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

//! Components for constructing HTTP responses.

mod body;

// re-exports
pub use self::body::ResponseBody;
pub(crate) use self::body::ResponseBodyKind;

/// The type representing outputs returned from handlers.
pub type Output = ::http::Response<ResponseBody>;

// ====

use futures::{Async, Future, Poll};
use http::header::HeaderValue;
use http::{header, Response, StatusCode};

use error::Error;
use input::{self, Input};

/// A trait representing the conversion to an HTTP response.
pub trait Responder {
    /// Converts `self` to an HTTP response.
    fn respond_to(self, input: &mut Input) -> Result<Output, Error>;
}

impl Responder for () {
    fn respond_to(self, _: &mut Input) -> Result<Output, Error> {
        let mut response = Response::new(Default::default());
        *response.status_mut() = StatusCode::NO_CONTENT;
        Ok(response)
    }
}

impl<T> Responder for Option<T>
where
    T: Responder,
{
    fn respond_to(self, input: &mut Input) -> Result<Output, Error> {
        self.ok_or_else(Error::not_found)?.respond_to(input)
    }
}

impl<T> Responder for Result<T, Error>
where
    T: Responder,
{
    fn respond_to(self, input: &mut Input) -> Result<Output, Error> {
        self?.respond_to(input)
    }
}

impl<T> Responder for Response<T>
where
    T: Into<ResponseBody>,
{
    #[inline]
    fn respond_to(self, _: &mut Input) -> Result<Output, Error> {
        Ok(self.map(Into::into))
    }
}

impl Responder for &'static str {
    #[inline]
    fn respond_to(self, _: &mut Input) -> Result<Output, Error> {
        Ok(text_response(self))
    }
}

impl Responder for String {
    #[inline]
    fn respond_to(self, _: &mut Input) -> Result<Output, Error> {
        Ok(text_response(self))
    }
}

fn text_response<T: Into<ResponseBody>>(body: T) -> Output {
    let mut response = Response::new(body.into());
    response.headers_mut().insert(
        header::CONTENT_TYPE,
        HeaderValue::from_static("text/plain; charset=utf-8"),
    );
    response
}

/// The async variant of `Responder`.
pub trait AsyncResponder: Send + 'static + sealed::Sealed {
    /// The inner type of this responder.
    type Output: Responder;

    /// Polls for a result of inner `Responder`.
    // FIXME: replace the receiver type with PinMut<Self>
    fn poll_respond_to(&mut self, input: &mut Input) -> Poll<Output, Error>;
}

impl<F> AsyncResponder for F
where
    F: Future + Send + 'static,
    F::Item: Responder,
    Error: From<F::Error>,
{
    type Output = F::Item;

    fn poll_respond_to(&mut self, input: &mut Input) -> Poll<Output, Error> {
        let x = try_ready!(input::with_set_current(input, || Future::poll(self)));
        x.respond_to(input).map(Async::Ready)
    }
}

// TODO: switch bracket impls to std::future::Future
//
//   impl<F> AsyncResponder for F
//   where
//       F: Future + Send + 'static,
//       F::Output: Responder,
//   {
//       type Output = F::Output;
//
//       fn poll_respond_to(
//           self: PinMut<Self>,
//           cx: &mut Context,
//           input: &mut Input,
//       ) -> Poll<Result<Output, Error>> {
//           let x = ready!(input::with_set_current(input, || Future::poll(self, cx)));
//           Poll::Ready(x.respond_to(input))
//       }
//   }

mod sealed {
    use futures::Future;

    use super::Responder;
    use error::Error;

    pub trait Sealed {}

    impl<F> Sealed for F
    where
        F: Future + Send + 'static,
        F::Item: Responder,
        Error: From<F::Error>,
    {
    }
}