Using Jetty's proxy in standalone Jetty application
jetty, jetty-9, maven-jetty-plugin, proxy
Solution
I found the hints I needed to solve this with jetty transparent proxy always returns 403 forbidden. The question didn't exactly pertain to my question, but the code snippet provided showed me what I needed in the `<servlet>` in `web.xml`.
Updated web.xml
<servlet>
<servlet-name>proxy</servlet-name>
<servlet-class>org.example.ProxyServletExtension$Transparent</servlet-class>
<init-param>
<param-name>maxThreads</param-name>
<param-value>1</param-value>
</init-param>
<init-param>
<param-name>proxyTo</param-name>
<param-value>http://localhost:8060</param-value>
</init-param>
<async-supported>true</async-supported>
</servlet>
<servlet-mapping>
<servlet-name>proxy</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
Required changes
- Set the `<servlet-class>` to `ProxyServletExtension$Transparent`, previously I wasn't using a trasparent proxy.
- Use an `<init-param>` of `proxyTo` using the address you would like to proxy the requests to. This also means that the `ProxyServletExtension.java` class above (in the question) is completely unnecessary.
Also, it is worth mentioning that there is a `prefix` `<init-param>` as well, which can be used to remove part of the incoming request before proxying to the proxied request.
Problem
I'm investigating using Jetty 9 as a proxy, using standalone Jetty, not embedded Jetty. I've looked for help in many places: Most of these are related to embedded Jetty: - How to create Proxy Server using jetty8? - Jetty ProxyServlet with SSL support This question is along the same lines: - Can stand-alone Jetty be used as a reverse proxy (without Apache mod-proxy) ...but the only answer is a link to a page that covers some parameters for the proxy, but no examples or other helpful hints. On to the question... I've created an extension to Jetty's ProxyServlet, which overrides the `rewriteURI()` method to actually change the request to a different URL. This custom proxy works when running Jetty embedded, but when I use a web.xml file and the jetty-maven-plugin to create a war to deploy, it no longer works. When I make a request, I can debug the application and see that it gets into the `rewriteURI()` method, it then calls Jetty's ProxyServlet's `service()` method, which runs to completion, but then nothing happens. The page remains blank, and eventually ProxyServlet's `onResponseFailure()` is called with a TimeoutException, "Total timeout elapsed". Dev tools shows the request receiving a 504 Gateway Timeout. It seems as though something is missing in how things are connected, but I can't tell what it might be. Any help would be greatly appreciated. I've included `web.xml` and the custom proxy (`ProxyServletExtension`) below. web.xml ``` <servlet> <servlet-name>proxy</servlet-name> <servlet-class>org.example.ProxyServletExtension</servlet-class> <init-param> <param-name>maxThreads</param-name> <param-value>1</param-value> </init-param> <async-supported>true</async-supported> </servlet> <servlet-mapping> <servlet-name>proxy</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> ``` ProxyServletExtension.java ``` ... import org.eclipse.jetty.proxy.ProxyServlet; ... public class ProxyServletExtension extends ProxyServlet { @Override protected URI rewriteURI(HttpServletRequest request) { // Forward all requests to another port on this machine String uri = "http://localhost:8060"; // Take the current path and append it to the new url String path = request.getRequestURI(); uri += path; // Add query params String query = request.getQueryString(); if (query != null && query.length() > 0) { uri += "?" + query; } return URI.create(uri).normalize(); } } ```