UrlRewriteFilter 2.6 - Manual

Examples - Manual
Install - Filter Parameters - Configuration - Testing - Performance - Ant Task

For commercial support contact sales@tuckey.co.nz. Community support is avaliable at urlrewrite google group.

Read examples of usage and a sample of the ant task report. If you have feedback, or conf you want to share with the world email me.


  1. Download the zip (or tar.gz) and extract it into your context's directory ie, so that urlrewrite.xml goes into the WEB-INF directory.
  2. Add the following to your WEB-INF/web.xml (add it near the top above your servlet mappings (if you have any)): (see filter parameters for more options)
  3. Add your own configuration to the WEB-INF/urlrewrite.xml that was created.
  4. Restart the context.

You can visit (or whatever the address of your local webapp and context) to see output (note: this page is only viewable from localhost).

Filter Parameters

There are a few advanced filter parameters for enabling conf file reloading etc. There are self-explanatory.


    <!-- set the amount of seconds the conf file will be checked for reload
    can be a valid integer (0 denotes check every time,
          empty/not set denotes no reload check) -->

    <!-- sets up log level (will be logged to context log)
    can be: TRACE, DEBUG, INFO (default), WARN, ERROR, FATAL, log4j, commons, sysout:{level} (ie, sysout:DEBUG)
          if you are having trouble using normal levels use sysout:DEBUG -->

    <!-- you can disable status page if desired
    can be: true, false (default true) -->

        <!-- you can change status path so that it does not
          conflict with your installed apps (note, defaults
          to /rewrite-status) note, must start with / -->


Note, setting logLevel to log4j or commons will cause the built in loging to call either log4j or commons-logging as if they were the logging framework, obviously you will need to have the jar for log4j or commons-logging in your classpath.

Configuration File WEB-INF/urlrewrite.xml

Configuration is done via a simple XML file that lives in your WEB-INF folder. It should be named urlrewrite.xml. It may be helpful to read the UrlRewriteFilter DTD (Document Type Definition). Please also make sure you look at the examples. A simple configuration file looks like:

    <?xml version="1.0" encoding="utf-8"?>

    <!DOCTYPE urlrewrite
    PUBLIC "-//tuckey.org//DTD UrlRewrite 2.6//EN"


    <to type="redirect">/very/newdir/$1</to>


The urlrewrite.xml file must have a root element called "urlrewrite" and must contain at least one "rule" element.

A "rule" must contain a "from" and a "to", and can have zero or more "condition" elements and zero or more and/or "set" elements.

When a "rule" is processed against an incoming request, all the "condition" elements must be met, then the "from" will be applied to the request URL and the final URL generated by applying the "to" to the "from" pattern. So long as the rule has matched then the "set" will be run.

Traps for young players:

When executing a rule the filter will (very simplified) do something like this psuedo code:

    Pattern.compile(<from> element);
    pattern.matcher(each request url);
    matcher.replaceAll(<to> element);
    if ( <condition> elements match && pattern matched ) {
    execute <run> elements (if any)
    perform <to> element (if any)

<rule> element

Zero or more. The basis of a rule.

Attribute Possible Value Explanation
true (default) Enable this rule.
false Disable this rule.

In the following example requests for /world/usa/nyc will be transparently forwarded to /world.jsp?country=usa&city=nyc

    <rule enabled="true">

<outbound-rule> element

Zero or more. This is very similar to a normal rule but it is used for rewriting urls that go through response.encodeURL().

Attribute Possible Value Explanation
true (default) Enable this rule.
false Disable this rule.
true Run encodeURL() before running this outbound rule.
false (default) Run encodeURL() after running this outbound rule.

May contain "run", "from", "to" and "set" element(s) also. Example:


Using the example above JSP's with the code
<a href="<%= response.encodeURL("/world.jsp?country=usa&amp;city=nyc") %>">nyc</a>
will output
<a href="/world/usa/nyc">nyc</a>

Note, If you are using JSTL (ie, <c:url) this will work also.

<name> element

An optional element used for documenting the name of the rule. This can be used with rule and outbound-rule. See ant task.

    <name>World Rule</name>

<note> element

A simple optional element used for documentation of the rule. This can be used with rule and outbound-rule. See ant task.

    <name>World Rule</name>
        Cleanly redirect world requests to JSP,
        a country and city must be specified.

<condition> element

An element that lets you choose conditions for the rule. Note, all conditions must be met for the rule to be run (unless "next" is set to "or" obvoiusly).

Value can be any Regular Expression (Perl5 style).

Attribute Possible Value Explanation
header (default)If used, the header name must be specified in the "name" attribute.
methodThe method of the request. GET, POST, HEAD etc.
portThe port that the web application server is running on.
time Current time at the server (this will be the number of seconds since 00:00:00 1970-01-01 UTC otherwise known as unix time).
i.e. (new Date()).getTime()
This can be used for making sure content goes live only at a time you set.
year Current year at the server.
i.e. (Calendar.getInstance()).get(Calendar.YEAR)
month Month at the server. January is 0
i.e. (Calendar.getInstance()).get(Calendar.MONTH)
dayofmonth Day of the month at the server. March first is 1
i.e. (Calendar.getInstance()).get(Calendar.DAY_OF_MONTH)
dayofweek Day of the week at the server. Saturday is 1, Sunday is 7
i.e. (Calendar.getInstance()).get(Calendar.DAY_OF_WEEK)
ampm AM or PM time at the server.
i.e. (Calendar.getInstance()).get(Calendar.AM_PM)
hourofday The hour of the day (24 hour clock) at the server. 10pm is 22
i.e. (Calendar.getInstance()).get(Calendar.HOUR_OF_DAY)
minute The minute field of the current time at the server.
i.e. (Calendar.getInstance()).get(Calendar.MINUTE)
second The second field of the current time at the server.
i.e. (Calendar.getInstance()).get(Calendar.SECOND)
millisecond The millisecond field of the current time at the server.
i.e. (Calendar.getInstance()).get(Calendar.MILLISECOND)
attribute Will check the value of a request attribute (don't confuse this with parameter!), name must be set when using this type.
i.e. request.getAttribute([name])
auth-type Will check the value of a request attribute (don't confuse this with parameter!)
i.e. request.getAuthType()
character-encoding The character encoding of the imcoming request.
i.e. request.getCharacterEncoding()
content-length The length of the imcoming request (can be useful if you want to deny large requests).
i.e. request.getContentLength()
content-type The type of the imcoming request. (this is probably not that useful)
i.e. request.getContentType()
context-path The context path of the imcoming request.
i.e. request.getContextPath()
cookie The value of a cookie, note, name must be specified to use this
i.e. request.getCookies() the find we the one with [name] specified and check the value.
parameter A tidier way of checking request parameters than looking for them in the query string. This will check for the parameter in GET or POST, note, name must be specified.
i.e. request.getParameter([name])
path-info i.e. request.getPathInfo()
path-translated i.e. request.getPathTranslated()
protocolThe protocol used to make the request, e.g. HTTP/1.1
i.e. request.getProtocol()
query-stringThe query string used to make the request (if any), e.g. id=2345&name=bob
i.e. request.getQueryString()
remote-addrThe IP address of the host making the request, e.g.
i.e. request.getRemoteAddr()
remote-hostThe host name of the host making the request, e.g. 123qw-dsl.att.com (note, this will only work if your app server is configured to lookup host names, most aren't).
i.e. request.getRemoteHost()
remote-userThe login of the user making this request, if the user has been authenticated, e.g. bobt
i.e. request.getRemoteUser()
requested-session-idReturns the session ID specified by the client, e.g. 2344asd234sada4
i.e. request.getRequestedSessionId()
request-uriReturns the part of this request's URL from the protocol name up to the query string in the first line of the HTTP request
i.e. request.getRequestURI()
request-urlReconstructs the URL the client used to make the request. The returned URL contains a protocol, server name, port number, and server path, but it does not include query string parameters.
i.e. request.getRequestURL()
session-attribute (note, name must be set)
i.e. session.getAttribute([name])
session-isnew Weather the session is new or not.
i.e. session.isNew()
server-name The host name of the server to which the request was sent (from the host header not the machine name).
i.e. request.getServerName()
scheme The scheme used for the request, e.g. http or https
i.e. request.getScheme()
user-in-role (Note, the value for this cannot be a regular expression)
i.e. request.isUserInRole([value])
(can be anything) If type is header, this specifies the name of the HTTP header used to run the value against.
and (default)The next "rule" and this "rule" must match.
orThe next "rule" or this "condition" may match.
equal (default) Equals. The operator to be used when the condition is run.
notequalNot equal to. (i.e. request value != condition value). Note, this operator only work with numeric rule types.
greaterGreater than. (i.e. request value > condition value). Note, this operator only work with numeric rule types.
lessLess than. (i.e. request value < condition value). Note, this operator only work with numeric rule types.
greaterorequalGreater to or equal to. (i.e. request value >= condition value). Note, this operator only work with numeric rule types.
lessorequalLess than or equal to. (i.e. request value <= condition value). Note, this operator only work with numeric rule types.


    <condition name="user-agent" operator="notequal">Mozilla/[1-4]</condition>

    <condition type="user-in-role" operator="notequal">bigboss</condition>

    <condition name="host" operator="notequal">www.example.com</condition>

    <condition type="method" next="or">PROPFIND</condition>
    <condition type="method">PUT</condition>

<from> element

You must always have exactly one from for each rule or outbound-rule. Value can be a regular expression in the Perl5 style. Note, from url's are relative to the context.

Attribute Possible Value Explanation
false (default) This value will be matched using case insentitive match. ie, "/WellingtoN" will match "/wellington".
true This value will be matched using case sentitive match. ie, "/aAa" will NOT match "/aaa".



<to> element

Value can be a regular replacement expression in the Perl5 style.

Attribute Possible Value Explanation
forward (default) Requests matching the "conditions" for this "rule", and the URL in the "from" element will be internally forwarded to the URL specified in the "to" element. Note: In this case the "to" URL must be in the same context as UrlRewriteFilter. This is the same as doing:
RequestDispatcher rq = request.getRequestDispatcher([to value]);
rq.forward(request, response);
passthrough Identical to "forward".
redirect Requests matching the "conditions" and the "from" for this rule will be HTTP redirected. This is the same a doing:
HttpServletResponse.sendRedirect([to value]))
permanent-redirect The same as doing:
response.setHeader("Location", [to value]);

(note, SC_MOVED_TEMPORARILY is HTTP status code 301)
temporary-redirect The same as doing:
response.setHeader("Location", [to value]);

(note, SC_MOVED_TEMPORARILY is HTTP status code 302)
false (default) The rest of the "rules" will be processed if this one succeeds.
true No more "rules" will be processed if this one is a match.
false (default if under rule) response.encodeURL([to]) will be run on the to url before performing the rewrite.
true (default if under outbound-rule) response.encodeURL([to]) will NOT be called.

Note, "to" can be null ie, <to>null</to>, this will mean that the request will go no further if the rule is matched (ie, this filter will not call chain.doFilter).


To elements can contain backreferences and variables.



Provides access to the grouped parts (parentheses!) of the pattern from the last matched Condition in the current rule. N must be less than 10 and greater than 0.



Any valid condition type can be used as a variable name. ie, '%{port}' will be translated to '80', '%{year}' to '2005', '%{cookie:myCookie}' would be translated to 'myCookieValue' (assuming the user had a cookie named myCookie with the value myCookieValue).

Valid types are and condition type, see condition for a full description.

<set> element

Allows you to set varous things if the rule is matched.

Attribute Possible Value Explanation
request (default) The same as request.setAttribute([name], [value]) (note, name must be set).
session The same as request.getSesison(true).setAttribute([name], [value]) (note, name must be set).
response-header The same as response.setHeader([name], [value]) (note, name must be set).
cookie Value can be in the format "[value][:domain[:lifetime[:path]]]". This sets a cookie on the client's browser. The cookie's name is specified by the name attribute. The domain field is the domain of the cookie, such as '.apache.org',the optional lifetime is the lifetime of the cookie in minutes, and the optional path is the path of the cookie (note, name must be set).
status The same as response.setStatus([value])
content-type The same as response.setContentType([value])
charset The same as response.setContentType([value])
locale The same as response.setLocale([value]) specify the Locale in the format (valid locales are, zh, zh-CN, zh-CN-southern i.e. "-" separating the language, country and variant (if any)).
(can be anything) If type is request, session, response-header, cookie this specifies the name item.

In the following example a request attribute "client" will be set to "AvantGo" or "Samsung SCH-6100", this can be fetched in a servlet or JSP using request.getAttribute("client").

    <condition name="user-agent">Mozilla/3\.0 (compatible; AvantGo .*)</from>
    <set name="client">AvantGo</set>
    <condition name="user-agent">UP\.Browser/3.*SC03 .* </from>
    <set name="client">Samsung SCH-6100</set>

<run> element

Allows you to run a method on an object when a rule and it's conditions are matched.

Attribute Explanation
class (default) The class you want to run a method on. Must be a fully qualified name.
method (optional, default run) The method you want to run, the method must have the parameters (HttpServletRequest, HttpServletResponse) e.g. run(HttpServletRequest request, HttpServletResponse response)
Note, if init(ServletConfig) or destroy() is found they will be run at when creating or destroying an instance.
neweachtime (optional, default false) If you want new instance of the class to be created before running each time set to true.

When the rule in the following example is matched, WorldServlet.goGet(HttpServletRequest, HttpServletResponse) will be invoked, the request will then be forwarded to /world-presentation.jsp.

    <run class="com.blah.web.WorldServlet" method="doGet" />

Note, you can specify init-param's the same way you would for a servlet.

    <run class="com.blah.web.MyServlet" method="doGet">

If the method being called throws an Exception the original exception will be re-thrown as if it were the original if it extends RuntimeException (eg, NullPointer), other exceptions are wrapped in a ServletException and thrown so your container can handle them.


Test cases have been written for most of the code. You can find them in the source distribution. UrlRewriteFilter has been tested using Cactus on the following web application servers:

If you have run the test cases on another application server please let me know.


UrlRewriteFilter has been written for maximum performance. Testing has indicated that it should only slow down a request by 0.0005 of a second under normal circumstances (depending on hardware and configuration etc.). Take a look at the source in the class UrlRewriterTest.testLoadsOfRules() for more information.

Ant Task

An Ant task has been written to allow validate the conf file and generation of documentation. You can view a sample.

Paste the following into your build.xml file, then change the dest and conf to point to the correct places. Note, the urlrewrite jar file will need to be in your classpath.

    <target name="urlrewrite-doc" depends="compile"
    description="UrlRewriteFilter validation and documenting">

    classname="org.tuckey.web.filters.urlrewrite.UrlRewriteDocTask" />
    dest="urlrewrite-conf-overview.html" />

Copyright 2007 Paul Tuckey