> ## Documentation Index
> Fetch the complete documentation index at: https://thrackle.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ProtocolERC721U

[Git Source](https://github.com/forte-service-company-ltd/forte-rules-engine/blob/6b9ac124d2cb0fe47a8b5c261a1dd458067f45ea/src/client/token/ERC721/upgradeable/ProtocolERC721U.sol)

**Inherits:**
Initializable, ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable, ERC721BurnableUpgradeable, OwnableUpgradeable, UUPSUpgradeable, [ProtocolTokenCommonU](/v1/reference/client/token/ProtocolTokenCommonU.sol/abstract.ProtocolTokenCommonU), ReentrancyGuard

**Author:**
@ShaneDuncan602, @oscarsernarosero, @TJ-Everett

This is the base contract for all protocol ERC721Upgradeables

## State Variables

### handlerAddress

```solidity
address public handlerAddress;
```

### handler

```solidity
IProtocolTokenHandler handler;
```

### \_tokenIdCounter

```solidity
CountersUpgradeable.Counter internal _tokenIdCounter;
```

### baseUri

Base Contract URI

```solidity
string public baseUri;
```

### \_\_gap

memory placeholders to allow variable addition without affecting client upgradeability

```solidity
uint256[49] __gap;
```

## Functions

### constructor

```solidity
constructor();
```

### initialize

This function should be called in an "atomic" deploy script when deploying an ERC721Upgradeable contract.
"Front Running" is possible if this function is called individually after the ERC721Upgradeable proxy is deployed.
It is critical to ensure your deploy process mitigates this risk.

*Initializer sets the name, symbol and base URI of NFT along with the App Manager and Handler Address*

```solidity
function initialize(
    string memory _nameProto,
    string memory _symbolProto,
    address _appManagerAddress,
    string memory _baseUri
) public virtual appAdministratorOnly(_appManagerAddress) initializer;
```

**Parameters**

| Name                 | Type      | Description            |
| -------------------- | --------- | ---------------------- |
| `_nameProto`         | `string`  | Name of NFT            |
| `_symbolProto`       | `string`  | Symbol for the NFT     |
| `_appManagerAddress` | `address` | Address of App Manager |
| `_baseUri`           | `string`  |                        |

### \_initializeProtocol

*Private Initializer sets the name, symbol and base URI of NFT along with the App Manager and Handler Address*

```solidity
function _initializeProtocol(address _appManagerAddress) private onlyInitializing;
```

**Parameters**

| Name                 | Type      | Description            |
| -------------------- | --------- | ---------------------- |
| `_appManagerAddress` | `address` | Address of App Manager |

### \_authorizeUpgrade

```solidity
function _authorizeUpgrade(address newImplementation) internal override onlyOwner;
```

### \_burn

*Function to burn or remove token from circulation*

```solidity
function _burn(uint256 tokenId) internal override(ERC721Upgradeable, ERC721URIStorageUpgradeable);
```

**Parameters**

| Name      | Type      | Description              |
| --------- | --------- | ------------------------ |
| `tokenId` | `uint256` | Id of token to be burned |

### \_baseURI

*Function to return baseURI for contract*

```solidity
function _baseURI() internal view override returns (string memory);
```

**Returns**

| Name     | Type     | Description                      |
| -------- | -------- | -------------------------------- |
| `<none>` | `string` | baseUri URI link to NFT metadata |

### tokenURI

*Function to return tokenURI for contract*

```solidity
function tokenURI(uint256 tokenId)
    public
    view
    virtual
    override(ERC721Upgradeable, ERC721URIStorageUpgradeable)
    returns (string memory);
```

**Returns**

| Name     | Type     | Description                   |
| -------- | -------- | ----------------------------- |
| `<none>` | `string` | tokenURI link to NFT metadata |

### setBaseURI

this is called in the constructor and can be called to update URI metadata pointer

*Function to set URI for contract.*

```solidity
function setBaseURI(string memory _baseUri) public virtual appAdministratorOnly(appManagerAddress);
```

**Parameters**

| Name       | Type     | Description                                  |
| ---------- | -------- | -------------------------------------------- |
| `_baseUri` | `string` | URI to the metadata file(s) for the contract |

### supportsInterface

*Returns true if this contract implements the interface defined by
`interfaceId`. See the corresponding
[https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified\[EIP](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified\[EIP) section]
to learn more about how these ids are created.
This function call must use less than 30 000 gas.*

```solidity
function supportsInterface(bytes4 interfaceId)
    public
    view
    override(ERC721Upgradeable, ERC721EnumerableUpgradeable, ERC721URIStorageUpgradeable)
    returns (bool);
```

### safeMint

END setters and getters \***\*\*\*\*\*\***

Add appAdministratorOnly modifier to restrict minting privilages

*Function mints new a new token to caller with tokenId incremented by 1 from previous minted token.*

```solidity
function safeMint(address to) public payable virtual appAdministratorOnly(appManagerAddress);
```

**Parameters**

| Name | Type      | Description          |
| ---- | --------- | -------------------- |
| `to` | `address` | Address of recipient |

### \_beforeTokenTransfer

*Function called before any token transfers to confirm transfer is within rules of the protocol*

```solidity
function _beforeTokenTransfer(address from, address to, uint256 tokenId, uint256 batchSize)
    internal
    override(ERC721Upgradeable, ERC721EnumerableUpgradeable)
    nonReentrant;
```

**Parameters**

| Name        | Type      | Description                                                                                                                      |
| ----------- | --------- | -------------------------------------------------------------------------------------------------------------------------------- |
| `from`      | `address` | sender address                                                                                                                   |
| `to`        | `address` | recipient address                                                                                                                |
| `tokenId`   | `uint256` | Id of token to be transferred                                                                                                    |
| `batchSize` | `uint256` | the amount of NFTs to mint in batch. If a value greater than 1 is given, tokenId will represent the first id to start the batch. |

### withdraw

Rule Processor Module Check

*Function to withdraw Ether sent to contract*

*AppAdministratorOnly modifier uses appManagerAddress. Only Addresses asigned as AppAdministrator can call function.*

```solidity
function withdraw() public payable virtual appAdministratorOnly(appManagerAddress);
```

### getHandlerAddress

*This function returns the handler address*

```solidity
function getHandlerAddress() external view returns (address);
```

**Returns**

| Name     | Type      | Description    |
| -------- | --------- | -------------- |
| `<none>` | `address` | handlerAddress |

### connectHandlerToToken

This function does not check for zero address. Zero address is a valid address for this function's purpose.

*Function to connect Token to previously deployed Handler contract*

```solidity
function connectHandlerToToken(address _deployedHandlerAddress) external appAdministratorOnly(appManagerAddress);
```

**Parameters**

| Name                      | Type      | Description                                       |
| ------------------------- | --------- | ------------------------------------------------- |
| `_deployedHandlerAddress` | `address` | address of the currently deployed Handler Address |