I see in the di.xml files from the core that some of the arguments have the type init_parameter but the values of the parameters are all constants.

<type name="Magento\Framework\View\Page\Config\Renderer">
        <argument name="appMode" xsi:type="init_parameter">Magento\Framework\App\State::PARAM_MODE</argument>

or this one

<type name="Magento\Framework\App\Cache\State">
        <argument name="banAll" xsi:type="init_parameter">Magento\Framework\App\Cache\State::PARAM_BAN_CACHE</argument>

and many others.
But from what I see in the interpreter associated to init_parameter, the constant interpreter is used Magento\Framework\App\Arguments\ArgumentInterpreter::evaluate

public function evaluate(array $data)
    return ['argument' => $this->constInterpreter->evaluate($data)];

But the result is a bit different from the Magento\Framework\Data\Argument\Interpreter\Constant::evaluate

 public function evaluate(array $data)
    if (!isset($data['value']) || !defined($data['value'])) {
        throw new \InvalidArgumentException('Constant name is expected.');
    return constant($data['value']);

Can someone explain please how the init_parameter type works and how everything happens under the hood?


Found it.
For const the value of the specified constant is used.
For init_parameter, the value provided must be a constant name but the actual value used is the value of $_SERVER[constant value here].

In the method Magento\Framework\ObjectManager\Factory\AbstractFactory::resolveArgument metohod you will find this

    else if ($argument === (array)$argument) {
        if (isset($argument['argument'])) {
            if (isset($this->globalArguments[$argument['argument']])) {
                $argument = $this->globalArguments[$argument['argument']];
            } else {
                $argument = $paramDefault;
        } else if (!empty($argument)) {

$argument['argument'] looks very similar to what the init parameter interpreter returns.
And if there is a value with the key $argument['argument'] in the globalArguments member that one is returned.
globalArguments member is populated with the arguments with which the bootstrap class is initialized.
So for the web application these arguments are $_SERVER. (see index.php).


<argument name="appMode" xsi:type="init_parameter">Magento\Framework\App\State::PARAM_MODE</argument>

means that the parameter named appMode will have the value $_SERVER[Magento\Framework\App\State::PARAM_MODE] if it is set.
Which means $_SERVER['MAGE_MODE']

| improve this answer | |
  • 2
    I think this information should be added to the official documentation. Thanks for the detailed exploration. :) – Siarhey Uchukhlebau May 3 '18 at 6:21

What are all the allowed `xsi:type` values in the xml's from Magento2


enter image description here

Node format: <argument xsi:type="init_parameter">{Constant::NAME}</argument>
Description: Global argument of an application represented by Constant::NAME is looked up and passed as an argument.
Possible values: Constant the global argumentcontaining name

Node format: <argument xsi:type="const">{Constant::NAME}</argument>
Description: Constant::NAME passed as an argument.
Possible values: All constant names are possible.

Let's take below example.


<type name="Magento\Store\Model\StoreResolver">
        <argument name="cache" xsi:type="object">Magento\Framework\App\Cache\Type\Config</argument>
        <argument name="runMode" xsi:type="init_parameter">Magento\Store\Model\StoreManager::PARAM_RUN_TYPE</argument>
        <argument name="scopeCode" xsi:type="init_parameter">Magento\Store\Model\StoreManager::PARAM_RUN_CODE</argument>


 * @var string
protected $runMode;

 * @var string
protected $scopeCode;

 * @param \Magento\Store\Api\StoreRepositoryInterface $storeRepository
 * @param StoreCookieManagerInterface $storeCookieManager
 * @param \Magento\Framework\App\RequestInterface $request
 * @param \Magento\Framework\Cache\FrontendInterface $cache
 * @param StoreResolver\ReaderList $readerList
 * @param string $runMode
 * @param null $scopeCode
public function __construct(
    \Magento\Store\Api\StoreRepositoryInterface $storeRepository,
    StoreCookieManagerInterface $storeCookieManager,
    \Magento\Framework\App\RequestInterface $request,
    \Magento\Framework\Cache\FrontendInterface $cache,
    StoreResolver\ReaderList $readerList,
    $runMode = ScopeInterface::SCOPE_STORE,
    $scopeCode = null
) {
    $this->storeRepository = $storeRepository;
    $this->storeCookieManager = $storeCookieManager;
    $this->request = $request;
    $this->cache = $cache;
    $this->readerList = $readerList;
    $this->runMode = $scopeCode ? $runMode : ScopeInterface::SCOPE_WEBSITE;
    $this->scopeCode = $scopeCode;

Idea is simple. You can directly pass your variables & it's value from di.xml file. Instead of defining that values in ur Model.

So u just need to initialize ur variables & u will get value from ur di.xml

Hope it helps

| improve this answer | |
  • It doens't really help because it does not answer my question. I asked for the difference between const and init_parameter in behavior. – Marius Feb 21 '17 at 5:56

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