# Using Function Modifiers

## Step By Step

1. Install the **Ironblocks CLI Tool** into your project by running:\
   `npm install @ironblocks/cli` \ <br>

2. From your project's root directory, run the **Firewall Integration** command:\
   `npx ib fw integ -d ./contracts`<br>

   1. **`ib`** is [Ironblocks' CLI tool](https://www.npmjs.com/package/@ironblocks/cli)
   2. **`fw integ`** runs the **Integration** command for the **Firewall** module of our tool
   3. **`-d ./contracts`** points to your smart contracts directory

3. Running the command above will make the following changes in your project:<br>
   1. Auto-Install the Firewall's dependencies
   2. Make your contracts inherit from [`FirewallConsumer`](/firewall/smart-contracts/firewallconsumer.sol.md)
   3. Add the [`firewallProtected`](/firewall/smart-contracts/firewallconsumer.sol.md#firewallprotected) modifier to any external function *(excluding **`view`** functions)*\ <br>

4. That's it!\
   Your smart contracts are now ready to use Ironblocks' Firewall.<br>

## Example

The following smart contract shows a typical integration of our Firewall into a consumer protocol:

```sol
pragma solidity ^0.8.19;

import "@ironblocks/firewall-consumer/FirewallConsumer.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Address.sol";

//
// STEP 1: Inherit from our FirewallConsumer
//
contract SampleConsumer is FirewallConsumer, Ownable {

    mapping (address => uint) public deposits;
    
    constructor() {}
  
    //
    // STEP 2: Add the "firewallProtected" modifier to functions you wish to protect
    //
    function deposit() external payable firewallProtected {
        deposits[msg.sender] += msg.value;
    }

    function withdraw(uint amount) external firewallProtected {
        deposits[msg.sender] -= amount;
        Address.sendValue(payable(msg.sender), amount);
    }

    function setOwner(address newOwner) external onlyOwner firewallProtected {
        _transferOwnership(newOwner);
    }
}
```

<br>

## Next Steps

* Head on to the [Configuration](/firewall/configuration.md) section to learn more about security policy management.<br>
* Review our [Smart Contracts](/firewall/smart-contracts.md)


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