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Architecture

Smart Contract Architecture#

A blockchain platform works like a distributed database that stores all smart contracts. Each contract has a unique address used for state queries and updates. Methods in the contract code handle permission checks and logic.

Smart Contract Parts in aelf#

  • Interface:
  • State:
  • Business Logic:

    • Smart contracts in aelf are divided across the Kernel, the runtime, and the SDK. The Kernel handles core components and execution abstractions. Contracts rely on runtime modules and the SDK.

    A smart contract consists of methods that interact with state variables. Transactions trigger these methods to modify the blockchain state.

    Architecture Overview#

    aelf defines Smart Contracts as micro-services, making them language-independent. For example, the Consensus Protocol is a service defined by a smart contract.

    Chain Interactions#

    Smart contracts interact with the chain and access contextual information via a bridge and a bridge host. The SDKs implement features to communicate through the bridge.

    Key contextual information provided by the bridge includes:

  • Self: Address of the current contract.
  • Sender: Address that sent the transaction.
  • Origin: Address that signed the transaction.
  • OriginTransactionId and TransactionId: IDs of the transactions involved.

    • The bridge also allows:

  • Firing events (similar to logging).
  • Calling methods on other contracts in a read-only manner.
  • Sending inline transactions, which can persist state changes.

    • State#

    Smart contracts read and/or modify state. The language SDKs provide state helpers and access through the bridge’s StateProvider.

    Runtime and Execution#

    When a block’s transactions are executed, each transaction generates a trace containing:

  • Return value of the called method.
  • Error outputs, if any.
  • Results from inner calls in InlineTraces.
  • Events launched in Logs.

    • SDK#

    aelf has a native C# SDK for developing smart contracts in C#. It includes:

  • Helpers to communicate with the bridge.
  • Type infrastructure like ContractState, MappedState, and SingletonState.

    • Any developer or company can create an SDK and runtime for a specific language by adapting it to communicate with the bridge through gRPC.

    Edited on: 15 July 2024 03:23:28 GMT+0