How do I setup an endpoint for amp-consent?

I have no idea what code I need to place in the document referenced by the URL for checkConsentHref.

I've used the example code from https://amp.dev/documentation/examples/user-consent/basic_user_consent_flow/?format=websites.

I know the checkConsentHref should be my own url, but what document needs to go in that location and what code should go in it?

<amp-consent layout="nodisplay" id="consent-element">
<script type="application/json">
{
  "consents": {
    "my-consent": {
      "checkConsentHref": "https://example.com/api/show-consent",
      "promptUI": "consent-ui"
    }
  }
}
</script>
</amp-consent>

I expect there to be some function at checkConsentHref location to take some kind of action.

Solution

I found a good explanation here: About consent

A CORS endpoint can be specified via the checkConsentHref attribute. The amp-consent component will check via a POST request if the consent UI needs to be shown. The response to this request should look like this:

{
  "promptIfUnknown": true
}

#or

{
  "promptIfUnknown": false
}

So you can add there e.g https://ampbyexample.com/samples_templates/consent/getConsent First time I saw this url, I thought that it is only exapmle, but it works. This url store information about showing the consent. You can check it in your JS console.

https://ampbyexample.com/samples_templates/consent/getConsent will returns "promptIfUnknown": true or "promptIfUnknown": false based on previous user action

I do not know If it is a good practice to use this "example" url instead own.