Add utoipa_axum bindings

This PR adds a new crate `utoipa-axum` which provides bindings between
`axum` and `utoipa`. It aims to blend as much as possible to the
existing philosophy of axum way of registering handlers.

This commit introduces new `OpenApiRouter` what wraps `OpenApi` and axum
`Router` which provides passthrough implementation for most of the axum
Router methods and collects and combines the `OpenApi` from registered
routes. Routes registred only via `routes!()` macro will get added to
the `OpenApi`.

Also this commit introduces `routes!()` macro which collects axum
handlers annotated with `#[utoipa::path()]` attribute macro to single
paths intance which is then provided to the `OpenApiRouter`.

Fixes #991

scripts/doc.sh

@@ -3,5 +3,5 @@
 # Generate utoipa workspace docs
 
 cargo +nightly doc -Z unstable-options --workspace --no-deps \
-    --features actix_extras,openapi_extensions,yaml,uuid,ulid,url,non_strict_integers,actix-web,axum,rocket,axum_handler \
+    --features actix_extras,openapi_extensions,yaml,uuid,ulid,url,non_strict_integers,actix-web,axum,rocket \
     --config 'build.rustdocflags = ["--cfg", "doc_cfg"]'

scripts/test.sh

@@ -22,7 +22,6 @@ for crate in $crates; do
         $CARGO test -p utoipa-gen --test path_derive_rocket --features rocket_extras
 
         $CARGO test -p utoipa-gen --test path_derive_axum_test --features axum_extras
-        $CARGO test -p utoipa-gen --test path_derive_axum_test --features axum_extras,axum_handler
         $CARGO test -p utoipa-gen --test path_derive_auto_into_responses_axum --features axum_extras,utoipa/auto_into_responses
     elif [[ "$crate" == "utoipa-swagger-ui" ]]; then
         $CARGO test -p utoipa-swagger-ui --features actix-web,rocket,axum
@@ -33,6 +32,6 @@ for crate in $crates; do
     elif [[ "$crate" == "utoipa-scalar" ]]; then
         $CARGO test -p utoipa-scalar --features actix-web,rocket,axum
     elif [[ "$crate" == "utoipa-axum" ]]; then
-        $CARGO test -p utoipa-axum 
+        $CARGO test -p utoipa-axum --features debug,utoipa/debug
     fi
 done

utoipa-axum/Cargo.toml

@@ -11,14 +11,20 @@ categories = ["web-programming"]
 authors = ["Juha Kukkonen <juha7kukkonen@gmail.com>"]
 rust-version.workspace = true
 
+[features]
+debug = []
+
 [dependencies]
 axum = { version = "0.7", default-features = false }
-once_cell = "1"
-utoipa = { version = "5.0.0-alpha.1", path = "../utoipa", default-features = false }
+utoipa = { version = "5.0.0-alpha", path = "../utoipa", default-features = false }
 async-trait = "0.1"
 tower-service = "0.3"
 tower-layer = "0.3.2"
+paste = "1.0"
 
 [package.metadata.docs.rs]
 features = []
 rustdoc-args = ["--cfg", "doc_cfg"]
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(doc_cfg)'] }