Rust Tauri command missing field even though it is provided

Question

I'm creating a tauri app. I want to call a command with some data (see code snippets below). But when I do I get the following error. This is weird since the field is provided as you can see (and tauri changes it to snake_case in the background). Could this have another cause?

ERROR invalid args `data` for command `decrypt_local_database_with_pin`: missing field `cause_error`

I should note that the property in question cause_error and the thread.sleep call are there to help me test this application until the backend is ready. So there is no real functionality, yet.

These are the code parts in question:

The Rust Part

#[derive(Debug, thiserror::Error)]
pub enum CommandError {
    #[error(transparent)]
    Error(#[from] anyhow::Error),
}

impl Serialize for CommandError {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer,
    {
        serializer.serialize_str(self.to_string().as_ref())
    }
}

pub type CommandResult<T, E = CommandError> = anyhow::Result<T, E>;

#[derive(Debug, Serialize, Deserialize)]
pub struct CommandValue<T> {
    pub cause_error: bool,
    pub values: T
}

#[derive(Debug, Deserialize)]
pub struct DecryptLocalDatabaseWithPinData {
    pub pin: String,
}

#[tauri::command]
pub fn decrypt_local_database_with_pin(data: CommandValue<DecryptLocalDatabaseWithPinData>) -> CommandResult<String> {
    thread::sleep(Duration::from_millis(2000));

    match data.cause_error {
        true => Ok(format!("Local database decrypted with pin: {}", data.values.pin)),
        false => Err(CommandError::Error(anyhow::anyhow!(format!("Local database was not decrypted with pin: {}", data.values.pin)))),
    }
}

The Typescript Part

encryptLocalDatabaseWithPin(pin: string) {
    return invoke("decrypt_local_database_with_pin", {
        data: { pin },
        causeError: true,
    });
}

Answer 1

You have structured your types and arguments wrong. With the Tauri command you've specified, you'd need to call it like this:

invoke("decrypt_local_database_with_pin", {
    data: { values: { pin }, cause_error: true },
});

And thus the error is correct: you provided cause_error, but in the wrong place.

Additionally:

• I've added values because that is how your Rust types are built, you can use #[serde(flatten)] to avoid that if you wish.
• The cause_error should be in snake_case; Tauri will translate the argument names between snake_case and camelCase, but not the contents of the values passed. Right now data is the only "argument" and what it holds will be un-touched. You can use #[serde(rename_all = "camelCase")] to avoid that if you wish.

If you were to want causeError to work as you tried, it would have to be a separate parameter on the command:

#[tauri::command]
pub fn decrypt_local_database_with_pin(data: ..., cause_error: bool) -> ...