A library that can be used to serialize closures (anonymous functions) and arbitrary objects.

3.99.99 2023-03-28 21:21 UTC

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Last update: 2024-04-28 23:30:59 UTC


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Serializable closures

Opis Closure is a library that aims to overcome PHP's limitations regarding closure serialization by providing a wrapper that will make all closures serializable.

The library's key features:

  • Serialize any closure
  • Serialize arbitrary objects
  • Doesn't use eval for closure serialization or unserialization
  • Works with any PHP version that has support for closures
  • Supports PHP 7 syntax
  • Handles all variables referenced/imported in use() and automatically wraps all referenced/imported closures for proper serialization
  • Handles recursive closures
  • Handles magic constants like __FILE__, __DIR__, __LINE__, __NAMESPACE__, __CLASS__, __TRAIT__, __METHOD__ and __FUNCTION__.
  • Automatically resolves all class names, function names and constant names used inside the closure
  • Track closure's residing source by using the #trackme directive
  • Simple and very fast parser
  • Any error or exception, that might occur when executing an unserialized closure, can be caught and treated properly
  • You can serialize/unserialize any closure unlimited times, even those previously unserialized (this is possible because eval() is not used for unserialization)
  • Handles static closures
  • Supports cryptographically signed closures
  • Provides a reflector that can give you information about the serialized closure
  • Provides an analyzer for SuperClosure library
  • Automatically detects when the scope and/or the bound object of a closure needs to be serialized in order for the closure to work after deserialization


The full documentation for this library can be found here.


Opis Closure is licensed under the MIT License (MIT).


  • PHP ^5.4 || ^7.0 || ^8.0


Opis Closure is available on Packagist and it can be installed from a command line interface by using Composer.

composer require opis/closure

Or you could directly reference it into your composer.json file as a dependency

    "require": {
        "opis/closure": "^3.5"

Migrating from 2.x

If your project needs to support PHP 5.3 you can continue using the 2.x version of Opis Closure. Otherwise, assuming you are not using one of the removed/refactored classes or features(see CHANGELOG), migrating to version 3.x is simply a matter of updating your composer.json file.

Semantic versioning

Opis Closure follows semantic versioning specifications.

Arbitrary object serialization

We've added this feature in order to be able to support the serialization of a closure's bound object. The implementation is far from being perfect, and it's really hard to make it work flawless. We will try to improve this, but we can't guarantee anything. So our advice regarding the Opis\Closure\serialize|unserialize functions is to use them with caution.