feat: Support selective ssl/tls backend in rust-server to avoid always requiring openssl

Author: dsteeley

.github/workflows/samples-rust-server.yaml

@@ -64,6 +64,13 @@ jobs:
             if cargo read-manifest | grep -q '"validate"'; then
               cargo build --features validate --all-targets
             fi
+            # Client without TLS (HTTP-only)
+            if cargo read-manifest | grep -q '"client-tls"'; then
+              cargo build --no-default-features --features=client --lib
+              # Client with selective TLS backend
+              cargo build --no-default-features --features=client,client-tls --lib
+              cargo build --no-default-features --features=server --lib
+            fi
             cargo fmt
             cargo test
             cargo clippy

modules/openapi-generator/src/main/resources/rust-server/Cargo.mustache

@@ -32,7 +32,7 @@ homepage = "{{.}}"
 {{/homePageUrl}}
 
 [features]
-default = ["client", "server"]
+default = ["client", "server", "client-tls", "client-openssl"]
 client = [
 {{#apiUsesMultipartFormData}}
     "multipart", "multipart/client", "swagger/multipart_form",
@@ -47,7 +47,19 @@ client = [
     "serde_ignored", "percent-encoding", {{^apiUsesByteArray}}"lazy_static", "regex",{{/apiUsesByteArray}}
 {{/hasCallbacks}}
 {{! Anything added to the list below, should probably be added to the callbacks list below }}
-    "hyper", "percent-encoding", "hyper-util/http1", "hyper-util/http2", "hyper-openssl", "hyper-tls", "native-tls", "openssl", "url"
+    "hyper", "percent-encoding", "hyper-util/http1", "hyper-util/http2", "url"
+]
+# TLS support using native-tls (macOS/Windows/iOS) or hyper-tls
+client-tls = [
+    "client",
+    "hyper-tls", "native-tls",
+    "swagger/tls"
+]
+# TLS support using OpenSSL (Linux and other platforms)
+client-openssl = [
+    "client",
+    "hyper-openssl", "openssl",
+    "swagger/tls"
 ]
 server = [
 {{#apiUsesMultipartFormData}}
@@ -57,7 +69,7 @@ server = [
     "mime_multipart", "swagger/multipart_related",
 {{/apiUsesMultipartRelated}}
 {{#hasCallbacks}}
-    "native-tls", "hyper-openssl", "hyper-tls", "openssl",
+    "client-tls",
 {{/hasCallbacks}}
 {{! Anything added to the list below, should probably be added to the callbacks list above }}
    "serde_ignored", "hyper", "percent-encoding", "url",
@@ -87,7 +99,7 @@ openssl = { version = "0.10", optional = true }
 async-trait = "0.1.88"
 chrono = { version = "0.4", features = ["serde"] }
 futures = "0.3"
-swagger = { version = "7.0.0", features = ["serdejson", "server", "client", "tls"] }
+swagger = { version = "7.0.0", features = ["serdejson", "server", "client"] }
 headers = "0.4.0"
 log = "0.4.27"
 

modules/openapi-generator/src/main/resources/rust-server/README.mustache

@@ -126,6 +126,12 @@ The generated library has a few optional features that can be activated through
 * `client`
     * This defaults to enabled and creates the basic skeleton of a client implementation based on hyper
     * The constructed client implements the API trait by making remote API call.
+* `client-tls`
+    * This defaults to enabled and provides HTTPS support using native-tls (macOS/Windows/iOS).
+    * Enable this feature for TLS support on Apple and Windows platforms.
+* `client-openssl`
+    * This defaults to enabled and provides HTTPS support using OpenSSL (Linux and other platforms).
+    * Enable this feature for TLS support on Linux and other Unix-like platforms.
 * `conversions`
     * This defaults to disabled and creates extra derives on models to allow "transmogrification" between objects of structurally similar types.
 * `cli`
@@ -134,6 +140,22 @@ The generated library has a few optional features that can be activated through
     * This defaults to disabled and allows JSON Schema validation of received data using `MakeService::set_validation` or `Service::set_validation`.
     * Note, enabling validation will have a performance penalty, especially if the API heavily uses regex based checks.
 
+### Minimal dependencies (no TLS)
+
+If you only need HTTP support and want to minimize dependencies (e.g., to avoid OpenSSL build requirements), you can disable the default TLS features:
+
+```toml
+[dependencies]
+{{{packageName}}} = { version = "{{{packageVersion}}}", default-features = false, features = ["server"] }
+```
+
+Or for client-only without TLS:
+
+```toml
+[dependencies]
+{{{packageName}}} = { version = "{{{packageVersion}}}", default-features = false, features = ["client"] }
+```
+
 See https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section for how to use features in your `Cargo.toml`.
 
 ## Documentation for API Endpoints

modules/openapi-generator/src/main/resources/rust-server/client-mod.mustache

@@ -121,6 +121,10 @@ impl<Connector, C> Client<
 #[derive(Debug, Clone)]
 pub enum HyperClient {
     Http(hyper_util::client::legacy::Client<hyper_util::client::legacy::connect::HttpConnector, BoxBody<Bytes, Infallible>>),
+    #[cfg(any(
+        all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")),
+        all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios")))
+    ))]
     Https(hyper_util::client::legacy::Client<HttpsConnector, BoxBody<Bytes, Infallible>>),
 }
 
@@ -132,7 +136,11 @@ impl Service<Request<BoxBody<Bytes, Infallible>>> for HyperClient {
     fn call(&self, req: Request<BoxBody<Bytes, Infallible>>) -> Self::Future {
        match self {
           HyperClient::Http(client) => client.request(req),
-          HyperClient::Https(client) => client.request(req)
+          #[cfg(any(
+              all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")),
+              all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios")))
+          ))]
+          HyperClient::Https(client) => client.request(req),
        }
     }
 }
@@ -158,12 +166,23 @@ impl<C> Client<DropContextService<HyperClient, C>, C> where
             "http" => {
                 HyperClient::Http(hyper_util::client::legacy::Client::builder(hyper_util::rt::TokioExecutor::new()).build(connector.build()))
             },
+            #[cfg(any(
+                all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")),
+                all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios")))
+            ))]
             "https" => {
                 let connector = connector.https()
                    .build()
                    .map_err(ClientInitError::SslError)?;
                 HyperClient::Https(hyper_util::client::legacy::Client::builder(hyper_util::rt::TokioExecutor::new()).build(connector))
             },
+            #[cfg(not(any(
+                all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")),
+                all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios")))
+            )))]
+            "https" => {
+                return Err(ClientInitError::TlsNotEnabled);
+            },
             _ => {
                 return Err(ClientInitError::InvalidScheme);
             }
@@ -206,12 +225,16 @@ impl<C> Client<
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))]
+#[cfg(all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")))]
 type HttpsConnector = hyper_tls::HttpsConnector<hyper_util::client::legacy::connect::HttpConnector>;
 
-#[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+#[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
 type HttpsConnector = hyper_openssl::client::legacy::HttpsConnector<hyper_util::client::legacy::connect::HttpConnector>;
 
+#[cfg(any(
+    all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")),
+    all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios")))
+))]
 impl<C> Client<
     DropContextService<
         hyper_util::service::TowerToHyperService<
@@ -244,7 +267,7 @@ impl<C> Client<
     /// # Arguments
     /// * `base_path` - base path of the client API, i.e. "<http://www.my-api-implementation.com>"
     /// * `ca_certificate` - Path to CA certificate used to authenticate the server
-    #[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+    #[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
     pub fn try_new_https_pinned<CA>(
         base_path: &str,
         ca_certificate: CA,
@@ -267,7 +290,7 @@ impl<C> Client<
     /// * `ca_certificate` - Path to CA certificate used to authenticate the server
     /// * `client_key` - Path to the client private key
     /// * `client_certificate` - Path to the client's public certificate associated with the private key
-    #[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+    #[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
     pub fn try_new_https_mutual<CA, K, D>(
         base_path: &str,
         ca_certificate: CA,
@@ -325,12 +348,15 @@ pub enum ClientInitError {
     /// Missing Hostname
     MissingHost,
 
+    /// HTTPS requested but TLS features not enabled
+    TlsNotEnabled,
+
     /// SSL Connection Error
-    #[cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))]
+    #[cfg(all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")))]
     SslError(native_tls::Error),
 
     /// SSL Connection Error
-    #[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+    #[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
     SslError(openssl::error::ErrorStack),
 }
 

modules/openapi-generator/src/main/resources/rust-server/server-callbacks.mustache

@@ -97,25 +97,29 @@ impl<C> Client<DropContextService<hyper_util::service::TowerToHyperService<hyper
     }
 }
 
-#[cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))]
+#[cfg(all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")))]
 type HttpsConnector = hyper_tls::HttpsConnector<hyper_util::client::legacy::connect::HttpConnector>;
 
-#[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+#[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
 type HttpsConnector = hyper_openssl::client::legacy::HttpsConnector<hyper_util::client::legacy::connect::HttpConnector>;
 
+#[cfg(any(
+    all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")),
+    all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios")))
+))]
 impl<C> Client<DropContextService<hyper_util::service::TowerToHyperService<hyper_util::client::legacy::Client<HttpsConnector, BoxBody<Bytes, Infallible>>>, C>, C> where
     C: Clone + Send + Sync + 'static
 {
     /// Create a client with a TLS connection to the server.
-    #[cfg(any(target_os = "macos", target_os = "windows", target_os = "ios"))]
+    #[cfg(all(feature = "client-tls", any(target_os = "macos", target_os = "windows", target_os = "ios")))]
     pub fn new_https()  -> Result<Self, native_tls::Error>
     {
         let https_connector = Connector::builder().https().build()?;
         Ok(Self::new_with_connector(https_connector))
     }
 
     /// Create a client with a TLS connection to the server.
-    #[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+    #[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
     pub fn new_https() -> Result<Self, openssl::error::ErrorStack>
     {
         let https_connector = Connector::builder().https().build()?;
@@ -126,7 +130,7 @@ impl<C> Client<DropContextService<hyper_util::service::TowerToHyperService<hyper
     ///
     /// # Arguments
     /// * `ca_certificate` - Path to CA certificate used to authenticate the server
-    #[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+    #[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
     pub fn new_https_pinned<CA>(
         ca_certificate: CA,
     ) -> Result<Self, openssl::error::ErrorStack> where
@@ -145,7 +149,7 @@ impl<C> Client<DropContextService<hyper_util::service::TowerToHyperService<hyper
     /// * `ca_certificate` - Path to CA certificate used to authenticate the server
     /// * `client_key` - Path to the client private key
     /// * `client_certificate` - Path to the client's public certificate associated with the private key
-    #[cfg(not(any(target_os = "macos", target_os = "windows", target_os = "ios")))]
+    #[cfg(all(feature = "client-openssl", not(any(target_os = "macos", target_os = "windows", target_os = "ios"))))]
     pub fn new_https_mutual<CA, K, D>(
         ca_certificate: CA,
         client_key: K,

samples/server/petstore/rust-server/output/multipart-v3/Cargo.toml

@@ -8,11 +8,23 @@ license = "Unlicense"
 edition = "2018"
 
 [features]
-default = ["client", "server"]
+default = ["client", "server", "client-tls", "client-openssl"]
 client = [
     "multipart", "multipart/client", "swagger/multipart_form",
     "mime_multipart", "swagger/multipart_related",
-    "hyper", "percent-encoding", "hyper-util/http1", "hyper-util/http2", "hyper-openssl", "hyper-tls", "native-tls", "openssl", "url"
+    "hyper", "percent-encoding", "hyper-util/http1", "hyper-util/http2", "url"
+]
+# TLS support using native-tls (macOS/Windows/iOS) or hyper-tls
+client-tls = [
+    "client",
+    "hyper-tls", "native-tls",
+    "swagger/tls"
+]
+# TLS support using OpenSSL (Linux and other platforms)
+client-openssl = [
+    "client",
+    "hyper-openssl", "openssl",
+    "swagger/tls"
 ]
 server = [
     "multipart", "multipart/server", "swagger/multipart_form",
@@ -41,7 +53,7 @@ openssl = { version = "0.10", optional = true }
 async-trait = "0.1.88"
 chrono = { version = "0.4", features = ["serde"] }
 futures = "0.3"
-swagger = { version = "7.0.0", features = ["serdejson", "server", "client", "tls"] }
+swagger = { version = "7.0.0", features = ["serdejson", "server", "client"] }
 headers = "0.4.0"
 log = "0.4.27"
 

samples/server/petstore/rust-server/output/multipart-v3/README.md

@@ -111,6 +111,12 @@ The generated library has a few optional features that can be activated through
 * `client`
     * This defaults to enabled and creates the basic skeleton of a client implementation based on hyper
     * The constructed client implements the API trait by making remote API call.
+* `client-tls`
+    * This defaults to enabled and provides HTTPS support using native-tls (macOS/Windows/iOS).
+    * Enable this feature for TLS support on Apple and Windows platforms.
+* `client-openssl`
+    * This defaults to enabled and provides HTTPS support using OpenSSL (Linux and other platforms).
+    * Enable this feature for TLS support on Linux and other Unix-like platforms.
 * `conversions`
     * This defaults to disabled and creates extra derives on models to allow "transmogrification" between objects of structurally similar types.
 * `cli`
@@ -119,6 +125,22 @@ The generated library has a few optional features that can be activated through
     * This defaults to disabled and allows JSON Schema validation of received data using `MakeService::set_validation` or `Service::set_validation`.
     * Note, enabling validation will have a performance penalty, especially if the API heavily uses regex based checks.
 
+### Minimal dependencies (no TLS)
+
+If you only need HTTP support and want to minimize dependencies (e.g., to avoid OpenSSL build requirements), you can disable the default TLS features:
+
+```toml
+[dependencies]
+multipart-v3 = { version = "1.0.7", default-features = false, features = ["server"] }
+```
+
+Or for client-only without TLS:
+
+```toml
+[dependencies]
+multipart-v3 = { version = "1.0.7", default-features = false, features = ["client"] }
+```
+
 See https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section for how to use features in your `Cargo.toml`.
 
 ## Documentation for API Endpoints