The following examples will help you implement Instance ID in an iOS client.
Note that these examples use the GCM scope, which you would use to
manage tokens for an iOS client for
[Firebase Cloud Messaging](https://firebase.google.com/docs/cloud-messaging/ios/client).

## Set up your CocoaPods dependencies


Instance ID uses
[CocoaPods](https://cocoapods.org/)
to install and manage dependencies. Open a terminal window and navigate to the
location of the Xcode project for your application. If you have not already
created a Podfile for your application, create one now:

```
pod init
```

Open the Podfile created for your application and add the following:

```
pod 'FirebaseInstanceId'
```

Save the file and run:

```
pod install
```

This creates an `.xcworkspace` file for your application. Use this file for all
future development on your application.

## Generate a token

Generating tokens requires a Project ID generated by the [Google Developers Console](https://console.developers.google.com/project).

    NSString *authorizedEntity = PROJECT_ID;
    String *scope = kFIRInstanceIDScopeFirebaseMessaging;
    NSDictionary *options = @{
      @"apns_token" : <APNS Token data>,
      // 1 if APNS sandbox token else 0
      @"apns_sandbox" : @(1),
    };
    [[FIRInstanceID instanceID] tokenWithAuthorizedEntity:authorizedEntity
                                                    scope:scope
                                                  options:options
                                                  handler:
                      ^(NSString * _Nullable token, NSError * _Nullable error) {
                          // ...
    }];

## Manage tokens and Instance IDs

Instance ID lets you delete and refresh tokens.

### Delete tokens and Instance IDs

    NSString *authorizedEntity = PROJECT_ID; // Project ID
    String *scope = kFIRInstanceIDScopeFirebaseMessaging;
    FIRInstanceIDDeleteTokenHandler handler = ^void(NSError *error) {
      if (error) {
        // Failed to delete the token. Check error and do an exponential
        // backoff to retry again.
      } else {
        // Successfully deleted the token.
      }
    };
    [[FIRInstanceID instanceID]
        deleteTokenWithAuthorizedEntity:authorizedEntity
                                  scope:scope
                                handler:handler];

You can also delete the Instance ID itself, in which case next time you call
`getInstance()` you will get a new Instance ID:

    [FIRInstanceID instanceID] deleteIDWithHandler:^(NSError *error) {
          if error != nil {
            NSLog(@"Error deleting instance ID: %@", error);
          }
        }];

### Refresh tokens

The Instance ID service may create or regenerate tokens. When this occurs, a
notification will be sent. You can listen to this notification by adding an
observer for notifications named `kFIRInstanceIDTokenRefreshNotification`.

    [[NSNotificationCenter defaultCenter] addObserver:self
             selector:@selector(tokenRefreshNotification:) 
             name:kFIRInstanceIDTokenRefreshNotification object:nil];

This observer must be created before the token is created, for example
prior to calling `[FIRApp configure]`. The latest token can be retrieved by
calling `[[FIRInstanceID instanceID] token]`.

Note that for observing generation of tokens for Cloud Messaging, there is a
specific [delegate](https://firebase.google.com/docs/cloud-messaging/ios/client#monitor-token-generation) available.