db4o Developer Community

• The user will upload a text file thru a browser
  With the sounds of this, it is an ASP.Net application. The text file is delimited and it can be translated into columns of data.
• After the file has been uploaded, a process should execute to transfer the data in the text file to my db4o database
  Each column of data in the text file will go to an object repository

Sounds simple. However, the text file is several MBs big so it will be a long running process. The user will be very bored uploading and processing the data. So I came up with the following additional requirements:

• Once the text file is uploaded, an asynchronous operation needs to be done so the processing will actually happen in the server where the db4o database is located.
• The processing logs certain information so that when the user inquires of it, he can see it in the browser page that displays the current status of the processing.
• The user can close the browser anytime after the processing starts or go to another page while the processing is being done. He can inquire later on a page where he can see the current status. Wow! This is something that will make the user more productive.
• In the server, I would like to know when a processing has been triggered and the current status of the processing so I cannot just shutdown the db4o server or do something bad for it.
• I can also do the uploading of the text file and processing in the server application.
  

Now this is something more complicated. It made me excited to do this so I started the research. I came thru the db4o reference documentation on Client Server regarding Out-of-Band Signaling. I read it and decided that this is the thing I need. How does it work? [...]