How to use Cognito for AppSync mutation call (Python) - python-3.x

Question

I'd like to call mutations from AppSync using my Python function but use a Cognito user for the authorization as "API-KEY", "IAM" and other methods are not suitable for my application.
My mutation looks like this (test purposes):
mutation XYZ {
updateTask(input: {id: "a1b2c3", name: "newTaskName"}) {
id
name
}
}

Answer 1

I am assuming that the user is already created and enabled by some means. If your AppSync API is secured only using Cognito, you are always going to need a username and a password to begin with. For example, you can use below code to login and get the AccessToken from the response:
import boto3
def get_user_auth(event, context):
client = boto3.client('cognito-idp')
response = client.initiate_auth(
UserPoolId='xxxxxxxxx',
ClientId='xxxxxxxxxxxxxx',
AuthFlow='USER_PASSWORD_AUTH',
AuthParameters={
'USERNAME': 'xxxxxx',
'PASSWORD': 'xxxxxx'
}
)
return response
Note: Make sure that you have "Enable username password based authentication (ALLOW_USER_PASSWORD_AUTH)" enabled.
Once you have the access token, you can use this in HTTP headers within your request as follows:
{
"authorization": "<YOUR-VERY-VERY-LONG-ACCESS-TOKEN>"
}
For example:
import requests
from requests_aws4auth import AWS4Auth
import boto3
session = requests.Session()
APPSYNC_API_ENDPOINT_URL = '<YOUR-API-URL>'
mutation = """mutation XYZ {updateTask(input: {id: "a1b2c3", name: "newTaskName"}) {id, name}}"""
response = session.request(
url=APPSYNC_API_ENDPOINT_URL,
method='POST',
headers={'authorization': '<YOUR-VERY-VERY-LONG-ACCESS-TOKEN>'},
json={'mutation': mutation}
)
print(response.json()['data'])
Since this access token has some expiration, you might also need to refresh this token by using the RefreshToken from the above response. Like so:
def refresh_token(self, username, refresh_token):
try:
return client.initiate_auth(
ClientId=self.client_id,
AuthFlow='REFRESH_TOKEN_AUTH',
AuthParameters={
'REFRESH_TOKEN': refresh_token,
# 'SECRET_HASH': self.get_secret_hash(username)
# If the User Pool has been defined with App Client secret,
# you will have to generate secret hash as well.
}
)
except botocore.exceptions.ClientError as e:
return e.response
Example of how you can generate secret hash.