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The NonFungibleToken contract interface implements the Fungible Token Standard. All NFT contracts are encouraged to import and implement this standard.

Source: NonFungibleToken.cdc

NetworkContract Address
Emulator0xf8d6e0586b0a20c7
Cadence Testing Framework0x0000000000000001
Testnet0x631e88ae7f1d7c20
Mainnet0x1d7e57aa55817448

Transactions

All NonFungibleToken projects are encouraged to use the generic token transactions and scripts in the flow-nft repo. They can be used for any token that implements the non-fungible token standard properly without changing any code besides import addresses on different networks.

Events

Events emitted from all contracts follow a standard format:


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A.{contract address}.{contract name}.{event name}

The components of the format are:

  • contract address - the address of the account the contract has been deployed to
  • contract name - the name of the contract in the source code
  • event name - the name of the event as declared in the source code

NonFungibleToken Events​

Contracts that implement the Non-Fungible Token standard get access to standard events that are emitted every time a relevant action occurs, like depositing and withdrawing tokens.

This means that projects do not have to implement their own custom events unless the standard events do not satisfy requirements they have for events.

The NonFungibleToken events will have the following format:


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A.{contract address}.NonFungibleToken.Deposited
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A.{contract address}.NonFungibleToken.Withdrawn

Where the contract address is the NonFungibleToken address on the network being queried. The addresses on the various networks are shown above.

NonFungibleToken.Deposited​


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access(all) event Deposited (
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type: String,
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id: UInt64,
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uuid: UInt64,
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to: Address?,
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collectionUUID: UInt64
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)

Whenever deposit() is called on a resource type that implements NonFungibleToken.Collection, the NonFungibleToken.Deposited event is emitted with the following arguments:

  • type: String: The type identifier of the token being deposited.
    • Example: A.4445e7ad11568276.TopShot.NFT
  • id: UInt64: The ID of the token that was deposited. Note: This may or may not be the UUID.
    • Example: 173838
  • uuid: UInt64: The UUID of the token that was deposited.
    • Example: 177021372071991
  • to: Address?: The address of the account that owns the Collection that received the token. If the collection is not stored in an account, to will be nil.
    • Example: 0x4445e7ad11568276
  • collectionUUID: UInt64: The UUID of the Collection that received the token.
    • Example: 177021372071991

NonFungibleToken.Withdrawn​


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access(all) event Withdrawn (
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type: String,
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id: UInt64,
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uuid: UInt64,
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from: Address?,
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providerUUID: UInt64
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)

Whenever withdraw() is called on a resource type that implements NonFungibleToken.Collection, the NonFungibleToken.Withdrawn event is emitted with the following arguments:

  • type: String: The type identifier of the token being withdrawn.
    • Example: A.4445e7ad11568276.TopShot.NFT
  • id: UInt64: The id of the token that was withdrawn. Note: May or may not be the UUID.
    • Example: 113838
  • uuid: UInt64: The UUID of the token that was withdrawn.
    • Example: 177021372071991
  • from: Address?: The address of the account that owns the Collection that the token was withdrawn from. If the collection is not stored in an account, to will be nil.
    • Example: 0x4445e7ad11568276
  • providerUUID: UInt64: The UUID of the Collection that the token was withdrawn from.
    • Example: 177021372071991

NonFungibleToken.Updated​


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access(all) event Updated(
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type: String,
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id: UInt64,
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uuid: UInt64,
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owner: Address?
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)

Whenever a non-fungible token is updated for whatever reason, projects should call the NonFungibleToken.emitNFTUpdated() function to emit this event. It indicates to event listeners that they should query the NFT to update any stored information they have about the NFT in their database.

  • type: String: The type identifier of the token that was updated.
    • Example: A.4445e7ad11568276.TopShot.NFT
  • id: UInt64: The ID of the token that was updated. Note: This may or may not be the UUID.
    • Example: 173838
  • uuid: UInt64: The UUID of the token that was updated.
    • Example: 177021372071991
  • owner: Address?: The address of the account that owns the Collection that owns the token. If the collection is not stored in an account, to will be nil.
    • Example: 0x4445e7ad11568276