Binary Support Not Working for Flask Application

[valeriozhang]

Context

I am trying to serve byte responses from my zappa flask app. I enabled binary content types on my API gateway but i am still getting the error
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte
when i run zappa tail

Expected Behavior

I should be able to receive byte responses from my flask API Gateway

Actual Behavior

receiving UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte error

Possible Fix

(https://docs.aws.amazon.com/apigateway/latest/developerguide/lambda-proxy-binary-media.html)

Steps to Reproduce

@app.route('/')
def get_bytes_obj(path, format):
try:
return requests.get("https://www.google.com").content
except Exception as e:
print(e)

Your Environment

• Zappa version used: 0.57.0
• Operating System and Python version:
• The output of pip freeze:
  Flask==2.2.2
  boto3==1.26.43
  requests==2.28.1
  PyJWT==2.6.0
  cryptography==39.0.1
  zappa==0.57.0
• Link to your project (optional):
• Your zappa_settings.json:
  {
  "prod": {
  "app_function": "app.app",
  "aws_region": "us-east-1",
  "profile_name": "default",
  "project_name": "flask-image-ser",
  "runtime": "python3.9",
  "s3_bucket": "flask-image-server-v2",
  "binary_support": true,
  "payload_compression": true
  }
  }

[monkut]

This may be a flask issue. By default I believe that flask attempts to return text/json as the response.

If you want to respond to your request with binary data, you need to prevent flask from attempting to convert the response content to text. I believe send_file can be used to return a binary response.

You can determine if this is a zappa issue by running flask locally and confirming that the error does not occur.

[valeriozhang]

Error does not occur locally, only when deployed to lambdas and api gateway.

[monkut]

Can you provide the traceback with line numbers?

[valeriozhang]

I did this instead and this worked!! just needed to wrap the response object

@app.route('/test.png') def get_test_png(): r = requests.get("https://www.google.com").content return Response( r.content, status=r.status_code, content_type=r.headers['content-type'], )

[monkut]

Closing this as it appears to be resolved by adjusting the response in the flask app.