How to provide access to an external resource (file) for a GlassFish web application?

Question

I am a bit of a GlassFish beginner, so please forgive my ingnorance on the subject.

Basically we are serving a game website, and to make the client downloadable by our web app we copy it into a directory within domain1. The problem with this is that when redeploying the web app the client downloadable is lost and we have to copy it across again.

I'd like to be able to store the client downloadable in some external location and have GlassFish provide access to it.

I could just hardcode the link into the web app, but then we would lose portability so that's the reason for having GlassFish handle it.

I could also put the client downloadable into our database but that seems like poor use of a database and could also result in poor database performance.

The third option I have found is to add a custom resource mapping from some name to the file location, and then provide a method in one of my beans to retrieve the file location. This seems like a lot of work just to have an external resource, I feel like there must be an easier way.

So what should I do?

Answer 1

The link to your downloadables needn't be in the same application as the game servlets, right?

One solution would be to create a new "pseudo" application containing only a web.xml and your static file content. You would of course not deploy it in war form (well, only if you really want to) but just copy the files into the unpacked directory when you want to change content. I use a setup like this to serve a bunch of files from a Web app server I run.

At work, in an "enterprise" kind of environment, we do things differently. We have an Apache HTTPD server working as the front end. It forwards to the app server for stuff that needs to be done in Java, but any static content, as well as cookie management, SSL, load balancing and other "web server-y" stuff is done by HTTPD. This yields a bit of a performance advantage with heavily loaded sites and lots of big but static files. It also lets us split the work among different physical boxes, which again can help with performance.

Answer 2

With GlassFish you can define an alternate document root to serve files from outside the war. From the documentation:

Alternate Document Roots

An alternate document root (docroot) allows a web application to serve requests for certain resources from outside its own docroot, based on whether those requests match one (or more) of the URI patterns of the web application's alternate docroots.

To specify an alternate docroot for a web application or a virtual server, use the *alternatedocroot_n* property, where n is a positive integer that allows specification of more than one. This property can be a subelement of a sun-web-app element in the sun-web.xml file or a virtual server property. For more information about these elements, see sun-web-app in Oracle GlassFish Server 3.0.1 Application Deployment Guide.

So you could configure something like this:

<property name="alternatedocroot_1" value="from=/ext/* dir=/path/to/ext"/>

Refer to the documentation for full details.