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choonkeat / elm-webapp

A setup for writing http based, client-server app in elm, inspired wholly by lamdera.com
https://package.elm-lang.org/packages/choonkeat/elm-webapp/latest
MIT License
57 stars 7 forks source link

Does this have lamdera evergreen? #6

Closed Dylanb-dev closed 2 years ago

Dylanb-dev commented 2 years ago

Or something like it for persisting data?

choonkeat commented 2 years ago

lamdera evergreen

my understanding of "evergreen" refers to the "msg migration" feature that allows deploying of new versions of the app and have the safety that a stale SPA instance on client browsers would still be able to auto upgrade itself and thus not lose a msg between client/server communications

elm-webapp does not come with "msg migration" feature. however as of 3.0.0, the generated MsgFromServer comes with ClientServerVersionMismatch

which is leveraged to know that the client/server is out of sync and present a "Please reload this browser page" message to the end user

persisting data

elm-webapp does not persist the "model" of the server (aka serverState), unlike Lamdera.

While you can still code to update the model of Server note that the values are only held in memory and is lost when the Server process exits. Doing so is still worthwhile during development though, enabling quick iteration of the app without messing with db & schema

For reference, in my own production apps, serverState is only ever used to hold immutable server config. For persisting data, my Server code

  1. makes regular HTTP requests to query and mutate persisted data on DynamoDB
  2. makes regular GraphQL HTTP requests to Hasura to query and mutate persisted data in a PostgreSQL database
Dylanb-dev commented 2 years ago

Thanks for the write up.

The elm-webapp solution for the frontend is great and I wish more frameworks adopted it by default.

I was curious how much of lamdera was borrowed by elm-webapp and agree persistence solutions are outside the scope of the project. Thanks for the examples on what is the correct way to get persistence in elm-webapp.

Massolari commented 2 years ago

Hey, @choonkeat . What do you think about putting this informations about ServerState in the README? About it not being persisted and some alternatives to do it, like you said about making HTTP requests to DynamoDB or to Hasura.

choonkeat commented 2 years ago

Good idea @Massolari ! I've written it down in README 🙇