Data Validation

Sword allows you to validate incoming data in Socket.IO events using the validator crate, similar to how validation works in web controllers.

For the full reference of try_data and try_validated_data, see Event handling and SocketContext reference.

Enabling validation-validator

To use validation in SocketContext, you must enable the validation-validator feature.

[dependencies]
validator = { features = ["derive"] }
sword = { version = "x.y.z", features = ["validation-validator"] }
serde = { features = ["derive"] }

Validatable DTO

use serde::Deserialize;
use validator::Validate;

#[derive(Debug, Deserialize, Validate)]
struct IncomingMessageDto {
    #[validate(length(min = 1, max = 200))]
    pub content: String,
}

Using try_validated_data

use sword::prelude::*;
use sword::socketio::*;

#[controller(kind = Controller::SocketIo, namespace = "/chat")]
pub struct ChatController;

impl ChatController {
    #[on("message")]
    async fn handle_message(&self, ctx: SocketContext) {
        let Ok(data) = ctx.try_validated_data::<IncomingMessageDto>() else {
            eprintln!("Failed to validate message data");
            return;
        };

        ctx.socket.emit("message", &data.content).ok();
    }
}

Difference with try_data

• try_data::<T>() only deserializes the payload.
• try_validated_data::<T>() deserializes and then runs the Validate trait.

If validation fails, the method returns an error, and you can decide how to handle it within the handler.