CQ & Sling servlets: resourceType

Last time we see how to use Sling servlets with old legacy URL. Today we’ll see how to create Sling Servlets in the Sling-way: using resourceType.

Scenario

We want a component that can be dragged into a parsys. With a form that submit data to a sling servlet. Then the servlet will do the operations required.

Process

Let’s create the component following the CQ guidelines for making it drag-droppable into a parsys (allowedParents): geometrixx/components/test003. The test003.jsp will look like the following:

<%@include file="/libs/foundation/global.jsp"%>
<form name="frm" method="post" action="<c:out value="${resource.path}" />.c">
    <input type="submit" />
</form>

This JSP will answer at a GET http call showing the form. In order to use, create a content page and drag the component into a parsys.

Now it’s time to create the servlet. As usual you’ll have to register it using some felix annotations. The following servlet will be used when posting (HTTP POST) to a resource of type geometrixx/components/test003 with an extension of “c”.

package com.samples.sling;

import java.io.IOException;
import javax.servlet.ServletException;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingAllMethodsServlet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @scr.component immediate="true" metatype="false"
 * @scr.service interface="javax.servlet.Servlet"
 * @scr.property name="sling.servlet.methods" values.0="POST"
 * @scr.property name="sling.servlet.resourceTypes" values.0="geometrixx/components/test003"
 * @scr.property name="sling.servlet.extensions" values.0="c"
 */

public class ResourceTypePostServlet extends SlingAllMethodsServlet {
   private static final long serialVersionUID = 8795673847499208743L;
   private final static Logger logger = LoggerFactory.getLogger(ResourceTypePostServlet.class);

   @Override
   protected void doPost(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException, IOException {
      logger.debug("ResourceTypePostServlet::doPost()");
      response.setContentType("text/plain");
      response.getOutputStream().print("Hello ResourceTypePostServlet World!");
   }
}

We used the sling.servlet.methods to specify which HTTP method the servlet listen to, the sling.servlet.resourceTypes to specify all the resource types is should listen to and the .extensions if you wish to specify an extension.

Remember that if you specify a sling.servlet.paths, resourceTypes, extensions and selectors will be ignored.

Now build the bundle and refresh the previously created content page (should not necessary actually). If you click on the “submit” button you’ll see the Hello World.

References:

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CQ & Sling servlets: old legacy URL

SlingIn this short article (first of a serie I hope) I’ll show you how to create a Sling Servlet in CQ.

Scenario

You are migrating your existing application in CQ a piece at time and it’s time for the Servlets (controllers) part, so for the first stage you’d like to keep the old URLs. Maybe because some other external services are calling you at these coordinates or because you don’t want to enter each jsp and change the forms action.

Ingredients

  • CQ instance running in Author (localhost:4502)
  • CRXDE (let’s ease the game for starting)

Process

Create a new OSGi bundle under geometrixx (or your app). In this create a new class that extends the SlingSafeMethodsServlet.
Then you have to register as a service in the OSGi container. This is done using the Felix annotations as following:

/**
 * @scr.component immediate="true" metatype="false"
 * @scr.service interface="javax.servlet.Servlet"
 * @scr.property name="sling.servlet.methods" values.0="GET"
 * @scr.property name="sling.servlet.paths" values.0="/path/to/my/servlet"
 *                                          values.1="/apps/path/to/my/servlet"
 */

I’ll leave you to the references section of this post for getting deeper into the meaning of each.

At the end your code will look something like the following:

package com.samples.sling;

import java.io.IOException;
import javax.servlet.ServletException;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @scr.component immediate="true" metatype="false"
 * @scr.service interface="javax.servlet.Servlet"
 * @scr.property name="sling.servlet.methods" values.0="GET"
 * @scr.property name="sling.servlet.paths" values.0="/path/to/my/servlet"
 *                values.1="/apps/path/to/my/servlet"
 */
public class AbsoluteUrlServlet extends SlingSafeMethodsServlet {
   private static final long serialVersionUID = -1920460619265757059L;
   private static final Logger logger = LoggerFactory.getLogger(AbsoluteUrlServlet.class);

   @Override
   protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException, IOException {
      logger.debug("AbsoluteUrlServlet::doGet()");
      response.setContentType("text/plain");
      response.getOutputStream().print("Hello AbsoluteUrlServlet World!");
   }
}

Looking at the sling.servlet.paths annotation we se on which url we are actually mapping the servlet: /path/to/my/servlet and /apps/path/to/my/servlet.

Building the bundle and CRXDE+felix will do the magic of the deployment.

Now if you try to run localhost:4502/apps/path/to/my/servlet you’ll see our beautiful Helloworld, but if you’ll try to access localhost:4502/path/to/my/servlet you’ll get a 404 or a content listing.
This is due to a settings in felix+Sling. Open the felix console at the configuration tab (/system/console/configMgr) and search for Apache Sling Servlet/Script Resolver and Error Handler. Here you’ll have to add “/path/” to the Execution Paths section.

Done done!

References

CQ5 “disable” linkcheker

Linkcheker it’s a very useful functionality that highlight to the author eventual broken links within, for example, a RichText widget. However when integrating already existent web application behind apache, there’s the need to “disable” completely it.

We won’t go to disable it properly but configuring it in a way that for him all links are not to be checked.

In CQ5.4, go into the Felix console and click con components (http://$server:$port/system/console/components) and search for: com.day.cq.rewriter.linkchecker.impl.LinkCheckerImpl. Click on the wrench (settings) and in the link check override patterns add the following regex (using the “+” button):

^.*$

Save and refresh the page in the author.

This will save the settings into the file crx-quickstart/launchpad/config/com/day/cq/rewriter/linkchecker/impl/LinkCheckerImpl.config.

This will work, but it will disable the Apache Sling JCR Resource Resolver as well, as it uses the LinkChecker service behind the scenes to transform the links.

A more intelligent approach is to use a negative RegEx saying to LinkChecker to ignore everything that is not in our /content/sitename. Use this regular expression:

^((?!/content/sitename).)*$

Replacing sitename with your correct path.

If you want to set the config into the CRX repository (so it can be exported/imported via package manager)  go to /libs/cq/linkchecker/config/com.day.cq.rewriter.linkchecker.impl.LinkCheckerImpl using Content Explorer and edit the property service.check_override_patterns adding the regex previously mentioned.

Easy peasy! 🙂

CQ5 author instance and Apache

Here at a customer site, we have a CQ application deployed into “/” context root (as usual) of weblogic 9.2 alongside other functional web apps. All of this sites behind Apache httpd which serves some html files as well as reverse proxies to weblogic based on some urls.

Generally there’s no problem in this except that in this case, when accessing from apache the “/” it serves its htdocs directory so we are not able to login to cq. When logging into CQ, the login form POSTs to http://admin:admin@<server>/?sling:authRequestLogin=1 which needs to be proxied to CQ’s / instead of Apache’s htdocs. As apache is serving its content, no CQ filter is fired.

If we make the weblogic-handler module to come in action for “/” we loose all the apache content. As well, we cannot move all the apache content into CQ.

So the problem is how do we make Apache to use weblogic handler only for a particular URL and query string? We’ve come to a solution combining both Apache configs and some crx node creation.

First, the apache configs:

<LocationMatch "^/(content|libs|siteadmin|apps|bin|home|etc|welcome|var|tmp|cf|useradmin|damadmin|miscadmin|workflow|tagging|inbox|cqauthurl)">
SetHandler weblogic-handler
</LocationMatch>

This sets all the urls in the LocationMatch to be handled by weblogic-handler to proxy to CQ.

As you may have noticed we are dealing with a /cqauthurl that is not a CQ url. We need to use Content Explorer to create the node /cqauthurl (nt:unstructured). This will avoid a 404.

The add the following rewrite rule in Apache configs; as general or within the location should make no difference:

RewriteRule ^/cqlogin$ /libs/cq/core/content/login.html?resource=/siteadmin [R]
RewriteCond %{QUERY_STRING}  ^sling:authRequestLogin=1$
RewriteRule (.*) /cqauthurl [PT]

The first line will allow the user to bookmark a simple url like http://<server>/cqlogin. When accessing this url there will be a redirect onto the CQ’s Login.

The second and third lines tells apache: when on the query string there’s sling:authRequestLogin=1 then rewrite to /cqauthurl.

This lets the user’s login go through to CQ and caches the basic auth credentials for all paths under http://author-server:port/

CQ Site admin needs to be accessed via http://author-server:port/siteadmin instead of the root context.

Weekly links 2011-07

Hello JavaFX 2! – Back To Java

Making of JBoss Enterprise Web Server

Applying agile practices in an environment of mistrust

ETL lessons learnt

Generate Test Data with DataFactory

The Roadmap for Day Software and LiveCycle ES – a Focus on UX

Springfuse generates Primefaces with Spring Web Flow front end

Spring MVC Development – Quick Tutorial

Open Letter from CEO Stephen Elop, Nokia and CEO Steve Ballmer, Microsoft

No more nokia phones for me.

OpenJDK Community Bylaws — DRAFT 7