Update README.md with Sample Code Snippets.

Author: zihzhan-msft

sdk/communication/azure-communication-callingserver/README.md

@@ -1,6 +1,6 @@
 # Azure Communication CallingServer Package client library for Python
 
-This package contains a Python SDK for Azure Communication Services for CallingServer.
+This package contains a Python SDK for Azure Communication Services of CallingServer.
 Read more about Azure Communication Services [here](https://docs.microsoft.com/azure/communication-services/overview)
 
 
@@ -22,43 +22,231 @@ pip install azure-communication-callingserver
 
 ## Key concepts
 
-`CallingServerClient` provides the functionality to make call connection, join call connection or initialize a server call.
+`CallingServerClient` provides the functionality to create a call connection, join call connection or join a call with CallLocator.
+Performing more functionality over the eastablised call.
 
 ## Examples
 
 The following section provides several code snippets covering some of the most common Azure Communication Services tasks, including:
 
-- [Client Initialization](#client-initialization)
-- [Make a call to a phone number recipient](#make-a-call-to-a-phone-number-recipient)
+Call Connection Client APIs:
+- [Client initialization](#client-initialization)
+- [Create a call connection](#create-a-call-connection)
+- [Add participant](#add-participant)
+- [Remove participant](#remove-participant)
+- [Play audio in the call connection](#play-audio-in-the-call-connection)
+- [Cancel all media operations in the call connection](#cancel-all-media-operations-in-the-call-connection)
+- [Hang up the call connection](#hang-up-the-call-connection)
 
-### Client Initialization
+Calling Server Client APIs:
+- [Client initialization](#client-initialization)
+- [Create a server Call](#create-a-call-connection)
+- [Add participant with calllocator to the server call](#add-participant-with-calllocator-to-the-server-call)
+- [Remove participant with calllocator from the server call](#remove-participant-with-calllocator-from-the-server-call)
+- [Play audio with calllocator in the server call](#play-audio-with-calllocator-in-the-server-call)
+- [Hang up the call connection](#hang-up-the-call-connection)
 
-To initialize the CallingServer Client, the connection string can be used to instantiate.
+### Client initialization
+
+To initialize the CallingServer Client, the connection string can be used to instantiate. Alternatively, you can also use Azure Active Directory-managed identities authentication using DefaultAzureCredential.
 
 ```Python
-from azure.communication.callingserver import CallingServerClient
+from azure.communication.callingserver.aio import CallingServerClient
 
-connection_str = "endpoint=ENDPOINT;accessKey=KEY"
+connection_string = "endpoint=ENDPOINT;accessKey=KEY"
 callingserver_client = CallingServerClient.from_connection_string(connection_string)
-
 ```
 
-### Make a call to a phone number recipient
+```Python
+# To use Azure Active Directory Authentication (DefaultAzureCredential) make sure to have
+# AZURE_TENANT_ID, AZURE_CLIENT_ID and AZURE_CLIENT_SECRET as env variables.
+# see here: https://docs.microsoft.com/en-us/dotnet/api/azure.identity.environmentcredential?view=azure-dotnet
+from azure.identity import DefaultAzureCredential
 
+endpoint = "https://<RESOURCE_NAME>.communication.azure.com"
+callingserver_client = CallingServerClient(endpoint, DefaultAzureCredential())
+```
+
+### Create a call connection
 Once the client is initialized, the `createCallConnection` method can be invoked:
 
 ```Python
-from azure.communication.callingserver import CreateCallOptions
+from azure.communication.callingserver import (
+    CreateCallOptions,
+    CommunicationUserIdentifier,
+    PhoneNumberIdentifier
+    )
+
+call_connection_async = callingserver_client.create_call_connection(
+    source=CommunicationUserIdentifier("<from-phone-number>"),
+    targets=[PhoneNumberIdentifier("<to-phone-number>")],
+    call_options=CreateCallOptions("<...>"))
+```
+
+- `source`: The source identity.
+- `targets`: The target identities.
+- `call_options`: The create call options.
+
+### Add participant
+Once the call is establised, the `add_participant` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    CommunicationUserIdentifier
+    )
+
+add_participant_result = await call_connection_async.add_participant(
+    participant=CommunicationUserIdentifier("<user-id>")
+    )
+```
+
+- `participant`: The participant to be added to the call.
+
+### Remove participant
+Once the participant_id is provided, the `remove_participant` method can be invoked:
+
+```Python
+await call_connection_async.remove_participant(participant_id)
+```
+
+- `participant_id`: The participant to be removed from the call.
+
+### Play audio in the call connection
+Once the call is establised, the `play_audio` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    PlayAudioOptions
+    )
+
+play_audio_result = await call_connection_async.play_audio(
+    audio_file_uri="<audio-file-uri>",
+    play_audio_options=PlayAudioOptions"<...>"))
+    )
+```
+
+- `audio_file_uri`: The uri of the audio file.
+- `play_audio_options`: The playAudio options.
+
+### Cancel all media operations in the call connection
+Once the call is establised, the `cancel_all_media_operations` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    PlayAudioOptions
+    )
+
+cancel_all_media_operations_result = await call_connection_async.cancel_all_media_operations()
+```
+
+### Hang up the call connection
+Once the call is establised, the `hang_up` method can be invoked:
+
+```Python
+await call_connection_async.hang_up()
+```
+
+### Create a server Call
+The call will be establised after the `join_call` method get invoked:
+
+```Python
+from azure.communication.callingserver import (
+    CommunicationUserIdentifier,
+    JoinCallOptions,
+    ServerCallLocator
+    )
+
+call_locator = ServerCallLocator("<server-call-id>")
+call_connection = await call_connection_async.join_call(
+    call_locator=call_locator,
+    source=CommunicationUserIdentifier("<user-id>"),
+    join_call_options=JoinCallOptions"<...>"))
+    )
+```
+
+- `call_locator`: The callLocator contains the call id.
+- `source`: The source identity which join the call.
+- `play_audio_options`: The joinCall options.
+
+### Add participant with calllocator to the server call
+Once the call is establised, the `add_participant` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    CommunicationUserIdentifier,
+    ServerCallLocator
+    )
+
+call_locator = ServerCallLocator("<server-call-id>")
+add_participant_result = await callingserver_client.add_participant(
+    call_locator=call_locator,
+    participant=CommunicationUserIdentifier("<user-id>")
+    callback_uri="<callback-uri>"
+    )
+```
 
-sms_responses = callingserver_client.createCallConnection(
-    source="<from-phone-number>",
-    targets="<to-phone-number-1>",
-    createCallOptions=Something)
+- `call_locator`: The callLocator contains the call id.
+- `participant`: The participant to be added to the call.
+- `callback_uri`: The callback uri.
+
+### Remove participant with callLocator from the server call
+Once the participant_id is provided, the `remove_participant` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    CommunicationUserIdentifier,
+    ServerCallLocator
+    )
+
+await callingserver_client.remove_participant(
+    call_locator=call_locator,
+    participant=CommunicationUserIdentifier("<user-id>")
+    callback_uri="<callback-uri>"
+    )
+```
+
+- `call_locator`: The callLocator contains the call id.
+- `participant`: The participant to be removed from the call.
+- `callback_uri`: The callback uri.
+
+### Play audio with callLocator in the server call
+Once the call is establised, the `play_audio` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    PlayAudioOptions,
+    ServerCallLocator
+    )
+
+call_locator = ServerCallLocator("<server-call-id>")
+play_audio_result = await callingserver_client.play_audio(
+    call_locator=call_locator,
+    audio_file_uri="<audio-file-uri>",
+    play_audio_options=PlayAudioOptions"<...>"))
+    )
+```
+
+- `call_locator`: The callLocator contains the call id.
+- `audio_file_uri`: The uri of the audio file.
+- `play_audio_options`: The playAudio options.
+
+### Cancel media operations with calllocator in the server call
+Once the call is establised, the `cancel_media_operation` method can be invoked:
+
+```Python
+from azure.communication.callingserver import (
+    ServerCallLocator
+    )
+
+call_locator = ServerCallLocator("<server-call-id>")
+cancel_all_media_operations_result = await call_connection_async.cancel_media_operation(
+    call_locator=call_locator,
+    media_operation_id=media_operation_id
+)
 ```
 
-- `from_`: Something.
-- `to`: Something.
-- `createCallOptions`: Something.
+- `audio_file_uri`: The callLocator contains the call id.
+- `media_operation_id`: The operationId of the media operation to cancel.
 
 
 ## Troubleshooting
@@ -67,7 +255,7 @@ Running into issues? This section should contain details as to what to do there.
 
 ## Next steps
 
-More sample code should go here, along with links out to the appropriate example tests.
+More sample code should go under samples folder, along with links out to the appropriate example tests.
 
 ## Provide Feedback