, "no output.type specified");
+local reader = require(itype).reader(config.input);
+local writer = require(otype).writer(config.output);
+
+local json = require "util.json";
+
+for x in reader do
+	--print(json.encode(x))
+	writer(x);
+end
+writer(nil); -- close
+

--- a/tools/migration/mtools.lua	Wed Feb 23 07:26:54 2011 +0500
+++ b/tools/migration/mtools.lua	Wed Feb 23 18:31:48 2011 +0000
@@ -1,56 +1,56 @@
-
-
-local print = print;
-local t_insert = table.insert;
-local t_sort = table.sort;
-
-module "mtools"
-
-function sorted(params)
-
-	local reader = params.reader; -- iterator to get items from
-	local sorter = params.sorter; -- sorting function
-	local filter = params.filter; -- filter function
-
-	local cache = {};
-	for item in reader do
-		if filter then item = filter(item); end
-		if item then t_insert(cache, item); end
-	end
-	if sorter then
-		t_sort(cache, sorter);
-	end
-	local i = 0;
-	return function()
-		i = i + 1;
-		return cache[i];
-	end;
-
-end
-
-function merged(reader, merger)
-
-	local item1 = reader();
-	local merged = { item1 };
-	return function()
-		while true do
-			if not item1 then return nil; end
-			local item2 = reader();
-			if not item2 then item1 = nil; return merged; end
-			if merger(item1, item2) then
-			--print("merged")
-				item1 = item2;
-				t_insert(merged, item1);
-			else
-			--print("unmerged", merged)
-				item1 = item2;
-				local tmp = merged;
-				merged = { item1 };
-				return tmp;
-			end
-		end
-	end;
-
-end
-
-return _M;
+
+
+local print = print;
+local t_insert = table.insert;
+local t_sort = table.sort;
+
+module "mtools"
+
+function sorted(params)
+
+	local reader = params.reader; -- iterator to get items from
+	local sorter = params.sorter; -- sorting function
+	local filter = params.filter; -- filter function
+
+	local cache = {};
+	for item in reader do
+		if filter then item = filter(item); end
+		if item then t_insert(cache, item); end
+	end
+	if sorter then
+		t_sort(cache, sorter);
+	end
+	local i = 0;
+	return function()
+		i = i + 1;
+		return cache[i];
+	end;
+
+end
+
+function merged(reader, merger)
+
+	local item1 = reader();
+	local merged = { item1 };
+	return function()
+		while true do
+			if not item1 then return nil; end
+			local item2 = reader();
+			if not item2 then item1 = nil; return merged; end
+			if merger(item1, item2) then
+			--print("merged")
+				item1 = item2;
+				t_insert(merged, item1);
+			else
+			--print("unmerged", merged)
+				item1 = item2;
+				local tmp = merged;
+				merged = { item1 };
+				return tmp;
+			end
+		end
+	end;
+
+end
+
+return _M;

--- a/tools/migration/prosody_files.lua	Wed Feb 23 07:26:54 2011 +0500
+++ b/tools/migration/prosody_files.lua	Wed Feb 23 18:31:48 2011 +0000
@@ -1,133 +1,133 @@
-
-local print = print;
-local assert = assert;
-local setmetatable = setmetatable;
-local tonumber = tonumber;
-local char = string.char;
-local coroutine = coroutine;
-local lfs = require "lfs";
-local loadfile = loadfile;
-local setfenv = setfenv;
-local pcall = pcall;
-local mtools = require "mtools";
-local next = next;
-local pairs = pairs;
-local json = require "util.json";
-
-prosody = {};
-local dm = require "util.datamanager"
-
-module "prosody_files"
-
-local function is_dir(path) return lfs.attributes(path, "mode") == "directory"; end
-local function is_file(path) return lfs.attributes(path, "mode") == "file"; end
-local function clean_path(path)
-	return path:gsub("\\", "/"):gsub("//+", "/");
-end
-local encode, decode; do
-	local urlcodes = setmetatable({}, { __index = function (t, k) t[k] = char(tonumber("0x"..k)); return t[k]; end });
-	decode = function (s) return s and (s:gsub("+", " "):gsub("%%([a-fA-F0-9][a-fA-F0-9])", urlcodes)); end
-	encode = function (s) return s and (s:gsub("%W", function (c) return format("%%%02x", c:byte()); end)); end
-end
-local function decode_dir(x)
-	if x:gsub("%%%x%x", ""):gsub("[a-zA-Z0-9]", "") == "" then
-		return decode(x);
-	end
-end
-local function decode_file(x)
-	if x:match(".%.dat$") and x:gsub("%.dat$", ""):gsub("%%%x%x", ""):gsub("[a-zA-Z0-9]", "") == "" then
-		return decode(x:gsub("%.dat$", ""));
-	end
-end
-local function prosody_dir(path, ondir, onfile, ...)
-	for x in lfs.dir(path) do
-		local xpath = path.."/"..x;
-		if decode_dir(x) and is_dir(xpath) then
-			ondir(xpath, x, ...);
-		elseif decode_file(x) and is_file(xpath) then
-			onfile(xpath, x, ...);
-		end
-	end
-end
-
-local function handle_root_file(path, name)
-	--print("root file: ", decode_file(name))
-	coroutine.yield { user = nil, host = nil, store = decode_file(name) };
-end
-local function handle_host_file(path, name, host)
-	--print("host file: ", decode_dir(host).."/"..decode_file(name))
-	coroutine.yield { user = nil, host = decode_dir(host), store = decode_file(name) };
-end
-local function handle_store_file(path, name, store, host)
-	--print("store file: ", decode_file(name).."@"..decode_dir(host).."/"..decode_dir(store))
-	coroutine.yield { user = decode_file(name), host = decode_dir(host), store = decode_dir(store) };
-end
-local function handle_host_store(path, name, host)
-	prosody_dir(path, function() end, handle_store_file, name, host);
-end
-local function handle_host_dir(path, name)
-	prosody_dir(path, handle_host_store, handle_host_file, name);
-end
-local function handle_root_dir(path)
-	prosody_dir(path, handle_host_dir, handle_root_file);
-end
-
-local function decode_user(item)
-	local userdata = {
-		user = item[1].user;
-		host = item[1].host;
-		stores = {};
-	};
-	for i=1,#item do -- loop over stores
-		local result = {};
-		local store = item[i];
-		userdata.stores[store.store] = store.data;
-		store.user = nil; store.host = nil; store.store = nil;
-	end
-	return userdata;
-end
-
-function reader(input)
-	local path = clean_path(assert(input.path, "no input.path specified"));
-	assert(is_dir(path), "input.path is not a directory");
-	local iter = coroutine.wrap(function()handle_root_dir(path);end);
-	-- get per-user stores, sorted
-	local iter = mtools.sorted {
-		reader = function()
-			local x = iter();
-			if x then
-				dm.set_data_path(path);
-				x.data = assert(dm.load(x.user, x.host, x.store));
-				return x;
-			end
-		end;
-		sorter = function(a, b)
-			local a_host, a_user, a_store = a.host or "", a.user or "", a.store or "";
-			local b_host, b_user, b_store = b.host or "", b.user or "", b.store or "";
-			return a_host > b_host or (a_host==b_host and a_user > b_user) or (a_host==b_host and a_user==b_user and a_store > b_store);
-		end;
-	};
-	-- merge stores to get users
-	iter = mtools.merged(iter, function(a, b)
-		return (a.host == b.host and a.user == b.user);
-	end);
-
-	return function()
-		local x = iter();
-		return x and decode_user(x);
-	end
-end
-
-function writer(output)
-	local path = clean_path(assert(output.path, "no output.path specified"));
-	assert(is_dir(path), "output.path is not a directory");
-	return function(item)
-		if not item then return; end -- end of input
-		dm.set_data_path(path);
-		for store, data in pairs(item.stores) do
-			assert(dm.store(item.user, item.host, store, data));
-		end
-	end
-end
-
-return _M;
+
+local print = print;
+local assert = assert;
+local setmetatable = setmetatable;
+local tonumber = tonumber;
+local char = string.char;
+local coroutine = coroutine;
+local lfs = require "lfs";
+local loadfile = loadfile;
+local setfenv = setfenv;
+local pcall = pcall;
+local mtools = require "mtools";
+local next = next;
+local pairs = pairs;
+local json = require "util.json";
+
+prosody = {};
+local dm = require "util.datamanager"
+
+module "prosody_files"
+
+local function is_dir(path) return lfs.attributes(path, "mode") == "directory"; end
+local function is_file(path) return lfs.attributes(path, "mode") == "file"; end
+local function clean_path(path)
+	return path:gsub("\\", "/"):gsub("//+", "/");
+end
+local encode, decode; do
+	local urlcodes = setmetatable({}, { __index = function (t, k) t[k] = char(tonumber("0x"..k)); return t[k]; end });
+	decode = function (s) return s and (s:gsub("+", " "):gsub("%%([a-fA-F0-9][a-fA-F0-9])", urlcodes)); end
+	encode = function (s) return s and (s:gsub("%W", function (c) return format("%%%02x", c:byte()); end)); end
+end
+local function decode_dir(x)
+	if x:gsub("%%%x%x", ""):gsub("[a-zA-Z0-9]", "") == "" then
+		return decode(x);
+	end
+end
+local function decode_file(x)
+	if x:match(".%.dat$") and x:gsub("%.dat$", ""):gsub("%%%x%x", ""):gsub("[a-zA-Z0-9]", "") == "" then
+		return decode(x:gsub("%.dat$", ""));
+	end
+end
+local function prosody_dir(path, ondir, onfile, ...)
+	for x in lfs.dir(path) do
+		local xpath = path.."/"..x;
+		if decode_dir(x) and is_dir(xpath) then
+			ondir(xpath, x, ...);
+		elseif decode_file(x) and is_file(xpath) then
+			onfile(xpath, x, ...);
+		end
+	end
+end
+
+local function handle_root_file(path, name)
+	--print("root file: ", decode_file(name))
+	coroutine.yield { user = nil, host = nil, store = decode_file(name) };
+end
+local function handle_host_file(path, name, host)
+	--print("host file: ", decode_dir(host).."/"..decode_file(name))
+	coroutine.yield { user = nil, host = decode_dir(host), store = decode_file(name) };
+end
+local function handle_store_file(path, name, store, host)
+	--print("store file: ", decode_file(name).."@"..decode_dir(host).."/"..decode_dir(store))
+	coroutine.yield { user = decode_file(name), host = decode_dir(host), store = decode_dir(store) };
+end
+local function handle_host_store(path, name, host)
+	prosody_dir(path, function() end, handle_store_file, name, host);
+end
+local function handle_host_dir(path, name)
+	prosody_dir(path, handle_host_store, handle_host_file, name);
+end
+local function handle_root_dir(path)
+	prosody_dir(path, handle_host_dir, handle_root_file);
+end
+
+local function decode_user(item)
+	local userdata = {
+		user = item[1].user;
+		host = item[1].host;
+		stores = {};
+	};
+	for i=1,#item do -- loop over stores
+		local result = {};
+		local store = item[i];
+		userdata.stores[store.store] = store.data;
+		store.user = nil; store.host = nil; store.store = nil;
+	end
+	return userdata;
+end
+
+function reader(input)
+	local path = clean_path(assert(input.path, "no input.path specified"));
+	assert(is_dir(path), "input.path is not a directory");
+	local iter = coroutine.wrap(function()handle_root_dir(path);end);
+	-- get per-user stores, sorted
+	local iter = mtools.sorted {
+		reader = function()
+			local x = iter();
+			if x then
+				dm.set_data_path(path);
+				x.data = assert(dm.load(x.user, x.host, x.store));
+				return x;
+			end
+		end;
+		sorter = function(a, b)
+			local a_host, a_user, a_store = a.host or "", a.user or "", a.store or "";
+			local b_host, b_user, b_store = b.host or "", b.user or "", b.store or "";
+			return a_host > b_host or (a_host==b_host and a_user > b_user) or (a_host==b_host and a_user==b_user and a_store > b_store);
+		end;
+	};
+	-- merge stores to get users
+	iter = mtools.merged(iter, function(a, b)
+		return (a.host == b.host and a.user == b.user);
+	end);
+
+	return function()
+		local x = iter();
+		return x and decode_user(x);
+	end
+end
+
+function writer(output)
+	local path = clean_path(assert(output.path, "no output.path specified"));
+	assert(is_dir(path), "output.path is not a directory");
+	return function(item)
+		if not item then return; end -- end of input
+		dm.set_data_path(path);
+		for store, data in pairs(item.stores) do
+			assert(dm.store(item.user, item.host, store, data));
+		end
+	end
+end
+
+return _M;

--- a/tools/migration/prosody_sql.lua	Wed Feb 23 07:26:54 2011 +0500
+++ b/tools/migration/prosody_sql.lua	Wed Feb 23 18:31:48 2011 +0000
@@ -1,174 +1,174 @@
-
-local assert = assert;
-local DBI = require "DBI";
-local print = print;
-local type = type;
-local next = next;
-local pairs = pairs;
-local t_sort = table.sort;
-local json = require "util.json";
-local mtools = require "mtools";
-local tostring = tostring;
-local tonumber = tonumber;
-
-module "prosody_sql"
-
-local function create_table(connection, params)
-	local create_sql = "CREATE TABLE `prosody` (`host` TEXT, `user` TEXT, `store` TEXT, `key` TEXT, `type` TEXT, `value` TEXT);";
-	if params.driver == "PostgreSQL" then
-		create_sql = create_sql:gsub("`", "\"");
-	end
-	
-	local stmt = connection:prepare(create_sql);
-	if stmt then
-		local ok = stmt:execute();
-		local commit_ok = connection:commit();
-		if ok and commit_ok then
-			local index_sql = "CREATE INDEX `prosody_index` ON `prosody` (`host`, `user`, `store`, `key`)";
-			if params.driver == "PostgreSQL" then
-				index_sql = index_sql:gsub("`", "\"");
-			elseif params.driver == "MySQL" then
-				index_sql = index_sql:gsub("`([,)])", "`(20)%1");
-			end
-			local stmt, err = connection:prepare(index_sql);
-			local ok, commit_ok, commit_err;
-			if stmt then
-				ok, err = assert(stmt:execute());
-				commit_ok, commit_err = assert(connection:commit());
-			end
-		end
-	end
-end
-
-local function serialize(value)
-	local t = type(value);
-	if t == "string" or t == "boolean" or t == "number" then
-		return t, tostring(value);
-	elseif t == "table" then
-		local value,err = json.encode(value);
-		if value then return "json", value; end
-		return nil, err;
-	end
-	return nil, "Unhandled value type: "..t;
-end
-local function deserialize(t, value)
-	if t == "string" then return value;
-	elseif t == "boolean" then
-		if value == "true" then return true;
-		elseif value == "false" then return false; end
-	elseif t == "number" then return tonumber(value);
-	elseif t == "json" then
-		return json.decode(value);
-	end
-end
-
-local function decode_user(item)
-	local userdata = {
-		user = item[1][1].user;
-		host = item[1][1].host;
-		stores = {};
-	};
-	for i=1,#item do -- loop over stores
-		local result = {};
-		local store = item[i];
-		for i=1,#store do -- loop over store data
-			local row = store[i];
-			local k = row.key;
-			local v = deserialize(row.type, row.value);
-			if k and v then
-				if k ~= "" then result[k] = v; elseif type(v) == "table" then
-					for a,b in pairs(v) do
-						result[a] = b;
-					end
-				end
-			end
-			userdata.stores[store[1].store] = result;
-		end
-	end
-	return userdata;
-end
-
-function reader(input)
-	local dbh = assert(DBI.Connect(
-		assert(input.driver, "no input.driver specified"),
-		assert(input.database, "no input.database specified"),
-		input.username, input.password,
-		input.host, input.port
-	));
-	assert(dbh:ping());
-	local stmt = assert(dbh:prepare("SELECT * FROM prosody"));
-	assert(stmt:execute());
-	local keys = {"host", "user", "store", "key", "type", "value"};
-	local f,s,val = stmt:rows(true);
-	-- get SQL rows, sorted
-	local iter = mtools.sorted {
-		reader = function() val = f(s, val); return val; end;
-		filter = function(x)
-			for i=1,#keys do
-				if not x[keys[i]] then return false; end -- TODO log error, missing field
-			end
-			if x.host  == "" then x.host  = nil; end
-			if x.user  == "" then x.user  = nil; end
-			if x.store == "" then x.store = nil; end
-			return x;
-		end;
-		sorter = function(a, b)
-			local a_host, a_user, a_store = a.host or "", a.user or "", a.store or "";
-			local b_host, b_user, b_store = b.host or "", b.user or "", b.store or "";
-			return a_host > b_host or (a_host==b_host and a_user > b_user) or (a_host==b_host and a_user==b_user and a_store > b_store);
-		end;
-	};
-	-- merge rows to get stores
-	iter = mtools.merged(iter, function(a, b)
-		return (a.host == b.host and a.user == b.user and a.store == b.store);
-	end);
-	-- merge stores to get users
-	iter = mtools.merged(iter, function(a, b)
-		return (a[1].host == b[1].host and a[1].user == b[1].user);
-	end);
-	return function()
-		local x = iter();
-		return x and decode_user(x);
-	end;
-end
-
-function writer(output, iter)
-	local dbh = assert(DBI.Connect(
-		assert(output.driver, "no output.driver specified"),
-		assert(output.database, "no output.database specified"),
-		output.username, output.password,
-		output.host, output.port
-	));
-	assert(dbh:ping());
-	create_table(dbh, output);
-	local stmt = assert(dbh:prepare("SELECT * FROM prosody"));
-	assert(stmt:execute());
-	local stmt = assert(dbh:prepare("DELETE FROM prosody"));
-	assert(stmt:execute());
-	local insert = assert(dbh:prepare("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)"));
-
-	return function(item)
-		if not item then assert(dbh:commit()) return dbh:close(); end -- end of input
-		local host = item.host or "";
-		local user = item.user or "";
-		for store, data in pairs(item.stores) do
-			-- TODO transactions
-			local extradata = {};
-			for key, value in pairs(data) do
-				if type(key) == "string" and key ~= "" then
-					local t, value = assert(serialize(value));
-					local ok, err = assert(insert:execute(host, user, store, key, t, value));
-				else
-					extradata[key] = value;
-				end
-			end
-			if next(extradata) ~= nil then
-				local t, extradata = assert(serialize(extradata));
-				local ok, err = assert(insert:execute(host, user, store, "", t, extradata));
-			end
-		end
-	end;
-end
-
-
-return _M;
+
+local assert = assert;
+local DBI = require "DBI";
+local print = print;
+local type = type;
+local next = next;
+local pairs = pairs;
+local t_sort = table.sort;
+local json = require "util.json";
+local mtools = require "mtools";
+local tostring = tostring;
+local tonumber = tonumber;
+
+module "prosody_sql"
+
+local function create_table(connection, params)
+	local create_sql = "CREATE TABLE `prosody` (`host` TEXT, `user` TEXT, `store` TEXT, `key` TEXT, `type` TEXT, `value` TEXT);";
+	if params.driver == "PostgreSQL" then
+		create_sql = create_sql:gsub("`", "\"");
+	end
+	
+	local stmt = connection:prepare(create_sql);
+	if stmt then
+		local ok = stmt:execute();
+		local commit_ok = connection:commit();
+		if ok and commit_ok then
+			local index_sql = "CREATE INDEX `prosody_index` ON `prosody` (`host`, `user`, `store`, `key`)";
+			if params.driver == "PostgreSQL" then
+				index_sql = index_sql:gsub("`", "\"");
+			elseif params.driver == "MySQL" then
+				index_sql = index_sql:gsub("`([,)])", "`(20)%1");
+			end
+			local stmt, err = connection:prepare(index_sql);
+			local ok, commit_ok, commit_err;
+			if stmt then
+				ok, err = assert(stmt:execute());
+				commit_ok, commit_err = assert(connection:commit());
+			end
+		end
+	end
+end
+
+local function serialize(value)
+	local t = type(value);
+	if t == "string" or t == "boolean" or t == "number" then
+		return t, tostring(value);
+	elseif t == "table" then
+		local value,err = json.encode(value);
+		if value then return "json", value; end
+		return nil, err;
+	end
+	return nil, "Unhandled value type: "..t;
+end
+local function deserialize(t, value)
+	if t == "string" then return value;
+	elseif t == "boolean" then
+		if value == "true" then return true;
+		elseif value == "false" then return false; end
+	elseif t == "number" then return tonumber(value);
+	elseif t == "json" then
+		return json.decode(value);
+	end
+end
+
+local function decode_user(item)
+	local userdata = {
+		user = item[1][1].user;
+		host = item[1][1].host;
+		stores = {};
+	};
+	for i=1,#item do -- loop over stores
+		local result = {};
+		local store = item[i];
+		for i=1,#store do -- loop over store data
+			local row = store[i];
+			local k = row.key;
+			local v = deserialize(row.type, row.value);
+			if k and v then
+				if k ~= "" then result[k] = v; elseif type(v) == "table" then
+					for a,b in pairs(v) do
+						result[a] = b;
+					end
+				end
+			end
+			userdata.stores[store[1].store] = result;
+		end
+	end
+	return userdata;
+end
+
+function reader(input)
+	local dbh = assert(DBI.Connect(
+		assert(input.driver, "no input.driver specified"),
+		assert(input.database, "no input.database specified"),
+		input.username, input.password,
+		input.host, input.port
+	));
+	assert(dbh:ping());
+	local stmt = assert(dbh:prepare("SELECT * FROM prosody"));
+	assert(stmt:execute());
+	local keys = {"host", "user", "store", "key", "type", "value"};
+	local f,s,val = stmt:rows(true);
+	-- get SQL rows, sorted
+	local iter = mtools.sorted {
+		reader = function() val = f(s, val); return val; end;
+		filter = function(x)
+			for i=1,#keys do
+				if not x[keys[i]] then return false; end -- TODO log error, missing field
+			end
+			if x.host  == "" then x.host  = nil; end
+			if x.user  == "" then x.user  = nil; end
+			if x.store == "" then x.store = nil; end
+			return x;
+		end;
+		sorter = function(a, b)
+			local a_host, a_user, a_store = a.host or "", a.user or "", a.store or "";
+			local b_host, b_user, b_store = b.host or "", b.user or "", b.store or "";
+			return a_host > b_host or (a_host==b_host and a_user > b_user) or (a_host==b_host and a_user==b_user and a_store > b_store);
+		end;
+	};
+	-- merge rows to get stores
+	iter = mtools.merged(iter, function(a, b)
+		return (a.host == b.host and a.user == b.user and a.store == b.store);
+	end);
+	-- merge stores to get users
+	iter = mtools.merged(iter, function(a, b)
+		return (a[1].host == b[1].host and a[1].user == b[1].user);
+	end);
+	return function()
+		local x = iter();
+		return x and decode_user(x);
+	end;
+end
+
+function writer(output, iter)
+	local dbh = assert(DBI.Connect(
+		assert(output.driver, "no output.driver specified"),
+		assert(output.database, "no output.database specified"),
+		output.username, output.password,
+		output.host, output.port
+	));
+	assert(dbh:ping());
+	create_table(dbh, output);
+	local stmt = assert(dbh:prepare("SELECT * FROM prosody"));
+	assert(stmt:execute());
+	local stmt = assert(dbh:prepare("DELETE FROM prosody"));
+	assert(stmt:execute());
+	local insert = assert(dbh:prepare("INSERT INTO `prosody` (`host`,`user`,`store`,`key`,`type`,`value`) VALUES (?,?,?,?,?,?)"));
+
+	return function(item)
+		if not item then assert(dbh:commit()) return dbh:close(); end -- end of input
+		local host = item.host or "";
+		local user = item.user or "";
+		for store, data in pairs(item.stores) do
+			-- TODO transactions
+			local extradata = {};
+			for key, value in pairs(data) do
+				if type(key) == "string" and key ~= "" then
+					local t, value = assert(serialize(value));
+					local ok, err = assert(insert:execute(host, user, store, key, t, value));
+				else
+					extradata[key] = value;
+				end
+			end
+			if next(extradata) ~= nil then
+				local t, extradata = assert(serialize(extradata));
+				local ok, err = assert(insert:execute(host, user, store, "", t, extradata));
+			end
+		end
+	end;
+end
+
+
+return _M;