Documentation - OpenZeppelin Docs (2024)

FAQs

When to use _disableInitializers? ›

_disableInitializers. Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call. Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized to any version.

UUPSUpgradeable : An upgradeability mechanism to be included in the implementation contract.

OpenZeppelin is an open-source framework to build secure smart contracts.

Universal Upgrade Proxy Standard (UUPS)

Not as common as the transparent proxy, but gaining traction. UUPS is a more gas-efficient way of achieving upgradability. Instead of defining storage in the proxy contract, it uses the same storage layout as its implementation contract.

If we were to use the transparent proxy pattern or UUPS pattern, we would need to update the address of the implementation contract in all the proxy contracts. However, with the beacon pattern, only the address in the beacon contract needs updating.

OwnableUpgradable is the upgradable counterpart of Ownable contract from Openzeppelin used for access control. It provides a modifier onlyOwner whose functionality you can very well guess.

DelegateCall is a low-level Solidity opcode that allows a contract to execute code from another contract, but it using the state and the storage of the calling contract. The syntax for DelegateCall is as follows: (bool success, bytes memory returnData) = address. delegatecall(bytes memory data);

Transparent proxies serve as a conduit between clients and the internet, intercepting connections. When a transparent proxy is used, a user's actual IP address is made public in the HTTP header. Such a proxy only verifies and identifies your connection; it does not protect or modify your IP address.

This capability can be integrated into smart contracts, enabling them to make informed decisions based on predictive analytics. For example, in the insurance industry, AI-coded smart contracts can assess risk factors and adjust premium rates in real-time.

What are the top 10 smart contracts examples? ›

The top 10 best smart contract platforms in 2024 are Ethereum, Binance Smart Chain (BSC), TRON, Arbitrum, Cardano, Solana, Polygon, Algorand, Avalanche, and Tezos.

Over the years, new smart contract programming languages such as Solidity, Vyper and Yul emerged specifically for writing more sophisticated applications. In addition, developers have created frameworks for executing smart contract programs written in legacy programming languages such as Java, JavaScript and C++.

We plan to make money by offering services and security audits to users of the framework.

Generally, OpenZeppelin's code can be considered safe, as long as you didn't make any changes to any of it. Your own code should be checked by experienced developers.

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Upgradeable contracts have no constructors but initializers, therefore they can't handle immutable variables. Since the immutable variable value is stored in the bytecode its value would be shared among all proxies pointing to a given contract instead of each proxy's storage.

The ERC1967Proxy contract is an upgradeable proxy contract that allows for the initialization of an initial implementation and provides a function to retrieve the current implementation address. It utilizes the ERC1967Utils library for upgrading and calling the implementation.

Storage Collisions: When a delegate call is used, the called contract has access to the calling contract's storage. Therefore, if the layout of the storage variables in the delegate contract doesn't match the layout in the proxy contract, unexpected behaviour or malicious attacks could occur.