FILEIO_INFO.txt

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FILE I/O INFORMATION
====================
This library has a basic issue: it still uses regular File I/O which is not
supported on Google App Engine.  As a remedy, we are changing references as 
needed.
See com/google/code/appengine/imageio/stream/FileCacheImageInputStream.java
for an example of a changed reference.
 
 
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IMPORTANT NOTES
===============
The new file system comes with some quirks.  But it isn't just the file system, it's the entirety of working with files on Google App Engine.

For more information, please read the gae vfs documentation here: https://code.google.com/p/gaevfs/wiki/UsingGaeVFS

Here are the basics.  Since Google App Engine run servlet code, everything discussed here is in the context of servlets (e.g. the init/destroy methods)

1. You must set a root path for the entire servlet to use.  The best place to do this is in the servlet's init method.  You can do this with something like this:

		GaeVFS.setRootPath(getServletContext().getRealPath("/"));
		
2. You *should* (in good practice) close GaeVFS in the destroy method:

		GaeVFS.close();
		
3. Now, it's important to clear the thread local cache.  All GAE operations should be placed in a try/finally clause with the clear cache operation appearing in the finally clause.  We should investigate putting this somewhere else (such as in the appengine-awt code in destroy code or something) because it seems like a bad practice to require library users (which means OEM customers) to call this in their code.

		GaeVFS.clearFilesCache();