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   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <fabien@symfony.com>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\HttpFoundation;
  13  
  14  /**
  15   * StreamedResponse represents a streamed HTTP response.
  16   *
  17   * A StreamedResponse uses a callback for its content.
  18   *
  19   * The callback should use the standard PHP functions like echo
  20   * to stream the response back to the client. The flush() function
  21   * can also be used if needed.
  22   *
  23   * @see flush()
  24   *
  25   * @author Fabien Potencier <fabien@symfony.com>
  26   */
  27  class StreamedResponse extends Response
  28  {
  29      protected $callback;
  30      protected $streamed;
  31      private $headersSent;
  32  
  33      /**
  34       * @param callable|null $callback A valid PHP callback or null to set it later
  35       * @param int           $status   The response status code
  36       * @param array         $headers  An array of response headers
  37       */
  38      public function __construct(callable $callback = null, $status = 200, $headers = [])
  39      {
  40          parent::__construct(null, $status, $headers);
  41  
  42          if (null !== $callback) {
  43              $this->setCallback($callback);
  44          }
  45          $this->streamed = false;
  46          $this->headersSent = false;
  47      }
  48  
  49      /**
  50       * Factory method for chainability.
  51       *
  52       * @param callable|null $callback A valid PHP callback or null to set it later
  53       * @param int           $status   The response status code
  54       * @param array         $headers  An array of response headers
  55       *
  56       * @return static
  57       */
  58      public static function create($callback = null, $status = 200, $headers = [])
  59      {
  60          return new static($callback, $status, $headers);
  61      }
  62  
  63      /**
  64       * Sets the PHP callback associated with this Response.
  65       *
  66       * @param callable $callback A valid PHP callback
  67       *
  68       * @return $this
  69       */
  70      public function setCallback(callable $callback)
  71      {
  72          $this->callback = $callback;
  73  
  74          return $this;
  75      }
  76  
  77      /**
  78       * {@inheritdoc}
  79       *
  80       * This method only sends the headers once.
  81       *
  82       * @return $this
  83       */
  84      public function sendHeaders()
  85      {
  86          if ($this->headersSent) {
  87              return $this;
  88          }
  89  
  90          $this->headersSent = true;
  91  
  92          return parent::sendHeaders();
  93      }
  94  
  95      /**
  96       * {@inheritdoc}
  97       *
  98       * This method only sends the content once.
  99       *
 100       * @return $this
 101       */
 102      public function sendContent()
 103      {
 104          if ($this->streamed) {
 105              return $this;
 106          }
 107  
 108          $this->streamed = true;
 109  
 110          if (null === $this->callback) {
 111              throw new \LogicException('The Response callback must not be null.');
 112          }
 113  
 114          \call_user_func($this->callback);
 115  
 116          return $this;
 117      }
 118  
 119      /**
 120       * {@inheritdoc}
 121       *
 122       * @throws \LogicException when the content is not null
 123       *
 124       * @return $this
 125       */
 126      public function setContent($content)
 127      {
 128          if (null !== $content) {
 129              throw new \LogicException('The content cannot be set on a StreamedResponse instance.');
 130          }
 131  
 132          $this->streamed = true;
 133  
 134          return $this;
 135      }
 136  
 137      /**
 138       * {@inheritdoc}
 139       */
 140      public function getContent()
 141      {
 142          return false;
 143      }
 144  }