Adding local file rendering support to Sample Container

This patch enables Shindig's Sample Container to render files local to the developer's machine.

This is facilitated by adding a Servlet that serves these files (only to localhost requests).

The Sample Container UI has been changed to support this feature (including allowing one to pick a file from the local filesystem via a file input control)

JIRA Issue: https://issues.apache.org/jira/browse/SHINDIG-775

[etnu00, 2008-12-10 23:38:00]

Why not just configure jetty to serve static files?

[louiscryan, 2008-12-12 02:09:35]

Overall looks fine, couple of minor comments.

http://codereview.appspot.com/10269/diff/1/5
File
java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/localfile/LocalFileServlet.java
(right):

http://codereview.appspot.com/10269/diff/1/5#newcode37
Line 37: * requests from localhost will be honored.
Add a comment making it obvious that this should only be used in test
environments.

http://codereview.appspot.com/10269/diff/1/5#newcode69
Line 69: in = new BufferedInputStream(new FileInputStream(file), BUFFER_SIZE);
Use the IOUtils class to do the IO handling, it has built in buffering and youll
have less code.

[levik, 2008-12-15 18:11:17]

Updated LocalServlet to use IOUtils, commented it out in web.xml files

[Henning, 2008-12-17 17:31:52]

First and most important question for me would be: What do you need this for? As
Kevin points out, let Jetty serve the static files.

If this is a debugging aid for the sample container, the code should not be in
the gadgets module. It belongs in the samples or server module (maybe server
will sprout its own java code base for pure sample purposes).

This thing as a tremendous potential to be abused, if it goes in, I expect a lot
of patch suggestions to remove the localhost test. And it breaks if I try to
access a file using my regular host name (which I do all the time), because it
resolves to my network Ip and not localhost.

Summary: Don't put this in. There are better ways to do it. If you insist to put
it in, please don't put it into the gadgets codebase, put it into the server or
samples and clearly mark it as "DEBUG CODE. DO NOT RUN IN PRODUCTION" (e.g. log
this on startup.

[levik, 2009-01-12 21:17:40]

Moved LocalFileServlet to server/src/main/java/.../sample