includes/config/ServiceOptions.php

   1 <?php
   2
   3 namespace MediaWiki\Config;
   4
   5 use Config;
   6 use InvalidArgumentException;
   7 use Wikimedia\Assert\Assert;
   8
   9 /**
  10  * A class for passing options to services. It can be constructed from a Config, and in practice
  11  * most options will be taken from site configuration, but they don't have to be. The options passed
  12  * are copied and will not reflect subsequent updates to site configuration (assuming they're not
  13  * objects).
  14  *
  15  * Services that take this type as a parameter to their constructor should specify a list of the
  16  * keys they expect to receive in an array. The convention is to make it a public static variable
  17  * called $constructorOptions. (When we drop HHVM support -- see T192166 -- it should become a
  18  * const.) In the constructor, they should call assertRequiredOptions() to make sure that they
  19  * weren't passed too few or too many options. This way it's clear what each class depends on, and
  20  * that it's getting passed the correct set of options. (This means there are no optional options.
  21  * This makes sense for services, since they shouldn't be constructed by outside code.)
  22  *
  23  * @since 1.34
  24  */
  25 class ServiceOptions {
  26         private $options = [];
  27
  28         /**
  29          * @param string[] $keys Which keys to extract from $sources
  30          * @param Config|array ...$sources Each source is either a Config object or an array. If the
  31          *  same key is present in two sources, the first one takes precedence. Keys that are not in
  32          *  $keys are ignored.
  33          * @throws InvalidArgumentException if one of $keys is not found in any of $sources
  34          */
  35         public function __construct( array $keys, ...$sources ) {
  36                 foreach ( $keys as $key ) {
  37                         foreach ( $sources as $source ) {
  38                                 if ( $source instanceof Config ) {
  39                                         if ( $source->has( $key ) ) {
  40                                                 $this->options[$key] = $source->get( $key );
  41                                                 continue 2;
  42                                         }
  43                                 } else {
  44                                         if ( array_key_exists( $key, $source ) ) {
  45                                                 $this->options[$key] = $source[$key];
  46                                                 continue 2;
  47                                         }
  48                                 }
  49                         }
  50                         throw new InvalidArgumentException( "Key \"$key\" not found in input sources" );
  51                 }
  52         }
  53
  54         /**
  55          * Assert that the list of options provided in this instance exactly match $expectedKeys,
  56          * without regard for order.
  57          *
  58          * @param string[] $expectedKeys
  59          */
  60         public function assertRequiredOptions( array $expectedKeys ) {
  61                 $actualKeys = array_keys( $this->options );
  62                 $extraKeys = array_diff( $actualKeys, $expectedKeys );
  63                 $missingKeys = array_diff( $expectedKeys, $actualKeys );
  64                 Assert::precondition( !$extraKeys && !$missingKeys,
  65                         (
  66                         $extraKeys
  67                                 ? 'Unsupported options passed: ' . implode( ', ', $extraKeys ) . '!'
  68                                 : ''
  69                         ) . ( $extraKeys && $missingKeys ? ' ' : '' ) . (
  70                         $missingKeys
  71                                 ? 'Required options missing: ' . implode( ', ', $missingKeys ) . '!'
  72                                 : ''
  73                         )
  74                 );
  75         }
  76
  77         /**
  78          * @param string $key
  79          * @return mixed
  80          */
  81         public function get( $key ) {
  82                 if ( !array_key_exists( $key, $this->options ) ) {
  83                         throw new InvalidArgumentException( "Unrecognized option \"$key\"" );
  84                 }
  85                 return $this->options[$key];
  86         }
  87 }