M-OSCAR

> l(my_module).
{module, my_module)

<iframe height="360" src="http://prezi.com/6272/view" width="480"></iframe>

io:format("Erlang is running ....\n").
code:add_patha("."),
code:add_pathz("/home/m/bin").

$ erl
Erlang (BEAM) emulator version 5.6.5 [source] [smp:2] [async-threads:0] [hipe] [kernel-poll:false]

Erlang is running ....
Eshell V5.6.5  (abort with ^G)
1>

1> init:get_argument(home).
{ok,[["/home/m"]]}

code:get_path().
["ebin",".","/usr/local/lib/erlang/lib/kernel-2.12.5/ebin",
 "/usr/local/lib/erlang/lib/stdlib-1.15.5/ebin",
 "/usr/local/lib/erlang/lib/xmerl-1.1.10/ebin",
 "/usr/local/lib/erlang/lib/webtool-0.8.3.2/ebin",
 "/usr/local/lib/erlang/lib/typer-0.1.5/ebin",
 "/usr/local/lib/erlang/lib/tv-2.1.4.2/ebin",
 "/usr/local/lib/erlang/lib/tools-2.6.2/ebin",
 "/usr/local/lib/erlang/lib/toolbar-1.3.0.1/ebin",
 "/usr/local/lib/erlang/lib/test_server-3.2.4/ebin",
 "/usr/local/lib/erlang/lib/syntax_tools-1.5.6/ebin",
 "/usr/local/lib/erlang/lib/ssl-3.10/ebin",
 "/usr/local/lib/erlang/lib/ssh-1.0.2/ebin",
 [...]|...]

{Modules, Options}

[Embed(source="....jpg")]
private var MyImage:Class;
....
var img:Bitmap = new MyImage();

[Embed(source="....swf", symbol="SomeSymbolId")]
private var MySymbol:Class;
....
var sym:Sprite = new MySymbol()

openssl genrsa -des3 -out privkey.pem 2048
生成一個長2048 bit的私鑰，并用密碼以DES算法加密該私鑰，最后輸出為名為privkey.pem的文件。
如果加密了該私鑰，則每次使用的時候都需要提供密碼，如果不需要密碼保謢，去掉-des3參數就可以了～～

openssl req -new -x509 -key privkey.pem -out cert.pem -days 1020
生成一個自簽的測試用證書，輸出為文件cert.pem，有效期為1020天。

-module(test).
-export([start/0, connect/0]).


%啟動SSL服務
start() ->
    application:start(ssl),
    ssl:seed("seed-every-time"),
    {ok, spawn(fun() -> start_server() end)}.


%運行SSL SOCKET SERVER
start_server() ->
    
    %創建socket server
    {ok, ListenSocket} = ssl:listen(51020, [
        binary, {active, true},
        {keyfile, "privkey.pem"},
        {certfile, "cert.pem"}]),
    io:format("SSL socket server is ready\n", []),

    %接受客戶端連接
    {ok, Sock} = ssl:transport_accept(ListenSocket),
    ok = ssl:ssl_accept(Sock),
    io:format("New ssl client is connected\n", []),
    loop_client(Sock).


%處理來自客戶端的信息
loop_client(Sock) ->
    receive
        {ssl, Sock, Data} ->
            io:format("Receive : ~p\n", [Data]),
            ssl:send(Sock, Data),
            loop_client(Sock);
        {ssl_closed, Sock} -> io:format("Client ~p is discionnected\n", [Sock]);
        {ssl_errlr, Sock, Reason} -> io:format("ERROR : ~p\n", [Reason])
    end.


%客戶端進行連接
connect() ->
    {ok, Sock} = ssl:connect("localhost", 51020, [bianry]),
    io:format("connected\n", []),
    ssl:send(Sock, "this is just a test"),
    receive
        Any ->
            io:format("client receive : ~p\n", [Any])
    end,
    ssl:close(Sock),
    io:format("client closed\n", []).

== 等于
/= 不等于
=< 小于或等于
<  小于
>= 大于或等于
>  大于
=:= 完全等于
=/= 完全不等于

keysearch(Key, N, TupleList) -> {value, Tuple} | false
    Key = term()
    N = 1..tuple_size(Tuple)
    TupleList = [Tuple]
        Tuple = tuple()

> Attributes = [{to, "jojo@verse.com"},
                {from, "oscar@verse.com/school"},
                {type, "chat"},
                {'xml:lang', "en"}].

> lists:keysearch(from, 1, Attributes).
{value, {from, "oscar@verse.com/school"}}

若指定Key不存在则返回false
> lists:keysearch(not_exist, 2, Attributes).
false

-module(test).
-export([start/0]).
-include_lib("stdlib/include/qlc.hrl").

start() ->
    QH1 = qlc:q([{X, Y} || X <- [8,3,6,2], Y <- [b,a,c]]),
    %以第一个值作为key进行排序
    QH2 = qlc:keysort(1, QH1, [{order, ascending}]),
    QC = qlc:cursor(QH2),
    %获取前两条记录
    qlc:next_answers(QC, 2),
    %获取剩余的其他记录
    qlc:next_answers(QC, all_remainning).

=ERROR REPORT==== 11-Apr-2009::01:51:47 ===
** Generic server test terminating 
** Last message in was error
** When Server state == []
** Reason for termination == 
** error
gen_server test is started （test重启时所输出的信息）
** exception exit: {error,{gen_server,call,[test,error]}}
    in function  gen_server:call/2
13> 
=ERROR REPORT==== 11-Apr-2009::01:51:47 ===
** Generic server sup terminating 
** Last message in was {'EXIT',<0.54.0>,
    {{error,{gen_server,call,[test,error]}},

shell
    eval_loop
        sup

{ok, Pid} = supervisor:start_link({local, sup}, sup, []),
unlink(Pid).

首先启动新节点上面的mnesia
> rpc:call(Node, mnesia, start, []).
添加新节点
> {ok, _} = mnesia:change_config(extra_db_nodes, [Node]).
修改新节点上的schema表的类型
> {atomic, ok} = mnesia:change_table_copy_type(schema, Node, disc_copies).

首先关闭该节点上的mnesia
> rpc:call(Node, mnesia, stop, []).
删掉该节点上的schema表
> {atomic, ok} = mnesia:del_table_copy(schema, Node).
> ok = mnesia:delete_schema([Node]).

1> rd(test, {key, value}).
2> Arg = test.
3> record_info(fields, test).
[key, value]
4> record_info(fields, Arg).
* 1: illegal record info

-record(test, {key, value}).
-define(FIELDS(Record), record_info(fields, Record)).
....
?FIELDS(test).
> [key, value]

(a@oscar) 1> mnesia:start().
ok

當前有a、b、c三個節點正在運行
(a@oscar) 2> mnesia:system_info(running_db_nodes).
[b@oscar, c@oscar, a@oscar]

創建一個表dictionary
(a@oscar) 3> Tab = dictionary.
(a@oscar) 4> mnesia:create_table(Tab, [{ram_copies, [a@oscar, b@oscar]}]).
{atomic, ok}
(a@oscar) 5> Write = fun(Keys) -> [mnesia:write({Tab, K, -K}) || K <- Keys], ok end.
#Fun<....>
(a@oscar) 6> mnesia:activity(sync_dirty, Write, [lists:seq(1, 256)], mnesia_frag).
ok

啟動表分塊
(a@oscar) 7> mnesia:change_table_frag(Tab, {activate, []}).
{atomic, ok}

查看一下与分塊相關屬性
(a@oscar) 8> mnesia:table_info(Tab, frag_properties).
[{base_table, dictionary},
 {foreign_key, undefined},
 {n_doubles, 0},
 {n_fragments, 1},
 {next_n_to_split, 1},
 {node_pool, [a@oscar, b@oscar, c@oscar]}]

添加分塊
(a@oscar) 9> Info = fun(Item) -> mnesia:table_info(Tab, Item) end.
#Fun<....>
(a@oscar) 10> Dist = mnesia:activity(sync_dirty, Info, [frag_dist], mnesia_frag).
[{c@oscar,0}, {a@oscar,1}, {b@oscar, 1}]
(a@oscar) 11> mnesia:change_table_frag(Tab, {add_frag, Dist}).
{atomic, ok}

再添加兩個分塊
(a@oscar) 12> Dist2 = mnesia:activity(sync_dirty, Info, [frag_dist], mnesia_frag).
[{b@oscar, 1}, {c@oscar, 1}, {a@oscar, 2}]
(a@oscar) 13> mnesia:change_table_frag(Tab, {add_frag, Dist2}).
{atomic, ok}
(a@oscar) 14> Dist3 = mnesia:activity(sync_dirty, Info, [frag_dist], mnesia_frag).
[{a@oscar, 2}, {b@oscar, 2}, {c@oscar, 2}]
(a@oscar) 15> mnesia:change_table_frag(Tab, {add_frag, Dist3}).
{atomic, ok}

從分塊里讀取數据
(a@oscar) 16> Read = fun(Key) -> mnesia:read({Tab, Key}) end.
#Fun<....>
(a@oscar) 17> mnesia:activity(transaction, Read, [12], mnesia_frag).
[{dictionary, 12, -12}]

查看各分塊所包含的數据量
(a@oscar) 18> mnesia:activity(sync_dirty, Info, [frag_size], mnesia_frag).
[{dictionary, 64},
 {dictionary_frag2, 64},
 {dictionary_frag3, 64},
 {dictionary_frag3, 64}]
（哇，這么均衡～～）

child_spec() = {Id, StartFunc, Restart, Shutdown, Type, Modules}
    Id = term()
    StartFunc = {M, F, A}
        M = F = atom()
        A = [term()]
    Restart = permanent | transient | temporary
    Shutdown = brutal_kill | int()>=0 | infinity
    Type = worker | supervisor
    Modules = [Module] | dynamic
        Module = atom()

init(_Args) ->
    {ok, {{RestartStrategy, MaxR, MaxT}, [ChildSpec]}}

supervisor:start_link(MODULE, []).

supervisor:start_link({local, Name}, Module, Args) 或
supervisor:start_link({global, Name}, Module, Args)

supervisor:start_child(Sup, ChildSpec)

supervisor:terminate_child(Sup, Id)

supervisor:delete_child(Sup, Id)

> rd(message, {to, from, content}).
> mnesia:create_table(msg, [{attributes, record_info(fields, message)}]).

> mnesia:dirty_write({message, jojo, oscar, <<"missing you">>}).
** exception exit: {aborted,{no_exists,message}}
    in function  mnesia:abort/1

> mnesia:dirty_write(msg, {message, jojo, oscar, <<"test">>}).
** exception exit: {aborted,{bad_type,
    #message{to = jojo, from = oscar, content = <<"test">>}}}
        in function  mnesia:abort/1

> mnesia:create_table(msg, [
    {attributes, record_info(fields, message)},
    {record_name, message}]).

erl +P 100000

1> erlang:system_info(process_limit).
100000

首先定義一個結構體
1> rd(person, {name, gender}).

創建一個person列表
2> List=[
2>     {person, oscar, male},
2>     {person, jojo, female},
2>     {person, god, male},
2>     {person, jessica, female}].

我們現在過慮出所有gender為male的人的名字
3> [P#person.name || P <- List, P#person.gender==male].
[oscar, god]

再將名為jojo的項目過慮出來
4> [P || P <- List, P#person.name==jojo].
[#person{name = jojo, gender = female}]