Play! + GAE + File Upload

Usually with the Play framework, when you upload a file, it appears as a File object to the controller, and the file itself is stored in a tmp f开发者_开发百科older. In GAE this won't work because GAE does not allow writing to the filesystem.

How would one upload a file and access the stream directly in the controller?

So i figured out the solution. In the controller, instead of passing in a File object, you just pass in a byte[], and use a ByeArrayInputStream to get that into a more usable form. In my case I needed to pass in the file data to a csv parser which takes an InputStream.

i'm not familiar with the play framework either but generally, for multipart requests (e.g. file uploads),

1. the data from the inputstream is written to a temporary file on the local filesystem if the input size is large enough
2. the request is then dispatched to your controller
3. your controller gets a File object from the framework. (this file object is pointing to the temporary file)

for the apache commons upload, you can use the DiskFileItemFactory to set the size threshold before the framework decides whether to write the file to disk or keep it in memory. If kept in memory, the framework copies the data to a DataOutputStream (this is done transparently so your servlet will still be working with the File object without having to know whether the file is on disk or in memory).

perhaps there is a similar configuration for the play framework.