import MetadataViews from 0xb6763b4399a888c8 import ViewResolver from 0xb6763b4399a888c8 import NonFungibleToken from 0xb6763b4399a888c8 import FungibleToken from 0xa0225e7000ac82a9 import FlowToken from 0x4445e7ad11568276 import ScopedFTProviders from 0x634acef27f871527 import EVM from 0xb6763b4399a888c8 import FlowEVMBridgeUtils from 0x634acef27f871527 import FlowEVMBridge from 0x634acef27f871527 import FlowEVMBridgeConfig from 0x634acef27f871527 /// Bridges an NFT from the signer's collection in Cadence to the signer's COA in FlowEVM /// NOTE: The NFT being bridged must have first been onboarded to the bridge. This can be checked for with the method /// FlowEVMBridge.typeRequiresOnboarding(type): Bool? /// /// @param nftContractAddress: The Flow account address hosting the NFT-defining Cadence contract /// @param nftContractName: The name of the NFT-defining Cadence contract /// @param id: The Cadence NFT.id of the NFT to bridge to EVM /// transaction(nftContractAddress: Address, nftContractName: String, ids: [UInt64]) { let nfts: @{UInt64 : {NonFungibleToken.NFT}} let coa: auth(EVM.Bridge) &EVM.CadenceOwnedAccount let scopedProvider: @ScopedFTProviders.ScopedFTProvider prepare(signer: auth(CopyValue, BorrowValue, IssueStorageCapabilityController, PublishCapability, SaveValue) &Account) { /* --- Reference the signer's CadenceOwnedAccount --- */ // // Borrow a reference to the signer's COA self.coa = signer.storage.borrow(from: /storage/evm) ?? panic("Could not borrow COA from provided gateway address") self.nfts <- {} /* --- Retrieve the NFT --- */ // // Borrow a reference to the NFT collection, configuring if necessary let viewResolver = getAccount(nftContractAddress).contracts.borrow<&{ViewResolver}>(name: nftContractName) ?? panic("Could not borrow ViewResolver from NFT contract") let collectionData = viewResolver.resolveContractView( resourceType: nil, viewType: Type() ) as! MetadataViews.NFTCollectionData? ?? panic("Could not resolve NFTCollectionData view") let collection = signer.storage.borrow( from: collectionData.storagePath ) ?? panic("Could not access signer's NFT Collection") // Withdraw the requested NFT & calculate the approximate bridge fee based on NFT storage usage let currentStorageUsage = signer.storage.used for id in ids { let nft <- collection.withdraw(withdrawID: id) self.nfts[id] <-! nft } // self.nft <- collection.withdraw(withdrawID: id) let withdrawnStorageUsage = signer.storage.used let approxFee = FlowEVMBridgeUtils.calculateBridgeFee( bytes: currentStorageUsage - withdrawnStorageUsage ) * 1.10 * UFix64(ids.length) /* --- Configure a ScopedFTProvider --- */ // // Issue and store bridge-dedicated Provider Capability in storage if necessary if signer.storage.type(at: FlowEVMBridgeConfig.providerCapabilityStoragePath) == nil { let providerCap = signer.capabilities.storage.issue( /storage/flowTokenVault ) signer.storage.save(providerCap, to: FlowEVMBridgeConfig.providerCapabilityStoragePath) } // Copy the stored Provider capability and create a ScopedFTProvider let providerCapCopy = signer.storage.copy>( from: FlowEVMBridgeConfig.providerCapabilityStoragePath ) ?? panic("Invalid Provider Capability found in storage.") let providerFilter = ScopedFTProviders.AllowanceFilter(approxFee) self.scopedProvider <- ScopedFTProviders.createScopedFTProvider( provider: providerCapCopy, filters: [ providerFilter ], expiration: getCurrentBlock().timestamp + 1.0 ) } execute { // Execute the bridge var idx = 0 while idx < ids.length { let nftId = ids[idx]! let nft <- self.nfts.remove(key: nftId)! as @{NonFungibleToken.NFT} self.coa.depositNFT( nft: <- nft!, feeProvider: &self.scopedProvider as auth(FungibleToken.Withdraw) &{FungibleToken.Provider} ) idx = idx + 1 } // Destroy the ScopedFTProvider destroy self.scopedProvider destroy self.nfts } }

🎶Happy diving into the flow

Transaction

🎶Happy diving into the flow