How to add Message Attributes to SNS Publish from API Gateway Integration Request

Question

I can find formats for this using the CLI

aws sns publish --topic-arn arn:aws:sns:us-west-2:111111111111:test
    --message "Testing the CLI" 
    --subject "From the CLI" --message-attributes "{\"somename\":
        {\"DataType\":\"String\",\"StringValue\":\"somevalue\"}}"

But what I can't find (or figure out) is how to do this from the Integration Request on an API Gateway.

I believe it needs to be done as Query Parameters of the Integration Request, but the syntax is not the same as adding Message Attributes for SQS. I tested that by using a parameter naming notation along the lines of this example:

MessageBody=This+is+a+test+message
MessageAttribute.1.Name=test_attribute_name_1
MessageAttribute.1.Value.StringValue=test_attribute_value_1
MessageAttribute.1.Value.DataType=String

I also tried:

MessageAttributes   '{"store":{"DataType":"String","StringValue":"example_corp"}}'

So far can't get it working, any help is much appreciated.

Answer 1

After thorough research into the AWS docs, I found that there is no accurate documentation of setting up SNS Publish MessageAttributes in an API Gateway Resource Method as URL Query String Parameters.

Based on the partial syntax example they give here: https://docs.aws.amazon.com/sns/latest/api/API_Publish.html, I was then able to throw things at it until something stuck.

This is the proper dot notation syntax and parameters you need to use:

MessageAttributes.entry.1.Name = "Attribute1"
MessageAttributes.entry.1.Value.DataType = 'String'
MessageAttributes.entry.1.Value.StringValue = 'Test'

Where "Name" and "DataType" are required.

Cheers!