mirror of
https://github.com/actix/actix-extras.git
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116 lines
3.4 KiB
Rust
116 lines
3.4 KiB
Rust
use error::ParseError;
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use header::from_one_raw_str;
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use header::{EntityTag, Header, HeaderName, HeaderValue, HttpDate, IntoHeaderValue,
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InvalidHeaderValueBytes, Writer};
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use http::header;
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use httpmessage::HttpMessage;
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use std::fmt::{self, Display, Write};
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/// `If-Range` header, defined in [RFC7233](http://tools.ietf.org/html/rfc7233#section-3.2)
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///
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/// If a client has a partial copy of a representation and wishes to have
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/// an up-to-date copy of the entire representation, it could use the
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/// Range header field with a conditional GET (using either or both of
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/// If-Unmodified-Since and If-Match.) However, if the precondition
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/// fails because the representation has been modified, the client would
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/// then have to make a second request to obtain the entire current
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/// representation.
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///
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/// The `If-Range` header field allows a client to \"short-circuit\" the
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/// second request. Informally, its meaning is as follows: if the
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/// representation is unchanged, send me the part(s) that I am requesting
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/// in Range; otherwise, send me the entire representation.
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///
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/// # ABNF
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///
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/// ```text
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/// If-Range = entity-tag / HTTP-date
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/// ```
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///
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/// # Example values
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///
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/// * `Sat, 29 Oct 1994 19:43:31 GMT`
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/// * `\"xyzzy\"`
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///
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/// # Examples
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///
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/// ```rust
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/// use actix_web::HttpResponse;
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/// use actix_web::http::header::{EntityTag, IfRange};
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///
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/// let mut builder = HttpResponse::Ok();
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/// builder.set(IfRange::EntityTag(EntityTag::new(
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/// false,
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/// "xyzzy".to_owned(),
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/// )));
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/// ```
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///
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/// ```rust
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/// use actix_web::HttpResponse;
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/// use actix_web::http::header::IfRange;
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/// use std::time::{Duration, SystemTime};
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///
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/// let mut builder = HttpResponse::Ok();
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/// let fetched = SystemTime::now() - Duration::from_secs(60 * 60 * 24);
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/// builder.set(IfRange::Date(fetched.into()));
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/// ```
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#[derive(Clone, Debug, PartialEq)]
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pub enum IfRange {
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/// The entity-tag the client has of the resource
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EntityTag(EntityTag),
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/// The date when the client retrieved the resource
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Date(HttpDate),
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}
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impl Header for IfRange {
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fn name() -> HeaderName {
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header::IF_RANGE
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}
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#[inline]
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fn parse<T>(msg: &T) -> Result<Self, ParseError>
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where
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T: HttpMessage,
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{
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let etag: Result<EntityTag, _> =
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from_one_raw_str(msg.headers().get(header::IF_RANGE));
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if let Ok(etag) = etag {
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return Ok(IfRange::EntityTag(etag));
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}
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let date: Result<HttpDate, _> =
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from_one_raw_str(msg.headers().get(header::IF_RANGE));
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if let Ok(date) = date {
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return Ok(IfRange::Date(date));
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}
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Err(ParseError::Header)
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}
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}
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impl Display for IfRange {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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match *self {
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IfRange::EntityTag(ref x) => Display::fmt(x, f),
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IfRange::Date(ref x) => Display::fmt(x, f),
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}
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}
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}
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impl IntoHeaderValue for IfRange {
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type Error = InvalidHeaderValueBytes;
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fn try_into(self) -> Result<HeaderValue, Self::Error> {
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let mut writer = Writer::new();
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let _ = write!(&mut writer, "{}", self);
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HeaderValue::from_shared(writer.take())
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}
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}
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#[cfg(test)]
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mod test_if_range {
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use super::IfRange as HeaderField;
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use header::*;
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use std::str;
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test_header!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
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test_header!(test2, vec![b"\"xyzzy\""]);
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test_header!(test3, vec![b"this-is-invalid"], None::<IfRange>);
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}
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