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<!DOCTYPE document [
  <!ENTITY project SYSTEM "project.xml">
]>
<document url="iis.html">

    &project; 

    <properties>
        <author email="mturk@apache.org">Mladen Turk</author>
        <title>Configuring the ISAPI redirector for Microsoft IIS</title>
    </properties>

<body>

<section name="Requirements">
<p>
The Tomcat redirector requires three entities:

<ul>
<li>
<b>isapi_redirect.dll</b> - The IIS ISAPI redirector plugin, either obtain a pre-built DLL or build it yourself (see the build section).
</li>
<li>
<b>workers.properties</b> - A file that describes the host(s) and port(s) used by the workers (Tomcat processes). 
A sample workers.properties can be found under the conf directory.
</li>
<li>
<b>uriworkermap.properties</b> - A file that maps URL-Path patterns to workers. 
A sample uriworkermap.properties can be found under the conf directory as well.
</li>
</ul>
</p>

<p>
The installation includes the following parts:

<ul>
<li>
Configuring the ISAPI redirector with a default /examples context and checking that you can serve servlets with IIS.
</li>
<li>
Adding more contexts to the configuration.
</li>
</ul>
</p>
<p>
Note that in a 64 Bit environment - at least for IIS 7 - the used IIS Application Pool
should have "Enable 32-bit Applications" set to "False". Otherwise the redirector will
not be called and returns an http code 404. If you think, the 32bit version of
isapi_redirect.dll would do the job instead, you will get an http code 500,
because the library is not loadable into a 64 Bit IIS.
</p>
</section>
<section name="Registry settings">
<p>
ISAPI redirector reads configuration from the registry, create a new registry key named:
</p>
<p>
<b>"HKEY_LOCAL_MACHINE\SOFTWARE\Apache Software Foundation\Jakarta Isapi Redirector\1.0"</b>
</p>
<p>
Attributes described below as a "string value representing a boolean"
can be set either using the numbers <b>0</b> (false) and <b>1</b> (true)
as values, or <b>off</b> (false) and <b>on</b> (true) or any other string
starting with the letters <b>f</b> (false), <b>n</b> (false),
<b>t</b> (true) or <b>y</b> (true).
The values are taken case insensitive. In this documentation we will stick
to <b>false</b> and <b>true</b>.
</p>
<attributes name="Key Name">
<attribute name="extension_uri" required="true"><p>
A string value pointing to the ISAPI extension <b>/jakarta/isapi_redirect.dll</b>
</p></attribute>
<attribute name="log_file" required="false"><p>
A value pointing to location where log file will be created.
(for example <b>c:\tomcat\logs\isapi.log</b>)
<br/>If one of the log rotation settings (<b>log_rotationtime</b> or <b>log_filesize</b>) are specified then the actual log file name is based on this setting.
If the log file name includes any '%' characters, then it is treated as a format string for <code>strftime(3)</code>, 
e.g. <b>c:\tomcat\logs\isapi-%Y-%m-%d-%H_%M_%S.log</b>. Otherwise, the suffix <em>.nnnnnnnnnn</em> is automatically added and is the time in seconds.
A full list of format string substitutions can be found in the <a href="http://httpd.apache.org/docs/2.4/programs/rotatelogs.html">Apache rotatelogs documentation</a>
</p></attribute>
<attribute name="log_level" required="false"><p>
A string value for log level 
(can be debug, info, warn, error or trace).</p>
<p>This directive was added in version 1.2.31</p>
</attribute>
<attribute name="log_rotationtime" required="false"><p>
The time between log file rotations in seconds.
Setting this to 0 (the default) disables log rotation based on time.</p>
<p>This directive was added in version 1.2.31</p>
</attribute>
<attribute name="log_filesize" required="false"><p>
The maximum log file size in megabytes, after which the log file will be rotated. Setting this to 0 (the default) disables log rotation based on file size.
<br/>The value can have an optional <b>M</b> suffix, i.e. both <b>5</b> and <b>5M</b> will rotate the log file when it grows to 5MB.
<br/>If <b>log_rotationtime</b> is specified, then this setting is ignored.  
</p></attribute>
<attribute name="worker_file" required="true"><p>
A string value which is the full path to workers.properties file
(for example <b>c:\tomcat\conf\workers.properties</b>)
</p></attribute>
<attribute name="worker_mount_file" required="true"><p>
A string value which is the full path to uriworkermap.properties file
(for example <b>c:\tomcat\conf\uriworkermap.properties</b>)
</p></attribute>
<attribute name="rewrite_rule_file" required="false"><p>
A string value which is the full path to rewrite.properties file
(for example <b>c:\tomcat\conf\rewrite.properties</b>)
</p></attribute>
<attribute name="shm_size" required="false"><p>
A DWORD value size of the shared memory. Set this value to be
the number of all defined workers * 400.
(Set this value only if you have <b>more</b> then <b>64</b> workers)
</p>
<p>This directive has been added in version 1.2.20</p>
<p>Starting with version 1.2.27 the size of the shared memory is determined
automatically, even for large numbers of workers. This attribute is not
needed any longer.</p>
</attribute>
<attribute name="worker_mount_reload" required="false"><p>
A DWORD value specifying the time in seconds upon which the
<b>worker_mount_file</b> will be reloaded.
</p>
<p>This directive has been added in version 1.2.20</p>
</attribute>
<attribute name="strip_session" required="false"><p>
A string value representing a boolean. If it is set to <b>true</b>,
URL session suffixes of the form ";jsessionid=..." get stripped of
URLs, if the are served locally by the web server.
</p>
<p>
The default value is false.
</p>
<p>This directive has been added in version 1.2.21</p>
</attribute>
<attribute name="auth_complete" required="false"><p>
A DWORD value representing "0" or "1". This is needed because
of minor incompatibilities with IIS 5.1.
</p>
<p>
By default its value is 1, which means we use the SF_NOTIFY_AUTH_COMPLETE
event. If you set this to 0, then we use SF_NOTIFY_PREPROC_HEADERS.
This might be needed for IIS 5.1 when handling requests using the
PUT HTTP method.
</p>
<p>This directive has been added in version 1.2.21</p>
</attribute>
<attribute name="uri_select" required="false"><p>
A string value which influences, how URIs are decoded and re-encoded
between IIS and Tomcat. You should leave this at it's default value,
unless you have a very good reason to change it.
</p>
<p>
If the value is "parsed", the forwarded URI
will be decoded and explicit path components like ".." will already
be resolved. This is less spec compliant and is <b>not safe</b>
if you are using prefix forwarding rules.
</p>
<p>
If the value is "unparsed", the forwarded URI
will be the original request URI. It's spec compliant and also
the safest option. Rewriting the URI and then forwarding the rewritten
URI will not work.
</p>
<p>
If the value is "escaped", the forwarded URI
will be the re-encoded form of the URI used by "parsed".
Explicit path components like ".." will already be resolved.
This will not work in combination with URL encoded session IDs.
</p>
<p>
If the value is "proxy", the forwarded URI
will be a partially re-encoded form of the URI used by "parsed".
Explicit path components like ".." will already be resolved.
and problematic are re-encoded.
</p>
<p>The default value since version 1.2.24 is "proxy". Before it was "parsed".</p>
</attribute>
<attribute name="reject_unsafe" required="false"><p>
A string value representing a boolean. If it is set to <b>true</b>,
URLs still containing percent signs '%' or backslashes '\'
after decoding will be rejected.
</p>
<p>
Most web apps do not use such URLs. By enabling <b>reject_unsafe</b> you
can block several well known URL encoding attacks.
</p>
<p>
The default value is false.
</p>
<p>This directive has been added in version 1.2.24</p>
</attribute>
<attribute name="collapse_slashes" required="false"><p>
This options is deprecated as of 1.2.44 and will be ignored if used.
</p>
<p>
Before version 1.2.41 collapsing was never done. Starting with
version 1.2.41 collapsing before looking for unmount matches
is the default to prevent easy bypassing of unmount rules.
As of 1.2.44, collpasing is always performed before looking for mount
or unmount rules.
</p>
<p>This directive has been added in version 1.2.41</p>
</attribute>
<attribute name="watchdog_interval" required="false"><p>
A DWORD value representing the watchdog thread interval in seconds.
The workers are maintained periodically by a background thread
running periodically every watchdog_interval seconds. Worker maintenance
checks for idle connections, corrects load status and is able
to detect backend health status.
</p>
<p>
The maintenance only happens, if since the last maintenance at
least <a href="workers.html"><code>worker.maintain</code></a>
seconds have passed. So setting the watchdog_interval
much smaller than <code>worker.maintain</code> is not useful.
</p>
<p>
The default value is 0 seconds, meaning the watchdog thread
will not be created, and the maintenance is done in combination
with normal requests instead.
</p>
<p>This directive has been added in version 1.2.27</p>
</attribute>
<attribute name="error_page" required="false"><p>
A string value representing the error page url redirection when
backend returns non-200 response. This directive can be used
to customise the error messages returned from backend server.
</p>
<p>The url must point to a valid server url and can contain
format string number <code>(%d)</code> that can be used to
separate the pages by error number. The redirect url in that
case is formatted by replacing <code>%d</code> from
<code>error_page</code> to returned error number.
</p>
<p>This directive has been added in version 1.2.27</p>
</attribute>
<attribute name="enable_chunked_encoding" required="false"><p>
A string value representing a boolean. If it is set to <b>true</b>,
chunked encoding is supported by the server.
</p>
<p>
The default value is false.
</p>
<p>This directive has been added in version 1.2.27. Until version 1.2.30 it
was considered experimental and only available when a special build containing
chunking support was used. Starting with 1.2.30 it is no longer considered
experimental.</p>
</attribute>
<attribute name="flush_packets" required="false"><p>
A string value representing a boolean. If it is set to <b>true</b>,
data is flushed immediately to the client as each AJP packet is received.
Otherwise, IIS buffers the data and only writes to the client when the buffer
is full or the response is complete.</p>
<p>
The default value is false.
</p>
<p>This directive has been added in version 1.2.42</p>
</attribute>
</attributes>
</section> 
<section name="Using a properties file for configuration">
<p>
The ISAPI redirector can read it's configuration from a properties file instead of the registry. 
This has the advantage that you can use multiple ISAPI redirectors with independent configurations on the same server.
The redirector will check for the properties file during initialisation, and use it in preference to the registry if present.
</p>
<p>
Create a properties file in the same directory as the ISAPI redirector called <b>isapi_redirect.properties</b> i.e.
with the same name as the ISAPI redirector DLL but with a <em>.properties</em> extension.
A sample isapi_redirect.properties can be found under the conf directory.
</p>
<p>
The property names and values in the properties file are the same as for the registry settings described above. For example:
</p>
<p>
<source>
# Configuration file for the Tomcat ISAPI Redirector

# The path to the ISAPI Redirector Extension, relative to the website
# This must be in a virtual directory with execute privileges
extension_uri=/jakarta/isapi_redirect.dll

# Full path to the log file for the ISAPI Redirector
log_file=c:\tomcat\logs\isapi_redirect.log

# Log level (debug, info, warn, error or trace)
log_level=info

# Full path to the workers.properties file
worker_file=c:\tomcat\conf\workers.properties

# Full path to the uriworkermap.properties file
worker_mount_file=c:\tomcat\conf\uriworkermap.properties
</source>
</p>
<p>
    Notes: 
    <ul>
        <li>
            Back-slashes - '\' - are not escape characters.
        </li>
        <li>
            Comment lines begin with '#'.
        </li>
    </ul>
</p>
<p>Starting with version 1.2.27 two environment variables are
automatically added to the environment that can be used inside
<code>.properties</code> files.
    <ul>
        <li>JKISAPI_PATH - Full path to the ISAPI Redirector.
        </li>
        <li>JKISAPI_NAME - Name of the ISAPI Redirector dll without extension
        </li>
    </ul>    
</p>
<p><source>
# Use the logs in the installation path of ISAPI Redirector
log_file=$(JKISAPI_PATH)\$(JKISAPI_NAME).log
</source></p>
</section>

<section name="Log file rotation">
<p>
The ISAPI redirector with version 1.2.31 can perform log rotation, with configuration and behaviour similar to the 
<a href="http://httpd.apache.org/docs/2.4/programs/rotatelogs.html">rotatelogs</a> program provided with Apache HTTP Server.
</p>
<p>
To configure log rotation, configure a <b>log_file</b>, and one of the <b>log_rotationtime</b> or <b>log_filesize</b> options.
If both are specified, the <b>log_rotationtime</b> will take precedence, and <b>log_filesize</b> will be ignored. 
<br/>For example, to configure daily rotation of the log file:
</p>
<source>
# Configuration file for the Tomcat ISAPI Redirector
...

# Full path to the log file for the ISAPI Redirector
log_file=c:\tomcat\logs\isapi_redirect.%Y-%m-%d.log

# Log level (debug, info, warn, error or trace)
log_level=info

# Rotate the log file every day
log_rotationtime=86400

...
</source>
<p>
Or to configure rotation of the log file when it reaches 5MB in size:
</p>
<source>
# Configuration file for the Tomcat ISAPI Redirector
...

# Full path to the log file for the ISAPI Redirector
log_file=c:\tomcat\logs\isapi_redirect.%Y-%m-%d-%H.log

# Log level (debug, info, warn, error or trace)
log_level=info

# Rotate the log file at 5 MB
log_filesize=5M

...
</source>
<p>
The log will be rotated whenever the configured limit is reached, but only if the log file name would change. If you configure
 a log file name with <code>strftime(3)</code> format codes in it, then ensure it specifies the same granularity
 as the rotation time configured, e.g. <b>%Y-%m-%d</b> if rotating daily (<b>log_rotationtime=86400</b>).
<br/>See the <a href="http://httpd.apache.org/docs/2.4/programs/rotatelogs.html">rotatelogs</a> documentation for more examples.
</p>

</section>

<section name="Using a simple rewrite rules">
<p>
The ISAPI redirector with version 1.2.16 can do a simple URL rewriting. Although not
as powerful as Apache HTTP Server's mod_rewrite, it allows a simple exchange of request URIs
</p>
<p>
The rule is in the form original-url-prefix=forward-url-prefix. For example:
</p>
<source>
# Simple rewrite rules, making examples
# available under shorter URLs
/jsp/=/examples/jsp/
/servlets/=/examples/servlets/
</source>
<p>
You can also use regular expressions, if you prefix the rule with a tilde <code>~</code>:
</p>
<source>
# Complex rewrite rule, prefixing "/examples/"
# to the first path component of all requests
~/([^/]*)=/examples/$1
</source>
<p>
Note that uriworkermap.properties must use the URLs before rewriting.
</p>
</section>

</body>
</document>
