`webhooks.verifyAndParse` and standalone `verifyAndParse` method

[gr2m]

What’s missing?

There is currently no simple way to parse and verify an incoming http request object at the same time. It's only possible as part of the event API of a webhooks instance, which might be overkill / not the best fit for a serverless/function environment

This would permit for code such as this:

export async function handler(event) {
  try {    
    const githubEvent = await verifyAndParse(secret, event)
    // handle valid event
    return { body: text, statusCode: 200 };
  } catch (error) {
    // handle errors
    return { body: 'oh noes!', statusCode: 500 }
  }
}

Why?

This is a follow up to #372 (comment), see the discussion for more reasoning.

In a nutshell, @G-Rath's use case is to separate receiving and verifying the event request from running any event handlers to avoid AWS Lambda timeouts.

Alternatives you tried

export async function handler(event) {
  const webhooks = new Webhooks(options)

  webhooks.on(['check_run', 'code_scanning_alert', 'commit_comment'], async (event) => {
    // handle valid events
  })

  try {
    await webhooks.verifyAndReceive(awsEventToOctokitEvent(event))
    return { statusCode: 200 };
  } catch (error) {
    // handle error
    return { body: 'oh noes!', statusCode: 500 }
  }
}