Google Speech to Text API Undefined Method - ruby

Question

I'm trying to learn how to use the google speech to text API but I'm getting an undefined method error when running the code. The code is taken from google cloud client library to use. I'm not sure how to fix the error.
Error: : undefined method alternatives for nil:NilClass (NoMethodError)
#use gem install google-cloud-speech
require "google/cloud/speech"
speech = Google::Cloud::Speech.speech
file_name = "file_path"
audio_file = File.binread file_name
config = { encoding: :LINEAR16,
sample_rate_hertz: 16_000,
language_code: "en-US" }
audio = { content: audio_file }
response = speech.recognize config: config, audio: audio
results = response.results
results.first.alternatives.each do |alternatives|
puts "Transcription: #{alternatives.transcript}"
end

Answer 1

I have tried to replicate your issue and I was able to successfully execute the code and other examples from the documentation. In addition, since you stated that you are learning how to use the Speech to Text API from Google, I will describe the steps I took.
It seems that you have taken the code from the documentation. However, you do not have the first lines and the last lines of the code, which respectively define transcription method and the call to execute it. For this reason, when you execute your code there is no call to any method and neither to the Speech-to-Text API. Your code should be as follows:
def speech_sync_recognize audio_file_path: nil
# [START speech_transcribe_sync]
# audio_file_path = "Path to file on which to perform speech recognition"
require "google/cloud/speech"
speech = Google::Cloud::Speech.speech
# [START speech_ruby_migration_sync_response]
audio_file = File.binread audio_file_path
config = { encoding: :LINEAR16,
sample_rate_hertz: 16_000,
language_code: "en-US" }
audio = { content: audio_file }
response = speech.recognize config: config, audio: audio
results = response.results
alternatives = results.first.alternatives
alternatives.each do |alternative|
puts "Transcription: #{alternative.transcript}"
end
# [END speech_ruby_migration_sync_response]
# [END speech_transcribe_sync]
end
if $PROGRAM_NAME == __FILE__
command = ARGV.shift
#I have added this part in order to use a command after to define which method to call within the code.
case command
when "recognize"
speech_sync_recognize audio_file_path: ARGV.first
end
end
And in order to run the sample,
bundle exec ruby speech_samples.rb
Notice the argument recognize which describes which method to execute from the code. In the above case, there is just one. However,using arguments in the call is very useful when there other methods available to call within the code.
Furthermore, I will describe the steps I took in order to execute the code properly. I have followed the steps described here,
I have have ran the code from Cloud Shell. However the speech.googleapis.com does not support end user authentication from Cloud Shell. For this reason, I have given the Service Account Token Creator from IAM Console to my user, so I could impersonate a Service Account and call the API.
Export your project_id to a environment variable such as export GOOGLE_CLOUD_PROJECT="YOUR-PROJECT-ID".
Download the Gemfile file from the documentation and run the command: bundle install
Copy the code speech_samples.rb to your environment.
Copy your file path to the variable audio_file_path and un-comment it. Notice that there will be many audio_file_path local variables, each one for a specific method. In my case, I copied the path only to the variable in the first function, audio_file_path = "home/alex/audio.wav".
Pay attention that each function has a specific configured argument (from line 437 onward). In my case, I wanted to use the recognize one.
Run the sample code with bundle exec ruby speech_samples.rb recognize.
Check your environment for a new directory called results. Then inspect the outputs.
Please, do not forget to copy your file path to all the functions you will be calling with the proper arguments.
UPDATE:
As I mentioned in the comment section, the code I shared above is part of the file speech_samples.rb which contains various examples of functions that calls the Speech-To-Text API. In my case, I just used part of the sample, which I pasted above.
Regarding the link you shared, there is a button to the GitHub source repo for the code, which is the same as the one with the example I used. Notice that your code in GitHub,here, it is wrapped in a function. Also, this function should be called in order to be executed, you can call it by simply writing its name after the function definition. Thus the code should look as follows,
def quickstart
# [START speech_quickstart]
# Imports the Google Cloud client library
# [START speech_ruby_migration_import]
require "google/cloud/speech"
# [END speech_ruby_migration_import]
# Instantiates a client
# [START speech_ruby_migration_client]
speech = Google::Cloud::Speech.speech
# [END speech_ruby_migration_client]
# The name of the audio file to transcribe
file_name = "./resources/brooklyn_bridge.raw"
# [START speech_ruby_migration_sync_request]
# [START speech_ruby_migration_config]
# The raw audio
audio_file = File.binread file_name
# The audio file's encoding and sample rate
config = { encoding: :LINEAR16,
sample_rate_hertz: 16_000,
language_code: "en-US" }
audio = { content: audio_file }
# Detects speech in the audio file
response = speech.recognize config: config, audio: audio
# [END speech_ruby_migration_config]
results = response.results
# [END speech_ruby_migration_sync_request]
# Get first result because we only processed a single audio file
# Each result represents a consecutive portion of the audio
results.first.alternatives.each do |alternatives|
puts "Transcription: #{alternatives.transcript}"
end
# [END speech_quickstart]
end
#call the function defined above
quickstart
NOTE: I must point out that I was also able to execute the code from your question as well, without wrapping in a function. I followed the steps described in the documentation and it successfully retrieved the output.