**Important**: This crate's functionality was incorporated into [`tonic-types`]
and will be actively maintained there. This repository is no longer maintained.  

[`tonic-types`]: https://crates.io/crates/tonic-types

---

# Tonic Richer Error
Assets for implementation of the gRPC Richer Error Model with tonic.

This crate introduces the [`WithErrorDetails`] trait and implements it in
[`tonic::Status`], allowing the implementation of the [gRPC Richer Error Model]
with [`tonic`] in a convenient way.

[![Crates.io](https://img.shields.io/crates/v/tonic-richer-error)](https://crates.io/crates/tonic-richer-error)
[![Documentation](https://docs.rs/tonic-richer-error/badge.svg)](https://docs.rs/tonic-richer-error)
[![Crates.io](https://img.shields.io/crates/l/tonic-richer-error)](LICENSE)

[Examples] | [Website] | [Docs] 

## Usage
The [`WithErrorDetails`] trait adds associated functions to [`tonic::Status`]
that can be used on the server side to create a status with error details, that
can then be returned to the gRPC client. Moreover, the trait also adds methods
to [`tonic::Status`] that can be used by a tonic client to extract error
details, and handle them with ease.

## Getting Started
To build this crate you must have the Protocol Buffer Compiler, `protoc`,
installed. Instructions can be found [here][protoc-install].

```
[dependencies]
tonic = "0.8"
tonic-richer-error = "0.3"
```

## Examples
The examples bellow cover a basic use case. More complete server and client
implementations can be found at the [examples] directory.

### Server Side: Generating `tonic::Status` with an `ErrorDetails` struct
```rust
use tonic::{Code, Status};
use tonic_richer_error::{ErrorDetails, WithErrorDetails};

// ...
// Inside a gRPC server endpoint that returns `Result<Response<T>, Status>`

// Create empty `ErrorDetails` struct
let mut err_details = ErrorDetails::new();

// Add error details conditionally
if some_condition {
    err_details.add_bad_request_violation(
        "field_a",
        "description of why the field_a is invalid"
    );
}

if other_condition {
    err_details.add_bad_request_violation(
        "field_b",
        "description of why the field_b is invalid",
    );
}

// Check if any error details were set and return error status if so
if err_details.has_bad_request_violations() {

    // Add additional error details if necessary
    err_details
        .add_help_link("description of link", "https://resource.example.local")
        .set_localized_message("en-US", "message for the user");

    let status = Status::with_error_details(
        Code::InvalidArgument,
        "bad request",
        err_details,
    );

    return Err(status);
}

// Handle valid request

// ...
```

### Client Side: Extracting an `ErrorDetails` struct from `tonic::Status`
```rust
use tonic::{Response, Status};
use tonic_richer_error::WithErrorDetails;

// ...

// Where `req_result` was returned by a gRPC client endpoint method
fn handle_request_result<T>(req_result: Result<Response<T>, Status>) {
    match req_result {
        Ok(response) => {
            // Handle successful response
        },
        Err(status) => {
            let err_details = status.get_error_details();
            if let Some(bad_request) = err_details.bad_request {
                // Handle bad_request details
            }
            if let Some(help) = err_details.help {
                // Handle help details
            }
            if let Some(localized_message) = err_details.localized_message {
                // Handle localized_message details
            }
        }
    };
}
```

### Send different standard error messages
Multiple examples are provided at the [`ErrorDetails`] doc. Instructions about
how to use the fields of the standard error message types correctly are
provided at [error_details.proto].

### Alternative `tonic::Status` associated functions and methods
In the [`WithErrorDetails`] doc, an alternative way of interacting with
[`tonic::Status`] is presented, using vectors of error details structs wrapped
with the [`ErrorDetail`] enum. This approach can provide more control over the
vector of standard error messages that will be generated or that was received,
if necessary. To see how to adopt this approach, please check the
[`WithErrorDetails::with_error_details_vec`] and
[`WithErrorDetails::get_error_details_vec`] docs, and also the
[examples] directory.  

Besides that, multiple examples with alternative error details extraction
methods are provided in the [`WithErrorDetails`] doc, which can be specially
useful if only one type of standard error message is being handled by the
client. For example, using [`WithErrorDetails::get_details_bad_request`] is a
more direct way of extracting a [`BadRequest`] error message from
[`tonic::Status`].

## License

This project is licensed under the [MIT license](LICENSE).

## Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion by you, shall be licensed as MIT, without any additional terms or
conditions.

[`tonic::Status`]: https://docs.rs/tonic/0.8.0/tonic/struct.Status.html
[`tonic`]: https://docs.rs/tonic/0.8.0/tonic/
[gRPC Richer Error Model]: https://www.grpc.io/docs/guides/error/
[Examples]: https://github.com/flemosr/tonic-richer-error/tree/main/examples
[Website]: https://github.com/flemosr/tonic-richer-error
[Docs]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/
[protoc-install]: https://grpc.io/docs/protoc-installation/
[examples]: https://github.com/flemosr/tonic-richer-error/tree/main/examples
[error_details.proto]: https://github.com/googleapis/googleapis/blob/master/google/rpc/error_details.proto
[`ErrorDetails`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/struct.ErrorDetails.html
[`WithErrorDetails`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/trait.WithErrorDetails.html
[`ErrorDetail`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/enum.ErrorDetail.html
[`WithErrorDetails::with_error_details_vec`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/trait.WithErrorDetails.html#tymethod.with_error_details_vec
[`WithErrorDetails::get_error_details_vec`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/trait.WithErrorDetails.html#tymethod.get_error_details_vec
[`WithErrorDetails::get_details_bad_request`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/trait.WithErrorDetails.html#tymethod.get_details_bad_request
[`BadRequest`]: https://docs.rs/tonic-richer-error/0.3.2/tonic_richer_error/struct.BadRequest.html