如何将 JSON 添加到一页的部分

Question

I want to add multiple Schema.org Event JSON objects to the head section of my front page. The start and end dates need to be modified programmatically as time moves forward. The Schema.org module does not meet my needs.

Playing around in html.html.twig, it looks like the output of the Metatag and Schema.org modules are in head-placeholder token="{{ placeholder_token }}". I think I need to append my JSON to that placeholder in template_preprocess_html.

I have only done a small amount of _preprocess modifications, so if that is correct, any hints on how to append to that placeholder? If is it not correct, can someone point me in the right direction?

Answer 1

I did some exploration into how the Metatag module inserted its json and came up with this. I believe it will work.

function hhc_page_attachments_alter(array &$attachments) {

   $path = \Drupal::request()->getRequestUri();

   //If it is not the home page, exit
   if ($path != '/')
     return;

  $attachments['#attached']['html_head'][] = [
    [
      '#type' => 'html_tag',
      '#tag' => 'script',
      '#value' => "JDD PUT JSON CODE HERE",
      '#attributes' => ['type' => 'application/ld+json'],
    ],
    'schema_metatag',
  ];
}

Answer 2

Here is the complete solution I came up with. I realize this would probably be better done with a module making full use of the Drupal framework, but I do not know how to do that, Small site, small company. and just me maintaining it, This works, is live. and validates at validator.schema,org. and passed the test for rich results at search.google.com/test/rich-results.

Perhaps this will help another beginner like myself.|

Problem Statement: Company has 2 events every month that start on the 1st and 15th of each month. Want Schema.org Event JSON for the next 4 upcoming events, output on the home page. The first event must start at least two weeks after "Today".

/*
*  Gets the next start date of a retreat to be used in the Schema.org Event Type
*  Retreats always begin on 1st of 15th of the month.
*  Retreats to display will alway begin at least two weeks in advance, so always the next month.
*  To get the first upcoming retreat (first call of function), if current day is < 15,
*  get 1st of next month.  If 15 or >, get 15th of next month.
*  For the second upcoming retreat,
*/
function nextRetreat(DateTime $now, bool $firstCall) {

  $nextRetreat = new DateTime();

  if ($firstCall) {
    $now->modify('+1 month');
    $day = ($now->format('d') < 15)? 1 : 15;
    $month = $now->format('m');
    $year = $now->format('Y');
    $nextRetreat->setDate($year, $month, $day);
  }
  else {
    //If second call or more, the day of $now should be 1 or 15.  If one, we want the 15th of same month
    //If 15, we want first day of next month.
    if ($now->format('d') < 15) {
      $nextRetreat = $now->modify('+14 days');
    }
    else {
      $nextRetreat = $now->modify('first day of next month');
    }
  }

  return  $nextRetreat;

}


/*
*  Builds the Schema.org Event type with a subset of hard coded values.
*  This is hard coded for a 12 day retreat, and the endDate of the event
*  is 11 days after the start.
*
*  $start:  The start date of the event
*/
function buildEventJSON(DateTime $start) {

  $end = (clone $start)->modify('+11 days');

  $event = [
    "@context" => "https://schema.org",
    "@type" => "Event",
    "name" => "12 Day  Retreat",
    "image" =>"https://example.com/images/some-image.jpg",
    "description" => "Worlds best retreat of type Retreat.  You can't get a better retreat than the ones we are Retreating!",
    "startDate" => $start->format('Y-m-d')."T10:00",
    "endDate" => $end->format('Y-m-d')."T10:00",
    "eventStatus" => "https://schema.org/EventScheduled",
    "eventAttendanceMode" => "https://schema.org/OfflineEventAttendanceMode",
    "location" => [
      "@type" => "Place",
      "name" => "Great Retreat Center",
      "address" => [
          "@type" => "PostalAddress",
          "streetAddress" => "Main Street #226",
          "addressLocality" => "Lima",
          "postalCode" => "00000",
          "addressCountry" => "PE"
        ]
      ],
      "offers" => [
        [
          "@type" => "Offer",
          "name" => "9 Day Retreat",
          "price" => "180",
          "priceCurrency" => "USD",
          "validFrom" => "2022-01-01",
          "url" => "https://example.com/9-day-retreats",
          "availability" => "https://schema.org/InStock"
        ],
        [
          "@type" => "Offer",
          "name" => "12 Day Retreat",
          "price" => "220",
          "priceCurrency" => "USD",
          "validFrom" => "2022-02-01",
          "url" => "https://example.com/12-day-retreats",
          "availability" => "https://schema.org/InStock"
        ]
      ]
    ];

  return  json_encode($event, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT | JSON_UNESCAPED_UNICODE);

}



function hhc_page_attachments_alter(array &$attachments) {

   $path = \Drupal::request()->getRequestUri();

   //If it is not the home page, exit
   if ($path != '/')
     return;

  $nextRetreatStart = nextRetreat(new DateTime(), true);

  $attachments['#attached']['html_head'][] = [
    [
      '#type' => 'html_tag',
      '#tag' => 'script',
      '#value' => buildEventJSON($nextRetreatStart),
      '#attributes' => ['type' => 'application/ld+json'],
    ],
    'my_event_1',
  ];

  // Change the start and end date and second event.
  $nextRetreatStart = nextRetreat($nextRetreatStart, false);
  $attachments['#attached']['html_head'][] = [
    [
      '#type' => 'html_tag',
      '#tag' => 'script',
      '#value' => buildEventJSON($nextRetreatStart),
      '#attributes' => ['type' => 'application/ld+json'],
    ],
    'my_event_2',
  ];

  // Change the start and end date and third event.
  $nextRetreatStart = nextRetreat($nextRetreatStart, false);
  $attachments['#attached']['html_head'][] = [
    [
      '#type' => 'html_tag',
      '#tag' => 'script',
      '#value' => buildEventJSON($nextRetreatStart),
      '#attributes' => ['type' => 'application/ld+json'],
    ],
    'my_event_3',
  ];

  // Change the start and end date and fourth event.
  $nextRetreatStart = nextRetreat($nextRetreatStart, false);
  $attachments['#attached']['html_head'][] = [
    [
      '#type' => 'html_tag',
      '#tag' => 'script',
      '#value' => buildEventJSON($nextRetreatStart),
      '#attributes' => ['type' => 'application/ld+json'],
    ],
    'my_event_4',
  ];

}