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Rails and Java EE integration - Native Rails on GlassFish v3

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Rails and Java EE integration - Native Rails on GlassFish v3

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The last part of this tri-series blog ( Part 1, Part 2) will show how a Rails application can be deployed on GlassFish - without the need of Goldspike, Warbler or any other gem or plugin. Yes, that's a native Rails app deployment on GlassFish v3.

GlassFish v3 is next version of GlassFish v2 and the focus is modularization, enablement of non-Java EE containers and modularity - download b09.

Rails powered by GlassFish provides all the details on why GlassFish provides an industry-grade and functionally-rich Application Server.

Now detailed steps:
  1. Using JRuby 1.1 (installed with Rails), create a Rails app "railsee3" as:

    ~/testbed/jruby-1.1/samples/rails >../../bin/jruby -S rails railsee3
          create 
          create  app/controllers
          create  app/helpers
          create  app/models
          . . .
          create  log/production.log
          create  log/development.log
          create  log/test.log
  2. Add Servlet descriptors
    1. Create a new directory "WEB-INF", and a new file "web.xml" in that directory using the following contents:

      <!DOCTYPE web-app PUBLIC
        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        "http://java.sun.com/dtd/web-app_2_3.dtd">
      <web-app>
              <servlet>
                      <servlet-name>HelloServlet</servlet-name>
                      <servlet-class>server.HelloServlet</servlet-class>
              </servlet>
              <servlet-mapping>
                      <servlet-name>HelloServlet</servlet-name>
                      <url-pattern>/hello</url-pattern>
              </servlet-mapping>
      </web-app>
    2. Create a new file "sun-web.xml" in "WEB-INF" using the following contents:

      <?xml version="1.0" encoding="UTF-8"?>
      <!DOCTYPE sun-web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Application Server 9.0 Servlet 2.5//EN" "http://www.sun.com/software
      /appserver/dtds/sun-web-app_2_5-0.dtd">
      <sun-web-app error-url="">
        <context-root>/servlet</context-root>
        <class-loader delegate="true"/>
      </sun-web-app>
    3. Create a new directory "WEB-INF/lib".
  3. Create and Copy Servlet
    1. Create a Java library with Servlet code as explained in bullet #5 here.
    2. Copy "HelloServlet.jar" from "dist" directory of NetBeans project to "WEB-INF/lib" directory.
  4. Configure JRuby-on-Rails in GlassFish - Edit "config/asenv.conf" in GlassFish directory and specify JRUBY_HOME as the last line:

    JRUBY_HOME="/Users/arungupta/testbed/jruby-1.1"
  5. Deploy the Rails application as:

  6. ~/testbed/jruby-1.1/samples/rails >~/testbed/glassfish/v3/p2b9/glassfish/bin/asadmin deploy --force=true railsee3
    railsee3 deployed successfully
    Command deploy executed successfully.
  7. The bundled Servlet is now accessible at "http://localhost:8080/servlet/hello". The default browser output looks like:



    And passing a parameter to the URL as "http://localhost:8080/railsee3/hello?name=Arun" shows the output as:

With this, your Java EE Servlet is now bundled with your Rails application deployed on GlassFish v3.

Now, lets add Controller and View to Rails application and invoke this servlet from there to show complete integration with Rails.
  1. Create a new Controller and View as

    ~/testbed/jruby-1.1/samples/rails/railsee3 >../../../bin/jruby script/generate controller home index
    JRuby limited openssl loaded. gem install jruby-openssl for full support.
    http://wiki.jruby.org/wiki/JRuby_Builtin_OpenSSL
          exists  app/controllers/
          exists  app/helpers/
          create  app/views/home
          exists  test/functional/
          create  app/controllers/home_controller.rb
          create  test/functional/home_controller_test.rb
          create  app/helpers/home_helper.rb
          create  app/views/home/index.html.erb
  2. Change the generated controller in "app/controllers/home_controller.rb" to:

    class HomeController < ApplicationController

    include Java

      def index
            url = java.net.URL.new("http://localhost:8080/servlet/hello");
            conn = url.open_connection;
            reader = java.io.BufferedReader.new(java.io.InputStreamReader.new(conn.get_input_stream));
            @servlet_output = "";
            input_line = reader.read_line;
            while input_line != nil
                    @servlet_output << input_line;
                    input_line = reader.read_line;
            end
            reader.close;
      end
    end
  3. Change the generated view in "app/views/home/index.rhtml.erb" to:

    <h1>Home#index</h1>
    <p>Find me in app/views/home/index.html.erb</p>

    <%= @servlet_output %>
  4. Re-deploy the Rails application as shown in bullet # 5 above and "http://localhost:8080/railsee3/home/index" shows the output as shown:

So this blog explained how a Rails application can be deployed on GlassFish v3 without the need of any gems like Warbler or plugin like Goldspike - total native deployment!

In summary, the tri-part blog showed the deployment models for a Rails application on GlassFish. Each model showed how a Java EE 5 Servlet can be co-bundled with Rails application and invoked from Rails view:
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Published at DZone with permission of Arun Gupta, DZone MVB. See the original article here.

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