Apollo-server: Apollo-server-Lambda: Why is the event.body being put through JSON.parse?

[gyfchong]

I'm looking at this line specifically:
https://github.com/apollographql/apollo-server/blame/f6cdc94f291a202344453027c6c8735841fc8eb6/packages/apollo-server-lambda/src/lambdaApollo.ts#L46

When I try to test my Lambda locally using this command:
SLS_DEBUG=* serverless invoke local --function graphql --data '{ "httpMethod": "POST", "body": { "query": "{ posts{ id description } }" } }'

I get this error:

SyntaxError: Unexpected token o in JSON at position 1
SyntaxError: Unexpected token o in JSON at position 1
    at JSON.parse (<anonymous>)
    at graphqlHandler (/Users/geoff/.../node_modules/apollo-server-lambda/dist/lambdaApollo.js:28:20)

If I modify that line to accept the event.body without Parsing, it works just fine. This even fails when writing a test in the Lambda management panel. So I thought I'd ask why is this the case? In what case would someone send JSON as a string when it seems like invoking with a body is always done as JSON.

[nh83012001]

@gyfchong I'm getting the same error. How did you get it to accept the body without parsing?

[gyfchong]

@gyfchong I'm getting the same error. How did you get it to accept the body without parsing?

Haven't touched this part of my code lately, but I essentially just modified it in my node_modules for the time being...

[rcliao]

Hi,

I ran into the same error earlier when invoking a GraphQL function locally. I eventually got local invoke to work with:

SLS_DEBUG=* serverless invoke local --function graphql --data '{ "httpMethod": "POST", "body": "{ \"query\": \"{ posts{ id description } }\" }" }'

The key difference is: surrounding the value of body with quotation to make it a valid JSON.

Hope it helps!

[Aposhian]

This is not only an issue for local invocation of the lambda. If the graphql server is given malformed JSON that is, for example, missing a comma, the production endpoint will simply respond with

{
    "errors": [
        {
            "message": "Internal server error"
        }
    ]
}

Which does not easily help the client-side developer find their error.

When I do the same test on serverless-offline I do see the error logged:

SyntaxError: Unexpected string in JSON at position 309               ApiGateway.js:991

and it does show up in on the serverless-offline endpoint as

{
     "errorMessage": "Uncaught error in your 'graphQL' handler",
     "errorType": "SyntaxError"
}

Is there a way to catch that error and indicate that it is a client error in the response?