get('ClassName') * * and a new instance of ClassName will be created and returned to you. * * Classes can have specific configuration defined for them to * indicate dependencies that should be injected. This takes the form of * a static variable $dependencies defined in the class (or configuration), * which indicates the name of a property that should be set. * * eg * * * class MyController extends Controller { * * public $permissions; * public $defaultText; * * static $dependencies = array( * 'defaultText' => 'Override in configuration', * 'permissions' => '%$PermissionService', * ); * } * * * will result in an object of type MyController having the defaultText property * set to 'Override in configuration', and an object identified * as PermissionService set into the property called 'permissions'. The %$ * syntax tells the injector to look the provided name up as an item to be created * by the Injector itself. * * A key concept of the injector is whether to manage the object as * * * A pseudo-singleton, in that only one item will be created for a particular * identifier (but the same class could be used for multiple identifiers) * * A prototype, where the same configuration is used, but a new object is * created each time * * unmanaged, in which case a new object is created and injected, but no * information about its state is managed. * * Additional configuration of items managed by the injector can be done by * providing configuration for the types, either by manually loading in an * array describing the configuration, or by specifying the configuration * for a type via SilverStripe's configuration mechanism. * * Specify a configuration array of the format * * array( * array( * 'id' => 'BeanId', // the name to be used if diff from the filename * 'priority' => 1, // priority. If another bean is defined with the same ID, * // but has a lower priority, it is NOT overridden * 'class' => 'ClassName', // the name of the PHP class * 'src' => '/path/to/file' // the location of the class * 'type' => 'singleton|prototype' // if you want prototype object generation, set it as the * // type * // By default, singleton is assumed * * 'construct' => array( // properties to set at construction * 'scalar', * '%$BeanId', * ) * 'properties' => array( * 'name' => 'value' // scalar value * 'name' => '%$BeanId', // a reference to another bean * 'name' => array( * 'scalar', * '%$BeanId' * ) * ) * ) * // alternatively * 'MyBean' => array( * 'class' => 'ClassName', * ) * // or simply * 'OtherBean' => 'SomeClass', * ) * * In addition to specifying the bindings directly in the configuration, * you can simply create a publicly accessible property on the target * class which will automatically be injected if the autoScanProperties * option is set to true. This means a class defined as * * * class MyController extends Controller { * * private $permissionService; * * public setPermissionService($p) { * $this->permissionService = $p; * } * } * * * will have setPermissionService called if * * * Injector::inst()->setAutoScanProperties(true) is called and * * A service named 'PermissionService' has been configured * * @author marcus@silverstripe.com.au * @package framework * @subpackage injector * @license BSD License http://silverstripe.org/bsd-license/ */ class Injector { /** * Local store of all services * * @var array */ private $serviceCache; /** * Cache of items that need to be mapped for each service that gets injected * * @var array */ private $injectMap; /** * A store of all the service configurations that have been defined. * * @var array */ private $specs; /** * A map of all the properties that should be automagically set on all * objects instantiated by the injector */ private $autoProperties; /** * A singleton if you want to use it that way * * @var Injector */ private static $instance; /** * Indicates whether or not to automatically scan properties in injected objects to auto inject * stuff, similar to the way grails does things. * * @var boolean */ private $autoScanProperties = false; /** * The object used to create new class instances * * Use a custom class here to change the way classes are created to use * a custom creation method. By default the InjectionCreator class is used, * which simply creates a new class via 'new', however this could be overridden * to use, for example, SilverStripe's Object::create() method. * * @var InjectionCreator */ protected $objectCreator; /** * Create a new injector. * * @param array $config * Service configuration */ public function __construct($config = null) { $this->injectMap = array(); $this->serviceCache = array( 'Injector' => $this, ); $this->specs = array( 'Injector' => array('class' => 'Injector') ); $this->autoProperties = array(); $creatorClass = isset($config['creator']) ? $config['creator'] : 'InjectionCreator'; $locatorClass = isset($config['locator']) ? $config['locator'] : 'ServiceConfigurationLocator'; $this->objectCreator = new $creatorClass; $this->configLocator = new $locatorClass; if ($config) { $this->load($config); } self::$instance = $this; } /** * If a user wants to use the injector as a static reference * * @param array $config * @return Injector */ public static function inst($config=null) { if (!self::$instance) { self::$instance = new Injector($config); } return self::$instance; } /** * Indicate whether we auto scan injected objects for properties to set. * * @param boolean $val */ public function setAutoScanProperties($val) { $this->autoScanProperties = $val; } /** * Sets the object to use for creating new objects * * @param InjectionCreator $obj */ public function setObjectCreator($obj) { $this->objectCreator = $obj; } /** * Accessor (for testing purposes) * @return InjectionCreator */ public function getObjectCreator() { return $this->objectCreator; } /** * Set the configuration locator * @param ServiceConfigurationLocator $configLocator */ public function setConfigLocator($configLocator) { $this->configLocator = $configLocator; } /** * Retrieve the configuration locator * @return ServiceConfigurationLocator */ public function getConfigLocator() { return $this->configLocator; } /** * Add in a specific mapping that should be catered for on a type. * This allows configuration of what should occur when an object * of a particular type is injected, and what items should be injected * for those properties / methods. * * @param type $class * The class to set a mapping for * @param type $property * The property to set the mapping for * @param type $injectType * The registered type that will be injected * @param string $injectVia * Whether to inject by setting a property or calling a setter */ public function setInjectMapping($class, $property, $toInject, $injectVia = 'property') { $mapping = isset($this->injectMap[$class]) ? $this->injectMap[$class] : array(); $mapping[$property] = array('name' => $toInject, 'type' => $injectVia); $this->injectMap[$class] = $mapping; } /** * Add an object that should be automatically set on managed objects * * This allows you to specify, for example, that EVERY managed object * will be automatically inject with a log object by the following * * $injector->addAutoProperty('log', new Logger()); * * @param string $property * the name of the property * @param object $object * the object to be set */ public function addAutoProperty($property, $object) { $this->autoProperties[$property] = $object; return $this; } /** * Load services using the passed in configuration for those services * * @param array $config */ public function load($config = array()) { $services = array(); foreach ($config as $specId => $spec) { if (is_string($spec)) { $spec = array('class' => $spec); } $file = isset($spec['src']) ? $spec['src'] : null; $name = null; if (file_exists($file)) { $filename = basename($file); $name = substr($filename, 0, strrpos($filename, '.')); } // class is whatever's explicitly set, $class = isset($spec['class']) ? $spec['class'] : $name; // or the specid if nothing else available. if (!$class && is_string($specId)) { $class = $specId; } // make sure the class is set... $spec['class'] = $class; $id = is_string($specId) ? $specId : (isset($spec['id']) ? $spec['id'] : $class); $priority = isset($spec['priority']) ? $spec['priority'] : 1; // see if we already have this defined. If so, check priority weighting if (isset($this->specs[$id]) && isset($this->specs[$id]['priority'])) { if ($this->specs[$id]['priority'] > $priority) { return; } } // okay, actually include it now we know we're going to use it if (file_exists($file)) { require_once $file; } // make sure to set the id for later when instantiating // to ensure we get cached $spec['id'] = $id; // We've removed this check because new functionality means that the 'class' field doesn't need to refer // specifically to a class anymore - it could be a compound statement, ala SilverStripe's old Object::create // functionality // // if (!class_exists($class)) { // throw new Exception("Failed to load '$class' from $file"); // } // store the specs for now - we lazy load on demand later on. $this->specs[$id] = $spec; // EXCEPT when there's already an existing instance at this id. // if so, we need to instantiate and replace immediately if (isset($this->serviceCache[$id])) { $this->instantiate($spec, $id); } } return $this; } /** * Update the configuration of an already defined service * * Use this if you don't want to register a complete new config, just append * to an existing configuration. Helpful to avoid overwriting someone else's changes * * updateSpec('RequestProcessor', 'filters', '%$MyFilter') * * @param string $id * The name of the service to update the definition for * @param string $property * The name of the property to update. * @param mixed $value * The value to set * @param boolean $append * Whether to append (the default) when the property is an array */ public function updateSpec($id, $property, $value, $append = true) { if (isset($this->specs[$id]['properties'][$property])) { // by ref so we're updating the actual value $current = &$this->specs[$id]['properties'][$property]; if (is_array($current) && $append) { $current[] = $value; } else { $this->specs[$id]['properties'][$property] = $value; } // and reload the object; existing bindings don't get // updated though! (for now...) if (isset($this->serviceCache[$id])) { $this->instantiate($spec, $id); } } } /** * Recursively convert a value into its proper representation with service references * resolved to actual objects * * @param string $value */ public function convertServiceProperty($value) { if (is_array($value)) { $newVal = array(); foreach ($value as $k => $v) { $newVal[$k] = $this->convertServiceProperty($v); } return $newVal; } if (is_string($value) && strpos($value, '%$') === 0) { $id = substr($value, 2); return $this->get($id); } return $value; } /** * Instantiate a managed object * * Given a specification of the form * * array( * 'class' => 'ClassName', * 'properties' => array('property' => 'scalar', 'other' => '%$BeanRef') * 'id' => 'ServiceId', * 'type' => 'singleton|prototype' * ) * * will create a new object, store it in the service registry, and * set any relevant properties * * Optionally, you can pass a class name directly for creation * * To access this from the outside, you should call ->get('Name') to ensure * the appropriate checks are made on the specific type. * * * @param array $spec * The specification of the class to instantiate * @param string $id * The name of the object being created. If not supplied, then the id will be inferred from the * object being created * @param string $type * Whether to create as a singleton or prototype object. Allows code to be explicit as to how it * wants the object to be returned */ protected function instantiate($spec, $id=null, $type = null) { if (is_string($spec)) { $spec = array('class' => $spec); } $class = $spec['class']; // create the object, using any constructor bindings $constructorParams = array(); if (isset($spec['constructor']) && is_array($spec['constructor'])) { $constructorParams = $spec['constructor']; } $object = $this->objectCreator->create($this, $class, $constructorParams); // figure out if we have a specific id set or not. In some cases, we might be instantiating objects // that we don't manage directly; we don't want to store these in the service cache below if (!$id) { $id = isset($spec['id']) ? $spec['id'] : null; } // now set the service in place if needbe. This is NOT done for prototype beans, as they're // created anew each time if (!$type) { $type = isset($spec['type']) ? $spec['type'] : null; } if ($id && (!$type || $type != 'prototype')) { // this ABSOLUTELY must be set before the object is injected. // This prevents circular reference errors down the line $this->serviceCache[$id] = $object; } // now inject safely $this->inject($object, $id); return $object; } /** * Inject $object with available objects from the service cache * * @todo Track all the existing objects that have had a service bound * into them, so we can update that binding at a later point if needbe (ie * if the managed service changes) * * @param object $object * The object to inject * @param string $asType * The ID this item was loaded as. This is so that the property configuration * for a type is referenced correctly in case $object is no longer the same * type as the loaded config specification had it as. */ public function inject($object, $asType=null) { $objtype = $asType ? $asType : get_class($object); $mapping = isset($this->injectMap[$objtype]) ? $this->injectMap[$objtype] : null; // first off, set any properties defined in the service specification for this // object type if (isset($this->specs[$objtype]) && isset($this->specs[$objtype]['properties'])) { foreach ($this->specs[$objtype]['properties'] as $key => $value) { $val = $this->convertServiceProperty($value); $this->setObjectProperty($object, $key, $val); } } // now, use any cached information about what properties this object type has // and set based on name resolution if (!$mapping) { if ($this->autoScanProperties) { // we use an object to prevent array copies if/when passed around $mapping = new ArrayObject(); // This performs public variable based injection $robj = new ReflectionObject($object); $properties = $robj->getProperties(); foreach ($properties as $propertyObject) { /* @var $propertyObject ReflectionProperty */ if ($propertyObject->isPublic() && !$propertyObject->getValue($object)) { $origName = $propertyObject->getName(); $name = ucfirst($origName); if ($this->hasService($name)) { // Pull the name out of the registry $value = $this->get($name); $propertyObject->setValue($object, $value); $mapping[$origName] = array('name' => $name, 'type' => 'property'); } } } // and this performs setter based injection $methods = $robj->getMethods(ReflectionMethod::IS_PUBLIC); foreach ($methods as $methodObj) { /* @var $methodObj ReflectionMethod */ $methName = $methodObj->getName(); if (strpos($methName, 'set') === 0) { $pname = substr($methName, 3); if ($this->hasService($pname)) { // Pull the name out of the registry $value = $this->get($pname); $methodObj->invoke($object, $value); $mapping[$methName] = array('name' => $pname, 'type' => 'method'); } } } // we store the information about what needs to be injected for objects of this // type here $this->injectMap[get_class($object)] = $mapping; } } else { foreach ($mapping as $prop => $spec) { if ($spec['type'] == 'property') { $value = $this->get($spec['name']); $object->$prop = $value; } else { $method = $prop; $value = $this->get($spec['name']); $object->$method($value); } } } $injections = Config::inst()->get(get_class($object), 'dependencies'); // If the type defines some injections, set them here if ($injections && count($injections)) { foreach ($injections as $property => $value) { // we're checking isset in case it already has a property at this name // this doesn't catch privately set things, but they will only be set by a setter method, // which should be responsible for preventing further setting if it doesn't want it. if (!isset($object->$property)) { $value = $this->convertServiceProperty($value); $this->setObjectProperty($object, $property, $value); } } } foreach ($this->autoProperties as $property => $value) { if (!isset($object->$property)) { $value = $this->convertServiceProperty($value); $this->setObjectProperty($object, $property, $value); } } // Call the 'injected' method if it exists if (method_exists($object, 'injected')) { $object->injected(); } } /** * Helper to set a property's value * * @param object $object * Set an object's property to a specific value * @param string $name * The name of the property to set * @param mixed $value * The value to set */ protected function setObjectProperty($object, $name, $value) { if (method_exists($object, 'set'.$name)) { $object->{'set'.$name}($value); } else { $object->$name = $value; } } /** * Does the given service exist, and if so, what's the stored name for it? * * We do a special check here for services that are using compound names. For example, * we might want to say that a property should be injected with Log.File or Log.Memory, * but have only registered a 'Log' service, we'll instead return that. * * Will recursively call hasService for each depth of dotting * * @return string * The name of the service (as it might be different from the one passed in) */ public function hasService($name) { // common case, get it overwith first if (isset($this->specs[$name])) { return $name; } // okay, check whether we've got a compound name - don't worry about 0 index, cause that's an // invalid name if (!strpos($name, '.')) { return null; } return $this->hasService(substr($name, 0, strrpos($name, '.'))); } /** * Register a service object with an optional name to register it as the * service for * * @param stdClass $service * The object to register * @param string $replace * The name of the object to replace (if different to the * class name of the object to register) * */ public function registerService($service, $replace=null) { $registerAt = get_class($service); if ($replace != null) { $registerAt = $replace; } $this->serviceCache[$registerAt] = $service; $this->inject($service); } /** * Register a service with an explicit name */ public function registerNamedService($name, $service) { $this->serviceCache[$name] = $service; $this->inject($service); } /** * Removes a named object from the cached list of objects managed * by the inject * * @param type $name * The name to unregister */ public function unregisterNamedObject($name) { unset($this->serviceCache[$name]); } /** * Clear out all objects that are managed by the injetor. */ public function unregisterAllObjects() { $this->serviceCache = array('Injector' => $this); } /** * Get a named managed object * * Will first check to see if the item has been registered as a configured service/bean * and return that if so. * * Next, will check to see if there's any registered configuration for the given type * and will then try and load that * * Failing all of that, will just return a new instance of the * specificied object. * * @param string $name * the name of the service to retrieve. If not a registered * service, then a class of the given name is instantiated * @param boolean $asSingleton * Whether to register the created object as a singleton * if no other configuration is found * @param array $constructorArgs * Optional set of arguments to pass as constructor arguments * if this object is to be created from scratch * (ie asSingleton = false) * */ public function get($name, $asSingleton = true, $constructorArgs = null) { // reassign the name as it might actually be a compound name if ($serviceName = $this->hasService($name)) { // check to see what the type of bean is. If it's a prototype, // we don't want to return the singleton version of it. $spec = $this->specs[$serviceName]; $type = isset($spec['type']) ? $spec['type'] : null; // if we're explicitly a prototype OR we're not wanting a singleton if (($type && $type == 'prototype') || !$asSingleton) { if ($spec && $constructorArgs) { $spec['constructor'] = $constructorArgs; } return $this->instantiate($spec, $serviceName, !$type ? 'prototype' : $type); } else { if (!isset($this->serviceCache[$serviceName])) { $this->instantiate($spec, $serviceName); } return $this->serviceCache[$serviceName]; } } $config = $this->configLocator->locateConfigFor($name); if ($config) { $this->load(array($name => $config)); if (isset($this->specs[$name])) { $spec = $this->specs[$name]; return $this->instantiate($spec, $name); } } // If we've got this far, we're dealing with a case of a user wanting // to create an object based on its name. So, we need to fake its config // if the user wants it managed as a singleton service style object $spec = array('class' => $name, 'constructor' => $constructorArgs); if ($asSingleton) { // need to load the spec in; it'll be given the singleton type by default $this->load(array($name => $spec)); return $this->instantiate($spec, $name); } return $this->instantiate($spec); } /** * Magic method to return an item directly * * @param string $name * The named object to retrieve * @return mixed */ public function __get($name) { return $this->get($name); } /** * Similar to get() but always returns a new object of the given type * * Additional parameters are passed through as * * @param type $name */ public function create($name) { $constructorArgs = func_get_args(); array_shift($constructorArgs); return $this->get($name, false, count($constructorArgs) ? $constructorArgs : null); } /** * Creates an object with the supplied argument array * * @param string $name * Name of the class to create an object of * @param array $args * Arguments to pass to the constructor * @return mixed */ public function createWithArgs($name, $constructorArgs) { return $this->get($name, false, $constructorArgs); } } /** * A class for creating new objects by the injector */ class InjectionCreator { /** * * @param string $object * A string representation of the class to create * @param array $params * An array of parameters to be passed to the constructor */ public function create(Injector $injector, $class, $params = array()) { $reflector = new ReflectionClass($class); if (count($params)) { return $reflector->newInstanceArgs($injector->convertServiceProperty($params)); } return $reflector->newInstance(); } } class SilverStripeInjectionCreator { /** * * @param string $object * A string representation of the class to create * @param array $params * An array of parameters to be passed to the constructor */ public function create(Injector $injector, $class, $params = array()) { $class = Object::getCustomClass($class); $reflector = new ReflectionClass($class); return $reflector->newInstanceArgs($injector->convertServiceProperty($params)); } } /** * Used to locate configuration for a particular named service. * * If it isn't found, return null */ class ServiceConfigurationLocator { public function locateConfigFor($name) { } } /** * Use the SilverStripe configuration system to lookup config for a particular service */ class SilverStripeServiceConfigurationLocator { private $configs = array(); public function locateConfigFor($name) { if (isset($this->configs[$name])) { return $this->configs[$name]; } $config = Config::inst()->get('Injector', $name); if ($config) { $this->configs[$name] = $config; return $config; } // do parent lookup if it's a class if (class_exists($name)) { $parents = array_reverse(array_keys(ClassInfo::ancestry($name))); array_shift($parents); foreach ($parents as $parent) { // have we already got for this? if (isset($this->configs[$parent])) { return $this->configs[$parent]; } $config = Config::inst()->get('Injector', $parent); if ($config) { $this->configs[$name] = $config; return $config; } else { $this->configs[$parent] = false; } } // there is no parent config, so we'll record that as false so we don't do the expensive // lookup through parents again $this->configs[$name] = false; } } }