Initialize rustls crypto provider if not otherwise done

Cargo.toml

@@ -27,7 +27,7 @@ name = "tests"
 required-features = ["hyper-rustls", "service_account"]
 
 [features]
-default = ["hyper-rustls", "service_account"]
+default = ["hyper-rustls", "rustls", "service_account"]
 service_account = ["hyper-rustls", "rustls", "rustls-pemfile"]
 
 [dependencies]
@@ -43,7 +43,7 @@ hyper-rustls = { version = "0.27", optional = true, default-features = false, fe
 hyper-tls = { version = "0.6.0", optional = true }
 log = "0.4"
 percent-encoding = "2"
-rustls = { version = "^0.23", optional = true, features = ["ring"] }
+rustls = { version = "^0.23", optional = true }
 rustls-pemfile = { version = "2.0.0", optional = true }
 seahash = "4"
 serde = { version = "1.0", features = ["derive"] }

src/authenticator.rs

@@ -463,7 +463,10 @@ impl ExternalAccountAuthenticator {
 /// #     .expect("failed to create authenticator");
 /// # }
 /// ```
+#[cfg(any(feature = "hyper-rustls", feature = "hyper-tls"))]
 pub struct AccessTokenAuthenticator;
+
+#[cfg(any(feature = "hyper-rustls", feature = "hyper-tls"))]
 impl AccessTokenAuthenticator {
     /// the builder pattern for the authenticator
     pub fn builder(
@@ -576,6 +579,7 @@ impl<C, F> AuthenticatorBuilder<C, F> {
     }
 
     fn new(auth_flow: F, hyper_client_builder: C) -> AuthenticatorBuilder<C, F> {
+        install_crypto_provider_if_not_set();
         AuthenticatorBuilder {
             hyper_client_builder,
             storage_type: StorageType::Memory,
@@ -1062,6 +1066,16 @@ enum StorageType {
     Custom(Box<dyn TokenStorage>),
 }
 
+#[cfg(feature = "hyper-rustls")]
+fn install_crypto_provider_if_not_set() {
+    if rustls::crypto::CryptoProvider::get_default().is_none() {
+        let _ = rustls::crypto::ring::default_provider().install_default();
+    }
+}
+
+#[cfg(not(feature = "hyper-rustls"))]
+fn install_crypto_provider_if_not_set() {}
+
 #[cfg(test)]
 mod tests {
     #[test]

src/lib.rs

@@ -102,11 +102,15 @@ pub use hyper_rustls;
 #[cfg(feature = "service_account")]
 #[doc(inline)]
 pub use crate::authenticator::ServiceAccountAuthenticator;
+
+#[cfg(any(feature = "hyper-rustls", feature = "hyper-tls"))]
+pub use crate::authenticator::AccessTokenAuthenticator;
+
 #[doc(inline)]
 pub use crate::authenticator::{
-    AccessTokenAuthenticator, ApplicationDefaultCredentialsAuthenticator,
-    AuthorizedUserAuthenticator, DeviceFlowAuthenticator, ExternalAccountAuthenticator,
-    InstalledFlowAuthenticator, ServiceAccountImpersonationAuthenticator,
+    ApplicationDefaultCredentialsAuthenticator, AuthorizedUserAuthenticator,
+    DeviceFlowAuthenticator, ExternalAccountAuthenticator, InstalledFlowAuthenticator,
+    ServiceAccountImpersonationAuthenticator,
 };
 
 pub use crate::helper::*;