Document case-insensitivity of 'from_ext'.

lib/src/http/content_type.rs

@@ -84,17 +84,20 @@ impl ContentType {
     /// extensions is not recognized, then this method returns `None`. The
     /// currently recognized extensions are txt, html, htm, xml, csv, js, css,
     /// json, png, gif, bmp, jpeg, jpg, webp, svg, pdf, ttf, otf, woff, and
-    /// woff2.
+    /// woff2. Extensions are matched case-insensitively.
     ///
     /// # Example
     ///
-    /// A recognized content type:
+    /// Recognized content types:
     ///
     /// ```rust
     /// use rocket::http::ContentType;
     ///
     /// let xml = ContentType::from_extension("xml");
     /// assert_eq!(xml, Some(ContentType::XML));
+    ///
+    /// let xml = ContentType::from_extension("XML");
+    /// assert_eq!(xml, Some(ContentType::XML));
     /// ```
     ///
     /// An unrecognized content type:

lib/src/http/media_type.rs

@@ -144,17 +144,20 @@ macro_rules! from_extension {
         /// extensions are recognized. If an extensions is not recognized,
         /// `None` is returned. The currently recognized extensions are
         $(#[doc=$ext]#[doc=","])*
-        /// and is likely to grow.
+        /// and is likely to grow. Extensions are matched case-insensitively.
         ///
         /// # Example
         ///
-        /// A recognized media type:
+        /// Recognized media types:
         ///
         /// ```rust
         /// use rocket::http::MediaType;
         ///
         /// let xml = MediaType::from_extension("xml");
         /// assert_eq!(xml, Some(MediaType::XML));
+        ///
+        /// let xml = MediaType::from_extension("XML");
+        /// assert_eq!(xml, Some(MediaType::XML));
         /// ```
         ///
         /// An unrecognized media type:

lib/src/response/named_file.rs

@@ -83,10 +83,8 @@ impl Responder<'static> for NamedFile {
     fn respond_to(self, _: &Request) -> Result<Response<'static>, Status> {
         let mut response = Response::new();
         if let Some(ext) = self.path().extension() {
-            // TODO: Use Cow for lowercase.
-            let ext_string = ext.to_string_lossy().to_lowercase();
-            if let Some(content_type) = ContentType::from_extension(&ext_string) {
-                response.set_header(content_type);
+            if let Some(ct) = ContentType::from_extension(&ext.to_string_lossy()) {
+                response.set_header(ct);
             }
         }