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LiveView is a nightmare from a deployment point of view. LiveView stores state on the server associated with the web socket connection. If the web socket connec

LiveView is a nightmare from a deployment point of view. LiveView stores state on the server associated with the web socket connection. If the web socket connection disappears which is what will happen during a deployment then the user's state will disappear. The value of LiveView is not having to write javascript but the only way to preserve any non-complicated state in LiveView when the web socket disappears is to write javascript. It is only recently that LiveView added support to automatically preserve form input values across a state crash. [https://github.com/phoenixframework/phoenix_live_view/blob/master/CHANGELOG.md https://github.com/phoenixframework/phoenix_live_view/blob/m... | Recovery form input data automatically on disconnects or crash recovery] Prior, to 0.7.0 if the web socket died while you were typing input values in a form then the page would reload and all your input into the form would be wiped out.

josevalim 6y ago
You are right that state is transient but JavaScript is not the only option. For transitions and screens, you can use live navigation. For forms there is automatic recovery (as you mentioned). Another option is to persist the state on the server. For example, go back to the Twitter timeline example. Imagine that you want to do a banner that says "N tweets unread - click here to expand them". You could keep this counter in the LiveView but if you reconnect the counter will be lost. But you can also solve this by storing a pointer to the last shown tweet on the DB. Then if you reconnect, you can compute how many tweets are pending. If you are doing a multi-step wizard you can persist each step on the DB too, etc. Depending on the use case, this could even yield further benefits, such as automatic synchronization between devices. I.e. if you read some tweets on your phone, you can automatically bump the "last shown index" on all devices. Or start the wizard in one place and finish it elsewhere. That's the point of LiveView, you can build interactive applications that are more server-centric. Some of those features are new but that should be no surprise, it is still pre-1.0 software. Even as we add new features, you may still have to (or want to) rely on JS on many scenarios, and that's totally fine.

josevalim 6y ago

You are right that state is transient but JavaScript is not the only option. For transitions and screens, you can use live navigation. For forms there is automatic recovery (as you mentioned). Another option is to persist the state on the server. For example, go back to the Twitter timeline example. Imagine that you want to do a banner that says "N tweets unread - click here to expand them". You could keep this counter in the LiveView but if you reconnect the counter will be lost. But you can also solve this by storing a pointer to the last shown tweet on the DB. Then if you reconnect, you can compute how many tweets are pending. If you are doing a multi-step wizard you can persist each step on the DB too, etc. Depending on the use case, this could even yield further benefits, such as automatic synchronization between devices. I.e. if you read some tweets on your phone, you can automatically bump the "last shown index" on all devices. Or start the wizard in one place and finish it elsewhere. That's the point of LiveView, you can build interactive applications that are more server-centric. Some of those features are new but that should be no surprise, it is still pre-1.0 software. Even as we add new features, you may still have to (or want to) rely on JS on many scenarios, and that's totally fine.