feat: Support */* and $name/* in accept headers

Author: bahlo

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.0.5] - 2025-07-08
+
+### Changed
+
+- This adds proper support for stars in accept headers
+- Forbid the use of * in definitions
+
 ## [0.0.4] - 2025-07-08
 
 ### Added

axum-accept-macros/src/lib.rs

@@ -4,6 +4,8 @@
 #![deny(missing_docs)]
 extern crate proc_macro;
 
+use std::collections::HashMap;
+
 use mediatype::MediaTypeBuf;
 use proc_macro::TokenStream;
 use quote::quote;
@@ -66,7 +68,12 @@ pub fn derive_accept_extractor(input: TokenStream) -> TokenStream {
         })
     });
 
+    // Match arms with ty, subty and suffix
     let mut match_arms = Vec::new();
+    // Match arms with ty only (for checking mediatypes like text/*)
+    let mut match_arms_tys = HashMap::new();
+    // Store first variant to fall back to if we don't have a default.
+    let mut first_variant_name = None;
 
     for variant in &data.variants {
         let variant_name = &variant.ident;
@@ -79,6 +86,16 @@ pub fn derive_accept_extractor(input: TokenStream) -> TokenStream {
             mediatype.suffix().map(|s| s.as_str()),
         );
 
+        if ty == "*" || subty == "*" {
+            panic!("Please use a concrete mediatype");
+        }
+
+        if first_variant_name.is_none() {
+            first_variant_name = Some(variant_name.clone());
+        }
+
+        match_arms_tys.insert(ty.to_string(), variant_name);
+
         match &variant.fields {
             Fields::Unit => {
                 // quote encodes None to empty string, so we need to take extra
@@ -107,6 +124,22 @@ pub fn derive_accept_extractor(input: TokenStream) -> TokenStream {
         None
     };
 
+    let handle_star_star = if has_default {
+        quote! {
+            return Ok(#name::default());
+        }
+    } else {
+        quote! {
+            return Ok(#name::#first_variant_name);
+        }
+    };
+
+    let match_arms_tys = match_arms_tys.iter().map(|(ty, variant_name)| {
+        quote! {
+            (#ty) => return Ok(#name::#variant_name),
+        }
+    });
+
     let expanded = quote! {
         impl #impl_generics axum::extract::FromRequestParts<S> for #name #ty_generics #where_clause {
             type Rejection = axum_accept::AcceptRejection;
@@ -115,9 +148,23 @@ pub fn derive_accept_extractor(input: TokenStream) -> TokenStream {
                 let mediatypes = axum_accept::parse_mediatypes(&parts.headers)?;
                 #check_and_return_default
                 for mt in mediatypes {
-                    match (mt.ty.as_str(), mt.subty.as_str(), mt.suffix.map(|s| s.as_str())) {
-                        #(#match_arms)*
-                        _ => {} // continue searching
+                    match (mt.ty.as_str(), mt.subty.as_str()) {
+                        ("*", "*") => {
+                            // return either the the default or the first
+                            // variant
+                            #handle_star_star
+                        },
+                        // do we have any mediatype that shares the main type?
+                        // e.g. we offer text/plain and get accept: text/*
+                        (_, "*") => match (mt.ty.as_str()) {
+                            #(#match_arms_tys)*
+                            _ => {} // continue searching
+                        },
+                        // do proper matching
+                        _ =>  match (mt.ty.as_str(), mt.subty.as_str(), mt.suffix.map(|s| s.as_str())) {
+                            #(#match_arms)*
+                            _ => {} // continue searching
+                        },
                     }
                 }
 

axum-accept/src/lib.rs

@@ -35,8 +35,6 @@ mod tests {
 
     #[derive(Debug, AcceptExtractor)]
     enum Accept {
-        #[accept(mediatype = "text/*")]
-        Text,
         #[accept(mediatype = "text/plain")]
         TextPlain,
         #[accept(mediatype = "application/json")]
@@ -118,13 +116,39 @@ mod tests {
         Ok(())
     }
 
+    #[tokio::test]
+    async fn test_accept_extractor_star() -> Result<(), Box<dyn std::error::Error>> {
+        let req = Request::builder()
+            .header("accept", "text/csv,text/*")
+            .body(Body::from(""))?;
+        let state = ();
+        let media_type = Accept::from_request(req, &state).await;
+        let Ok(Accept::TextPlain) = media_type else {
+            panic!("expected text/*, got {:?}", media_type)
+        };
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn test_accept_extractor_star_star() -> Result<(), Box<dyn std::error::Error>> {
+        let req = Request::builder()
+            .header("accept", "text/csv,*/*")
+            .body(Body::from(""))?;
+        let state = ();
+        let media_type = Accept::from_request(req, &state).await;
+        let Ok(Accept::TextPlain) = media_type else {
+            panic!("expected text/plain")
+        };
+        Ok(())
+    }
+
     #[derive(Debug, AcceptExtractor, Default)]
     enum AcceptWithDefault {
+        #[accept(mediatype = "application/json")]
+        ApplicationJson,
         #[default]
         #[accept(mediatype = "text/plain")]
         TextPlain,
-        #[accept(mediatype = "application/json")]
-        ApplicationJson,
     }
 
     #[tokio::test]
@@ -146,4 +170,17 @@ mod tests {
         };
         Ok(())
     }
+
+    #[tokio::test]
+    async fn test_accept_extractor_star_star_default() -> Result<(), Box<dyn std::error::Error>> {
+        let req = Request::builder()
+            .header("accept", "text/csv,*/*")
+            .body(Body::from(""))?;
+        let state = ();
+        let media_type = AcceptWithDefault::from_request(req, &state).await;
+        let Ok(AcceptWithDefault::TextPlain) = media_type else {
+            panic!("expected text/plain (default)")
+        };
+        Ok(())
+    }
 }