Update Objective-C documentation to v0.6

grpc-auth-support.md

@@ -247,7 +247,7 @@ GIDSignIn.sharedInstance.scopes = @[@"https://www.googleapis.com/auth/grpc-testi
 
 ...
 
-#import <gRPC/ProtoRPC.h>
+#import <ProtoRPC/ProtoRPC.h>
 
 // Create a not-yet-started RPC. We want to set the request headers on this object before starting
 // it.
@@ -258,8 +258,7 @@ ProtoRPC *call =
 
 // Set the access token to be used.
 NSString *accessToken = GIDSignIn.sharedInstance.currentUser.authentication.accessToken;
-call.requestMetadata = [NSMutableDictionary dictionaryWithDictionary:
-    @{@"Authorization": [@"Bearer " stringByAppendingString:accessToken]}];
+call.requestMetadata[@"Authorization"] = [@"Bearer " stringByAppendingString:accessToken]}];
 
 // Start the RPC.
 [call start];

objective-c/auth_sample/README.md

@@ -115,7 +115,7 @@ In addition, an `RPCToUnaryCallWithRequest:handler:` method is generated, which
 not-yet-started RPC object:
 
 ```objective-c
-#import <gRPC/ProtoRPC.h>
+#import <ProtoRPC/ProtoRPC.h>
 
 ProtoRPC *call =
     [client RPCToUnaryCallWithRequest:request handler:^(AUTHResponse *response, NSError *error) {
@@ -132,10 +132,11 @@ The RPC represented by this object can be started at any later time like this:
 <a name="request-metadata"></a>
 ## Set request metadata of a call: Authorization header with an access token
 
-The `ProtoRPC` class has a `requestMetadata` property defined like this:
+The `ProtoRPC` class has a `requestMetadata` property (inherited from `GRPCCall`) defined like this:
 
 ```objective-c
-@property(nonatomic, readwrite) NSMutableDictionary *requestMetadata;
+- (NSMutableDictionary *)requestMetadata; // nonatomic
+- (void)setRequestMetadata:(NSDictionary *)requestMetadata; // nonatomic, copy
 ```
 
 Setting it to a dictionary of metadata keys and values will have them sent on the wire when the call
@@ -143,33 +144,46 @@ is started. gRPC metadata are pieces of information about the call sent by the c
 (and vice versa). They take the form of key-value pairs and are essentially opaque to gRPC itself.
 
 ```objective-c
-call.requestMetadata = [NSMutableDictionary dictionaryWithDictionary:
-    @{@"My-Header": @"Value for this header",
-      @"Another-Header": @"Its value"}];
+call.requestMetadata = @{@"My-Header": @"Value for this header",
+                         @"Another-Header": @"Its value"};
+```
+
+For convenience, the property is initialized with an empty `NSMutableDictionary`, so that request
+metadata elements can be set like this:
+
+```objective-c
+call.requestMetadata[@"My-Header"] = @"Value for this header";
 ```
 
 If you have an access token, OAuth2 specifies it is to be sent in this format:
 
 ```objective-c
-@{@"Authorization": [@"Bearer " stringByAppendingString:accessToken]}
+call.requestMetadata[@"Authorization"] = [@"Bearer " stringByAppendingString:accessToken];
 ```
 
 <a name="response-metadata"></a>
 ## Get response metadata of a call: Auth challenge header
 
-The `ProtoRPC` class also has a `responseMetadata` property, analogous to the request metadata we
-just looked at. It's defined like this:
+The `ProtoRPC` class also inherits a `responseMetadata` property, analogous to the request metadata
+we just looked at. It's defined like this:
 
 ```objective-c
 @property(atomic, readonly) NSDictionary *responseMetadata;
 ```
 
-Because gRPC metadata keys can be repeated, the values of the `responseMetadata` dictionary are
-always `NSArray`s. Thus, to access OAuth2's authentication challenge header you write:
+To access OAuth2's authentication challenge header you write:
 
 ```objective-c
-call.responseMetadata[@"www-authenticate"][0]
+call.responseMetadata[@"www-authenticate"]
 ```
 
 Note that, as gRPC metadata elements are mapped to HTTP/2 headers (or trailers), the keys of the
 response metadata are always ASCII strings in lowercase.
+
+Many uses cases of response metadata are getting more details about an RPC error. For convenience,
+when a `NSError` instance is passed to an RPC handler block, the response metadata dictionary can
+also be accessed this way:
+
+```objective-c
+error.userInfo[kGRPCStatusMetadataKey]
+```

objective-c/helloworld/README.md

@@ -2,15 +2,17 @@
 
 ## Installation
 
-To run this example you should have [Cocoapods](https://cocoapods.org/#install) installed, as well as the relevant tools to generate the client library code (and a server in another language, for testing). You can obtain the latter by following [these setup instructions](https://github.com/grpc/homebrew-grpc).
+To run this example you should have [Cocoapods](https://cocoapods.org/#install) installed, as well
+as the relevant tools to generate the client library code (and a server in another language, for
+testing). You can obtain the latter by following [these setup instructions](https://github.com/grpc/homebrew-grpc).
 
 ## Hello Objective-C gRPC!
 
-Here's how to build and run the Objective-C implementation of the [Hello World](https://github.com/grpc/grpc-common/blob/master/protos/helloworld.proto) example used in [Getting started](https://github.com/grpc/grpc-common).
+Here's how to build and run the Objective-C implementation of the [Hello World](https://github.com/grpc/grpc-common/blob/master/protos/helloworld.proto)
+example used in [Getting started](https://github.com/grpc/grpc-common).
 
-The example code for this and our other examples lives in the `grpc-common`
-GitHub repository. Clone this repository to your local machine by running the
-following command:
+The example code for this and our other examples lives in the `grpc-common` GitHub repository. Clone
+this repository to your local machine by running the following command:
 
 
 ```sh
@@ -24,7 +26,8 @@ $ cd grpc-common/objective-c/helloworld
 ```
 
 ### Try it!
-To try the sample app, we need a gRPC server running locally. Let's compile and run, for example, the C++ server in this repository:
+To try the sample app, we need a gRPC server running locally. Let's compile and run, for example,
+the C++ server in this repository:
 
 ```shell
 $ pushd ../../cpp/helloworld
@@ -39,12 +42,15 @@ Now have Cocoapods generate and install the client library for our .proto files:
 $ pod install
 ```
 
-This might have to compile OpenSSL, which takes around 15 minutes if Cocoapods doesn't have it yet on your computer's cache).
+(This might have to compile OpenSSL, which takes around 15 minutes if Cocoapods doesn't have it yet
+on your computer's cache.)
 
-Finally, open the XCode workspace created by Cocoapods, and run the app. You can check the calling code in `main.m` and see the results in XCode's log console.
+Finally, open the XCode workspace created by Cocoapods, and run the app. You can check the calling
+code in `main.m` and see the results in XCode's log console.
 
-The code sends a `HLWHelloRequest` containing the string "Objective-C" to a local server. The server responds with a `HLWHelloResponse`, which contains a string that is then output to the log.
+The code sends a `HLWHelloRequest` containing the string "Objective-C" to a local server. The server
+responds with a `HLWHelloResponse`, which contains a string that is then output to the log.
 
 ## Tutorial
 
-You can find a more detailed tutorial in [gRPC Basics: Objective-C](https://github.com/grpc/grpc-common/blob/master/objective-c/route_guide/README.md)
+You can find a more detailed tutorial in [gRPC Basics: Objective-C](https://github.com/grpc/grpc-common/blob/master/objective-c/route_guide/README.md).
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