S3 Client send Throws/Rejects on 304

[ambroselittle]

Describe the bug

S3 JS client throws when IfNoneMatch causes a 304 response.

Your environment

SDK version number

@aws-sdk/[email protected]

Is the issue in the browser/Node.js/ReactNative?

Node.js

Details of the browser/Node.js/ReactNative version

Paste output of npx envinfo --browsers or node -v or react-native -v
v14.17.3

Steps to reproduce

Pared down to the essentials. (Will not run as-is, but you can supply the vars, of course.)

import { S3, GetObjectCommand, GetObjectCommandInput } from '@aws-sdk/client-s3'

const s3 = new S3({
    region: region,
});


const commandOptions = { Bucket: bucket, Key: s3FilePath, } as GetObjectCommandInput;
if (etag) {
    commandOptions.IfNoneMatch = etag;
}

const obj = await s3.send(new GetObjectCommand(commandOptions));

Observed behavior

That last line throws:

Error: 
    at deserializeAws_restXmlGetObjectCommandError (/Volumes/Dev/Repos/some-app/node_modules/@aws-sdk/client-s3/protocols/Aws_restXml.ts:7251:39)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
    at /Volumes/Dev/Repos/some-app/node_modules/@aws-sdk/middleware-serde/src/deserializerMiddleware.ts:20:15
    at /Volumes/Dev/Repos/some-app/node_modules/@aws-sdk/middleware-signing/src/middleware.ts:26:22
    at StandardRetryStrategy.retry (/Volumes/Dev/Repos/some-app/node_modules/@aws-sdk/middleware-retry/src/StandardRetryStrategy.ts:83:38)
    at /Volumes/Dev/Repos/some-app/node_modules/@aws-sdk/middleware-logger/src/loggerMiddleware.ts:22:22
    at getObject (/Volumes/Dev/Repos/some-app/src/stuff/helpers/s3/s3CodeClient.ts:128:19)
    at loadFile (/Volumes/Dev/Repos/some-app/src/stuff/helpers/s3/s3CodeClient.ts:156:107)
    at realDownload (/Volumes/Dev/Repos/some-app/src/stuff/helpers/s3/s3CodeClient.spec.ts:193:5)
    at Object.<anonymous> (/Volumes/Dev/Repos/some-app/src/stuff/helpers/s3/s3CodeClient.spec.ts:185:5) {
  '$fault': 'client',
  '$metadata': {
    httpStatusCode: 304,
    requestId: undefined,
    extendedRequestId: '[the-id-was-here]',
    cfId: undefined,
    attempts: 1,
    totalRetryDelay: 0
  }
}

Expected behavior

I do not consider 304 to be an exception. When I supply IfNoneMatch, I am explicitly anticipating that I may receive a 304 and have code to handle it as normal, non-exceptional flow.

I am (currently) catching and checking the metadata on the thrown Error, but I expect to check the status code in the GetObjectCommandOutput metadata (obj.$metadata.httpStatusCode) without an exception in this case.

Additional context

I am partly filing this because it is not at all clear that this is the intended behavior. It is certainly not what I expeected, and despite searching, I cannot find anything about if it is expected on your end. It was not clear what the deserializer in your deserializerMiddleware is expecting after a quick look.

I would suggest documenting here the cases where it will throw. For example, if any non-200 is considered to warrant throwing/rejecting, then mention that. However, as I said, I don't see handling this case to be exceptional. I'd prefer to avoid the overhead of error handling for it.

[thebengeu]

@AllanZhengYP made #1591 throw 3xx response as exceptions here. I understand why other 3xx redirections are thrown as exceptions, but should 304 be thrown as an exception?

[github-actions]

Greetings! We’re closing this issue because it has been open a long time and hasn’t been updated in a while and may not be getting the attention it deserves. We encourage you to check if this is still an issue in the latest release and if you find that this is still a problem, please feel free to comment or open a new issue.

[github-actions]

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