use std::fmt::{self, Display, Write}; use super::{ from_one_raw_str, EntityTag, Header, HeaderName, HeaderValue, HttpDate, InvalidHeaderValue, TryIntoHeaderValue, Writer, }; use crate::error::ParseError; use crate::http::header; use crate::HttpMessage; /// `If-Range` header, defined /// in [RFC 7233 ยง3.2](https://datatracker.ietf.org/doc/html/rfc7233#section-3.2) /// /// If a client has a partial copy of a representation and wishes to have /// an up-to-date copy of the entire representation, it could use the /// Range header field with a conditional GET (using either or both of /// If-Unmodified-Since and If-Match.) However, if the precondition /// fails because the representation has been modified, the client would /// then have to make a second request to obtain the entire current /// representation. /// /// The `If-Range` header field allows a client to \"short-circuit\" the /// second request. Informally, its meaning is as follows: if the /// representation is unchanged, send me the part(s) that I am requesting /// in Range; otherwise, send me the entire representation. /// /// # ABNF /// ```plain /// If-Range = entity-tag / HTTP-date /// ``` /// /// # Example Values /// /// * `Sat, 29 Oct 1994 19:43:31 GMT` /// * `\"xyzzy\"` /// /// # Examples /// ``` /// use actix_web::HttpResponse; /// use actix_web::http::header::{EntityTag, IfRange}; /// /// let mut builder = HttpResponse::Ok(); /// builder.insert_header( /// IfRange::EntityTag( /// EntityTag::new(false, "abc".to_owned()) /// ) /// ); /// ``` /// /// ``` /// use std::time::{Duration, SystemTime}; /// use actix_web::{http::header::IfRange, HttpResponse}; /// /// let mut builder = HttpResponse::Ok(); /// let fetched = SystemTime::now() - Duration::from_secs(60 * 60 * 24); /// builder.insert_header( /// IfRange::Date(fetched.into()) /// ); /// ``` #[derive(Clone, Debug, PartialEq)] pub enum IfRange { /// The entity-tag the client has of the resource. EntityTag(EntityTag), /// The date when the client retrieved the resource. Date(HttpDate), } impl Header for IfRange { fn name() -> HeaderName { header::IF_RANGE } #[inline] fn parse(msg: &T) -> Result where T: HttpMessage, { let etag: Result = from_one_raw_str(msg.headers().get(&header::IF_RANGE)); if let Ok(etag) = etag { return Ok(IfRange::EntityTag(etag)); } let date: Result = from_one_raw_str(msg.headers().get(&header::IF_RANGE)); if let Ok(date) = date { return Ok(IfRange::Date(date)); } Err(ParseError::Header) } } impl Display for IfRange { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match *self { IfRange::EntityTag(ref x) => Display::fmt(x, f), IfRange::Date(ref x) => Display::fmt(x, f), } } } impl TryIntoHeaderValue for IfRange { type Error = InvalidHeaderValue; fn try_into_value(self) -> Result { let mut writer = Writer::new(); let _ = write!(&mut writer, "{}", self); HeaderValue::from_maybe_shared(writer.take()) } } #[cfg(test)] mod test_parse_and_format { use std::str; use super::IfRange as HeaderField; use crate::http::header::*; crate::http::header::common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]); crate::http::header::common_header_test!(test2, vec![b"\"abc\""]); crate::http::header::common_header_test!(test3, vec![b"this-is-invalid"], None::); }