Salesforce's Database.com and Google App Engine via JPA

Currently i try to connect (via JPA/Datanucleus) with an application, hosted by Google App Engine, to the database service of database.com (Salesforce)

After many hours of reading and trying, i could not find any solution.

So, is it even possible??

Some Information.... Database.com provides JPA: http://forcedotcom.github.com/java-sdk/jpa-provider, but i could not found any sdk on this side, but i found a jar-file hosted by grepcode http://grepcode.com/snapshot/repo1.maven.org/maven2/com.force.sdk/force-jpa/22.0.7-BETA/ - Possibly there is currently no official release ...

The problem is that this SDK from Salesforce needs datanucleus 2.0, but Google App Engine includes only datanucleus 1.1.5开发者_开发知识库. So i try to update theses libaries and found this.... code.google.com/p/datanucleus-appengine/ . I tried a few hours to replace the old libaries and to use the newer, but unsuccessfully. The error was that eclipse could not find some libaries, because the newer libaries, provided by the side above, have different package structure -

I am thankful for any help...

Kotake

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The official release of the JPA provider is available on Maven Central: http://search.maven.org/remotecontent?filepath=com/force/sdk/force-jpa/22.0.7-BETA/force-jpa-22.0.7-BETA.jar

The external connection restriction won't be a limiting factor because the JPA adapter connects to Database.com over https using a SOAP API.

I can't speak to the challenges around getting DN 2.0 running on GAE. Perhaps GAE support can help with that?

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As stated here in the App Engine docs, you cannot make direct connections to external servers from GAE (except over http or https using the app engine specific url APIs). You will need to find some other way to get data out of your remote database.

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This link describes how to solve your problem:

How to use Force.com Database SDK on Google APP Engine

(He has updated the Saleforce SDK source code to allow it to work without problem on GAE.)