refactor(http): return Option<&str> from HttpMessage::content_type

actix-http/CHANGES.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Update `HttpMessage::content_type()` to return `Option<&str>`. [#3797]
+
+[#3797]: https://github.com/actix/actix-web/issues/3797
+
 ## 3.13.5
 
 - Reject invalid WebSocket close-frame status codes, malformed payloads, and invalid UTF-8 close reasons.

actix-http/src/http_message.rs

@@ -44,15 +44,15 @@ pub trait HttpMessage: Sized {
         }
     }
 
-    /// Read the request content type. If request did not contain a *Content-Type* header, an empty
-    /// string is returned.
-    fn content_type(&self) -> &str {
-        if let Some(content_type) = self.headers().get(header::CONTENT_TYPE) {
-            if let Ok(content_type) = content_type.to_str() {
-                return content_type.split(';').next().unwrap().trim();
-            }
-        }
-        ""
+    /// Read the request content type.
+    ///
+    /// If request does not contain a *Content-Type* header, or if the header value is not valid
+    /// UTF-8, `None` is returned.
+    fn content_type(&self) -> Option<&str> {
+        self.headers()
+            .get(header::CONTENT_TYPE)
+            .and_then(|ct| ct.to_str().ok())
+            .map(|ct| ct.split_once(';').map_or(ct, |(ct, _)| ct).trim())
     }
 
     /// Get content type encoding.
@@ -142,13 +142,20 @@ mod tests {
         let req = TestRequest::default()
             .insert_header(("content-type", "text/plain"))
             .finish();
-        assert_eq!(req.content_type(), "text/plain");
+        assert_eq!(req.content_type(), Some("text/plain"));
         let req = TestRequest::default()
             .insert_header(("content-type", "application/json; charset=utf-8"))
             .finish();
-        assert_eq!(req.content_type(), "application/json");
+        assert_eq!(req.content_type(), Some("application/json"));
         let req = TestRequest::default().finish();
-        assert_eq!(req.content_type(), "");
+        assert_eq!(req.content_type(), None);
+        let req = TestRequest::default()
+            .insert_header((
+                header::CONTENT_TYPE,
+                header::HeaderValue::from_bytes(b"\xff").unwrap(),
+            ))
+            .finish();
+        assert_eq!(req.content_type(), None);
     }
 
     #[test]

actix-web/CHANGES.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Update `HttpMessage::content_type()` (and `HttpRequest` / `ServiceRequest` implementations) to return `Option<&str>`. [#3797]
+
+[#3797]: https://github.com/actix/actix-web/issues/3797
+
 ## 4.15.0
 
 - Add `Error::add_response_mapper()` to allow middleware to modify error-generated responses before they are sent.

actix-web/src/test/test_utils.rs

@@ -505,7 +505,10 @@ mod tests {
             .set_form(&payload)
             .to_request();
 
-        assert_eq!(req.content_type(), "application/x-www-form-urlencoded");
+        assert_eq!(
+            req.content_type(),
+            Some("application/x-www-form-urlencoded")
+        );
 
         let result: Person = call_and_read_body_json(&app, req).await;
         assert_eq!(&result.id, "12345");
@@ -549,7 +552,7 @@ mod tests {
             .set_json(&payload)
             .to_request();
 
-        assert_eq!(req.content_type(), "application/json");
+        assert_eq!(req.content_type(), Some("application/json"));
 
         let result: Person = call_and_read_body_json(&app, req).await;
         assert_eq!(&result.id, "12345");

actix-web/src/types/form.rs

@@ -289,7 +289,10 @@ impl<T> UrlEncoded<T> {
     /// Create a new future to decode a URL encoded request payload.
     pub fn new(req: &HttpRequest, payload: &mut Payload) -> Self {
         // check content type
-        if req.content_type().to_lowercase() != "application/x-www-form-urlencoded" {
+        if !req
+            .content_type()
+            .is_some_and(|ct| ct.eq_ignore_ascii_case("application/x-www-form-urlencoded"))
+        {
             return Self::err(UrlencodedError::ContentType);
         }
         let encoding = match req.encoding() {
@@ -484,6 +487,12 @@ mod tests {
             .to_http_parts();
         let info = UrlEncoded::<Info>::new(&req, &mut pl).await;
         assert!(eq(info.err().unwrap(), UrlencodedError::ContentType));
+
+        let (req, mut pl) = TestRequest::default()
+            .insert_header((CONTENT_LENGTH, 10))
+            .to_http_parts();
+        let info = UrlEncoded::<Info>::new(&req, &mut pl).await;
+        assert!(eq(info.err().unwrap(), UrlencodedError::ContentType));
     }
 
     #[actix_rt::test]
@@ -520,6 +529,21 @@ mod tests {
                 counter: 123
             }
         );
+
+        let (req, mut pl) = TestRequest::default()
+            .insert_header((CONTENT_TYPE, "APPLICATION/X-WWW-FORM-URLENCODED"))
+            .insert_header((CONTENT_LENGTH, 11))
+            .set_payload(Bytes::from_static(b"hello=world&counter=123"))
+            .to_http_parts();
+
+        let info = UrlEncoded::<Info>::new(&req, &mut pl).await.unwrap();
+        assert_eq!(
+            info,
+            Info {
+                hello: "world".to_owned(),
+                counter: 123
+            }
+        );
     }
 
     #[actix_rt::test]