1 files changed, 15 insertions, 0 deletions
diff --git a/src/objective-c/GRPCClient/GRPCCall+OAuth2.h b/src/objective-c/GRPCClient/GRPCCall+OAuth2.h
index 65465e9523..adb1042aa0 100644
--- a/src/objective-c/GRPCClient/GRPCCall+OAuth2.h
+++ b/src/objective-c/GRPCClient/GRPCCall+OAuth2.h
@@ -18,6 +18,13 @@
 
 #import "GRPCCall.h"
 
+/**
+ * The protocol of an OAuth2 token object from which GRPCCall can acquire a token.
+ */
+@protocol GRPCAuthorizationProtocol
+- (void)getTokenWithHandler:(void (^)(NSString *token))hander;
+@end
+
 /** Helpers for setting and reading headers compatible with OAuth2. */
 @interface GRPCCall (OAuth2)
 
@@ -33,4 +40,12 @@
 /** Returns the value (if any) of the "www-authenticate" response header (the challenge header). */
 @property(atomic, readonly) NSString *oauth2ChallengeHeader;
 
+/**
+ * The authorization token object to be used when starting the call. If the value is set to nil, no
+ * oauth authentication will be used.
+ *
+ * If tokenProvider exists, it takes precedence over the token set by oauth2AccessToken.
+ */
+@property(atomic, strong) id<GRPCAuthorizationProtocol> tokenProvider;
+
 @end