Added UI validation when creating a Webhook connector with invalid URL

[YulNaumenko]

Resolve #68662

Resolved by adding placeholder info for Webhook URL and proper URL client side validation on input:

[gmmorris]

This is a good approach to validating the Front End input, but I don't think this fully addresses the issue.

The main problem, as I can see, is that the input is throwing an error as if it isn't whitelisted - which isn't accurate, because the whitelist is * by default (allow all).
Looking at the code in isWhitelistedHostnameInUri I noticed that the reason we think it isn't whitelisted is that parsing example.com/do-something as a URI fails on line 68:

kibana/x-pack/plugins/actions/server/actions_config.ts

Lines 66 to 73 in 40ff82d

	function isWhitelistedHostnameInUri(config: ActionsConfigType, uri: string): boolean {
	return pipe(
	tryCatch(() => new URL(uri)),
	map((url) => url.hostname),
	mapNullable((hostname) => isWhitelisted(config, hostname)),
	getOrElse<boolean>(() => false)
	);
	}

What I think this PR should also do (in addition to what's already done) is validate the URL in the schema on the server side before checking the whitelist.

kibana/x-pack/plugins/actions/server/builtin_action_types/webhook.ts

Lines 73 to 79 in 40ff82d

	validate: {
	config: schema.object(configSchemaProps, {
	validate: curry(validateActionTypeConfig)(configurationUtilities),
	}),
	secrets: SecretsSchema,
	params: ParamsSchema,
	},

This will achieve two things:

1. Creating a webhook via the http API will result in the same errors that the UI shows (the current PR will not catch this error on the server)
2. It will correct the whitelist validation so that it will pass for example.com/do-something as it should have done if the format were correct.

[pmuellr]

Noted that I think we should use the built-in URL parser to check for validity, rather than a regexp.

[YulNaumenko]

isWhitelistedHostnameInUri

Added server API validation for URL.

[pmuellr]

LGTM, but made note about the server-side error message being generated.

[gmmorris]

LGTM, thanks for making the changes 👍

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 5143df6

Build metrics

@kbn/optimizer bundle module count

id	value	diff	baseline
triggers_actions_ui	147	+1	146

History

• 💔 Build #59182 failed f412fe8
• 💔 Build #59170 failed d99cf6b
• 💔 Build #57945 failed c54ce78
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• 💔 Build #57590 failed e725ed9

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