return validation json response

[kaplanelad]

Previously, the controller did not support automatic validation of POST parameters. Validation was done manually after deserialization using the serde_json library. For instance, the developer would create a struct, add validation rules using the Validate trait, and manually handle the validation errors in the controller.

#[derive(Debug, Deserialize, Validate)]
pub struct DataParams {
    #[validate(length(min = 5, message = "message_str"))]
    pub name: String,
    #[validate(email)]
    pub email: String,
}

#[debug_handler]
pub async fn index(
    State(_ctx): State<AppContext>,
    Json(params): Json<DataParams>,
) -> Result<Response> {
    // Manual validation
    let validate_res = params.validate();
    if let Err(errors) = validate_res {
        // Handle errors manually
        return Err(errors.into());
    }

    // Continue processing if validation succeeds
    format::empty()
}

New Implementation:
The updated implementation introduces a JsonValidate and FormValidate and with messages response: JsonValidateWithMessage and FormValidateWithMessage extractors, which automatically handles validation and returns a JSON response for validation errors. This eliminates the need for manual validation logic in the controller.

#[derive(Debug, Deserialize, Validate)]
pub struct DataParams {
    #[validate(length(min = 5, message = "message_str"))]
    pub name: String,
    #[validate(email)]
    pub email: String,
}

#[debug_handler]
pub async fn index(
    State(_ctx): State<AppContext>,
    JsonValidate(params): JsonValidate<DataParams>,
) -> Result<Response> {
    // Validation is automatically handled by JsonValidate
    format::empty()
}

If validation fails, JsonValidate automatically returns a structured JSON response like the following:

{
  "errors": {
    "email": [
      {
        "code": "email",
        "message": null,
        "params": { "value": "invalid" }
      }
    ],
    "name": [
      {
        "code": "length",
        "message": "message_str",
        "params": { "min": 5, "value": "test" }
      }
    ]
  }
}

[turboladen]

I'm a bit confused here and was wondering if I might get a hand? After trying to implement this pattern for my own type and route, I copied the example code and brought it into my project, and it doesn't compile:

 3  error[E0277]: the trait bound `loco_rs::prelude::JsonValidate<DataParams>: FromRequest<loco_rs::prelude::AppContext, _>` is not satisfied                                                                          ▐
   --> crates/ding/src/controllers/chat.rs:72:27                                                                                                                                                                       ▐
    |                                                                                                                                                                                                                  ▐
 72 |     JsonValidate(params): JsonValidate<DataParams>,                                                                                                                                                              ▐
    |                           ^^^^^^^^^^^^ the trait `FromRequest<loco_rs::prelude::AppContext, _>` is not implemented for `loco_rs::prelude::JsonValidate<DataParams>`                                              ▐
    |                                                                                                                                                                                                                  ▐
    = note: Function argument is not a valid axum extractor.                                                                                                                                                           ▐
            See `https://docs.rs/axum/0.8/axum/extract/index.html` for details                                                                                                                                         ▐
    = help: the trait `FromRequest<S>` is implemented for `loco_rs::prelude::JsonValidate<T>`                                                                                                                          ▐
 note: required by a bound in `chat::__axum_macros_check_index_1_from_request_check`                                                                                                                                   ▐
   --> crates/ding/src/controllers/chat.rs:72:27                                                                                                                                                                       ▐
    |                                                                                                                                                                                                                  ▐
 72 |     JsonValidate(params): JsonValidate<DataParams>,                                                                                                                                                              ▐
    |                           ^^^^^^^^^^^^ required by this bound in `__axum_macros_check_index_1_from_request_check`  

Any thoughts on what I might be missing?

[turboladen]

Any thoughts on what I might be missing?

I figured it out: I was running validator 0.20.0, but looks like loco-rs wants 0.19.0. Once I downgraded to that, I was in business.