View source for JANUS WEB rule matching order and examples

<span class="pageSubtitle">WEB rule matching order and examples</span>

Each execution of a <var>JANUS WEB</var> command adds to the set of rules for the specified <var>WEBSERV</var> port. Individual rules cannot be deleted nor modified; all rules can be deleted only by stopping and deleting the port definition. However, this should not be necessary, as long as you follow the two golden rules:
<ol>

<li>Specify the most general rules first and the most specific last. 
<li>Specify a first rule that will "clear" all related rules.
</ol>

The following example illustrates these principles:
<p class="code">JANUS WEB TEST21 DISALLOW *
JANUS WEB TEST21 ALLOW IPADDR 198.242.244.0-24
JANUS WEB TEST21 ALLOW IPADDR 169.84.128.0-3
JANUS WEB TEST21 DISALLOW IPADDR 169.84.128.17
JANUS WEB TEST21 ALLOW USER *
</p>

In this example, any previously specified ALLOW rules on port <code>TEST21</code> are made obsolete by the first <var>DISALLOW</var> rule. Once the <code>TEST21</code> access rules are cleared, two subnets are given access permission, and then a single specific IP address within one of those subnets has its access revoked. Finally, the <code>ALLOW USER *</code> forces logon processing for all users. 

Similar processing takes place for redirection commands. To redirect a specified URL to another URL, use the <var>REDIRECT</var> command:
<p class="code">JANUS WEB SIRIUS REDIRECT *.jav <nowiki>http://sirius-software.com:8080/java/*.jav</nowiki>
</p>

In the example above, requests for Java executables are routed out of the [[Janus Web Server]] <code>SIRIUS</code> and onto a java directory at port 8080 at <code>sirius-software.com</code>.
A block of redirection commands might look like this:
<p class="code">JANUS WEB SIRIUS NOREDIRECT
JANUS WEB SIRIUS REDIRECT *.jav <nowiki>http://sirius-software.com:8080/java/*.jav</nowiki>
JANUS WEB SIRIUS REDIRECT *.jpg <nowiki>http://sirius-software.com:8001/images/*.jpg</nowiki>
</p>

In this example, all previously defined redirection is removed, Java executables are routed out of the Janus Web Server <code>SIRIUS</code> and onto a java directory at port 8080 at <code>sirius-software.com</code>, and JPEG images are redirected to an <code>IMAGES</code> directory on port 8001 at 
<code>sirius-software.com</code>.

<var>TYPE</var> rules are used to customize processing for certain patterns of incoming URLs. For example
<p class="code">JANUS WEB SIRIUS TYPE *.HTML HTML_*
</p>
The Janus Web Server default assumption is that the requested URL is stored in a <var class="product">Model 204</var> procedure. If the above <var>TYPE</var> rule is in effect and a request comes in for <code>WELCOME.HTML</code>, the server looks in the default procedure file for procedure <code>HTML_WELCOME</code> and returns its contents to the user. 

Virtually any character that is valid in a URL specification is valid as part of a <var class="product">Model 204</var> procedure name, so the Janus Web Server satisfies by default a request for 
<code><nowiki>http://www.x.com:80/staff/bobsmith/welcome.html</nowiki></code> by sending the contents of the procedure "staff/bobsmith/welcome.HTML" from the default <var class="product">Model 204</var> file to the client. 

To change this default behavior, you can use an <var>ON</var> rule to cause a request for a specific URL to initiate some other process, as in:
<p class="code">JANUS WEB SIRIUS ON /pensions/* OPEN GROUP PENSIONS CMD 'I PENSIONS_DRIVER'
</p>

In the above example, any request for access to the <code>/pensions</code> directory instead causes the <var class="product">Model 204</var> group <code>PENSIONS</code> to open and the routine <code>PENSIONS_DRIVER</code> to be invoked.

==See also==
<ul>
<li>[[List of Janus commands]]
<li>[[List of JANUS WEB subcommands]]
</ul>

[[Category:JANUS WEB subcommands|JANUS WEB Rule matching order and examples]]