Tuesday, January 13, 2015


It seems like if someone was reading through this, it would be helpful if I stated the problem first and then the solution later. Right? Yesterday I sat at this very page, which was blank at that time, and desperately sought the words to clearly describe the potential steps to solve our question. That question is to alert the user to how many potential signees are on the currant network. The problem is two-fold. Currently, once someone announces their data, the system does not update their list of server-side clients. I could announce a key and, even though I've turned off the application, my data continues to reside in the clients list of discovered services. The next issue, which is much broader in scope, is that if I'm running the application in client mode I do not publish services. In effect I am invisible on the network. 

The sub-problem of revising the list of discovered services is almost an extension of my first task. Thus, it was the best place to start. Yesterday as I sat in front of a blank page, I realized that even though Tobi and I had gone through sketch of how one might go about implementing a solution, I didn't fully comprehend the problem. Even as I write this, I continue to think of things that may complicate or impact the solution. On a more general level, there are a few ways to tackle this problem. We can update the list by having Avahi announce that they are removing their services. Or, the browser can continually check for published data and revise the list by who is currently emitting a fingerprint. I went ahead an implemented a rough draft in which Avahi announces that they are removing their services. This "draft" is by no means ready to merge, since there are several smaller details and a few integral aspects that will need to be addressed. Briefly summarized, when the user clicks the back button to return to the original window of the application, the program tells Avahi to shut down the server. In my version, the server stops and then is re-initialized. I took advantage of the fact that the fingerprint in this case would be equal to None. When Avahi browser encounters a server-side client with a fingerprint set to None, it then removes that client's information from the on discovered list. It seems to work. I think a little tweaking and it should be okay. 

Once the feature is finished, I can compare the result to this post and reflect on the differences.

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