Allow suppressing or forcing generation of IntoResponse implementation (#64)

Allow suppressing and forcing IntoResponse implementation

Author: casey

.github/workflows/ci.yaml

@@ -43,7 +43,8 @@ jobs:
 
     - run: |
         rustup target add thumbv6m-none-eabi
-        cargo build --no-default-features --target thumbv6m-none-eabi
+        cargo build --target thumbv6m-none-eabi --package boilerplate
+        cargo build --target thumbv6m-none-eabi --package boilerplate-tests
 
   lint:
     runs-on: ubuntu-latest

Cargo.lock

@@ -3,6 +3,7 @@ use super::*;
 #[derive(FromDeriveInput)]
 #[darling(attributes(boilerplate))]
 pub(crate) struct Boilerplate {
+  axum: Option<bool>,
   filename: Option<String>,
   generics: Generics,
   ident: Ident,
@@ -40,12 +41,13 @@ impl Boilerplate {
     let guess = new_mime_guess::from_path(&filename).first_or_text_plain();
 
     let mime = if guess.type_() == mime::TEXT && guess.get_param(mime::CHARSET).is_none() {
-      format!("{guess}; charset=utf-8").parse().unwrap()
+      format!("{guess};charset=utf-8").parse().unwrap()
     } else {
       guess
     };
 
     Template {
+      axum: self.axum,
       escape,
       generics: self.generics,
       ident: self.ident,

crates/boilerplate-macros/src/boilerplate.rs

@@ -25,10 +25,12 @@ pub fn boilerplate(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 
   quote! {
     {
+      extern crate alloc;
+
       use ::core::fmt::Write;
 
       let boilerplate_text = &[ #(#text),* ];
-      let mut boilerplate_output = ::std::string::String::new();
+      let mut boilerplate_output = alloc::string::String::new();
 
       #body
 

crates/boilerplate-macros/src/lib.rs

@@ -1,6 +1,7 @@
 use super::*;
 
 pub(crate) struct Template {
+  pub(crate) axum: Option<bool>,
   pub(crate) escape: bool,
   pub(crate) generics: Generics,
   pub(crate) ident: Ident,
@@ -12,7 +13,7 @@ impl Template {
   pub(crate) fn impls(self) -> TokenStream {
     let display_impl = self.display_impl();
 
-    let axum_into_response_impl = if cfg!(feature = "axum") {
+    let axum_into_response_impl = if self.axum.unwrap_or(cfg!(feature = "axum")) {
       Some(self.axum_into_response_impl())
     } else {
       None
@@ -113,6 +114,8 @@ impl Template {
     quote! {
       impl #impl_generics ::axum::response::IntoResponse for #ident #ty_generics #where_clause {
         fn into_response(self) -> ::axum::response::Response {
+          extern crate alloc;
+          use alloc::string::ToString;
           (
             [(::axum::http::header::CONTENT_TYPE, #content_type)],
             self.to_string(),
@@ -161,11 +164,12 @@ mod tests {
 
     assert_eq!(
       Template {
-        ident: Ident::new("Foo", Span::call_site()),
-        source: Source::Literal(LitStr::new("", Span::call_site())),
-        mime: mime::TEXT_PLAIN,
+        axum: None,
         escape: false,
         generics: Generics::default(),
+        ident: Ident::new("Foo", Span::call_site()),
+        mime: mime::TEXT_PLAIN,
+        source: Source::Literal(LitStr::new("", Span::call_site())),
       }
       .display_impl()
       .to_string(),
@@ -327,17 +331,21 @@ mod tests {
   fn axum_into_response_impl() {
     assert_eq!(
       Template {
-        ident: Ident::new("Foo", Span::call_site()),
-        source: Source::Literal(LitStr::new("", Span::call_site())),
-        mime: mime::TEXT_PLAIN,
+        axum: Some(true),
         escape: false,
         generics: Generics::default(),
+        ident: Ident::new("Foo", Span::call_site()),
+        mime: mime::TEXT_PLAIN,
+        source: Source::Literal(LitStr::new("", Span::call_site())),
       }
       .axum_into_response_impl()
       .to_string(),
       quote!(
         impl ::axum::response::IntoResponse for Foo {
           fn into_response(self) -> ::axum::response::Response {
+            extern crate alloc;
+            use alloc::string::ToString;
+
             (
               [(::axum::http::header::CONTENT_TYPE, "text/plain")],
               self.to_string(),

crates/boilerplate-macros/src/template.rs

@@ -0,0 +1,15 @@
+[package]
+name = "boilerplate-tests"
+version = "0.0.0"
+authors.workspace = true
+categories.workspace = true
+edition.workspace = true
+homepage.workspace = true
+license.workspace = true
+repository.workspace = true
+
+[dependencies]
+boilerplate = { path = "../../" }
+
+[lints]
+workspace = true

crates/boilerplate-tests/Cargo.toml

@@ -0,0 +1,13 @@
+#![no_std]
+
+#[allow(unused)]
+#[derive(boilerplate::Boilerplate)]
+#[boilerplate(axum = false, text = "Hello, {{ self.name }}!")]
+struct Context {
+  name: &'static str,
+}
+
+#[allow(unused)]
+fn foo() {
+  boilerplate::boilerplate!("Hello!");
+}

crates/boilerplate-tests/src/lib.rs

@@ -7,7 +7,8 @@ ci:
   cargo test --all
   cargo test --all --features axum
   cargo test --all --features reload
-  cargo build --no-default-features --target thumbv6m-none-eabi
+  cargo build --target thumbv6m-none-eabi --package boilerplate
+  cargo build --target thumbv6m-none-eabi --package boilerplate-tests
 
 # publish current GitHub master branch
 publish:

justfile

@@ -363,7 +363,7 @@
 //!       .headers()
 //!       .get("content-type")
 //!       .unwrap(),
-//!     "text/html; charset=utf-8",
+//!     "text/html;charset=utf-8",
 //!   );
 //! }
 //! ```
@@ -380,11 +380,38 @@
 //!       .headers()
 //!       .get("content-type")
 //!       .unwrap(),
-//!     "text/plain; charset=utf-8",
+//!     "text/plain;charset=utf-8",
 //!   );
 //! }
 //! ```
 //!
+//! The `axum` attribute can be used to suppress or force generation of
+//! `IntoResponse` implementations, regardless of whether the `axum` feature is
+//! enabled:
+//!
+//! ```
+//! use axum::response::IntoResponse;
+//! #[derive(boilerplate::Boilerplate)]
+//! #[boilerplate(axum = true)]
+//! struct GuessHtml {}
+//! assert_eq!(
+//!   GuessHtml {}
+//!     .into_response()
+//!     .headers()
+//!     .get("content-type")
+//!     .unwrap(),
+//!   "text/html;charset=utf-8",
+//! );
+//! ```
+//!
+//! ```rust,compile_fail
+//! use axum::response::IntoResponse;
+//! #[derive(boilerplate::Boilerplate)]
+//! #[boilerplate(axum = false)]
+//! struct GuessHtml {}
+//! GuessHtml {}.into_response();
+//! ```
+//!
 //! ### Reloading Templates
 //!
 //! When the `reload` feature is enabled, templates support a limited form of