Blue Coat Systems Time Clock Proxy SG Manuale Utente

Chapter 5: Action Reference

237

rewrite( )

Rewrites the request URL, URL host, or components of the specified header if it matches the 
regular-expression pattern. This action is often used in conjunction with the URL rewrite form of the 
transform action in a server portal application. 

The URL form of the 

rewrite( )

 action does not rewrite some URL components for Windows 

Media (MMS) transactions. The URL scheme, host, and port are restored to their original 
values and an error logged if the URL specified by 

 attempts to change 

these components.

An error results if the URL or URL host form of this action conflicts with another URL 
rewriting action. The error is noted at compile time if the conflicting actions are within the 
same action definition block. A runtime error is recorded in the event log if the conflicting 
actions are defined in different blocks.

Similarly, an error results if two header modifications act on the same header.

Only the host and port are available for rewriting by the URL or URL host form when the client 
browser is using a proxy for an HTTPS connection and the CONNECT or TUNNEL method is used. 
This is because the URL path is encrypted and unavailable for rewriting.

rewrite(url, regex_pattern, replacement_url[, URL_form1, ...])

rewrite(url.host, regex_pattern, replacement_host[, URL_form1, ...])

rewrite(header, regex_pattern, replacement_component)

where:

•

url

—Specifies a rewrite of the entire URL.

•

url.host

—Specifies a rewrite of the host portion of the URL.

•

—Specifies the header to rewrite, using the following form. For a list of recognized 

headers, see Appendix C.

❐

request.header.header_name

—Identifies a recognized HTTP request header.

❐

response.header.header_name

—Identifies a recognized HTTP response header.

❐

request.x_header.header_name

—Identifies any request header, including custom headers.

❐

response.x_header.header_name

—Identifies any response header, including custom 

headers.

•

—A quoted regular-expression pattern that is compared with the URL, host or 

header as specified, based on an anchored match. If the 

 does not match, the 

rewrite action is ignored. A 

 match sets the values for substitution variables. If the 

rewrite should always be applied, but no variable substitution is required for the replacement 
string, specify 

".* "

 for 

. For more information about regular expressions, refer to 

Appendix E, “Using Regular Expressions,” in the Blue Coat ProxySG Configuration and Management 
Guide.

•

—A quoted string that can optionally include one or more variable 

substitutions, which replaces the entire URL once the substitutions are performed. The resulting