How to upload photos via VK API correctly?

Question

PHP

Hello!
I have been struggling with the VK API for the second day now and I want to make it possible to upload images to the VK servers, and then attach this image to the post. I know how to attach an image, but I had problems uploading an image. Everything is written in the documentation in such a way that it is difficult for a beginner like me to understand. Below I will give a small piece of code with comments, which is responsible for loading the image:

// получаю ссылку, куда загружать изображение
  $upl_url = vk_api("photos.getWallUploadServer", "group_id=".$community);
  
  // отправляю изображение по ссылке
  if (isset($upl_url["response"]["upload_url"])) {
    $photo['photo'] = '@'.'/home/a7223299/public_html/images_b/'.$picture;
    $curl = curl_init($upl_url["response"]["upload_url"]);
    curl_setopt($curl, CURLOPT_POST, 1);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($curl, CURLOPT_POSTFIELDS, $photo);
    // получаю ответ
    $s = curl_exec($curl);
    curl_close($curl);
  }
  else {
    echo 'Server is not responding.';
  }
  
  // проверка #1
  print_r($s);
  echo '<br>';
  echo '<br>';
  
  // преобразую ответ в массив
  $data_ph = json_decode($s, true);
  
  // проверка #2
  print_r($data_ph);
  echo '<br>';
  echo '<br>';
  
  // сохраняю фотографию
  $photo_id = vk_api("photos.saveWallPhoto", "&server=".$data_ph['server']."&hash=".$data_ph['hash']."photo=".$data_ph['photo']);
  
  // проверка #3
  print_r($photo_id);

This is how the vk_api() function looks like:

function vk_api($method, $params) {
    $json = file_get_contents("https://api.vk.com/method/".$method."?".$params."&access_token=".$access_tocken."&v=".$version);
    return json_decode($json, true);
  }

I apologize in advance for such a terrible text format. I'm scared myself too. Here is what the first print_r() function returns:

{"server":623229,"photo":"[{\"photo\":\"73f87c2dc5:z\",\"sizes\":,\"kid\":\"8bee91a57a9a42f79f87a04a46708486\"}]","hash":"929481842a51b72f8fdb44a229e829b6"}

Second:

Array ( [server] => 623229 [photo] => [{"photo":"73f87c2dc5:z","sizes":,"kid":"8bee91a57a9a42f79f87a04a46708486"}] [hash] => 929481842a51b72f8fdb44a229e829b6 )

Third:

Array ( [error] => Array ( [error_code] => 100 [error_msg] => One of the parameters specified was missing or invalid: photo is undefined [request_params] => Array ( [0] => Array ( [key] => oauth [value] => 1 ) [1] => Array ( [key] => method [value] => photos.saveWallPhoto ) [2] => Array ( [key] => [value] => ) [3] => Array ( [key] => server [value] => 623229 ) [4] => Array ( [key] => hash [value] => 929481842a51b72f8fdb44a229e829b6photo=[{"photo":"73f87c2dc5:z","sizes":,"kid":"8bee91a57a9a42f79f87a04a46708486"}] ) [5] => Array ( [key] => v [value] => 5.29 ) ) ) )

Please tell me where I screwed up and what to do with this terrible code. Thank you.

Answer 1

On the error page, [error_code] => 100
means that one of the required parameters was not passed or is incorrect.
Check the list of required parameters and their format on the method page