mod_proxy_html: Configuration

mod_proxy_html Version 2.4 (Sept-Nov 2004)

Configuration Directives

The following can be used anywhere in an httpd.conf or included configuration file.


Syntax: ProxyHTMLURLMap from-pattern to-pattern flags

This is the key directive for rewriting HTML links. When parsing a document, whenever a link target matches from-pattern, the matching portion will be rewritten to to-pattern.

Starting at version 2.0, this supports a wider range of pattern-matching and substitutions, including regular expression search and replace, controlled by the optional third flags argument.

Flags for ProxyHTMLURLMap

Flags are case-sensitive.


Ignore HTML links (pass through unchanged)


Ignore scripting events (pass through unchanged)


Pass embedded script and style sections through untouched.


Last-match. If this rule matches, no more rules are applied (note that this happens automatically for HTML links).


Use Regular Expression matching-and-replace. from-pattern is a regexp, and to-pattern a replacement string that may be based on the regexp. Regexp memory is supported: you can use brackets () in the from-pattern and retrieve the matches with $1 to $9 in the to-pattern.

If R is not set, it will use string-literal search-and-replace, as in versions 1.x. Logic is starts-with in HTML links, but contains in scripting events and embedded script and style sections.


Use POSIX extended Regular Expressions. Only applicable with R.


Case-insensitive matching. Only applicable with R.


Disable regexp memory (for speed). Only applicable with R.


Line-based regexp matching. Only applicable with R.


Match at start only. This applies only to string matching (not regexps) and is irrelevant to HTML links.


Match at end only. This applies only to string matching (not regexps) and is irrelevant to HTML links.


Syntax: ProxyHTMLDoctype HTML|XHTML [Legacy]

Alternative Syntax: ProxyHTMLDocType fpi [SGML|XML]

In the first form, documents will be declared as HTML 4.01 or XHTML 1.0 according to the option selected. This option also determines whether HTML or XHTML syntax is used for output. Note that the format of the documents coming from the backend server is immaterial: the parser will deal with it automatically. If the optional second argument is set to "Legacy", documents will be declared "Transitional", an option that may be necessary if you are proxying pre-1998 content or working with defective authoring/publishing tools.

In the second form, it will insert your own FPI. The optional second argument determines whether SGML/HTML or XML/XHTML syntax will be used.

Starting at version 2.0, the default is changed to omitting any FPI, on the grounds that no FPI is better than a bogus one. If your backend generates decent HTML or XHTML, set it accordingly.


Syntax: ProxyHTMLFixups [lowercase] [dospath] [reset]

This directive takes one to three arguments as follows:

  • lowercase Urls are rewritten to lowercase
  • dospath Backslashes in URLs are rewritten to forward slashes.
  • reset Unset any options set at a higher level in the configuration.

Take care when using these. The fixes will correct certain authoring mistakes, but risk also erroneously fixing links that were correct to start with. Only use them if you know you have a broken backend server.


Syntax ProxyHTMLMeta [On|Off]

Parses <meta http-equiv ...> elements to real HTTP headers.


Syntax ProxyHTMLExtended [On|Off]

Set to Off, this gives the same behaviour as 1.x versions of mod_proxy_html. HTML links are rewritten according the ProxyHTMLURLMap directives, but links appearing in Javascript and CSS are ignored.

Set to On, all scripting events and embedded scripts or stylesheets are also processed by the ProxyHTMLURLMap rules, according to the flags set for each rule. Since this requires more parsing, performance will be best if you only enable it when strictly necessary.


Syntax ProxyHTMLStripComments [On|Off]

This directive will cause mod_proxy_html to strip HTML comments. Note that this will also kill off any scripts or styles embedded in comments (a bogosity introduced in 1995/6 with Netscape 2 for the benefit of then-older browsers, but still in use today). It may also interfere with comment-based processors such as SSI or ESI: be sure to run any of those before mod_proxy_html in the filter chain if stripping comments!


Syntax ProxyHTMLLogVerbose [On|Off]

Turns on verbose logging. This causes mod_proxy_html to make error log entries (at LogLevel Info) about charset detection and about all meta substitutions and rewrites made. When Off, only errors and warnings (if any) are logged.


Syntax ProxyHTMLBufSize nnnn

Set the buffer size increment for buffering inline stylesheets and scripts.

In order to parse non-HTML content (stylesheets and scripts), mod_proxy_html has to read the entire script or stylesheet into a buffer. This buffer will be expanded as necessary to hold the largest script or stylesheet in a page, in increments of [nnnn] as set by this directive.

The default is 8192, and will work well for almost all pages. However, if you know you're proxying a lot of pages containing stylesheets and/or scripts bigger than 8K, it will be more efficient to set a larger buffer size and avoid the need to resize the buffer dynamically during a request.