问如何用PHP手动解析原始多部分/表单数据？

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Content-Disposition: form-data; name="user_id"

3
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Content-Disposition: form-data; name="post_id"

5
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Content-Disposition: form-data; name="image"; filename="/tmp/current_file"
Content-Type: application/octet-stream

�����JFIF���������... a bunch of binary data

curl_setopt_array(
  CURLOPT_POSTFIELDS => array(
    'user_id' => 3, 
    'post_id' => 5, 
    'image' => '@/tmp/current_file'),
  CURLOPT_CUSTOMREQUEST => 'PUT'
  );