Smart Contract Functions and Chainlink Data Integration

Smart contracts must be marked payable to receive native blockchain tokens like Ethereum.

### Quick Review of Smart Contract Functions and Chainlink Integration
* 📜 In order for a function to receive native blockchain tokens like Ethereum, it must be marked as **payable**.
* ⚠ To ensure that a transaction must meet specific criteria, a **require statement** can be used to **enforce conditions**, failing the transaction if not met.
* 🔄 A transaction that reverts **undoes any previous work** and **returns gas to the user**, ensuring that **no unintended changes are made**.
* 💰 To access the value sent with a transaction, the Solidity global variable **`message.value`** can be utilized.
* 🌐 Chainlink serves as a technology that facilitates the **integration of external data and computation** into smart contracts in a **decentralized manner**.
* 📊 In this context, we will use a **Chainlink data feed**, specifically a **Chainlink price feed**, to obtain pricing information from real-world assets for our smart contracts.

Now I know we haven't actually written that much code, but we've gone over a ton, so I want to do a quick review. In order for a function to receive native blockchain tokens like Ethereum, you need to mark that function as payable. If you want to force a transaction to do

something and you want it to fail if that wasn't done, you can use a require statement. A transaction that reverts means it undoes any work that it did previously and returns any gas to the user. To get the value sent with a transaction, you can use the Solidity

global message.value. Chainlink is a technology for getting external data and computation into our smart contracts and most importantly getting that data in a decentralized context. In this example, we're going to be using a Chainlink data feed or a Chainlink price feed, which is a

decentralized way to get pricing information from real-world assets into our smart contracts.

Lesson 4 Part 6 | Quick Recap - Solidity & Foundry Full Course

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Functions receiving native tokens need the 'payable' modifier.

'require' statements enforce transaction conditions; failure reverts the transaction.

Reverted transactions undo work and return gas.

Use `msg.value` to access the value sent in a transaction.

Introduction to Chainlink for Smart Contracts

Chainlink enables decentralized data and computation in smart contracts.

Chainlink price feeds provide decentralized pricing information for real-world assets.