Serverless function with authorizer arn provided returns 401 - serverless-framework

Question

I am using serverless.
When I setup one of my functions as the following, which includes authorizer, on the client, I receive 401.
However when I remove it, there are no problems.
provider:
name: aws
runtime: nodejs8.10
region: eu-west-1
environment:
USER_POOL_ARN: "arn:aws:cognito-idp:eu-west-1:974280.....:userpool/eu-west-1........"
functions:
create:
handler: handlers/create.main
events:
- http:
path: create
method: post
cors: true
authorizer:
type: COGNITO_USER_POOLS
name: serviceBAuthFunc
arn: ${self:provider.environment.USER_POOL_ARN}
On the client, I expect a logged in user of the same user pool could get expected response. However it returns 401.
Any help is appreciated. Thanks.

Answer 1

After desperate hours spent, I have come up with the solution.
For anyone who comes across the same issue, here is a solution that worked for me.
Add integration: lambda after cors: true (though the order doesn't matter).
Below is just demonstrating that.
functions:
create:
handler: handlers/create.main
events:
- http:
path: create
method: post
cors: true
integration: lambda // this solves the problem
authorizer:
type: COGNITO_USER_POOLS
name: serviceBAuthFunc
arn: ${self:provider.environment.USER_POOL_ARN}
Send Authorization header with the value of Auth.currentSession().idToken.jwtToken while making the request.
Below is an example for sending headers using API of #aws-amplify/api and Auth of #aws-amplify/auth.
const currentSession = await Auth.currentSession()
await API.post(
'your-endpoint-name',
"/your-endpoint-path/..",
{
headers: {
'Authorization': currentSession.idToken.jwtToken
}
}
)