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本文的目的是设计一个完成URL编码的C++类。在我曾经的项目中,我需要从VC++ 6.0应用程序中POST数据,而这些数据需要进行URL编码。我在MSDN中查找能根据提供的字符串生成URL编码的相关类或API,但我没有找到,因此我必须设计一个自己的URLEncode C++类。
URLEncoder.exe是一个使用URLEncode类的MFC对话框程序。
如何处理
一些特殊字符在Internet上传送是件棘手的事情, 经URL编码特殊处理,可以使所有字符安全地从Internet传送。
例如,回车的ASCII值是13,在发送FORM数据时候这就认为是一行数据的结束。
通常,所有应用程序采用HTTP或HTTPS协议在客户端和服务器端传送数据。服务器端从客户端接收数据有两种基本方法:
1、数据可以从HTTP头传送(COOKIES或作为FORM数据发送)
2、可以包含在URL中的查询部分
当数据包含在URL,它必须遵循URL语法进行编码。在WEB服务器端,数据自动解码。考虑一下下面的URL,哪个数据是作为查询参数。
例如:http://WebSite/ResourceName?Data=Data
WebSite是URL名称
ResourceName可以是ASP或Servlet名称
Data是需要发送的数据。如果MIME类型是Content-Type: application/x-www-form-urlencoded,则要求进行编码。
RFC 1738
RFC 1738指明了统一资源定位(URLs)中的字符应该是US-ASCII字符集的子集。这是受HTML的限制,另一方面,允许在文档中使用所有ISO-8859-1(ISO-Latin)字符集。这将意味着在HTML FORM里POST的数据(或作为查询字串的一部分),所有HTML编码必须被编码。
ISO-8859-1 (ISO-Latin)字符集
在下表中,包含了完整的ISO-8859-1 (ISO-Latin)字符集,表格提供了每个字符范围(10进制),描述,实际值,十六进制值,HTML结果。某个范围中的字符是否安全。
Character range(decimal)
Type
Values
Safe/Unsafe
0-31
ASCII Control Characters
These characters are not printable
Unsafe
32-47
Reserved Characters
'' ''!?#$%&''()*+,-./
Unsafe
48-57
ASCII Characters and Numbers
0-9
Safe
58-64
Reserved Characters
:;?@
Unsafe
65-90
ASCII Characters
A-Z
Safe
91-96
Reserved Characters
[\]^_`
Unsafe
97-122
ASCII Characters
a-z
Safe
123-126
Reserved Characters
{|}~
Unsafe
127
Control Characters
'' ''
Unsafe
128-255
Non-ASCII Characters
'' ''
Unsafe
所有不安全的ASCII字符都需要编码,例如,范围(32-47, 58-64, 91-96, 123-126)。
下表描述了这些字符为什么不安全。
Character
Unsafe Reason
Character Encode
"
Delimiters around URLs in free text
%3C
>
Delimiters around URLs in free text
%3E
.
Delimits URLs in some systems
%22
#
It is used in the World Wide Web and in other systems to delimit a URL from a fragment/anchor identifier that might follow it.
%23
{
Gateways and other transport agents are known to sometimes modify such characters
%7B
}
Gateways and other transport agents are known to sometimes modify such characters
%7D
|
Gateways and other transport agents are known to sometimes modify such characters
%7C
\
Gateways and other transport agents are known to sometimes modify such characters
%5C
^
Gateways and other transport agents are known to sometimes modify such characters
%5E
~
Gateways and other transport agents are known to sometimes modify such characters
%7E
[
Gateways and other transport agents are known to sometimes modify such characters
%5B
]
Gateways and other transport agents are known to sometimes modify such characters
%5D
`
Gateways and other transport agents are known to sometimes modify such characters
%60
+
Indicates a space (spaces cannot be used in a URL)
%20
/
Separates directories and subdirectories
%2F
?
Separates the actual URL and the parameters
%3F
&
Separator between parameters specified in the URL
%26
如何实现
字符的URL编码是将字符转换到8位16进制并在前面加上''%''前缀。例如,US-ASCII字符集中空格是10进制
的32或16进制的20,因此,URL编码是%20。
URLEncode: URLEncode是一个C++类,来实现字符串的URL编码。CURLEncode类包含如下函数:
isUnsafeString
decToHex
convert
URLEncode
URLEncode()函数完成编码过程,URLEncode检查每个字符,看是否安全。如果不安全将用%16进制值进行转换并添加
到原始字符串中。
代码片断:
class CURLEncode{private: static CString csUnsafeString; CString (char num, int radix); bool isUnsafe(char compareChar); CString convert(char val);public: CURLEncode() { }; virtual ~CURLEncode() { }; CString (CString vData);};bool CURLEncode::isUnsafe(char compareChar){ bool bcharfound = false; char tmpsafeChar; int m_strLen = 0; m_strLen = csUnsafeString.GetLength(); for(int ichar_pos = 0; ichar_pos 32 && char_ascii_value = radix) { temp = num_char % radix; num_char = (int)floor(num_char / radix); csTmp = hexVals[temp]; } csTmp += hexVals[num_char]; if(csTmp.GetLength()
本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u2/64804/showart_1777549.html |
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