About httputility. urlencode, httputility. urldecode, server. urlencode, server. urldecode

 

Httputility. urlencode method:

Encode the URL string to implement reliable HTTP transmission from the Web server to the client.

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Converts byte arrays to encoded URL strings for reliable HTTP transmission from the Web server to the client.
[C #] public static string urlencode (byte []);

Encode the URL string to implement reliable HTTP transmission from the Web server to the client.
[C #] public static string urlencode (string );

The URL string is encoded using the specified encoding object to implement reliable HTTP transmission from the Web server to the client.
[C #] public static string urlencode (string, encoding );

Converts a byte array into a URL-encoded string from the specified position in the array to the specified number of bytes, so as to ensure reliability from the Web server to the client.

.
[C #] public static string urlencode (byte [], Int, INT );

Httputility. urldecode method:

Converts a string that has been encoded for transmission in a URL into a decoded string.

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Converts a string that has been encoded for transmission in a URL into a decoded string.
[C #] public static string urldecode (string );

Use the specified decoded object to convert the URL-encoded byte array to a decoded string.
[C #] public static string urldecode (byte [], encoding );

Use the specified encoding object to convert a URL-encoded string to a decoded string.
[C #] public static string urldecode (string, encoding );

Use the specified encoding object to convert the URL encoded byte array to a decoded string starting from the specified position in the array to the specified number of bytes.
[C #] public static string urldecode (byte [], Int, Int, encoding );

Server is an instance of the httpserverutility class and a property of system. Web. UI. Page.
Httpserverutility. urlencode method:
Encode the string for reliable HTTP transmission from the Web server to the client through the URL.

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Encode the string and return the encoded string.
[C #] Public String urlencode (string );

The URL encodes the string and sends the result output to the textwriter output stream.
[C #] public void urlencode (string, textwriter );
Example:
String teststring = "This Is A <test string> .";
Stringwriter writer = new stringwriter ();
Server. urlencode (teststring, writer );
String encodedstring = writer. tostring ();

Httpserverutility. urldecode method:
Decodes a string that is encoded for HTTP transmission and sent to the server in the URL.

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Perform URL Decoding on the string and return the decoded string.
[C #] Public String urldecode (string );

Decodes the HTML string received in the URL and sends the result output to the textwriter output stream.
[C #] public void urldecode (string, textwriter );

 

Notes:
1. httputility. urlencode and httputility. urldecode are static methods, while server. urlencode and server. urldecode are instance methods.
2. Server is an instance of the httpserverutility class and a property of system. Web. UI. Page.
3. the string encoded with httputility. urlencode is different from the string object encoded with server. urlencode:
For example:
String url = "http://search.99read.com/index.aspx? Book_search = All & main_str = omyr ";
Response. Write (httputility. urlencode (URL ));
Response. Write ("<br> ");
Response. Write (server. urlencode (URL ));

The output result is:
HTTP % 3A % 2f % 2fsearch.99read.com % 2findex. aspx % 3fbook_search % 3 Dall % 26main_str % 3d % E5 % a5 % a5 % E8 % BF % B7 % E5 % B0 % 94
HTTP % 3A % 2f % 2fsearch.99read.com % 2findex. aspx % 3fbook_search % 3 Dall % 26main_str % 3d % B0 % C2 % C3 % D4 % B6 % FB

Cause: the encoding method of server. urlencode is based on the encoding method set by the local program, while httputility. urlencode is Based on. NET by default.

UTF-8 encoding.

If you change the program:
String url1 = "http://search.99read.com/index.aspx? Book_search = All & main_str = omyr ";
Response. Write (httputility. urlencode (url1, system. Text. encoding. getencoding ("gb2312 ")));
Response. Write ("<br> ");
Response. Write (server. urlencode (url1 ));

The output result is:
HTTP % 3A % 2f % 2fsearch.99read.com % 2findex. aspx % 3fbook_search % 3 Dall % 26main_str % 3d % B0 % C2 % C3 % D4 % B6 % FB
HTTP % 3A % 2f % 2fsearch.99read.com % 2findex. aspx % 3fbook_search % 3 Dall % 26main_str % 3d % B0 % C2 % C3 % D4 % B6 % FB

4. Sometimes the URLs transmitted by other systems are encoded in other encoding methods.
This section describes a self-written method to obtain the querystring of the specified encoding format.

Public String getnonnullquerystring (string key, encoding)
{
// Reference the system. Collections. Specialized and system. Text namespaces.
String stringvalue;
System. Collections. Specialized. namevaluecollection encodingquerystring;
// This method is added in 2.0.
Encodingquerystring = httputility. parsequerystring (request. url. query, encoding );
// The key in 'is the key of the parameter you submitted
Return encodingquerystring [Key]! = NULL? Encodingquerystring [Key]. Trim ():"";
}

Call:
String url = getnonnullquerystring ("url", encoding. utf8). Trim ();

 

Which one should I use for URL encoding? Are there any differences between these two methods?
Test:
String file = "file (upload document .doc ";
String server_urlencode = server. urlencode (File );
String server_urldecode = server. urldecode (server_urlencode );
String httputility_urlencode = system. Web. httputility. urlencode (File );
String httputility_urldecode = system. Web. httputility. urldecode (httputility_urlencode );
Response. Write ("original data:" + file );
Sfun. writeline ("server. urlencode:" + server_urlencode );
Sfun. writeline ("server. urldecode:" + server_urldecode );
Sfun. writeline ("httputility. urlencode:" + httputility_urlencode );
Sfun. writeline ("httputility. urldecode:" + httputility_urldecode );

Output:
Original data: file (upload document .doc
Server. urlencode: performance%c41_bc1_few.c91_cf1_a3%a8%b4% AB %a3%a9%c6%aa.doc
Server. urldecode: file (upload example .doc
Httputility. urlencode: Invalid
Httputility. urldecode: file (upload example .doc

The difference is that httputility. urlencode () is UTF-8 encoded by default, while server. urlencode () is encoded by default.

When developing pages using ASP. NET, we often use system. Web. httputility. urlencode and urldecode to pass parameters between pages through URLs.

The use of encode and decode in pairs is correct.

However, when writing a file download page, we often use the following method to specify the name of the downloaded file:
Response. addheader ("content-disposition", "attachment; filename ="
+ Httputility. urlencode (filename, encoding. utf8 ));
The reason for conversion to utf8 is to support Chinese file names.

This problem occurs because httputility. urlencode converts the space to the plus sign ('+') during encode and converts the plus sign to null during decode.

But the browser cannot understand that the plus sign is a space. Therefore, if the file name contains spaces, the space of the file downloaded from the browser becomes a plus sign.

One solution is to replace "+" with "% 20" after the urlencode of httputility (if it is "+", it is converted to "% 2B"), for example:
Filename = httputility. urlencode (filename, encoding. utf8 );
Filename = filename. Replace ("+", "% 20 ");
I don't understand why Microsoft converts spaces to plus signs instead of "% 20". Remember that JDK urlencoder converts spaces to "% 20.
After checking, the same is true in. NET 2.0.

The above is copied from other places and is well written. I encountered the same problem in one of my own programs. By default, aspx is encoded with UTF-8, which is required in my program.

Use gb2312 as the default encoding (<globalization requestencoding = "gb2312" responseencoding = "gb2312"/>). The problem occurs. No problem occurred before.

The value of httputility. urldecode returned by page. Request is garbled. This is the above-mentioned httputility. urldecode uses utf8 to encode the URL by default.

In this case, you only need to change httputility. urldecode to server. urlencode.