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//! Reply to requests.
//!
//! A [`Reply`](./trait.Reply.html) is a type that can be converted into an HTTP
//! response to be sent to the client. These are typically the successful
//! counterpart to a [rejection](../reject).
//!
//! The functions in this module are helpers for quickly creating a reply.
//! Besides them, you can return a type that implements [`Reply`](./trait.Reply.html). This
//! could be any of the following:
//!
//! - `String`
//! - `&'static str`
//! - `http::StatusCode`
//!
//! # Example
//!
//! ```
//! use warp::{Filter, http::Response};
//!
//! // Returns an empty `200 OK` response.
//! let empty_200 = warp::any().map(warp::reply);
//!
//! // Returns a `200 OK` response with custom header and body.
//! let custom = warp::any().map(|| {
//! Response::builder()
//! .header("my-custom-header", "some-value")
//! .body("and a custom body")
//! });
//!
//! // GET requests return the empty 200, POST return the custom.
//! let routes = warp::get().and(empty_200)
//! .or(warp::post().and(custom));
//! ```
use std::borrow::Cow;
use std::convert::TryFrom;
use std::error::Error as StdError;
use std::fmt;
use crate::generic::{Either, One};
use http::header::{HeaderName, HeaderValue, CONTENT_TYPE};
use http::StatusCode;
use hyper::Body;
use serde::Serialize;
use serde_json;
// This re-export just looks weird in docs...
pub(crate) use self::sealed::Reply_;
use self::sealed::{BoxedReply, Internal};
#[doc(hidden)]
pub use crate::filters::reply as with;
/// Response type into which types implementing the `Reply` trait are convertable.
pub type Response = ::http::Response<Body>;
/// Returns an empty `Reply` with status code `200 OK`.
///
/// # Example
///
/// ```
/// use warp::Filter;
///
/// // GET /just-ok returns an empty `200 OK`.
/// let route = warp::path("just-ok")
/// .map(|| {
/// println!("got a /just-ok request!");
/// warp::reply()
/// });
/// ```
#[inline]
pub fn reply() -> impl Reply {
StatusCode::OK
}
/// Convert the value into a `Reply` with the value encoded as JSON.
///
/// The passed value must implement [`Serialize`][ser]. Many
/// collections do, and custom domain types can have `Serialize` derived.
///
///
/// # Example
///
/// ```
/// use warp::Filter;
///
/// // GET /ids returns a `200 OK` with a JSON array of ids:
/// // `[1, 3, 7, 13]`
/// let route = warp::path("ids")
/// .map(|| {
/// let our_ids = vec![1, 3, 7, 13];
/// warp::reply::json(&our_ids)
/// });
/// ```
///
/// # Note
///
/// If a type fails to be serialized into JSON, the error is logged at the
/// `error` level, and the returned `impl Reply` will be an empty
/// `500 Internal Server Error` response.
pub fn json<T>(val: &T) -> Json
where
T: Serialize,
{
Json {
inner: serde_json::to_vec(val).map_err(|err| {
tracing::error!("reply::json error: {}", err);
}),
}
}
/// A JSON formatted reply.
#[allow(missing_debug_implementations)]
pub struct Json {
inner: Result<Vec<u8>, ()>,
}
impl Reply for Json {
#[inline]
fn into_response(self) -> Response {
match self.inner {
Ok(body) => {
let mut res = Response::new(body.into());
res.headers_mut()
.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
res
}
Err(()) => StatusCode::INTERNAL_SERVER_ERROR.into_response(),
}
}
}
#[derive(Debug)]
pub(crate) struct ReplyJsonError;
impl fmt::Display for ReplyJsonError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("warp::reply::json() failed")
}
}
impl StdError for ReplyJsonError {}
/// Reply with a body and `content-type` set to `text/html; charset=utf-8`.
///
/// # Example
///
/// ```
/// use warp::Filter;
///
/// let body = r#"
/// <html>
/// <head>
/// <title>HTML with warp!</title>
/// </head>
/// <body>
/// <h1>warp + HTML = ♥</h1>
/// </body>
/// </html>
/// "#;
///
/// let route = warp::any()
/// .map(move || {
/// warp::reply::html(body)
/// });
/// ```
pub fn html<T>(body: T) -> Html<T>
where
Body: From<T>,
T: Send,
{
Html { body }
}
/// An HTML reply.
#[allow(missing_debug_implementations)]
pub struct Html<T> {
body: T,
}
impl<T> Reply for Html<T>
where
Body: From<T>,
T: Send,
{
#[inline]
fn into_response(self) -> Response {
let mut res = Response::new(Body::from(self.body));
res.headers_mut().insert(
CONTENT_TYPE,
HeaderValue::from_static("text/html; charset=utf-8"),
);
res
}
}
/// Types that can be converted into a `Response`.
///
/// This trait is implemented for the following:
///
/// - `http::StatusCode`
/// - `http::Response<impl Into<hyper::Body>>`
/// - `String`
/// - `&'static str`
///
/// # Example
///
/// ```rust
/// use warp::{Filter, http::Response};
///
/// struct Message {
/// msg: String
/// }
///
/// impl warp::Reply for Message {
/// fn into_response(self) -> warp::reply::Response {
/// Response::new(format!("message: {}", self.msg).into())
/// }
/// }
///
/// fn handler() -> Message {
/// Message { msg: "Hello".to_string() }
/// }
///
/// let route = warp::any().map(handler);
/// ```
pub trait Reply: BoxedReply + Send {
/// Converts the given value into a [`Response`].
///
/// [`Response`]: type.Response.html
fn into_response(self) -> Response;
/*
TODO: Currently unsure about having trait methods here, as it
requires returning an exact type, which I'd rather not commit to.
Additionally, it doesn't work great with `Box<Reply>`.
A possible alternative is to have wrappers, like
- `WithStatus<R: Reply>(StatusCode, R)`
/// Change the status code of this `Reply`.
fn with_status(self, status: StatusCode) -> Reply_
where
Self: Sized,
{
let mut res = self.into_response();
*res.status_mut() = status;
Reply_(res)
}
/// Add a header to this `Reply`.
///
/// # Example
///
/// ```rust
/// use warp::Reply;
///
/// let reply = warp::reply()
/// .with_header("x-foo", "bar");
/// ```
fn with_header<K, V>(self, name: K, value: V) -> Reply_
where
Self: Sized,
HeaderName: TryFrom<K>,
HeaderValue: TryFrom<V>,
{
match <HeaderName as TryFrom<K>>::try_from(name) {
Ok(name) => match <HeaderValue as TryFrom<V>>::try_from(value) {
Ok(value) => {
let mut res = self.into_response();
res.headers_mut().append(name, value);
Reply_(res)
},
Err(err) => {
tracing::error!("with_header value error: {}", err.into());
Reply_(::reject::server_error()
.into_response())
}
},
Err(err) => {
tracing::error!("with_header name error: {}", err.into());
Reply_(::reject::server_error()
.into_response())
}
}
}
*/
}
impl<T: Reply + ?Sized> Reply for Box<T> {
fn into_response(self) -> Response {
self.boxed_into_response(Internal)
}
}
fn _assert_object_safe() {
fn _assert(_: &dyn Reply) {}
}
/// Wrap an `impl Reply` to change its `StatusCode`.
///
/// # Example
///
/// ```
/// use warp::Filter;
///
/// let route = warp::any()
/// .map(warp::reply)
/// .map(|reply| {
/// warp::reply::with_status(reply, warp::http::StatusCode::CREATED)
/// });
/// ```
pub fn with_status<T: Reply>(reply: T, status: StatusCode) -> WithStatus<T> {
WithStatus { reply, status }
}
/// Wrap an `impl Reply` to change its `StatusCode`.
///
/// Returned by `warp::reply::with_status`.
#[derive(Debug)]
pub struct WithStatus<T> {
reply: T,
status: StatusCode,
}
impl<T: Reply> Reply for WithStatus<T> {
fn into_response(self) -> Response {
let mut res = self.reply.into_response();
*res.status_mut() = self.status;
res
}
}
/// Wrap an `impl Reply` to add a header when rendering.
///
/// # Example
///
/// ```
/// use warp::Filter;
///
/// let route = warp::any()
/// .map(warp::reply)
/// .map(|reply| {
/// warp::reply::with_header(reply, "server", "warp")
/// });
/// ```
pub fn with_header<T: Reply, K, V>(reply: T, name: K, value: V) -> WithHeader<T>
where
HeaderName: TryFrom<K>,
<HeaderName as TryFrom<K>>::Error: Into<http::Error>,
HeaderValue: TryFrom<V>,
<HeaderValue as TryFrom<V>>::Error: Into<http::Error>,
{
let header = match <HeaderName as TryFrom<K>>::try_from(name) {
Ok(name) => match <HeaderValue as TryFrom<V>>::try_from(value) {
Ok(value) => Some((name, value)),
Err(err) => {
let err = err.into();
tracing::error!("with_header value error: {}", err);
None
}
},
Err(err) => {
let err = err.into();
tracing::error!("with_header name error: {}", err);
None
}
};
WithHeader { header, reply }
}
/// Wraps an `impl Reply` and adds a header when rendering.
///
/// Returned by `warp::reply::with_header`.
#[derive(Debug)]
pub struct WithHeader<T> {
header: Option<(HeaderName, HeaderValue)>,
reply: T,
}
impl<T: Reply> Reply for WithHeader<T> {
fn into_response(self) -> Response {
let mut res = self.reply.into_response();
if let Some((name, value)) = self.header {
res.headers_mut().insert(name, value);
}
res
}
}
impl<T: Send> Reply for ::http::Response<T>
where
Body: From<T>,
{
#[inline]
fn into_response(self) -> Response {
self.map(Body::from)
}
}
impl Reply for ::http::StatusCode {
#[inline]
fn into_response(self) -> Response {
let mut res = Response::default();
*res.status_mut() = self;
res
}
}
impl Reply for ::http::Error {
#[inline]
fn into_response(self) -> Response {
tracing::error!("reply error: {:?}", self);
StatusCode::INTERNAL_SERVER_ERROR.into_response()
}
}
impl<T, E> Reply for Result<T, E>
where
T: Reply,
E: Reply,
{
#[inline]
fn into_response(self) -> Response {
match self {
Ok(t) => t.into_response(),
Err(e) => e.into_response(),
}
}
}
fn text_plain<T: Into<Body>>(body: T) -> Response {
let mut response = ::http::Response::new(body.into());
response.headers_mut().insert(
CONTENT_TYPE,
HeaderValue::from_static("text/plain; charset=utf-8"),
);
response
}
impl Reply for String {
#[inline]
fn into_response(self) -> Response {
text_plain(self)
}
}
impl Reply for Vec<u8> {
#[inline]
fn into_response(self) -> Response {
::http::Response::builder()
.header(
CONTENT_TYPE,
HeaderValue::from_static("application/octet-stream"),
)
.body(Body::from(self))
.unwrap()
}
}
impl Reply for &'static str {
#[inline]
fn into_response(self) -> Response {
text_plain(self)
}
}
impl Reply for Cow<'static, str> {
#[inline]
fn into_response(self) -> Response {
match self {
Cow::Borrowed(s) => s.into_response(),
Cow::Owned(s) => s.into_response(),
}
}
}
impl Reply for &'static [u8] {
#[inline]
fn into_response(self) -> Response {
::http::Response::builder()
.header(
CONTENT_TYPE,
HeaderValue::from_static("application/octet-stream"),
)
.body(Body::from(self))
.unwrap()
}
}
impl<T, U> Reply for Either<T, U>
where
T: Reply,
U: Reply,
{
#[inline]
fn into_response(self) -> Response {
match self {
Either::A(a) => a.into_response(),
Either::B(b) => b.into_response(),
}
}
}
impl<T> Reply for One<T>
where
T: Reply,
{
#[inline]
fn into_response(self) -> Response {
self.0.into_response()
}
}
impl Reply for std::convert::Infallible {
#[inline(always)]
fn into_response(self) -> Response {
match self {}
}
}
mod sealed {
use super::{Reply, Response};
// An opaque type to return `impl Reply` from trait methods.
#[allow(missing_debug_implementations)]
pub struct Reply_(pub(crate) Response);
impl Reply for Reply_ {
#[inline]
fn into_response(self) -> Response {
self.0
}
}
#[allow(missing_debug_implementations)]
pub struct Internal;
// Implemented for all types that implement `Reply`.
//
// A user doesn't need to worry about this, it's just trait
// hackery to get `Box<dyn Reply>` working.
pub trait BoxedReply {
fn boxed_into_response(self: Box<Self>, internal: Internal) -> Response;
}
impl<T: Reply> BoxedReply for T {
fn boxed_into_response(self: Box<Self>, _: Internal) -> Response {
(*self).into_response()
}
}
}
#[cfg(test)]
mod tests {
use std::collections::HashMap;
use super::*;
#[test]
fn json_serde_error() {
// a HashMap<Vec, _> cannot be serialized to JSON
let mut map = HashMap::new();
map.insert(vec![1, 2], 45);
let res = json(&map).into_response();
assert_eq!(res.status(), 500);
}
#[test]
fn response_builder_error() {
let res = ::http::Response::builder()
.status(1337)
.body("woops")
.into_response();
assert_eq!(res.status(), 500);
}
#[test]
fn boxed_reply() {
let r: Box<dyn Reply> = Box::new(reply());
let resp = r.into_response();
assert_eq!(resp.status(), 200);
}
}