GWT Application gets “404 The requested resource is not available”.

[Ananchai Srirochanakul]

Hi there.

I do not know why I keep getting "404 The requested resource is not available", when I am accessing my GWT Application. I am hosting my GWT application, on my TomEE/8.5.6 (7.0.2) at home, currently. Here is the situation. I am able to use my GWT application from "TomEE Web Application Manager" as (http)://192.168.1.70:8080/Index However, when I type (http)://www.zethanath.tk in the browser, I would get (https)://www.zethanath.tk/ with HTTP Status 404. Here is the details of my configuration. Ubuntu:/opt/tomcat/webapps$ ls -l total 20932 drwxrwxr-x 14 tomcat tomcat 4096 Aug 4 11:46 docs drwxrwxr-x 5 tomcat tomcat 4096 Aug 4 11:46 host-manager drwxrwxrwx 5 tomcat tomcat 4096 Aug 25 08:46 Index -rwxrwxrwx 1 tomcat tomcat 21411520 Aug 25 08:46 Index.war drwxrwxr-x 5 tomcat tomcat 4096 Aug 4 11:46 manager drwxrwxr-x 3 tomcat tomcat 4096 Aug 8 17:30 ROOT sudo nano 000-default.conf <VirtualHost *:80 > Protocols h2 http/1.1 ServerAdmin erick9.hi5@gmail.com ServerName www.zethanath.tk ServerAlias servlet.zethanath.tk zethanath.tk DocumentRoot "/opt/tomcat/webapps/Index" ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined RewriteEngine on RewriteCond %{SERVER_NAME} =www.zethanath.tk RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent] </VirtualHost> # vim: syntax=apache ts=4 sw=4 sts=4 sr noet sudo nano default-ssl.conf <IfModule mod_ssl.c> <VirtualHost _default_:443> Protocols h2 http/1.1 ServerAdmin erick9.hi5@gmail.com ServerName www.zethanath.tk ServerAlias servlet.zethanath.tk zethanath.tk DocumentRoot "/opt/tomcat/webapps/Index" JKMountCopy On JKMount /* ajp13_worker ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined SSLEngine on SSLCertificateFile /etc/letsencrypt/live/zethanath.tk/fullchain.pem SSLCertificateKeyFile /etc/letsencrypt/live/zethanath.tk/privkey.pem Include /etc/letsencrypt/options-ssl-apache.conf <FilesMatch "\.(cgi|shtml|phtml|php)$"> SSLOptions +StdEnvVars </FilesMatch> <Directory /usr/lib/cgi-bin> SSLOptions +StdEnvVars </Directory> </VirtualHost> </IfModule> # vim: syntax=apache ts=4 sw=4 sts=4 sr noet I keep thinking that I need to associate port 8080 with "DocumentRoot "/opt/tomcat/webapps/Index", but I am unsure how. Here is the details of my UFW. I have similar setup in the router. sudo ufw status Status: active To Action From -- ------ ---- OpenSSH ALLOW Anywhere Apache Full ALLOW Anywhere 20/tcp ALLOW Anywhere 21/tcp ALLOW Anywhere 990/tcp ALLOW Anywhere 40000:50000/tcp ALLOW Anywhere Apache Secure ALLOW Anywhere 8080 ALLOW Anywhere OpenSSH (v6) ALLOW Anywhere (v6) Apache Full (v6) ALLOW Anywhere (v6) 20/tcp (v6) ALLOW Anywhere (v6) 21/tcp (v6) ALLOW Anywhere (v6) 990/tcp (v6) ALLOW Anywhere (v6) 40000:50000/tcp (v6) ALLOW Anywhere (v6) Apache Secure (v6) ALLOW Anywhere (v6) 8080 (v6) ALLOW Anywhere (v6) Help is greatly appreciated.

[Jens]

Looks like you want to use Apache + Tomcat. In that case you need to configure Apache as reverse proxy to your Tomcat. There are basically two variants:

1.) Your complete GWT app (GWT JavaScript, index.html, all server code) is inside your *.war file. In that case you would proxy any request to your domain to tomcat which usually runs on localhost:8080. So your virtual host in Apache would contain something like ProxyPass / http://localhost:8080/Index 

2.) You let Apache serve all the static files (GWT JavaScript, index.html) and tomcat only has the server code of your app in your *.war file. In that case your Apache virtual host would have a document root pointing to the folder of your GWT app and only requests to tomcat (server requests your app  makes using GWT-RPC, RequestBuilder, REST, whatever you use) would need to be proxied by Apache. So you might end up having more proxy configuration. This is more an optimization solution because you can now tune apache to serve static files and tune tomcat to deliver dynamic content.

You should google for Apache mod_proxy to find some more documentation on reverse proxying using Apache.

-- J.

[Ananchai Srirochanakul]

Hi Jen,

Thank you so much for your reply. However, I heard that mod_proxy is slower that Mod JK, so I made a switch just a little while ago :)

Here is what the users expect.

1.If the users type (http://)www.zethanath.tk in the browser, mod_rewrite, near the end of http vhost conf, 
would redirect the user to (https://www.zethanath.tk). I am using mod_rewrite here.  

<VirtualHost *:80 >

...

RewriteEngine on
RewriteCond %{SERVER_NAME} =www.zethanath.tk
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]

</VirtualHost>

 
2. At this point, SSL vhost should use Mod JK to redirect the users to my GWT application on TomEE Server. My GWT application, in this case, is stored at /opt/tomcat/webapps/ with the name Index.war. but I do not know why I keep getting "404 The resource is not available".

<IfModule mod_ssl.c>
  <VirtualHost _default_:443

>
  ...

  
  DocumentRoot "/opt/tomcat/webapps/Index"

  JKMountCopy On
  JKMount /* ajp13_worker

  ...  

  </VirtualHost>
</IfModule>

I can see my GWT application working correct as http://192.168.1.70:8080/Index from Firefox, but I do not know why I got 404 error.
I allow 8080 on my firewall and router. I assigned 775 permission on Index.war, as well as the associated Index directory.

Maybe the statement here does not take port 8080 into consideration ? -> "DocumentRoot "/opt/tomcat/webapps/Index"
Maybe I should try get rid of this same line within http vhost config file?



[Jens]

Thank you so much for your reply. However, I heard that mod_proxy is slower that Mod JK, so I made a switch just a little while ago :)

Oh sorry, somehow missed you are using mod_jk. Never really used it but then I guess you are missing some configuration needed on your production system.

Maybe the statement here does not take port 8080 into consideration ? -> "DocumentRoot "/opt/tomcat/webapps/Index"
Maybe I should try get rid of this same line within http vhost config file?

I think you should have a workers.properties file which is used to tell apache / mod_jk how to access the worker you have named "ajp13_worker". It should have host and port config values. But I guess if these values would be wrong you would get a HTTP 5xx status code and not a 4xx one.

Maybe change mod_jk logging to debug to get more information.

-- J.

[Ananchai Srirochanakul]

Hi Jen,

I have done what you mentioned as well. Here is the content of /opt/tomcat/conf/server.xml 

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.tomee.catalina.ServerListener" />
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <GlobalNamingResources>
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>
  <Service name="Catalina">
    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" xpoweredBy="false" server="Apache TomEE" />

   <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
   <Engine name="Catalina" defaultHost="localhost">
   <Realm className="org.apache.catalina.realm.LockOutRealm">
   <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
   </Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>
    </Engine>
  </Service>
</Server>

Here is the content of "/etc/libapache2-mod-jk/workers.properties".

workers.tomcat_home=/opt/tomcat
workers.java_home=/usr/lib/jvm/java-8-oracle/jre
ps=/
worker.list=ajp13_worker
worker.ajp13_worker.port=8009
worker.ajp13_worker.host=localhost
worker.ajp13_worker.type=ajp13
worker.ajp13_worker.lbfactor=1
worker.loadbalancer.type=lb
worker.loadbalancer.balance_workers=ajp13_worker

I found some article online mentioned that I need to create symbolic link for GWT application. I can't figure out if it is true or not, though. It said I need to add something like below to 
SSL vhost configuration file.

      DocumentRoot "/opt/tomcat/webapps/Index"

      Alias /Index "/opt/tomcat/webapps/Index"
      <Directory "/opt/tomcat/webapps/Index">
         Options Indexes FollowSymLinks
         AllowOverride NONE
         Order allow,deny
         Allow from all
      </Directory>

      <Location "/Index/WEB-INF/">
         AllowOverride None
         Deny from all
      </Location>

      JKMountCopy On
      JKMount /* ajp13_worker

[Ananchai Srirochanakul]

Help is greatly appreciated.

Thanks.