Class: Aws::TranscribeStreamingService::AsyncClient

Seahorse::Client::AsyncBase show all
Defined in:

Instance Attribute Summary

Attributes inherited from Seahorse::Client::AsyncBase


Attributes inherited from Seahorse::Client::Base

#config, #handlers

API Operations collapse

Instance Method Summary collapse

Methods included from AsyncClientStubs


Methods included from ClientStubs

#api_requests, #stub_data, #stub_responses

Methods inherited from Seahorse::Client::AsyncBase

#close_connection, #connection_errors, #new_connection, #operation_names

Methods inherited from Seahorse::Client::Base

add_plugin, api, clear_plugins, define, new, #operation_names, plugins, remove_plugin, set_api, set_plugins

Methods included from Seahorse::Client::HandlerBuilder

#handle, #handle_request, #handle_response

Constructor Details

#initialize(*args) ⇒ AsyncClient

@option options [required, Aws::CredentialProvider] :credentials Your AWS credentials. This can be an instance of any one of the following classes:

* `Aws::Credentials` - Used for configuring static, non-refreshing

* `Aws::InstanceProfileCredentials` - Used for loading credentials
  from an EC2 IMDS on an EC2 instance.

* `Aws::SharedCredentials` - Used for loading credentials from a
  shared file, such as `~/.aws/config`.

* `Aws::AssumeRoleCredentials` - Used when you need to assume a role.

When `:credentials` are not configured directly, the following
locations will be searched for credentials:

* `Aws.config[:credentials]`
* The `:access_key_id`, `:secret_access_key`, and `:session_token` options.
* `~/.aws/credentials`
* `~/.aws/config`
* EC2 IMDS instance profile - When used by default, the timeouts are
  very aggressive. Construct and pass an instance of
  `Aws::InstanceProfileCredentails` to enable retries and extended

@option options [required, String] :region The AWS region to connect to. The configured :region is used to determine the service :endpoint. When not passed, a default :region is searched for in the following locations:

* `Aws.config[:region]`
* `~/.aws/credentials`
* `~/.aws/config`

@option options [String] :access_key_id

@option options [Boolean] :adaptive_retry_wait_to_fill (true) Used only in adaptive retry mode. When true, the request will sleep until there is sufficent client side capacity to retry the request. When false, the request will raise a RetryCapacityNotAvailableError and will not retry instead of sleeping.

@option options [Boolean] :convert_params (true) When true, an attempt is made to coerce request parameters into the required types.

@option options [Boolean] :correct_clock_skew (true) Used only in standard and adaptive retry modes. Specifies whether to apply a clock skew correction and retry requests with skewed client clocks.

@option options [String] :endpoint The client endpoint is normally constructed from the :region option. You should only configure an :endpoint when connecting to test or custom endpoints. This should be a valid HTTP(S) URI.

@option options [Proc] :event_stream_handler When an EventStream or Proc object is provided, it will be used as callback for each chunk of event stream response received along the way.

@option options [Proc] :input_event_stream_handler When an EventStream or Proc object is provided, it can be used for sending events for the event stream.

@option options [Aws::Log::Formatter] :log_formatter (Aws::Log::Formatter.default) The log formatter.

@option options [Symbol] :log_level (:info) The log level to send messages to the :logger at.

@option options [Logger] :logger The Logger instance to send log messages to. If this option is not set, logging will be disabled.

@option options [Integer] :max_attempts (3) An integer representing the maximum number attempts that will be made for a single request, including the initial attempt. For example, setting this value to 5 will result in a request being retried up to 4 times. Used in standard and adaptive retry modes.

@option options [Proc] :output_event_stream_handler When an EventStream or Proc object is provided, it will be used as callback for each chunk of event stream response received along the way.

@option options [String] :profile ("default") Used when loading credentials from the shared credentials file at HOME/.aws/credentials. When not specified, 'default' is used.

@option options [Proc] :retry_backoff A proc or lambda used for backoff. Defaults to 2**retries * retry_base_delay. This option is only used in the legacy retry mode.

@option options [Float] :retry_base_delay (0.3) The base delay in seconds used by the default backoff function. This option is only used in the legacy retry mode.

@option options [Symbol] :retry_jitter (:none) A delay randomiser function used by the default backoff function. Some predefined functions can be referenced by name - :none, :equal, :full, otherwise a Proc that takes and returns a number. This option is only used in the legacy retry mode.


@option options [Integer] :retry_limit (3) The maximum number of times to retry failed requests. Only ~ 500 level server errors and certain ~ 400 level client errors are retried. Generally, these are throttling errors, data checksum errors, networking errors, timeout errors, auth errors, endpoint discovery, and errors from expired credentials. This option is only used in the legacy retry mode.

@option options [Integer] :retry_max_delay (0) The maximum number of seconds to delay between retries (0 for no limit) used by the default backoff function. This option is only used in the legacy retry mode.

@option options [String] :retry_mode ("legacy") Specifies which retry algorithm to use. Values are:

* `legacy` - The pre-existing retry behavior.  This is default value if
  no retry mode is provided.

* `standard` - A standardized set of retry rules across the AWS SDKs.
  This includes support for retry quotas, which limit the number of
  unsuccessful retries a client can make.

* `adaptive` - An experimental retry mode that includes all the
  functionality of `standard` mode along with automatic client side
  throttling.  This is a provisional mode that may change behavior
  in the future.

@option options [String] :secret_access_key

@option options [String] :session_token

@option options [Boolean] :stub_responses (false) Causes the client to return stubbed responses. By default fake responses are generated and returned. You can specify the response data to return or errors to raise by calling ClientStubs#stub_responses. See ClientStubs for more information.

** Please note ** When response stubbing is enabled, no HTTP
requests are made, and retries are disabled.

@option options [Boolean] :validate_params (true) When true, request parameters are validated before sending the request.

# File 'gems/aws-sdk-transcribestreamingservice/lib/aws-sdk-transcribestreamingservice/async_client.rb', line 216

def initialize(*args)
  unless Kernel.const_defined?("HTTP2")
    raise "Must include http/2 gem to use AsyncClient instances."

Instance Method Details

#start_stream_transcription(params = {}) ⇒ Types::StartStreamTranscriptionResponse

Starts a bidirectional HTTP2 stream where audio is streamed to Amazon Transcribe and the transcription results are streamed to your application.

The following are encoded as HTTP2 headers:

  • x-amzn-transcribe-language-code

  • x-amzn-transcribe-media-encoding

  • x-amzn-transcribe-sample-rate

  • x-amzn-transcribe-session-id


Bi-directional EventStream Operation Example

You can signal input events after initial request is
established, events will be sent to stream
immediately (once stream connection is established successfully).

To signal events, you can call #signal methods from an Aws::TranscribeStreamingService::EventStreams::AudioStream object.
Make sure signal events before calling #wait or #join! at async response.

  input_stream =

  async_resp = client.start_stream_transcription( # params input,
    input_event_stream_handler: input_stream) do |out_stream|

    # register callbacks for events arrival
    out_stream.on_transcript_event_event do |event|
      event # => Aws::TranscribeStreamingService::Types::TranscriptEvent
    out_stream.on_bad_request_exception_event do |event|
      event # => Aws::TranscribeStreamingService::Types::BadRequestException
    out_stream.on_limit_exceeded_exception_event do |event|
      event # => Aws::TranscribeStreamingService::Types::LimitExceededException
    out_stream.on_internal_failure_exception_event do |event|
      event # => Aws::TranscribeStreamingService::Types::InternalFailureException
    out_stream.on_conflict_exception_event do |event|
      event # => Aws::TranscribeStreamingService::Types::ConflictException
    out_stream.on_service_unavailable_exception_event do |event|
      event # => Aws::TranscribeStreamingService::Types::ServiceUnavailableException

  # => returns Aws::Seahorse::Client::AsyncResponse

  # signal events
  input_stream.signal_audio_event_event( ... )

  # make sure signaling :end_stream in the end

  # wait until stream is closed before finalizing sync response
  resp = async_resp.wait
  # Or close stream and finalizing sync response immediately
  # resp = async_resp.join!

Inorder to streamingly processing events received, you can also provide an Aws::TranscribeStreamingService::EventStreams::TranscriptResultStream
object to register callbacks before initializing request instead of processing from request block

  output_stream =
  # register callbacks for events arrival
  output_stream.on_transcript_event_event do |event|
    event # => Aws::TranscribeStreamingService::Types::TranscriptEvent
  output_stream.on_bad_request_exception_event do |event|
    event # => Aws::TranscribeStreamingService::Types::BadRequestException
  output_stream.on_limit_exceeded_exception_event do |event|
    event # => Aws::TranscribeStreamingService::Types::LimitExceededException
  output_stream.on_internal_failure_exception_event do |event|
    event # => Aws::TranscribeStreamingService::Types::InternalFailureException
  output_stream.on_conflict_exception_event do |event|
    event # => Aws::TranscribeStreamingService::Types::ConflictException
  output_stream.on_service_unavailable_exception_event do |event|
    event # => Aws::TranscribeStreamingService::Types::ServiceUnavailableException
  output_stream.on_error_event do |event|
    # catch unmodeled error event in the stream
    raise event
    # => Aws::Errors::EventError
    # event.event_type => :error
    # event.error_code => String
    # event.error_message => String

  async_resp = client.start_stream_transcription ( #params input,
    input_event_stream_handler: input_stream
    output_event_stream_handler: output_stream

  resp = async_resp.wait!

Besides above usage patterns for process events when they arrive immediately, you can also
iterate through events after response complete.

Events are available at resp.transcript_result_stream # => Enumerator

Request syntax with placeholder values

async_resp = async_client.start_stream_transcription({
  language_code: "en-US", # required, accepts en-US, en-GB, es-US, fr-CA, fr-FR, en-AU
  media_sample_rate_hertz: 1, # required
  media_encoding: "pcm", # required, accepts pcm
  vocabulary_name: "VocabularyName",
  session_id: "SessionId",
  vocabulary_filter_name: "VocabularyFilterName",
  vocabulary_filter_method: "remove", # accepts remove, mask, tag
# => Seahorse::Client::AsyncResponse
# => Seahorse::Client::Response
# Or use async_resp.join!

Response structure

resp.request_id #=> String
resp.language_code #=> String, one of "en-US", "en-GB", "es-US", "fr-CA", "fr-FR", "en-AU"
resp.media_sample_rate_hertz #=> Integer
resp.media_encoding #=> String, one of "pcm"
resp.vocabulary_name #=> String
resp.session_id #=> String
All events are available at resp.transcript_result_stream:
resp.transcript_result_stream #=> Enumerator
resp.transcript_result_stream.event_types #=> [:transcript_event, :bad_request_exception, :limit_exceeded_exception, :internal_failure_exception, :conflict_exception, :service_unavailable_exception]

For :transcript_event event available at #on_transcript_event_event callback and response eventstream enumerator:
event.transcript.results #=> Array
event.transcript.results[0].result_id #=> String
event.transcript.results[0].start_time #=> Float
event.transcript.results[0].end_time #=> Float
event.transcript.results[0].is_partial #=> Boolean
event.transcript.results[0].alternatives #=> Array
event.transcript.results[0].alternatives[0].transcript #=> String
event.transcript.results[0].alternatives[0].items #=> Array
event.transcript.results[0].alternatives[0].items[0].start_time #=> Float
event.transcript.results[0].alternatives[0].items[0].end_time #=> Float
event.transcript.results[0].alternatives[0].items[0].type #=> String, one of "pronunciation", "punctuation"
event.transcript.results[0].alternatives[0].items[0].content #=> String
event.transcript.results[0].alternatives[0].items[0].vocabulary_filter_match #=> Boolean

For :bad_request_exception event available at #on_bad_request_exception_event callback and response eventstream enumerator:
event.message #=> String

For :limit_exceeded_exception event available at #on_limit_exceeded_exception_event callback and response eventstream enumerator:
event.message #=> String

For :internal_failure_exception event available at #on_internal_failure_exception_event callback and response eventstream enumerator:
event.message #=> String

For :conflict_exception event available at #on_conflict_exception_event callback and response eventstream enumerator:
event.message #=> String

For :service_unavailable_exception event available at #on_service_unavailable_exception_event callback and response eventstream enumerator:
event.message #=> String

resp.vocabulary_filter_name #=> String
resp.vocabulary_filter_method #=> String, one of "remove", "mask", "tag"


  • params (Hash) (defaults to: {})


Options Hash (params):

  • :language_code (required, String)

    Indicates the source language used in the input audio stream.

  • :media_sample_rate_hertz (required, Integer)

    The sample rate, in Hertz, of the input audio. We suggest that you use 8000 Hz for low quality audio and 16000 Hz for high quality audio.

  • :media_encoding (required, String)

    The encoding used for the input audio.

  • :vocabulary_name (String)

    The name of the vocabulary to use when processing the transcription job.

  • :session_id (String)

    A identifier for the transcription session. Use this parameter when you want to retry a session. If you don't provide a session ID, Amazon Transcribe will generate one for you and return it in the response.

  • :vocabulary_filter_name (String)

    The name of the vocabulary filter you've created that is unique to your AWS accountf. Provide the name in this field to successfully use it in a stream.

  • :vocabulary_filter_method (String)

    The manner in which you use your vocabulary filter to filter words in your transcript. Remove removes filtered words from your transcription results. Mask masks those words with a *** in your transcription results. Tag keeps the filtered words in your transcription results and tags them. The tag appears as VocabularyFilterMatch equal to True


  • (output_event_stream_handler)


See Also:

# File 'gems/aws-sdk-transcribestreamingservice/lib/aws-sdk-transcribestreamingservice/async_client.rb', line 442

def start_stream_transcription(params = {}, options = {}, &block)
  params = params.dup
  input_event_stream_handler = _event_stream_handler(
  output_event_stream_handler = _event_stream_handler(
    params.delete(:output_event_stream_handler) || params.delete(:event_stream_handler),

  yield(output_event_stream_handler) if block_given?

  req = build_request(:start_stream_transcription, params)

  req.context[:input_event_stream_handler] = input_event_stream_handler
  req.handlers.add(Aws::Binary::EncodeHandler, priority: 95)
  req.context[:output_event_stream_handler] = output_event_stream_handler
  req.handlers.add(Aws::Binary::DecodeHandler, priority: 95)

  req.send_request(options, &block)