Passing Parameters using jetty contextHandler - jetty

Question

I'm wanting to make some custom endpoints that point to another endpoint in my jetty setup. For example, I already have and endpoint like http://myserver.com/app that serves up a help page. Further, if I pass certain arguments, I get different pages. So for example http://myserver.com/app?app_id=56 might serve one app and http://myserver.com/app?app_id=48 might serve a static html page that documents functions.
For the sake of some of the users, I'd like to set up simple endpoints for a few of the commonly used apps. So if a user went to http://myserver.com/docs, they'd should see the same thing as http://myserver.com/app?app_id=48.
I've been trying to accomplish this with .xml Configuration files. So far I've got it almost working.
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE Configure PUBLIC "-//Mort Bay Consulting//DTD Configure//EN" "http://jetty.eclipse.org/configure.dtd">
<Configure class="org.eclipse.jetty.server.handler.ContextHandler">
<Set name="contextPath">/docs</Set>
<Set name="resourceBase">http://localhost:8080</Set>
<Set name="handler">
<New class="org.eclipse.jetty.server.handler.ResourceHandler">
<Set name="welcomeFiles">
<Array type="String">
<Item>app</Item>
</Array>
</Set>
<Set name="cacheControl">max-age=3600,public</Set>
</New>
</Set>
</Configure>
Using this config file going to /docs serves the aforementioned help page which I would normally see by loading http://myserver.com/app, my hangup is I can't figure out how to pass the appropriate app_id.
I think I may end up creating some sort of custom handler but I'm not exactly sure how to go about implementing it.
And just to complicate the issue, I also want to be able to pass some arbitrary parameter to my endpoint and have it passed along. So http://myserver.com/docs?foo=bar would display http://myserver.com/app?app_id=48&foo=bar.
Should I be going about this another way or can this all be accomplished through the config xml files?

Answer 1

If using Jetty 9.2+ you can just use the built-in static resource serving (magic provided by the deploy module)
Eg:
$ cd /path/to/my.base
$ ls -l webapps
total 4
lrwxrwxrwx. 1 joakim joakim 84 Oct 27 17:24 docs -> /opt/my/docs
$ java -jar /path/to/jetty-dist/start.jar
But if you really want to handle static resources with an XML ...
Don't use ContextHandler and ResourceHandler they are only for the most simplistic and naive of file serving scenarios.
Use an anonymous WebAppContext
Set resourceBase to the directory where your documents are
Here's how you setup a static file serving XML (done right)
$ cd /path/to/my.base
$ cat webapps/docs.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://www.eclipse.org/jetty/configure_9_3.dtd">
<Configure class="org.eclipse.jetty.webapp.WebAppContext">
<Set name="contextPath">/docs</Set>
<Set name="resourceBase">/opt/my/docs</Set>
<Set name="defaultsDescriptor"><Property name="jetty.base" default="."/>/etc/docs-web.xml</Set>
</Configure>
$ cat etc/docs-web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
metadata-complete="false"
version="3.1">
<servlet>
<servlet-name>default</servlet-name>
<servlet-class>org.eclipse.jetty.servlet.DefaultServlet</servlet-class>
<init-param>
<param-name>aliases</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>acceptRanges</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>dirAllowed</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>welcomeServlets</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>redirectWelcome</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>maxCacheSize</param-name>
<param-value>256000000</param-value>
</init-param>
<init-param>
<param-name>maxCachedFileSize</param-name>
<param-value>200000000</param-value>
</init-param>
<init-param>
<param-name>maxCachedFiles</param-name>
<param-value>2048</param-value>
</init-param>
<init-param>
<param-name>gzip</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>etags</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>useFileMappedBuffer</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>cacheControl</param-name>
<param-value>max-age=3600,public</param-value>
</init-param>
<load-on-startup>0</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
</welcome-file-list>
</web-app>
$ java -jar /path/to/jetty-dist/start.jar