今天電視新聞裡播著某傳銷公司的激烈爭執,裡面有這麼一段對話,讀書怎麼會無用的? 這不是我說的,是大前研一說的...我們似乎還是非常習慣穿著名牌,描述著事不關己的事物,引經據典;卻不深究字義外的涵義,囫圇吞棗的消化大量沒有營養的口號,前幾天;甚至看到有人問一個蠢問題~~...那些趨勢大師 管理大師...之云...,如果沒有自己的思考觀點,不如;不要知悉這些所謂的名人語錄,盡信書不如無書,我想;他的重點不是無書對吧!
新聞裡另外一個有趣的對話是這樣說的: 你是誰ㄚ! 我台大的, 呵呵... 用自己的學歷來陳述讀書不重要的論點,呵呵...真是有趣的邏輯,對照他的同事所說的話,萬般皆下品惟有讀書高... 這句話不知道是矛還是盾
Thursday, September 27, 2007
Monday, September 24, 2007
Quicksort in Erlang
-module(sort).
-export([sort/1]).
sort([]) -> [];
sort([PivotRest]) ->
{Smaller, Bigger} = split(Pivot, Rest),
lists:append(sort(Smaller), [Pivotsort(Bigger)]).
split(Pivot, L) ->
split(Pivot, L, [], []).
split(Pivot, [], Smaller, Bigger) ->
{Smaller, Bigger};
split(Pivot, [HdTl], Smaller, Bigger) when Hd <>
split(Pivot, Tl, [HdSmaller], Bigger);
split(Pivot, [HdTl], Smaller, Bigger) when Hd >= Pivot ->
split(Pivot, T, Smaller, [HdBigger]).
-export([sort/1]).
sort([]) -> [];
sort([PivotRest]) ->
{Smaller, Bigger} = split(Pivot, Rest),
lists:append(sort(Smaller), [Pivotsort(Bigger)]).
split(Pivot, L) ->
split(Pivot, L, [], []).
split(Pivot, [], Smaller, Bigger) ->
{Smaller, Bigger};
split(Pivot, [HdTl], Smaller, Bigger) when Hd <>
split(Pivot, Tl, [HdSmaller], Bigger);
split(Pivot, [HdTl], Smaller, Bigger) when Hd >= Pivot ->
split(Pivot, T, Smaller, [HdBigger]).
Thursday, September 20, 2007
我們需要的是思考而不是口號
很多人都在談M型社會的來臨,似乎大前言一帶來了這個口號的趨勢,有很多似是而非的觀念由此衍伸,新聞裡動不動就是M型社會這個詞,然而;我們需要的是思考並不是口號;難道百年前的日本,天皇與庶民的結構就不是M型社會? 這值得我們思考,我並沒有指出現在貧富差距的現象是否正在擴大的問題,我只是講出很多人盲目追求口號的事實;是不是M化反而不是重點,我們思考口號背後的邏輯或是只是盲目 急躁的替自己或別人貼上標籤?很多東西不能囫圇吞棗照單全收的, 趨勢大師說的是方向,除了羅盤,船還需要舵才能航向目標,管理要配合規模,當規模不夠大,細部的作為應重於方向,不是說方向不重要而是對這種規模的組織;管理不是第一要務,太多的方向與趨勢預測像是座在沒有舵的船上,有再多的方向預測再精準的羅盤也無法到達目的
我們需要的是思考不是口號,這好像有點偏離這個BLOG 的調性,但是請思考看看;.NET 與JAVA 這幾年的纏鬥,以及網路上只有.NET才是王道的言論...與前述觀點是否異曲同工? 我們需要的其實是理解技術背後的邏輯,單純的技術觀點與思考,而不是隨波逐流,我們可以反過來看郭台銘最近的言論,請問他一件事,如果鴻海的績效這麼好,那麼是否代表鴻海的員工為的是興趣而不是錢;那麼在這樣的前提下,鴻海的配股如果少一半,我們應該有理由相信,鴻海會更賺錢,因為這些員工是為了興趣而工作 不會為了錢而離開,如果這個答案是否定的,那麼代表鴻海的員工是為了錢而非興趣而工作,那麼;鴻海又為何高薪聘僱那些他們自認為不是最好的員工?這似乎自相矛盾到不行,這裡只點出部份學而不思的毛病 盲從 且不經思考地"引經據典" 以及這類速食未經消化的謬誤,切勿淪為英國詩人Robert Browning在童話故事[吹笛人]所描述的耗子只知盲從起舞,多思考一些口號或技術背後真實的觀點,這樣對整體才是有益
我們需要的是思考不是口號,這好像有點偏離這個BLOG 的調性,但是請思考看看;.NET 與JAVA 這幾年的纏鬥,以及網路上只有.NET才是王道的言論...與前述觀點是否異曲同工? 我們需要的其實是理解技術背後的邏輯,單純的技術觀點與思考,而不是隨波逐流,我們可以反過來看郭台銘最近的言論,請問他一件事,如果鴻海的績效這麼好,那麼是否代表鴻海的員工為的是興趣而不是錢;那麼在這樣的前提下,鴻海的配股如果少一半,我們應該有理由相信,鴻海會更賺錢,因為這些員工是為了興趣而工作 不會為了錢而離開,如果這個答案是否定的,那麼代表鴻海的員工是為了錢而非興趣而工作,那麼;鴻海又為何高薪聘僱那些他們自認為不是最好的員工?這似乎自相矛盾到不行,這裡只點出部份學而不思的毛病 盲從 且不經思考地"引經據典" 以及這類速食未經消化的謬誤,切勿淪為英國詩人Robert Browning在童話故事[吹笛人]所描述的耗子只知盲從起舞,多思考一些口號或技術背後真實的觀點,這樣對整體才是有益
Monday, September 17, 2007
Tuesday, September 11, 2007
Sunday, September 9, 2007
Metaweb Query Language 這個有趣
The Metaweb Query Language (MQL) is based on JSON and query-by-example. The MQL and API documentation can be found on the Freebase website in the developers' area. There is also an online Query Editor tool, with many examples of MQL, at http://www.freebase.com/view/queryeditor/
perl CPAN Module:http://search.cpan.org/~skud/Metaweb-0.05/
perl CPAN Module:http://search.cpan.org/~skud/Metaweb-0.05/
Friday, September 7, 2007
pure function
A pure function:
Has no side effects
Return value depends only on arguments
Example:
sub factorial {
my $n = shift;
$n == 0 ? 1 : $n * factorial($n-1);
}
cache 只對pure function 有意義;這可以思考,查詢一個檔案的修改時間的這種function,他並非一個pure function,所以;對非pure function做cache 是沒有意義的,這裡有一個例子:
Highly Recursive Functions
sub fib {
my ($n) = @_;
return $n if $n ==0 || $n == 1;
return fib($n-2) + fib($n-1);
}
This function is very very slow!
Caching Fixes Recursion
Solution: Caching
@fib = (0, 1);
sub fib {
my ($n) = @_;
return $fib[$n] if defined $fib[$n];
return $fib[$n] = fib($n-1) + fib($n-2);
}
fib(20) computes fib(18) and fib(19)
fib(19) goes to compute fib(18)
But it is already in $fib[18]
Function is now very fast,Almost as fast as a pure iterative version,
Unlike the iterative version, this version required no ingenuity
以上文章節錄自 http://perl.plover.com/yak/hw-dcpm/
Has no side effects
Return value depends only on arguments
Example:
sub factorial {
my $n = shift;
$n == 0 ? 1 : $n * factorial($n-1);
}
cache 只對pure function 有意義;這可以思考,查詢一個檔案的修改時間的這種function,他並非一個pure function,所以;對非pure function做cache 是沒有意義的,這裡有一個例子:
Highly Recursive Functions
sub fib {
my ($n) = @_;
return $n if $n ==0 || $n == 1;
return fib($n-2) + fib($n-1);
}
This function is very very slow!
Caching Fixes Recursion
Solution: Caching
@fib = (0, 1);
sub fib {
my ($n) = @_;
return $fib[$n] if defined $fib[$n];
return $fib[$n] = fib($n-1) + fib($n-2);
}
fib(20) computes fib(18) and fib(19)
fib(19) goes to compute fib(18)
But it is already in $fib[18]
Function is now very fast,Almost as fast as a pure iterative version,
Unlike the iterative version, this version required no ingenuity
以上文章節錄自 http://perl.plover.com/yak/hw-dcpm/
Monday, September 3, 2007
[微程式-技術研討會]xmpp(rfc-3920) 導讀
XMPP協定導讀
一. 什麼是jabber? 什麼是xmpp?
The Extensible Messaging and Presence Protocol (XMPP) is an open Extensible Markup Language XML [XML] protocol for near-real-time messaging, presence, and request-response services. The basic syntax and semantics were developed originally within the Jabber open-source community, mainly in 1999. In 2002, the XMPP WG was chartered with developing an adaptation of the Jabber protocol that would be suitable as an IETF instant messaging (IM) and presence technology. As a result of work by the XMPP WG, the current memo defines the core features of XMPP 1.0; the extensions required to provide the instant messaging and presence functionality defined in RFC 2779 [IMP REQS] are specified in Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence [XMPP IM].
二. Socket/XMPP 程式需注意的幾個重點
1.架構(select poll epoll AIO kqueue IOCP / Thread / Process / LWP)
2.setsockopt比較值得討論的參數
setsockopt( $listen,SOL_SOCKET,SO_REUSEADDR,1); 伺服端
setsockopt( $sockfd,SOL_SOCKET,SO_KEEPALIVE,pack("l",$SO_KEEPALIVE ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_KEEPIDLE,pack( "l", $TCP_KEEPIDLE ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_KEEPCNT,pack( "l", $TCP_KEEPCNT ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_KEEPINTVL,pack( "l", $TCP_KEEPINTVL ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_NODELAY,pack( "l", 1 ) );
setsockopt( $listen, SOL_SOCKET, SO_RCVBUF, 8192 );
setsockopt( $listen, SOL_SOCKET, SO_SNDBUF, 8192 );
3.flow(read/sysread/write/syswrite buffer)
4.XML Stream (SAX/DOM)
三. XMPP (RFC-3920 導讀)
1. XMPP 協定
Rfc-3920
Rfc-3921
Rfc-3922
Rfc-3923
Rfc-4622
可參考網站
http://www.xmpp.org/rfcs/
http://www.xmpp.org/extensions/
http://wiki.jabbercn.org/space/start
http://hi.baidu.com/jabber/blog/category/Jep
2. XML STREAM
<stream>
<presence>
<show/>
</presence>
<message to='foo'>
<body/>
</message>
<iq to='bar'>
<query/>
</iq>
…
</stream>
3. xmpp 的主要xml 標籤
訊息傳遞:<message/>
線上資訊:<presence/>
查詢與回應:<iq/>
目前實做的功能
<query xmlns=‘http://jabber.org/protocol/disco#info’>
<identity category='server' name='MJS' type='im'/>
<feature var='http://jabber.org/protocol/disco#info'/>
<feature var='http://jabber.org/protocol/disco#items'/>
<feature var='jabber:iq:private'/>
<feature var='jabber:iq:roster'/>
<feature var='jabber:iq:time'/>
<feature var='msgoffline'/>
</query>
4. 交易
以下定義
C->S 為CLIENT 傳送資料到 SERVER,
S->C 定義為伺服器傳遞資料給CLIENT,
Cn 代表第n個client
C1->S (Part1)
<?xml version='1.0'?>
<stream:stream
to='127.0.0.1'
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
version='1.0'>
S->C1 (Part2)
<?xml version='1.0'?>
<stream:stream
from='127.0.0.1’
id='someid'
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
version='1.0'>
.認證與BINDING過程…(文件稍後會解釋交易過程) ,目前server不支援tls 的交易
C1->S
<message from='luke_shei@127.0.0.1/Resource1'
to=' admin@127.0.0.1/Resource2'
xml:lang='zh-tw' id=’R1-2’><body><測試訊息></body></message>
C1->S->C2(C1傳遞資訊給SERVER ,再經由JID 的資訊傳送給C2)
C2->S
<message from=' admin@127.0.0.1/Resource2'
to=' luke_shei@127.0.0.1/Resource1'
xml:lang='zh-tw' id=’R1-2’>
<body>回應訊息</body>
</message>
C2->S->C1(C2傳遞資訊給SERVER ,再經由JID 的資訊傳送給C1)
C1->S
</stream:stream>
S->C1
</stream:stream>
4.1 from/to 屬性:
a.C->S
b.S->C
Att /Action initiating to receiving receiving to initiating
to hostname of receiver silently ignored
From silently ignored hostname of receiver
id silently ignored session key
xml:lang default language default language
version signals XMPP 1.0 support signals XMPP 1.0 support
4.2 jid(Jabber Identifier) 形式:
a.node@domain/resource
b.node@domain
ps:事實上node 指的是用後帳號,目前;我們不支援將a,b 視為同一帳號的兩個不同的資
源binding,因此; node@domain/resource1 與node@domain/resource2 再目前的
系統是視為同一帳號的登入,而目前不支援同一帳號重覆登入
5. XMPP 需注意的事項
A. 內容替換
#x22 (")
#x26 (&)
#x27 (')
#x2F (/)
#x3A (:)
#x3C (<)
#x3E (>)
#x40 (@)
B. XML為case sensitive, 包括:認證所使用的UID
C.屬性皆以 ‘ 做為分隔
D.屬性是沒有順序性的
E.文件字集應該使用UTF-8
F.同一帳號應該以登入一次為限
G. 不應該預期交易的過程是否有斷行
I.Client 要斷線前,應保持良好習慣先傳遞
<presence type="unavailable"/></stream:stream> 再執行斷線
6. 認證交易(SASL RFC-2831)
(前略) 參考前述Part1 Part2
<Server 告知Client , 目前支援的認證型態>
S->C
<stream:features>
<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
<mechanism>DIGEST-MD5</mechanism>
<mechanism>PLAIN</mechanism>
</mechanisms>
</stream:features>
Ps:目前規劃使用的是 DIGEST-MD5 , PLAIN是為了讓SPARK(Jabber Client可以進行測試),而jabber::component 目前使用的是另一種handshark的機制
<Client 選擇一個認證機制>
C->S
<auth xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechani
sm='DIGEST-MD5'/>
Server 傳送challenge code
S->C
<challenge xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
cmVhbG09InNvbWVyZWFsbSIsbm9uY2U9Ik9BNk1HOX
RFUUdtMmhoIixxb3A9ImF1dGgiLGNoYXJzZXQ9dXRmL
TgsYWxnb3JpdGhtPW1kNS1zZXNzCg==</challenge>
中間這字串解開base 64 後的資訊為
realm="somerealm",nonce="OA6MG9tEQGm2hh",qop="auth",
charset=utf-8,algorithm=md5-sess
Client 傳送challenge code 給server
C->S
<response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
dXNlcm5hbWU9InNvbWVub2RlIixyZWFsbT0ic29tZXJlY
WxtIixub25jZT0iT0E2TUc5dEVRR20yaGgiLGNub25jZT0i
T0E2TUhYaDZWcVRyUmsiLG5jPTAwMDAwMDAxLHFv
cD1hdXRoLGRpZ2VzdC11cmk9InhtcHAvZXhhbXBsZS5j
b20iLHJlc3BvbnNlPWQzODhkYWQ5MGQ0YmJkNzYwY
TE1MjMyMWYyMTQzYWY3LGNoYXJzZXQ9dXRmLTgK
</response>
中間字串的base64解碼為
username="somenode",realm="somerealm",nonce="
OA6MG9tEQGm2hh",cnonce="OA6MHXh6VqTrRk",
nc=00000001,qop=auth,digest-uri="xmpp/example.com"
,response=d388dad90d4bbd760a152321f2143af7,charset=utf-8
<如驗證失敗 伺服器回應認證失敗>
S->C
<failure xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
<temporary-auth-failure/>
</failure>
</stream:stream>
隨即斷線
<伺服器傳送驗證碼>
S->C
<challenge xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>cn
NwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJh
YmNkZmZmZAo=</challenge>
中間字串BASE64解碼為
rspauth=ea40f60335c427b5527b84dbabcdfffd
<CLIENT 回應驗證碼正確性>
C->S
<response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'/>
<伺服器回應認證成功>
S->C
<success xmlns='urn:ietf:params:xml:ns:xmpp-sasl'/>
<認證成功後 Client 重新初始化 xml stream>
C->S
<stream:stream
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
to='example.com'
version='1.0'>
<伺服器回應所支援的feature>
S->C
<stream:stream
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
id='c2s_345'
from='example.com'
version='1.0'>
<stream:features>
<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'/>
<session xmlns='urn:ietf:params:xml:ns:xmpp-session'/>
</stream:features>
<Client 請求Binding>
C->S
<iq id="jcl_8" type="set"><bind xmlns="urn:ietf:
params:xml:ns:xmpp-bind"><resource>Exodus<
/resource>
</bind></iq>
<伺服器回應Bind 的資源>
S->C
<iq type='result' id='jcl_8'><bind xmlns='urn:ietf:params
:xml:ns:xmpp-bind'><jid>admin@127.0.0.1/Exodus<
/jid><
/bind></iq>
<Client 請求session 交易>
C->S
<iq id="jcl_9" type="set"><session xmlns="urn:ietf:params:
xml:ns:xmpp-session"/></iq>
<Server 回應 session 交易>
S->C
<iq type='result' id='jcl_9'><session xmlns='urn:ietf:params:xml:
ns:xmpp-session'></session></iq>
5.認證演算過程
A. Server 傳送challenge code
S->C
BASE64(realm="elwood.innosoft.com",nonce="OA6MG9tEQGm2hh",
qop="auth", algorithm=md5-sess,charset=utf-8)
B. Client 傳送challenge code 給server
以下定義
開頭為$者為變數
開頭為 $$realm_xyz 代表該變數來自於realm 的屬性,而範例的值為xyz
以下範例 chris 為一個帳號名稱
+ 代表字串相加
‘ 代表固定字串內的值
MD5 代表其內字串使用MD5做簽章但不轉成HEX CODE
MD5_HEX 代表其內字串使用MD5做簽章且轉成HEX CODE
C->S
$PASSWORD 為該USER 的密碼
$A1=(MD5(‘chris’ + ‘:’ + $$realm_elwood.innosoft.com + ‘:’ + $PASSWORD) + ‘:’ + $$nonce _OA6MG9tEQGm2hh + ‘:’ + $$conce_OA6MHXh6VqTrRk)
$A2=’AUTHENTICATE’ + ‘:’ + $$realm_jabber/elwood.innosoft.com
$response=MD5_HEX(MD5_HEX($A1)+’:’+ $$nonce_OA6MG9tEQGm2hh +’:’+ $$nc_00000001 + ’:’ + $$conce_OA6MHXh6VqTrRk+’:’+ $$qop_auth +’:’ + MD5_HEX($A2))
Base64(charset=utf-8,username="chris",realm="elwood.innosoft.com", nonce="OA6MG9tEQGm2hh",nc=00000001,cnonce="OA6MHXh6VqTrRk", digest-uri="jabber/elwood.innosoft.com",response=$response,qop=auth)
Server 隨即驗證 $response 如失敗則回傳失敗,否則進行下一個動作
C: 伺服器傳送驗證碼
rspauth=MD5_HEX(MD5_HEX($A1) + ‘:’ + $$nonce_OA6MG9tEQGm2hh + ’:’ + $$nc_00000001 + ’:’ + $$conce_OA6MHXh6VqTrRk + ’:’ + $$qop_auth+MD5_HEX(‘:’ + $$digest-uri _jabber/elwood.innosoft.com))
Client 應該檢驗 rspauth
七.相關資源
Jabber Client下載位置
Exodus ( http://www.jabberstudio.org/projects/exodus/releases/ )
Pandion( http://www.pandion.be/download/ )
Spaek( http://www.igniterealtime.org/downloads/download-landing.jsp?file=spark/spark_2_5_2.exe )
C 所常用的 XML parser library
http://expat.sourceforge.net/
msxml sax相關資源
http://www.perfectxml.com/msxmlSAX.asp
一. 什麼是jabber? 什麼是xmpp?
The Extensible Messaging and Presence Protocol (XMPP) is an open Extensible Markup Language XML [XML] protocol for near-real-time messaging, presence, and request-response services. The basic syntax and semantics were developed originally within the Jabber open-source community, mainly in 1999. In 2002, the XMPP WG was chartered with developing an adaptation of the Jabber protocol that would be suitable as an IETF instant messaging (IM) and presence technology. As a result of work by the XMPP WG, the current memo defines the core features of XMPP 1.0; the extensions required to provide the instant messaging and presence functionality defined in RFC 2779 [IMP REQS] are specified in Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence [XMPP IM].
二. Socket/XMPP 程式需注意的幾個重點
1.架構(select poll epoll AIO kqueue IOCP / Thread / Process / LWP)
2.setsockopt比較值得討論的參數
setsockopt( $listen,SOL_SOCKET,SO_REUSEADDR,1); 伺服端
setsockopt( $sockfd,SOL_SOCKET,SO_KEEPALIVE,pack("l",$SO_KEEPALIVE ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_KEEPIDLE,pack( "l", $TCP_KEEPIDLE ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_KEEPCNT,pack( "l", $TCP_KEEPCNT ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_KEEPINTVL,pack( "l", $TCP_KEEPINTVL ) );
setsockopt( $sockfd,IPPROTO_TCP,TCP_NODELAY,pack( "l", 1 ) );
setsockopt( $listen, SOL_SOCKET, SO_RCVBUF, 8192 );
setsockopt( $listen, SOL_SOCKET, SO_SNDBUF, 8192 );
3.flow(read/sysread/write/syswrite buffer)
4.XML Stream (SAX/DOM)
三. XMPP (RFC-3920 導讀)
1. XMPP 協定
Rfc-3920
Rfc-3921
Rfc-3922
Rfc-3923
Rfc-4622
可參考網站
http://www.xmpp.org/rfcs/
http://www.xmpp.org/extensions/
http://wiki.jabbercn.org/space/start
http://hi.baidu.com/jabber/blog/category/Jep
2. XML STREAM
<stream>
<presence>
<show/>
</presence>
<message to='foo'>
<body/>
</message>
<iq to='bar'>
<query/>
</iq>
…
</stream>
3. xmpp 的主要xml 標籤
訊息傳遞:<message/>
線上資訊:<presence/>
查詢與回應:<iq/>
目前實做的功能
<query xmlns=‘http://jabber.org/protocol/disco#info’>
<identity category='server' name='MJS' type='im'/>
<feature var='http://jabber.org/protocol/disco#info'/>
<feature var='http://jabber.org/protocol/disco#items'/>
<feature var='jabber:iq:private'/>
<feature var='jabber:iq:roster'/>
<feature var='jabber:iq:time'/>
<feature var='msgoffline'/>
</query>
4. 交易
以下定義
C->S 為CLIENT 傳送資料到 SERVER,
S->C 定義為伺服器傳遞資料給CLIENT,
Cn 代表第n個client
C1->S (Part1)
<?xml version='1.0'?>
<stream:stream
to='127.0.0.1'
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
version='1.0'>
S->C1 (Part2)
<?xml version='1.0'?>
<stream:stream
from='127.0.0.1’
id='someid'
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
version='1.0'>
.認證與BINDING過程…(文件稍後會解釋交易過程) ,目前server不支援tls 的交易
C1->S
<message from='luke_shei@127.0.0.1/Resource1'
to=' admin@127.0.0.1/Resource2'
xml:lang='zh-tw' id=’R1-2’><body><測試訊息></body></message>
C1->S->C2(C1傳遞資訊給SERVER ,再經由JID 的資訊傳送給C2)
C2->S
<message from=' admin@127.0.0.1/Resource2'
to=' luke_shei@127.0.0.1/Resource1'
xml:lang='zh-tw' id=’R1-2’>
<body>回應訊息</body>
</message>
C2->S->C1(C2傳遞資訊給SERVER ,再經由JID 的資訊傳送給C1)
C1->S
</stream:stream>
S->C1
</stream:stream>
4.1 from/to 屬性:
a.C->S
b.S->C
Att /Action initiating to receiving receiving to initiating
to hostname of receiver silently ignored
From silently ignored hostname of receiver
id silently ignored session key
xml:lang default language default language
version signals XMPP 1.0 support signals XMPP 1.0 support
4.2 jid(Jabber Identifier) 形式:
a.node@domain/resource
b.node@domain
ps:事實上node 指的是用後帳號,目前;我們不支援將a,b 視為同一帳號的兩個不同的資
源binding,因此; node@domain/resource1 與node@domain/resource2 再目前的
系統是視為同一帳號的登入,而目前不支援同一帳號重覆登入
5. XMPP 需注意的事項
A. 內容替換
#x22 (")
#x26 (&)
#x27 (')
#x2F (/)
#x3A (:)
#x3C (<)
#x3E (>)
#x40 (@)
B. XML為case sensitive, 包括:認證所使用的UID
C.屬性皆以 ‘ 做為分隔
D.屬性是沒有順序性的
E.文件字集應該使用UTF-8
F.同一帳號應該以登入一次為限
G. 不應該預期交易的過程是否有斷行
I.Client 要斷線前,應保持良好習慣先傳遞
<presence type="unavailable"/></stream:stream> 再執行斷線
6. 認證交易(SASL RFC-2831)
(前略) 參考前述Part1 Part2
<Server 告知Client , 目前支援的認證型態>
S->C
<stream:features>
<mechanisms xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
<mechanism>DIGEST-MD5</mechanism>
<mechanism>PLAIN</mechanism>
</mechanisms>
</stream:features>
Ps:目前規劃使用的是 DIGEST-MD5 , PLAIN是為了讓SPARK(Jabber Client可以進行測試),而jabber::component 目前使用的是另一種handshark的機制
<Client 選擇一個認證機制>
C->S
<auth xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechani
sm='DIGEST-MD5'/>
Server 傳送challenge code
S->C
<challenge xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
cmVhbG09InNvbWVyZWFsbSIsbm9uY2U9Ik9BNk1HOX
RFUUdtMmhoIixxb3A9ImF1dGgiLGNoYXJzZXQ9dXRmL
TgsYWxnb3JpdGhtPW1kNS1zZXNzCg==</challenge>
中間這字串解開base 64 後的資訊為
realm="somerealm",nonce="OA6MG9tEQGm2hh",qop="auth",
charset=utf-8,algorithm=md5-sess
Client 傳送challenge code 給server
C->S
<response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
dXNlcm5hbWU9InNvbWVub2RlIixyZWFsbT0ic29tZXJlY
WxtIixub25jZT0iT0E2TUc5dEVRR20yaGgiLGNub25jZT0i
T0E2TUhYaDZWcVRyUmsiLG5jPTAwMDAwMDAxLHFv
cD1hdXRoLGRpZ2VzdC11cmk9InhtcHAvZXhhbXBsZS5j
b20iLHJlc3BvbnNlPWQzODhkYWQ5MGQ0YmJkNzYwY
TE1MjMyMWYyMTQzYWY3LGNoYXJzZXQ9dXRmLTgK
</response>
中間字串的base64解碼為
username="somenode",realm="somerealm",nonce="
OA6MG9tEQGm2hh",cnonce="OA6MHXh6VqTrRk",
nc=00000001,qop=auth,digest-uri="xmpp/example.com"
,response=d388dad90d4bbd760a152321f2143af7,charset=utf-8
<如驗證失敗 伺服器回應認證失敗>
S->C
<failure xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
<temporary-auth-failure/>
</failure>
</stream:stream>
隨即斷線
<伺服器傳送驗證碼>
S->C
<challenge xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>cn
NwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJh
YmNkZmZmZAo=</challenge>
中間字串BASE64解碼為
rspauth=ea40f60335c427b5527b84dbabcdfffd
<CLIENT 回應驗證碼正確性>
C->S
<response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'/>
<伺服器回應認證成功>
S->C
<success xmlns='urn:ietf:params:xml:ns:xmpp-sasl'/>
<認證成功後 Client 重新初始化 xml stream>
C->S
<stream:stream
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
to='example.com'
version='1.0'>
<伺服器回應所支援的feature>
S->C
<stream:stream
xmlns='jabber:client'
xmlns:stream='http://etherx.jabber.org/streams'
id='c2s_345'
from='example.com'
version='1.0'>
<stream:features>
<bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'/>
<session xmlns='urn:ietf:params:xml:ns:xmpp-session'/>
</stream:features>
<Client 請求Binding>
C->S
<iq id="jcl_8" type="set"><bind xmlns="urn:ietf:
params:xml:ns:xmpp-bind"><resource>Exodus<
/resource>
</bind></iq>
<伺服器回應Bind 的資源>
S->C
<iq type='result' id='jcl_8'><bind xmlns='urn:ietf:params
:xml:ns:xmpp-bind'><jid>admin@127.0.0.1/Exodus<
/jid><
/bind></iq>
<Client 請求session 交易>
C->S
<iq id="jcl_9" type="set"><session xmlns="urn:ietf:params:
xml:ns:xmpp-session"/></iq>
<Server 回應 session 交易>
S->C
<iq type='result' id='jcl_9'><session xmlns='urn:ietf:params:xml:
ns:xmpp-session'></session></iq>
5.認證演算過程
A. Server 傳送challenge code
S->C
BASE64(realm="elwood.innosoft.com",nonce="OA6MG9tEQGm2hh",
qop="auth", algorithm=md5-sess,charset=utf-8)
B. Client 傳送challenge code 給server
以下定義
開頭為$者為變數
開頭為 $$realm_xyz 代表該變數來自於realm 的屬性,而範例的值為xyz
以下範例 chris 為一個帳號名稱
+ 代表字串相加
‘ 代表固定字串內的值
MD5 代表其內字串使用MD5做簽章但不轉成HEX CODE
MD5_HEX 代表其內字串使用MD5做簽章且轉成HEX CODE
C->S
$PASSWORD 為該USER 的密碼
$A1=(MD5(‘chris’ + ‘:’ + $$realm_elwood.innosoft.com + ‘:’ + $PASSWORD) + ‘:’ + $$nonce _OA6MG9tEQGm2hh + ‘:’ + $$conce_OA6MHXh6VqTrRk)
$A2=’AUTHENTICATE’ + ‘:’ + $$realm_jabber/elwood.innosoft.com
$response=MD5_HEX(MD5_HEX($A1)+’:’+ $$nonce_OA6MG9tEQGm2hh +’:’+ $$nc_00000001 + ’:’ + $$conce_OA6MHXh6VqTrRk+’:’+ $$qop_auth +’:’ + MD5_HEX($A2))
Base64(charset=utf-8,username="chris",realm="elwood.innosoft.com", nonce="OA6MG9tEQGm2hh",nc=00000001,cnonce="OA6MHXh6VqTrRk", digest-uri="jabber/elwood.innosoft.com",response=$response,qop=auth)
Server 隨即驗證 $response 如失敗則回傳失敗,否則進行下一個動作
C: 伺服器傳送驗證碼
rspauth=MD5_HEX(MD5_HEX($A1) + ‘:’ + $$nonce_OA6MG9tEQGm2hh + ’:’ + $$nc_00000001 + ’:’ + $$conce_OA6MHXh6VqTrRk + ’:’ + $$qop_auth+MD5_HEX(‘:’ + $$digest-uri _jabber/elwood.innosoft.com))
Client 應該檢驗 rspauth
七.相關資源
Jabber Client下載位置
Exodus ( http://www.jabberstudio.org/projects/exodus/releases/ )
Pandion( http://www.pandion.be/download/ )
Spaek( http://www.igniterealtime.org/downloads/download-landing.jsp?file=spark/spark_2_5_2.exe )
C 所常用的 XML parser library
http://expat.sourceforge.net/
msxml sax相關資源
http://www.perfectxml.com/msxmlSAX.asp
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