1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

use std::error::Error;
use std::fmt::{self, Debug, Display, Formatter};

use hyper::{Body, Response, StatusCode};
use log::{debug, trace};

use crate::handler::IntoResponse;
use crate::helpers::http::response::create_empty_response;
use crate::state::{request_id, State};

/// Describes an error which occurred during handler execution, and allows the creation of a HTTP
/// `Response`.
pub struct HandlerError {
    status_code: StatusCode,
    cause: Box<dyn Error + Send>,
}

/// Allows conversion into a HandlerError from an implementing type.
///
/// Futures returned from handlers can resolve to an error type with a value of `(State,
/// HandlerError)`.
///
/// ```rust
/// # extern crate gotham;
/// # extern crate futures;
/// #
/// # use std::fs::File;
/// # use std::pin::Pin;
/// # use gotham::state::State;
/// # use gotham::handler::{IntoHandlerError, HandlerFuture};
/// # use futures::prelude::*;
/// #
/// # #[allow(dead_code)]
/// fn my_handler(state: State) -> Pin<Box<HandlerFuture>> {
///     match File::open("config.toml") {
///         Err(e) => future::err((state, e.into_handler_error())).boxed(),
///         Ok(_) => // Create and return a response
/// #                unimplemented!(),
///     }
/// }
/// #
/// # fn main() {}
pub trait IntoHandlerError {
    /// Convert `self` into a `HandlerError`.
    ///
    /// The return value will have a `500 Internal Server Error` as the HTTP status code. See
    /// `HandlerError::with_status` for an example of changing it.
    fn into_handler_error(self) -> HandlerError;
}

impl<E> IntoHandlerError for E
where
    E: Error + Send + 'static,
{
    fn into_handler_error(self) -> HandlerError {
        trace!(" converting Error to HandlerError: {}", self);

        HandlerError {
            status_code: StatusCode::INTERNAL_SERVER_ERROR,
            cause: Box::new(self),
        }
    }
}

impl Display for HandlerError {
    fn fmt(&self, out: &mut Formatter) -> fmt::Result {
        out.write_str("handler failed to process request")
    }
}

impl Debug for HandlerError {
    fn fmt(&self, out: &mut Formatter) -> fmt::Result {
        Display::fmt(self, out)?;
        out.write_str(" (")?;
        Debug::fmt(&*self.cause, out)?;
        out.write_str(")")
    }
}

impl Error for HandlerError {
    fn description(&self) -> &str {
        "handler failed to process request"
    }

    fn cause(&self) -> Option<&dyn Error> {
        Some(&*self.cause)
    }
}

impl HandlerError {
    /// Sets the HTTP status code of the response which is generated by the `IntoResponse`
    /// implementation.
    ///
    /// ```rust
    /// # extern crate gotham;
    /// # extern crate hyper;
    /// # extern crate futures;
    /// #
    /// # use std::pin::Pin;
    /// #
    /// # use futures::prelude::*;
    /// # use hyper::StatusCode;
    /// # use gotham::state::State;
    /// # use gotham::handler::{IntoHandlerError, HandlerFuture};
    /// # use gotham::test::TestServer;
    /// #
    /// fn handler(state: State) -> Pin<Box<HandlerFuture>> {
    ///     // It's OK if this is bogus, we just need something to convert into a `HandlerError`.
    ///     let io_error = std::io::Error::last_os_error();
    ///
    ///     let handler_error = io_error
    ///         .into_handler_error()
    ///         .with_status(StatusCode::IM_A_TEAPOT);
    ///
    ///     future::err((state, handler_error)).boxed()
    /// }
    ///
    /// # fn main() {
    /// #
    /// let test_server = TestServer::new(|| Ok(handler)).unwrap();
    /// let response = test_server.client().get("http://example.com/").perform().unwrap();
    /// assert_eq!(response.status(), StatusCode::IM_A_TEAPOT);
    /// #
    /// # }
    /// ```
    pub fn with_status(self, status_code: StatusCode) -> HandlerError {
        HandlerError {
            status_code,
            ..self
        }
    }
}

impl IntoResponse for HandlerError {
    fn into_response(self, state: &State) -> Response<Body> {
        debug!(
            "[{}] HandlerError generating {} {} response: {}",
            request_id(state),
            self.status_code.as_u16(),
            self.status_code
                .canonical_reason()
                .unwrap_or("(unregistered)",),
            self.source().map(Error::description).unwrap_or("(none)"),
        );

        create_empty_response(state, self.status_code)
    }
}