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use crate::request::Request; use crate::response::{self, Response, Responder}; use crate::http::Status; use yansi::Paint; /// Debug prints the internal value before responding with a 500 error. /// /// This value exists primarily to allow handler return types that would not /// otherwise implement [`Responder`]. It is typically used in conjunction with /// `Result<T, E>` where `E` implements `Debug` but not `Responder`. /// /// # Example /// /// Because of the generic `From<E>` implementation for `Debug<E>`, conversions /// from `Result<T, E>` to `Result<T, Debug<E>>` through `?` occur /// automatically: /// /// ```rust /// # #![feature(proc_macro_hygiene, decl_macro)] /// use std::io::{self, Read}; /// /// # use rocket::post; /// use rocket::Data; /// use rocket::response::Debug; /// /// #[post("/", format = "plain", data = "<data>")] /// fn post(data: Data) -> Result<String, Debug<io::Error>> { /// let mut name = String::with_capacity(32); /// data.open().take(32).read_to_string(&mut name)?; /// Ok(name) /// } /// ``` /// /// It is also possible to map the error directly to `Debug` via /// [`Result::map_err()`]: /// /// ```rust /// # #![feature(proc_macro_hygiene, decl_macro)] /// use std::string::FromUtf8Error; /// /// # use rocket::get; /// use rocket::response::Debug; /// /// #[get("/")] /// fn rand_str() -> Result<String, Debug<FromUtf8Error>> { /// # /* /// let bytes: Vec<u8> = random_bytes(); /// # */ /// # let bytes: Vec<u8> = vec![]; /// String::from_utf8(bytes).map_err(Debug) /// } /// ``` #[derive(Debug)] pub struct Debug<E>(pub E); impl<E> From<E> for Debug<E> { #[inline(always)] fn from(e: E) -> Self { Debug(e) } } impl<'r, E: std::fmt::Debug> Responder<'r> for Debug<E> { fn respond_to(self, _: &Request<'_>) -> response::Result<'r> { warn_!("Debug: {:?}", Paint::default(self.0)); warn_!("Debug always responds with {}.", Status::InternalServerError); Response::build().status(Status::InternalServerError).ok() } }