Unity WebGL Polly SynthesizeSpeechAsync does not work.

[srcnalt]

Describe the bug

SynthesizeSpeechAsync method does not work in Unity WebGL builds. And returns a console error about stream being null.

Expected Behavior

Getting a successful response.

Current Behavior

WebGL.framework.js.gz:3 ArgumentNullException: Value cannot be null.
Parameter name: stream
  at System.IO.StreamReader..ctor (System.IO.Stream stream, System.Text.Encoding encoding, System.Boolean detectEncodingFromByteOrderMarks, System.Int32 bufferSize, System.Boolean leaveOpen) [0x00000] in <00000000000000000000000000000000>:0 
  at System.IO.StreamReader..ctor (System.IO.Stream stream, System.Boolean detectEncodingFromByteOrderMarks) [0x00000] in <00000000000000000000000000000000>:0 
  at System.IO.StreamReader..ctor (System.IO.Stream stream) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Internal.RegionEndpointProviderV3..ctor () [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.RegionEndpoint.get_RegionEndpointProvider () [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.RegionEndpoint.get_InternedRegionEndpoint () [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.RegionEndpoint.GetEndpointForService (System.String serviceName, Amazon.Internal.GetEndpointForServiceOptions options) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Auth.AWS4Signer.DetermineSigningRegion (Amazon.Runtime.IClientConfig clientConfig, System.String serviceName, Amazon.RegionEndpoint alternateEndpoint, Amazon.Runtime.Internal.IRequest request) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Auth.AWS4Signer.SignRequest (Amazon.Runtime.Internal.IRequest request, Amazon.Runtime.IClientConfig clientConfig, Amazon.Runtime.Internal.Util.RequestMetrics metrics, System.String awsAccessKeyId, System.String awsSecretAccessKey) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Auth.AWS4Signer.Sign (Amazon.Runtime.Internal.IRequest request, Amazon.Runtime.IClientConfig clientConfig, Amazon.Runtime.Internal.Util.RequestMetrics metrics, System.String awsAccessKeyId, System.String awsSecretAccessKey) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Auth.AWS4Signer.Sign (Amazon.Runtime.Internal.IRequest request, Amazon.Runtime.IClientConfig clientConfig, Amazon.Runtime.Internal.Util.RequestMetrics metrics, Amazon.Runtime.ImmutableCredentials credentials) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Auth.AbstractAWSSigner.SignAsync (Amazon.Runtime.Internal.IRequest request, Amazon.Runtime.IClientConfig clientConfig, Amazon.Runtime.Internal.Util.RequestMetrics metrics, Amazon.Runtime.ImmutableCredentials credentials, System.Threading.CancellationToken token) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Signer.SignRequestAsync (Amazon.Runtime.IRequestContext requestContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Signer.SignRequestAsync (Amazon.Runtime.IRequestContext requestContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Signer.PreInvokeAsync (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Signer.PreInvokeAsync (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Signer.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Signer.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.EndpointDiscoveryHandler.<>n__0[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.EndpointDiscoveryHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.EndpointDiscoveryHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CredentialsRetriever.<>n__0[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CredentialsRetriever.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CredentialsRetriever.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.RetryHandler.<>n__0[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.RetryHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.RetryHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CallbackHandler.<>n__0[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CallbackHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[TResult].Start[TStateMachine] (TStateMachine& stateMachine) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CallbackHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.BaseEndpointResolver.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.Marshaller.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.PipelineHandler.InvokeAsync[T] (Amazon.Runtime.IExecutionContext executionContext) [0x00000] in <00000000000000000000000000000000>:0 
  at Amazon.Runtime.Internal.CallbackHand

Reproduction Steps

Running the following code in Unity Editor and I can get back the audio result. However, the WebGL build will fail due to stream being null when the request is awaited.

var credentials = new BasicAWSCredentials(akey, skey);
var client = new AmazonPollyClient(credentials: credentials, region: RegionEndpoint.EUCentral1);
var request = new SynthesizeSpeechRequest()
{
    OutputFormat = OutputFormat.Mp3,
    VoiceId = VoiceId.Arthur,
    Text = "Testing Polly."
};

var response = await client.SynthesizeSpeechAsync(request);

Possible Solution

No response

Additional Information/Context

No response

AWS .NET SDK and/or Package version used

Unity 2021.3.5f1
AWSSDK.Core.3.7.105.10
AWSSDK.Polly.3.7.106.31

Targeted .NET Platform

.NET Standard 2.1

Operating System and version

Windows 11

[ashishdhingra]

@srcnalt Thanks for reporting the issue. Please advise if you followed the recommendation at Special considerations for Unity support to reference the AWS SDK for .NET assemblies (DLL files) directly rather than using NuGet.

Thanks,
Ashish

[srcnalt]

Hi @ashishdhingra, yes followed the exact page while implementing. I included MS and System DLLs along with Core and Polly.

[ashishdhingra]

Needs investigation.

[srcnalt]

Thank you for taking care of it @ashishdhingra, If that would help further I can create an example Unity project where the issue is reproducible.

[var1ap-WA]

Hello @ashishdhingra I think I have the same issue. I did screenshot on your example code [repo](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/dotnetv3/Polly)

[dadoktor8nft]

is there a possible workaround to achieve the desired solution for this problem? Perhaps a band-aid solution?