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   1  <?php
   2  
   3  /**
   4  * @package   s9e\TextFormatter
   5  * @copyright Copyright (c) 2010-2022 The s9e authors
   6  * @license   http://www.opensource.org/licenses/mit-license.php The MIT License
   7  */
   8  namespace s9e\TextFormatter\Configurator\JavaScript\Minifiers;
   9  
  10  use RuntimeException;
  11  use s9e\TextFormatter\Configurator\JavaScript\OnlineMinifier;
  12  
  13  class ClosureCompilerService extends OnlineMinifier
  14  {
  15      /**
  16      * @var string Closure Compiler's compilation level
  17      */
  18      public $compilationLevel = 'ADVANCED_OPTIMIZATIONS';
  19  
  20      /**
  21      * @var bool Whether to exclude Closure Compiler's default externs
  22      */
  23      public $excludeDefaultExterns = true;
  24  
  25      /**
  26      * @var string Externs used for compilation
  27      */
  28      public $externs;
  29  
  30      /**
  31      * @var string Closure Compiler Service's URL
  32      */
  33      public $url = 'https://closure-compiler.appspot.com/compile';
  34  
  35      /**
  36      * Constructor
  37      */
  38  	public function __construct()
  39      {
  40          parent::__construct();
  41          $this->externs = file_get_contents(__DIR__ . '/../externs.service.js');
  42      }
  43  
  44      /**
  45      * {@inheritdoc}
  46      */
  47  	public function getCacheDifferentiator()
  48      {
  49          $key = [$this->compilationLevel, $this->excludeDefaultExterns];
  50  
  51          if ($this->excludeDefaultExterns)
  52          {
  53              $key[] = $this->externs;
  54          }
  55  
  56          return $key;
  57      }
  58  
  59      /**
  60      * Compile given JavaScript source via the Closure Compiler Service
  61      *
  62      * @param  string $src JavaScript source
  63      * @return string      Compiled source
  64      */
  65  	public function minify($src)
  66      {
  67          $body     = $this->generateRequestBody($src);
  68          $response = $this->query($body);
  69          if ($response === false)
  70          {
  71              throw new RuntimeException('Could not contact the Closure Compiler service');
  72          }
  73  
  74          return $this->decodeResponse($response);
  75      }
  76  
  77      /**
  78      * Decode the response returned by the Closure Compiler service
  79      *
  80      * @param  string $response Response body
  81      * @return string           Minified code
  82      */
  83  	protected function decodeResponse($response)
  84      {
  85          $response = json_decode($response, true);
  86          if (is_null($response))
  87          {
  88              throw new RuntimeException('Closure Compiler service returned invalid JSON: ' . json_last_error_msg());
  89          }
  90  
  91          if (isset($response['serverErrors'][0]))
  92          {
  93              $error = $response['serverErrors'][0];
  94  
  95              throw new RuntimeException('Server error ' . $error['code'] . ': ' . $error['error']);
  96          }
  97  
  98          if (isset($response['errors'][0]))
  99          {
 100              $error = $response['errors'][0];
 101  
 102              throw new RuntimeException('Compilation error: ' . $error['error']);
 103          }
 104  
 105          return $response['compiledCode'];
 106      }
 107  
 108      /**
 109      * Generate the request body for given code
 110      *
 111      * @param  string $src JavaScript source
 112      * @return string      Compiled source
 113      */
 114  	protected function generateRequestBody($src)
 115      {
 116          $params = [
 117              'compilation_level' => $this->compilationLevel,
 118              'js_code'           => $src,
 119              'output_format'     => 'json',
 120              'output_info'       => 'compiled_code'
 121          ];
 122  
 123          // Add our custom externs if default externs are disabled
 124          if ($this->excludeDefaultExterns && $this->compilationLevel === 'ADVANCED_OPTIMIZATIONS')
 125          {
 126              $params['exclude_default_externs'] = 'true';
 127              $params['js_externs'] = $this->externs;
 128          }
 129  
 130          // Add dupe variables by hand
 131          $body = http_build_query($params) . '&output_info=errors';
 132  
 133          return $body;
 134      }
 135  
 136      /**
 137      * Query the Closure Compiler service
 138      *
 139      * @param  string       $body Request body
 140      * @return string|false       Response body, or FALSE
 141      */
 142  	protected function query($body)
 143      {
 144          return $this->httpClient->post(
 145              $this->url,
 146              ['headers' => ['Content-Type: application/x-www-form-urlencoded']],
 147              $body
 148          );
 149      }
 150  }