Bug: 'isBase64Encoded: true' not working in local sam. about aws-sam-cli

[dyingsunlight]

Thanks, it's looks working now!

[hnnasit]

Hi @dyingsunlight, thanks for reporting the issue. I tried to deploy the app and browse the URL but could not see the image. As for the isBase64Encoded: False in the debug logs, it seems this is for the input event sent to the lambda function. I think what you are looking for is the response to return True for isBase64Encoded and looking at this code, the boolean value is a string. Can you check if setting it to a string works?

[dyingsunlight]

It's not working... I tried setting isBase64Encoded to 'true' and 'True', but the debug message still outputs: 'isBase64Encoded': False.

The debug logs:

Constructed Event 1.0 to invoke Lambda. Event: {'version': '1.0', 'httpMethod': 'GET', 'body': None, 'resource': '/hello-world', 'requestContext': {'resourceId': '123456', 'apiId': '1234567890',        
'resourcePath': '/hello-world', 'httpMethod': 'GET', 'requestId': '35b543fb-3f9b-4ba4-80a0-c1983c882814', 'accountId': '123456789012', 'stage': 'Prod', 'identity': {'apiKey': None, 'userArn': None, 'cognitoAuthenticationType':  
None, 'caller': None, 'userAgent': 'Custom User Agent String', 'user': None, 'cognitoIdentityPoolId': None, 'cognitoAuthenticationProvider': None, 'sourceIp': '127.0.0.1', 'accountId': None}, 'extendedRequestId': None, 'path':  
'/hello-world', 'protocol': 'HTTP/1.1', 'domainName': '127.0.0.1:8090', 'requestTimeEpoch': 1702792298, 'requestTime': '17/Dec/2023:05:51:38 +0000'}, 'queryStringParameters': None, 'multiValueQueryStringParameters': None,       
'headers': {'Host': '127.0.0.1:8090', 'Connection': 'keep-alive', 'Cache-Control': 'max-age=0', 'Sec-Ch-Ua': '"Not_A Brand";v="8", "Chromium";v="120", "Google Chrome";v="120"', 'Sec-Ch-Ua-Mobile': '?0', 'Sec-Ch-Ua-Platform':    
'"Windows"', 'Upgrade-Insecure-Requests': '1', 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36', 'Accept':
'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7', 'Sec-Fetch-Site': 'none', 'Sec-Fetch-Mode': 'navigate', 'Sec-Fetch-User': '?1',
'Sec-Fetch-Dest': 'document', 'Accept-Encoding': 'gzip, deflate, br', 'Accept-Language': 'zh-CN,zh;q=0.9,zh-TW;q=0.8,en;q=0.7,ja;q=0.6,ru;q=0.5', 'X-Forwarded-Proto': 'http', 'X-Forwarded-Port': '8090'}, 'multiValueHeaders':    
{'Host': ['127.0.0.1:8090'], 'Connection': ['keep-alive'], 'Cache-Control': ['max-age=0'], 'Sec-Ch-Ua': ['"Not_A Brand";v="8", "Chromium";v="120", "Google Chrome";v="120"'], 'Sec-Ch-Ua-Mobile': ['?0'], 'Sec-Ch-Ua-Platform':     
['"Windows"'], 'Upgrade-Insecure-Requests': ['1'], 'User-Agent': ['Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'], 'Accept':
['text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7'], 'Sec-Fetch-Site': ['none'], 'Sec-Fetch-Mode': ['navigate'], 'Sec-Fetch-User': ['?1'],  
'Sec-Fetch-Dest': ['document'], 'Accept-Encoding': ['gzip, deflate, br'], 'Accept-Language': ['zh-CN,zh;q=0.9,zh-TW;q=0.8,en;q=0.7,ja;q=0.6,ru;q=0.5'], 'X-Forwarded-Proto': ['http'], 'X-Forwarded-Port': ['8090']},
'pathParameters': None, 'stageVariables': None, 'path': '/hello-world', 'isBase64Encoded': False}

I believe the issue is that, according to the documentation, the 'isBase64Encoded' value should be a boolean type, not a string type.

https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.html#http-api-develop-integrations-lambda.response

[hnnasit]

Marking this as a bug for the team to investigate the right behavior here.

[sidhujus]

Hi, It looks like because in the template provided the api definition does not have anything declared for the BinaryMediaTypes property SAM CLI does not try to decode the image. Changing the template to the following fixed the issue for me

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Transform": "AWS::Serverless-2016-10-31",
  "Description": "",
  "Resources": {
    "HelloWorld": {
      "Type": "AWS::Serverless::Function",
      "Properties": {
        "CodeUri": "./lambda",
        "Handler": "hello-word.handler",
        "Runtime": "nodejs18.x",
        "Events": {
          "HelloWorldEvent0": {
            "Type": "Api",
            "Properties": {
              "Path": "/hello-world",
              "Method": "get",
              "RestApiId": {
                "Ref": "HelloWorldApi"
              }
            }
          }
        },
        "Timeout": 60,
        "MemorySize": 1024
      }
    },
    "HelloWorldApi": {
    "Type": "AWS::Serverless::Api",
    "Properties": {
      "StageName": "prod",
      "BinaryMediaTypes": ["image/png"]
    }
  }
  }
}

Alternatively changing the event type to HttpApi will also cause the image to be decoded. It looks like the behaviour for decoding base64 images is defined here

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