Application design for data persistence over unreliable internet

Question

I've an Flex actionscript 3 schedule reminding app which talks to a web-service through the internet over wifi. The problem is the wifi connection is unreliable and there are frequent dropouts. The schedule which the app reminds doesn't change very frequently. So instead of calling the web-service for finding the schedule every day/hour the app can store the data locally. Also, if the user updates the schedule on the app, the web-service is updated that the task on the schedule is complete. This data can also be stored locally so that when the user uses the app next time and there is an internet connection, the app can update the web-service. What are the suggestions for the application design in such a case? Are there any examples?

Answer 1

For storing the schedule locally, use a shared object. Here is a tutorial on the subject, if you haven't used them before.

Any time the user adds/edits an item, attempt to send it to the server. Make sure to store the changed/new item in the shared object. If it fails, have the application periodically (eg every min or every 10 sec or every 15 mins, depending on how you want to set it up) check for a successful connection. As soon as it has a successful connection, have the app sync with the server. Make sure the server sends back a signal for successful saving before the app stops trying to send changes.

Does your application run all the time, or just for brief stints? It would only be able to sync when the app is open on the user's computer, of course. How frequently do you lose/regain connectivity?