Serverless-express: Does not support array query string parameters

[drdator]

aws-serverless-express cannot parse array query string parameters

For example ?a=1&a=2 exposes only {a: 1} to express. Normally this would result in {a: [1, 2]}

API Gateway supports array query string parameters using multiValueQueryStringParameters
instead of queryStringParameters.

https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#apigateway-multivalue-headers-and-parameters

[autolistben]

Wow would be really nice to get this merged in!

[xintellion]

I am also waiting for this to get merged.

[alexmantaut]

Is there an ETA on this merge?

[alexmantaut]

@sapessi any chance we can get this merged before the next release?

[sapessi]

Hi @alexmantaut. My next step is to start looking into the v4 branch and publish a major update to the library. I'll get this change in there.

[jvinai]

Any update ?

[alexmantaut]

Just opened a PR to formalise the solution @drdator suggested to the problem...

I tested the changes locally and with lambdas and it works perfectly.

If anyone else wants to test the changes it will also be good.

Thanks @drdator for the fix...

[smirkovic]

Hi @sapessi, any update on this ? You mentioned it will get merged with V4. Is there any ETA ? v4 branch looks like it wasn't updated in 10months.

Is there a chance that https://github.com/awslabs/aws-serverless-express/pull/291 gets merged ?

[pejulian]

Hello, is there some workaround that can be used while waiting for this issue to be fixed?

[pejulian]

After searching around the code a little, I came up with a temporary hack in my code that overrides the queryStringParameters field in the event to use multiValueQueryStringParameters instead.

import produce from 'immer';

// Do setup...

const nextEvent = produce(event, (draftEvent) => {
        // [22-05-2020]:
        // A bug in aws-serverless-express prevents proper
        // handling of multi value query string params.. Therefore, apply this hack to
        // force aws-serverless-express to take multi value query string params...
        // This hack should be removed after this issue is fixed:
        // https://github.com/awslabs/aws-serverless-express/issues/214
        // eslint-disable-next-line @typescript-eslint/no-explicit-any
        draftEvent.queryStringParameters = event.multiValueQueryStringParameters as any;
    });

// Return the new instance
return proxy(cachedServer, nextEvent, context, 'PROMISE').promise;

Perhaps this may help someone until the proper fix is published.

[alexmantaut]

Hi @pejulian,

For my project what I ended up doing is patching the library manually inside the node_modules dir, and converting that into a patch by using patch-package.

What patch-package does is, it creates a patch that gets applied after yarn install.

I know this is not an ideal solution, but this bug was wasting too much of my time on workarounds...

[github-actions[bot]]

:tada: This issue has been resolved in version 4.1.1 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: