HTTP Basic Authentication认证

 

什么是HTTP Basic Authentication？直接看http://en.wikipedia.org/wiki/Basic_authentication_scheme吧。
在你访问一个需要HTTP Basic Authentication的URL的时候，如果你没有提供用户名和密码，服务器就会返回401，如果你直接在浏览器中打开，浏览器会提示你输入用户名和密码(google浏览器不会，bug？)。你可以尝试点击这个url看看效果：http://api.minicloud.com.cn/statuses/friends_timeline.xml
要在发送请求的时候添加HTTP Basic Authentication认证信息到请求中，有两种方法：
一是在请求头中添加Authorization：
Authorization: "Basic 用户名和密码的base64加密字符串"
二是在url中添加用户名和密码：
http://userName:[email protected]/statuses/friends_timeline.xml

//需要Base64见：http://www.webtoolkit.info/javascript-base64.html
function make_base_auth(user, password) {
  var tok = user + ':' + pass;
  var hash = Base64.encode(tok);
  return "Basic " + hash;
} 

var auth = make_basic_auth('QLeelulu','mypassword');
var url = 'http://example.com'; 

// 原始JavaScript
xml = new XMLHttpRequest();
xml.setRequestHeader('Authorization', auth);
xml.open('GET',url) 

// ExtJS
Ext.Ajax.request({
    url : url,
    method : 'GET',
    headers : { Authorization : auth }
}); 

// jQuery
$.ajax({
    url : url,
    method : 'GET',
    beforeSend : function(req) {
        req.setRequestHeader('Authorization', auth);
    }
});

下面摘录一段 Jsp实现鉴权的代码逻辑

 以下是一段Jsp鉴权操作 
1、server发送一个要求认证代码401和一个头信息WWW-authenticate，激发browser弹出一个认证窗口
 2、server取得browser送来的认证头"Authorization",它是加密的了，要用Base64方法解密，取得明文的用户名和密码
  
3、检查用户名和密码，根据结果传送不同的页面

 

=========Jsp代码===================

<jsp:useBean id="base64" scope="page" class="Base64"/>  
<%   
if(request.getHeader("Authorization")==null){   
response.setStatus(401);   
response.setHeader("WWW-authenticate", "Basic realm="unixboy.com"");   
}else{   
String encoded=(request.getHeader("Authorization"));   
String tmp=encoded.substring(6);   
String up=Base64.decode(tmp);   
String user="";   
String password="";   
if(up!=null){   
user=up.substring(0,up.indexOf(":"));   
password=up.substring(up.indexOf(":")+1);   
}   
if(user.equals("unixboy")&&password.equals("123456")){   
//认证成功   
}else{   
//认证失败   
}   
}   
%> 

=======Java段代码==================

//消息加解密class   
public class Base64   
{   
/** decode a Base 64 encoded String.   
* <p><h4>String to byte conversion</h4>  
* This method uses a naive String to byte interpretation, it simply gets each   
* char of the String and calls it a byte.</p>  
* <p>Since we should be dealing with Base64 encoded Strings that is a reasonable   
* assumption.</p>  
* <p><h4>End of data</h4>  
* We don′t try to stop the converion when we find the "=" end of data padding char.   
* We simply add zero bytes to the unencode buffer.</p>  
*/   
public static String decode(String encoded)   
{   
StringBuffer sb=new StringBuffer();   
int maxturns;   
//work out how long to loop for.   
if(encoded.length()%3==0)   
maxturns=encoded.length();   
else   
maxturns=encoded.length()+(3-(encoded.length()%3));   
//tells us whether to include the char in the unencode   
boolean skip;   
//the unencode buffer   
byte[] unenc=new byte[4];   
byte b;   
for(int i=0,j=0; i<maxturns; i++)   
{   
skip=false;   
//get the byte to convert or 0   
if(i<encoded.length())   
b=(byte)encoded.charAt(i);   
else   
b=0;   
//test and convert first capital letters, lowercase, digits then ′+′ and ′/′   
if(b>=65 && b<91)   
unenc[j]=(byte)(b-65);   
else if(b>=97 && b<123)   
unenc[j]=(byte)(b-71);   
else if(b>=48 && b<58)   
unenc[j]=(byte)(b+4);   
else if(b==′+′)   
unenc[j]=62;   
else if(b==′/′)   
unenc[j]=63;   
//if we find "=" then data has finished, we′re not really dealing with this now   
else if(b==′=′)   
unenc[j]=0;   
else   
{   
char c=(char)b;   
if(c==′ ′ || c==′ ′ || c==′ ′ || c==′ ′)   
skip=true;   
else   
//could throw an exception here? it′s input we don′t understand.   
;   
}   
//once the array has boiled convert the bytes back into chars   
if(!skip && ++j==4)   
{   
//shift the 6 bit bytes into a single 4 octet word   
int res=(unenc[0] << 18)+(unenc[1] << 12)+(unenc[2] << 6)+unenc[3];   
byte c;   
int k=16;   
//shift each octet down to read it as char and add to StringBuffer   
while(k>=0)   
{   
c=(byte)(res >> k);   
if ( c > 0 )   
sb.append((char)c);   
k-=8;   
}   
//reset j and the unencode buffer   
j=0;   
unenc[0]=0;unenc[1]=0;unenc[2]=0;unenc[3]=0;   
}   
}   
return sb.toString();   
}   
  
/** encode plaintext data to a base 64 string   
* @param plain the text to convert. If plain is longer than 76 characters this method   
* returns null (see RFC2045).   
* @return the encoded text (or null if string was longer than 76 chars).   
*/   
public static String encode(String plain)   
{   
if(plain.length()>76)   
return null;   
int maxturns;   
StringBuffer sb=new StringBuffer();   
//the encode buffer   
byte[] enc=new byte[3];   
boolean end=false;   
for(int i=0,j=0; !end; i++)   
{   
char _ch=plain.charAt(i);   
if(i==plain.length()-1)   
end=true;   
enc[j++]=(byte)plain.charAt(i);   
if(j==3 || end)   
{   
int res;   
//this is a bit inefficient at the end point   
//worth it for the small decrease in code size?   
res=(enc[0] << 16)+(enc[1] << 8)+enc[2];   
int b;   
int lowestbit=18-(j*6);   
for(int toshift=18; toshift>=lowestbit; toshift-=6)   
{   
b=res >>> toshift;   
b&=63;   
if(b>=0 && b<26)   
sb.append((char)(b+65));   
if(b>=26 && b<52)   
sb.append((char)(b+71));   
if(b>=52 && b<62)   
sb.append((char)(b-4));   
if(b==62)   
sb.append(′+′);   
if(b==63)   
sb.append(′/′);   
if(sb.length()%76==0)   
sb.append(′ ′);   
}   
//now set the end chars to be pad character if there    
//was less than integral input (ie: less than 24 bits)   
if(end)   
{   
if(j==1)   
sb.append("==");   
if(j==2)   
sb.append(′=′);   
}   
enc[0]=0; enc[1]=0; enc[2]=0;   
j=0;   
}   
}   
return sb.toString();   
}   
}