new conditional submodule for if_range

src/conditional/if_range.rs

@@ -0,0 +1,213 @@
+use crate::conditional::ETag;
+use crate::headers::{HeaderName, HeaderValue, Headers, ToHeaderValues, IF_RANGE};
+use crate::utils::{fmt_http_date, parse_http_date};
+
+use std::fmt::{self, Display};
+use std::option;
+use std::time::SystemTime;
+
+/// Apply the HTTP method if the ETag or date matches
+///
+/// # Specifications
+///
+/// - [RFC 7233, section 3.2: Range](https://tools.ietf.org/html/rfc7233#section-3.2)
+/// - [RFC 7232, section 2.3: ETag](https://tools.ietf.org/html/rfc7232#section-2.3)
+/// - [RFC 7231, section 7.1.1.1: Date/Time Formats](https://tools.ietf.org/html/rfc7231#section-7.1.1.1)
+///
+/// # Examples
+///
+/// If-Range with strong ETag:
+///
+/// ```
+/// # fn main() -> http_types::Result<()> {
+/// #
+/// use http_types::conditional::{ETag, IfRange};
+/// use http_types::Response;
+///
+/// let strong_etag = ETag::new(String::from("aBcdEFghijkl"));
+/// let ifrange = IfRange::from(strong_etag.clone());
+///
+/// let mut res = Response::new(200);
+/// ifrange.apply(&mut res);
+///
+/// let ifrange = IfRange::from_headers(res)?.unwrap();
+/// assert_eq!(ifrange, IfRange::ETag(strong_etag));
+/// #
+/// # Ok(()) }
+/// ```
+///
+/// If-Range with HTTP Date:
+///
+/// ```
+/// # fn main() -> http_types::Result<()> {
+/// #
+/// use http_types::conditional::IfRange;
+/// use http_types::{Error, Response, StatusCode};
+/// use std::time::{Duration, SystemTime};
+///
+/// let time = SystemTime::now() + Duration::from_secs(5 * 60);
+/// let ifrange = IfRange::from(time);
+///
+/// let mut res = Response::new(200);
+/// ifrange.apply(&mut res);
+///
+/// let ifrange = IfRange::from_headers(res)?.unwrap();
+///
+/// let response_time = match ifrange {
+///     IfRange::Date(d) => d,
+///     _ => {
+///         return Err(Error::from_str(
+///             StatusCode::RequestedRangeNotSatisfiable,
+///             "Invalid If-Range header",
+///         ))
+///     }
+/// };
+///
+/// // HTTP dates only have second-precision.
+/// let elapsed = time.duration_since(response_time)?;
+/// assert_eq!(elapsed.as_secs(), 0);
+/// #
+/// # Ok(()) }
+/// ```
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum IfRange {
+    /// If-Range condition expressed with an `ETag`.
+    ETag(ETag),
+    /// If-Range condition expressed with an `HTTP Date`.
+    Date(SystemTime),
+}
+
+impl IfRange {
+    /// Create an instance of `IfRange` from a `Headers` instance.
+    pub fn from_headers(headers: impl AsRef<Headers>) -> crate::Result<Option<Self>> {
+        let headers = match headers.as_ref().get(IF_RANGE) {
+            Some(headers) => headers,
+            None => return Ok(None),
+        };
+
+        // If we successfully parsed the header then there's always at least one
+        // entry. We want the last entry.
+        let header = headers.iter().last().unwrap();
+        let header_str = header.as_str();
+
+        parse_http_date(header_str)
+            .map(|d| Some(IfRange::from(d)))
+            .or_else(|_| Ok(Some(IfRange::from(ETag::from_str(header_str)?))))
+    }
+
+    /// Insert a `HeaderName` + `HeaderValue` pair into a `Headers` instance.
+    pub fn apply(&self, mut headers: impl AsMut<Headers>) {
+        headers.as_mut().insert(IF_RANGE, self.value());
+    }
+
+    /// Get the `HeaderName`.
+    pub fn name(&self) -> HeaderName {
+        IF_RANGE
+    }
+
+    /// Get the `HeaderValue`.
+    pub fn value(&self) -> HeaderValue {
+        let output = self.to_string();
+
+        // SAFETY: the internal string is validated to be ASCII.
+        unsafe { HeaderValue::from_bytes_unchecked(output.into()) }
+    }
+}
+
+impl Display for IfRange {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let s = match self {
+            IfRange::ETag(t) => t.to_string(),
+            IfRange::Date(d) => fmt_http_date(*d),
+        };
+        write!(f, "{}", s)
+    }
+}
+
+impl ToHeaderValues for IfRange {
+    type Iter = option::IntoIter<HeaderValue>;
+    fn to_header_values(&self) -> crate::Result<Self::Iter> {
+        // A HeaderValue will always convert into itself.
+        Ok(self.value().to_header_values().unwrap())
+    }
+}
+
+impl From<ETag> for IfRange {
+    fn from(etag: ETag) -> Self {
+        IfRange::ETag(etag)
+    }
+}
+
+impl From<SystemTime> for IfRange {
+    fn from(time: SystemTime) -> Self {
+        IfRange::Date(time)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::headers::Headers;
+    use crate::{Error, StatusCode};
+
+    use std::time::Duration;
+
+    #[test]
+    fn if_range_time() -> crate::Result<()> {
+        let time = SystemTime::now() + Duration::from_secs(5 * 60);
+        let if_range = IfRange::from(time);
+
+        let mut headers = Headers::new();
+        if_range.apply(&mut headers);
+
+        let if_range = IfRange::from_headers(headers)?.unwrap();
+
+        let header_time = match if_range {
+            IfRange::Date(d) => d,
+            _ => {
+                return Err(Error::from_str(
+                    StatusCode::RequestedRangeNotSatisfiable,
+                    "Invalid If-Range header",
+                ))
+            }
+        };
+
+        // HTTP dates only have second-precision
+        let elapsed = time.duration_since(header_time)?;
+        assert_eq!(elapsed.as_secs(), 0);
+        Ok(())
+    }
+
+    #[test]
+    fn if_range_etag() -> crate::Result<()> {
+        let etag = ETag::new(String::from("foobar"));
+        let if_range = IfRange::from(etag.clone());
+
+        let mut headers = Headers::new();
+        if_range.apply(&mut headers);
+
+        let if_range = IfRange::from_headers(headers)?.unwrap();
+
+        let header_etag = match if_range {
+            IfRange::ETag(t) => t,
+            _ => {
+                return Err(Error::from_str(
+                    StatusCode::RequestedRangeNotSatisfiable,
+                    "Invalid If-Range header",
+                ))
+            }
+        };
+
+        assert_eq!(header_etag, etag);
+        Ok(())
+    }
+
+    #[test]
+    fn bad_request_on_parse_error() -> crate::Result<()> {
+        let mut headers = Headers::new();
+        headers.insert(IF_RANGE, "<nori ate the tag. yum.>");
+        let err = IfRange::from_headers(headers).unwrap_err();
+        assert_eq!(err.status(), 400);
+        Ok(())
+    }
+}

src/conditional/mod.rs

@@ -10,6 +10,7 @@
 
 mod etag;
 mod if_modified_since;
+mod if_range;
 mod if_unmodified_since;
 mod last_modified;
 mod vary;
@@ -27,6 +28,8 @@ pub use if_modified_since::IfModifiedSince;
 #[doc(inline)]
 pub use if_none_match::IfNoneMatch;
 #[doc(inline)]
+pub use if_range::IfRange;
+#[doc(inline)]
 pub use if_unmodified_since::IfUnmodifiedSince;
 #[doc(inline)]
 pub use last_modified::LastModified;