Why this event does'nt work?

[shadow3aaa]

I'm writing an rust ide on android.

Since tauri(2.0-beta) doesn't yet support mobile to use sidecar/resources, I use rust_embed crate to embed resources directly into the library.

Then I need to extract some resources(like proot, rootfs, prebuilted rust-analyzer, etc.) when the program starts and put them in a place like /data/data/package_name/res.

I want users to see the progress of resource extraction, So I do this(vue3):

• frontend

import { ref, onMounted, onUnmounted } from "vue";
import { useRouter } from "vue-router";
import { VList, VListItem, VIcon } from "vuetify/components";
import { listen, UnlistenFn } from "@tauri-apps/api/event";
import { invoke } from "@tauri-apps/api/core";

interface Payload {
  message: string;
}

let unlisten: UnlistenFn | null = null;

const router = useRouter();
const setupProcess = ref("Waiting until setup process complete...");
const setupCompleted = ref(false);

onMounted(async () => {
  invoke("init_resources").then(() => {
    setupCompleted.value = true;
  });

  unlisten = await listen<Payload>("setup-process", (event) => {
    const { message } = event.payload;
    setupProcess.value += `\n${message}`;
  });
});

onUnmounted(() => {
  unlisten?.();
});

function routeToProjectView() {
  router.push("/project");
}

• backend
  payload.rs

#[derive(Clone, serde::Serialize)]
pub struct Payload {
    message: String,
}

impl Payload {
    pub fn new(message: String) -> Self {
        Self { message }
    }
}

lib.rs

#[tauri::command]
fn init_resources(app: AppHandle) {
    app.emit("setup-process", Payload::new("Checking resources".into()))
        .unwrap();
    
    async_runtime::block_on(Resources::auto_update()).unwrap();
    app.emit(
        "setup-process",
        Payload::new("Checking proot rootfs".into()),
    )
    .unwrap();
    setup_rootfs().unwrap();
    app.emit("setup-process", Payload::new("All done.".into()))
        .unwrap();
}

#[cfg_attr(mobile, tauri::mobile_entry_point)]
pub fn run() {
    tauri::Builder::default()
        .plugin(tauri_plugin_shell::init())
        .invoke_handler(tauri::generate_handler![init_resources])
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}

However, when I was testing it, I found that no events were received, and if I tried to await listen, it just kept blocking current thread.

[FabianLars]

Did you try changing this

onMounted(async () => {
  invoke("init_resources").then(() => {
    setupCompleted.value = true;
  });

  unlisten = await listen<Payload>("setup-process", (event) => {
    const { message } = event.payload;
    setupProcess.value += `\n${message}`;
  });
});

to this?

onMounted(async () => {
  unlisten = await listen<Payload>("setup-process", (event) => {
    const { message } = event.payload;
    setupProcess.value += `\n${message}`;
  });

  invoke("init_resources").then(() => {
    setupCompleted.value = true;
  });
});

If the command executes too fast it will be finished before you have a chance to register the events, so just make sure the listeners are registered beforehand and it should work.

[shadow3aaa]

I tried this:

const init_resources = async () => {
  await invoke("init_resources").then(() => {
    setupCompleted.value = true;
  });
};

onMounted(async () => {
  unlisten = listen<Payload>("setup-process", (event) => {
    const { message } = event.payload;
    setupProcess.value = `\n${message}`;
  });

  init_resources();
});

but still, it didn't work(invoke works fine)

[FabianLars]

Can you check the devtools console (right click -> inspect) for any errors? Maybe also try to console.log the event payload in the listener to be sure it never triggers

[shadow3aaa]

Can you check the devtools console (right click -> inspect) for any errors? Maybe also try to console.log the event payload in the listener to be sure it never triggers

SO THAT'S IT. There is a permission error. That's strange, I think it should be allowed by default

[FabianLars]

Well, it is if you add the default permissions (event:default).

[shadow3aaa]

So this is my solution:

• create dir src-tauri/capabilities(if not created yet)
• create file src-tauri/capabilities/mobile.json(or desktop.json, main.json, etc):

{
  "$schema": "../gen/schemas/mobile-schema.json",
  "identifier": "main-capability",
  "description": "Capability for the main window",
  "windows": ["main"],
  "permissions": ["event:default"] // add any other permissions you need!
}

and event should work fine