Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 274)

258 Brocade Virtual ADX Server Load Balancing Guide
53-1003247-01
Layer 7 content switching
5
The URL prefix "/abc" is matched, offset 0 is at the second "/", which is right after the matched
prefix "/abc" in the URL, which is defined in CSW "r12a"; so offset 4 is number "1" which is 4 bytes
away after the letter "c". The result is that the 2 bytes containing "12" are deleted in the URL.
Example Original HTTP request:
GET /abc/xyz12/index.html HTTP/1.1\r\n
Host: www.foo.com\r\n
User-Agent: Mozilla/5.0 Netscape/7.02\r\n
Accept-Charset: ISO-8859-1\r\n
Cookie: name=brocadenet; userid=12345\r\n
\r\n
Example Rewritten HTTP request:
GET /abc/xyz/index.html HTTP/1.1\r\n
Host: www.foo.com\r\n
User-Agent: Mozilla/5.0 Netscape/7.02\r\n
Accept-Charset: ISO-8859-1\r\n
Cookie: name=brocadenet; userid=12345\r\n
\r\n
Deleting content at negative offset
NOTE
For more information about offsets, refer to “Explanation of offsets” on page 265.
To configure a request to delete content at a negative offset, follow these steps.
1. Define a CSW rule to search for the suffix ".html" at end of URL.
Virtual ADX(config)#csw-rule r12b url suffix ".html"
Syntax: csw-rule rule-name url suffix content
2. Define a CSW policy.
Virtual ADX(config)#csw-policy mypolicy
Syntax: csw-policy policy-name
3. Specify a primary action.
Virtual ADX(config-csw-mypolicy)#match r12b forward 1025
Syntax: match rule-name forward server-id
4. Specify a dependent rewrite action.
Virtual ADX(config-csw-mypolicy)#match r12b rewrite request-delete neg-offset
11 6
Syntax: match rule-name rewrite request-delete neg-offset offset length
NOTE
The following information assumes you have configured the previous scenario.
When ".html" is matched, offset 0 is the white space after letter "l", letter "l" is neg-offset 1, letter
"m" is neg-offset 2, letter "t" is neg-offset 3 and so on. As a result, neg-offset 11 is "_". By counting
6 bytes from left to right starting with "_", you can see that "_index" is to be deleted.