route53: " not escaped correctly

[dbartholomae]

Describe the bug

Hi there!

    new TxtRecord(this, "TxtRecord", {
      recordName: "xxx.example.com",
      values: [
        'a""b',
      ],
      zone,
    });

Expected Behavior

This should generate a text record with a""b

Current Behavior

It creates a\"\"b instead.

Reproduction Steps

See example

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.72.1

Framework Version

No response

Node.js Version

16.14.2

OS

Mac

Language

Typescript

Language Version

No response

Other information

No response

[stefanfreitag]

Hi @dbartholomae ,

I have seen this behavior also when creating a TXT record in the AWS Management Console itself.
The double quotes are escaped in the way you described: a""b -> a\"\"b,

The latter seems to be in line with the Route53 documentation available here. There is an information about using double quotes:

To include a quotation mark (") in a string, put a backslash (\) character before the quotation mark: \".

An example is also provided

"This string includes \"quotation marks\"."

Hope this helps a bit.

[peterwoodworth]

We seem to do this intentionally

aws-cdk/packages/@aws-cdk/aws-route53/lib/record-set.ts

Lines 336 to 364 in 9752ed2

	export class TxtRecord extends RecordSet {
	constructor(scope: Construct, id: string, props: TxtRecordProps) {
	super(scope, id, {
	...props,
	recordType: RecordType.TXT,
	target: RecordTarget.fromValues(...props.values.map(v => formatTxt(v))),
	});
	}
	}
	/**
	* Formats a text value for use in a TXT record
	*
	* Use `JSON.stringify` to correctly escape and enclose in double quotes ("").
	*
	* DNS TXT records can contain up to 255 characters in a single string. TXT
	* record strings over 255 characters must be split into multiple text strings
	* within the same record.
	*
	* @see https://aws.amazon.com/premiumsupport/knowledge-center/route53-resolve-dkim-text-record-error/
	*/
	function formatTxt(string: string): string {
	const result = [];
	let idx = 0;
	while (idx < string.length) {
	result.push(string.slice(idx, idx += 255)); // chunks of 255 characters long
	}
	return result.map(r => JSON.stringify(r)).join('');
	}

Thanks for the additional context @stefanfreitag. @dbartholomae is there a specific value you're trying to provide that doesn't want to have the backslash?

[dbartholomae]

Thanks! I'm currently transferring an existing Hosted Zone to CDK and compare the records with help of aws route53 list-resource-record-sets. The specific record that I can't seem to match exactly is a verification record from an external provider and I will reach out to them to understand whether the quote is intentional, but given that the current version works, I'm hesitant to just change it to a version with backslash.
Do you know if there is a workaround to manually set the value to include the quotation mark?

[dbartholomae]

Thanks! The difference came because the record was larger than maximum length and CDK split it at a different point than the previous setup. Since this doesn't have an effect on the actual record, the current behavior should be fine except for very weird special cases.

[github-actions]

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