Merge pull request #254 from http-rs/allow

Add `server::Allow`

Author: yoshuawuyts

src/lib.rs

@@ -124,6 +124,7 @@ pub mod headers;
 pub mod mime;
 pub mod other;
 pub mod proxies;
+pub mod server;
 
 mod body;
 mod error;

src/server/allow.rs

@@ -0,0 +1,208 @@
+//! List the set of methods supported by a resource.
+
+use crate::headers::{HeaderName, HeaderValue, Headers, ToHeaderValues, ALLOW};
+use crate::Method;
+
+use std::collections::{hash_set, HashSet};
+use std::fmt::{self, Debug, Write};
+use std::iter::Iterator;
+use std::option;
+use std::str::FromStr;
+
+/// List the set of methods supported by a resource.
+///
+/// # Specifications
+///
+/// - [RFC 7231, section 7.4.1: Allow](https://tools.ietf.org/html/rfc7231#section-7.4.1)
+///
+/// # Examples
+///
+/// ```
+/// # fn main() -> http_types::Result<()> {
+/// #
+/// use http_types::{Method, Response};
+/// use http_types::server::Allow;
+///
+/// let mut allow = Allow::new();
+/// allow.insert(Method::Put);
+/// allow.insert(Method::Post);
+///
+/// let mut res = Response::new(200);
+/// allow.apply(&mut res);
+///
+/// let allow = Allow::from_headers(res)?.unwrap();
+/// assert!(allow.contains(Method::Put));
+/// assert!(allow.contains(Method::Post));
+/// #
+/// # Ok(()) }
+/// ```
+pub struct Allow {
+    entries: HashSet<Method>,
+}
+
+impl Allow {
+    /// Create a new instance of `Allow`.
+    pub fn new() -> Self {
+        Self {
+            entries: HashSet::new(),
+        }
+    }
+
+    /// Create a new instance from headers.
+    pub fn from_headers(headers: impl AsRef<Headers>) -> crate::Result<Option<Self>> {
+        let mut entries = HashSet::new();
+        let headers = match headers.as_ref().get(ALLOW) {
+            Some(headers) => headers,
+            None => return Ok(None),
+        };
+
+        for value in headers {
+            for part in value.as_str().trim().split(',') {
+                let method = Method::from_str(part.trim())?;
+                entries.insert(method);
+            }
+        }
+
+        Ok(Some(Self { entries }))
+    }
+
+    /// Sets the `Allow` header.
+    pub fn apply(&self, mut headers: impl AsMut<Headers>) {
+        headers.as_mut().insert(ALLOW, self.value());
+    }
+
+    /// Get the `HeaderName`.
+    pub fn name(&self) -> HeaderName {
+        ALLOW
+    }
+
+    /// Get the `HeaderValue`.
+    pub fn value(&self) -> HeaderValue {
+        let mut output = String::new();
+        for (n, method) in self.entries.iter().enumerate() {
+            match n {
+                0 => write!(output, "{}", method).unwrap(),
+                _ => write!(output, ", {}", method).unwrap(),
+            };
+        }
+
+        // SAFETY: the internal string is validated to be ASCII.
+        unsafe { HeaderValue::from_bytes_unchecked(output.into()) }
+    }
+
+    /// Push a method into the set of methods.
+    pub fn insert(&mut self, method: Method) {
+        self.entries.insert(method);
+    }
+
+    /// An iterator visiting all server entries.
+    pub fn iter(&self) -> Iter<'_> {
+        Iter {
+            inner: self.entries.iter(),
+        }
+    }
+
+    /// Returns `true` if the header contains the `Method`.
+    pub fn contains(&self, method: Method) -> bool {
+        self.entries.contains(&method)
+    }
+}
+
+impl IntoIterator for Allow {
+    type Item = Method;
+    type IntoIter = IntoIter;
+
+    #[inline]
+    fn into_iter(self) -> Self::IntoIter {
+        IntoIter {
+            inner: self.entries.into_iter(),
+        }
+    }
+}
+
+impl<'a> IntoIterator for &'a Allow {
+    type Item = &'a Method;
+    type IntoIter = Iter<'a>;
+
+    #[inline]
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}
+
+/// A borrowing iterator over entries in `Allow`.
+#[derive(Debug)]
+pub struct IntoIter {
+    inner: hash_set::IntoIter<Method>,
+}
+
+impl Iterator for IntoIter {
+    type Item = Method;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.inner.next()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
+}
+
+/// A lending iterator over entries in `Allow`.
+#[derive(Debug)]
+pub struct Iter<'a> {
+    inner: hash_set::Iter<'a, Method>,
+}
+
+impl<'a> Iterator for Iter<'a> {
+    type Item = &'a Method;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.inner.next()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
+}
+
+impl ToHeaderValues for Allow {
+    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 Debug for Allow {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut list = f.debug_list();
+        for method in &self.entries {
+            list.entry(method);
+        }
+        list.finish()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::headers::Headers;
+
+    #[test]
+    fn smoke() -> crate::Result<()> {
+        let mut allow = Allow::new();
+        allow.insert(Method::Put);
+        allow.insert(Method::Post);
+
+        let mut headers = Headers::new();
+        allow.apply(&mut headers);
+
+        let allow = Allow::from_headers(headers)?.unwrap();
+        assert!(allow.contains(Method::Put));
+        assert!(allow.contains(Method::Post));
+        Ok(())
+    }
+}

src/server/mod.rs

@@ -0,0 +1,6 @@
+//! HTTP Server Context headers.
+
+pub mod allow;
+
+#[doc(inline)]
+pub use allow::Allow;