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AppSync pass querystring/variables to authentication lambda for subscription request

1

We are using AppSync with Lambda authentication. I front-end, we are using Amplify package. For each subscription request, we want to authenticate the user by checking if the current user has permission to subscribe to the given channel. Currently, the queryString and variables are not passed to lambda function for a subscription request. How can we handle this?

  • mhanley
    8 months ago

    We're having the same issue with lambda auth. Intermittently (more often it fails than succeeds) the query string and variables for subscriptions are not sent. We still receive the authorizationToken but without the query string and variables we cannot validate the request.

    Queries and mutations are always successful but subscriptions are random. Sometimes they work and sometimes they don't without changing anything.

Topics
ServerlessFront-End Web & MobileApplication Integration
Tags
AWS AppSync
Language
English
Ajay Singh Deopa
asked 10 months ago247 views
2 Answers
0

After some troubleshooting, I'm nearly certain this results from AppSync sending the connection init message to the authorizer. This message doesn't contain the query or the variables. The start subscription message will include them. So if you do not allow the init to go through, neither will the variables or query.

This presents other problems with lambda auth caching in AppSync because the token is already authorized and cached without actually validating the values from the query.

mhanley
answered 8 months ago
-2

You could check the “Lambda Proxy Integration” in API Gateway, ensure your Lambda function has correct permissions.

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EXPERT
Giovanni Lauria
answered 10 months ago
  • Ajay Singh Deopa
    10 months ago

    We are not using API gateway here. AppSync is calling the lambda function to authenticate the request. For mutation and query request, the data is properly going. Only for subscription request, the data is not going.

  • Slavomir Tecl
    8 months ago

    I'm facing the same issue - a request going through a custom authorizer Lambda does not include queryString and variables in the payload.

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