Merge pull request #256 from pepoviola/header-content-location

Add `content::ContentLocation` header

Author: yoshuawuyts

src/content/content_location.rs

@@ -0,0 +1,123 @@
+use crate::headers::{HeaderName, HeaderValue, Headers, CONTENT_LOCATION};
+use crate::{bail_status as bail, Status, Url};
+
+use std::convert::TryInto;
+
+/// Indicates an alternate location for the returned data.
+///
+/// # Specifications
+///
+/// - [RFC 7231, section 3.1.4.2: Content-Location](https://tools.ietf.org/html/rfc7231#section-3.1.4.2)
+///
+/// # Examples
+///
+/// ```
+/// # fn main() -> http_types::Result<()> {
+/// #
+/// use http_types::{Response,Url};
+/// use http_types::content::{ContentLocation};
+///
+/// let content_location = ContentLocation::new(Url::parse("https://example.net/")?);
+///
+/// let mut res = Response::new(200);
+/// content_location.apply(&mut res);
+///
+/// let url = Url::parse("https://example.net/")?;
+/// let content_location = ContentLocation::from_headers(url, res)?.unwrap();
+/// assert_eq!(content_location.location(), "https://example.net/");
+/// #
+/// # Ok(()) }
+/// ```
+#[derive(Debug)]
+pub struct ContentLocation {
+    url: Url,
+}
+
+impl ContentLocation {
+    /// Create a new instance of `Content-Location` header.
+    pub fn new(url: Url) -> Self {
+        Self { url }
+    }
+
+    /// Create a new instance from headers.
+    pub fn from_headers<U>(base_url: U, headers: impl AsRef<Headers>) -> crate::Result<Option<Self>>
+    where
+        U: TryInto<Url>,
+        U::Error: std::fmt::Debug,
+    {
+        let headers = match headers.as_ref().get(CONTENT_LOCATION) {
+            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 value = headers.iter().last().unwrap();
+        let base = match base_url.try_into() {
+            Ok(b) => b,
+            Err(_) => bail!(400, "Invalid base url provided"),
+        };
+
+        let url = base.join(value.as_str().trim()).status(400)?;
+        Ok(Some(Self { url }))
+    }
+
+    /// Sets the header.
+    pub fn apply(&self, mut headers: impl AsMut<Headers>) {
+        headers.as_mut().insert(self.name(), self.value());
+    }
+
+    /// Get the `HeaderName`.
+    pub fn name(&self) -> HeaderName {
+        CONTENT_LOCATION
+    }
+
+    /// Get the `HeaderValue`.
+    pub fn value(&self) -> HeaderValue {
+        let output = self.url.to_string();
+
+        // SAFETY: the internal string is validated to be ASCII.
+        unsafe { HeaderValue::from_bytes_unchecked(output.into()) }
+    }
+
+    /// Get the url.
+    pub fn location(&self) -> String {
+        self.url.to_string()
+    }
+
+    /// Set the url.
+    pub fn set_location(&mut self, location: Url) {
+        self.url = location
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::headers::Headers;
+
+    #[test]
+    fn smoke() -> crate::Result<()> {
+        let content_location = ContentLocation::new(Url::parse("https://example.net/test.json")?);
+
+        let mut headers = Headers::new();
+        content_location.apply(&mut headers);
+
+        let content_location =
+            ContentLocation::from_headers(Url::parse("https://example.net/").unwrap(), headers)?
+                .unwrap();
+        assert_eq!(content_location.location(), "https://example.net/test.json");
+        Ok(())
+    }
+
+    #[test]
+    fn bad_request_on_parse_error() -> crate::Result<()> {
+        let mut headers = Headers::new();
+        headers.insert(CONTENT_LOCATION, "htt://<nori ate the tag. yum.>");
+        let err =
+            ContentLocation::from_headers(Url::parse("https://example.net").unwrap(), headers)
+                .unwrap_err();
+        assert_eq!(err.status(), 400);
+        Ok(())
+    }
+}

src/content/mod.rs

@@ -9,6 +9,7 @@ pub mod accept_encoding;
 pub mod content_encoding;
 
 mod content_length;
+mod content_location;
 mod encoding;
 mod encoding_proposal;
 
@@ -17,5 +18,6 @@ pub use accept_encoding::AcceptEncoding;
 #[doc(inline)]
 pub use content_encoding::ContentEncoding;
 pub use content_length::ContentLength;
+pub use content_location::ContentLocation;
 pub use encoding::Encoding;
 pub use encoding_proposal::EncodingProposal;