Elm Tauri Example

Connects elm to the file system etc using Tauri.app via lobanov/elm-taskport. Mini HowTo below.

There's an example app with LOTS of buttons in Main.elm with persistent Main/Congfig.elm.

Stuff

Mainly I'm providing Tasks because you can chain them with andThen. You'll want to turn them into Cmds and you can use Tauri.toCmd3 or Tauri.toCommand1 etc to help that. I import it but define my own local one to keep the Interop errors (probably broken javascript in index.html) and the Javascript errors (usually runtime errors) separate from my messages.

• src/Main.elm has lots of examples, some of them simple like asking a question, some multi-stage interactions like the user choosing a source and a destination, confirming to go ahead and then copying the file.
• src/Tauri/FS.elm is FileSystem functions
• src/Tauri has functions to turn the Tasks into commands
• src/Tauri/TaskUtils has lots of tools for
  • Using Task rather than Cmd so you can use andThen to conditionally run other Tasks, for if stuff's absent or the user says yes or no etc.
  • Keeping errors out of fail state: I find it's useful to usually return a Result Msg a so that Tauri.andThen chains them together OK. Once an error is in the fail part of the Task, your Task is stopping and your error recovery is up to the calling code.

How To

If you're cloning it to edit, you'll certainly want to edit tauri.conf.json from what I put:

"package": {
    "productName": "ElmTauriGUI",
"tauri": {
    ...
    ...
    ...
    "identifier": "Andrew-Clow.ElmTauriGUI",

How to set everything up for Elm talking to Tauri via TaskPort:

1. Follow

   • https://tauri.app/v1/guides/getting-started/prerequisites
   • https://tauri.app/v1/guides/getting-started/setup/

2. elm init

3. (create IDE project from existing sources)

4. Install elm modules:

   • elm install mdgriffith/elm-ui
   • elm install lobanov/elm-taskport
   • elm install elm/json

5. Copy taskport.min.js into publicUI. See https://package.elm-lang.org/packages/lobanov/elm-taskport/latest/

6. Make a viable Main.elm

7. Create index.html in putblicUI from the Elm guide with Taskport entries for Tauri stuff as per the TaskPort guide and Tauri API, like

   <script src="./taskport.min.js"></script>
   <script>
      TaskPort.install(); // can pass a settings object as a parameter, see lobanov/elm-taskport/
      TaskPort.register("readTextFile", (args) => {return window.__TAURI__.fs.readTextFile(args)});
      TaskPort.register("open", (args) => {return window.__TAURI__.dialog.open(args)});
      TaskPort.register("ask", (args) => {return window.__TAURI__.dialog.ask(args)});
   </script>
   

   Note that if you get an interop error like Not Installed, you probably just have a typo in the javascript above. If it says Not Found, it's probably because you omitted that line altogether or commented it out and didn't reinstate it.

8. cargo tauri init

   • dev server ../publicUI
   • dev command elm make src/Main.elm --output=publicUI/main.js
   • build command elm make src/Main.elm --output=publicUI/main.js --optimize
   • On Windows you may need to edit the borked tauri.conf.json to include the = sign instead of UUencoded nonsense in what you just typed.

9. Add FS and Path and Dialog stuff on allowlist in tauri.conf.json. See the one here for examples.

   • Note the ["$APPCONFIG/*","$APPCONFIG", ... ] to workaround the lack of access to root directory malfeature in Tauri.

10. Add "withGlobalTauri": true into the build section of tauri.conf.json to enable all that window.__TAURI__. stuff.

11. cargo tauri dev to check it's working.

12. The stuff in Tauri.Modified requires edits to your src-tauri/main.rs to give the rust code backing that up as it's not part of tauri.

13. Antivirus: Norton AV panics about build-script-build.exe. Restore it.

    • Exclude the whole folder from further interruption:
    • https://support.norton.com/sp/en/us/home/current/solutions/v3672136

Handy hot reloading of everything in sight:

• npx elm-watch hot
• cargo tauri dev

Todo

I haven't tested all of the functions! Sorry. I've tested most of them, and more than listed here.