// Flow Wallet - mainnet Script bridgeTokensFromEvmToFlowV2 - v2.35 // Extension-2.5.20 import MetadataViews from 0x1d7e57aa55817448 import ViewResolver from 0x1d7e57aa55817448 import NonFungibleToken from 0x1d7e57aa55817448 import FungibleToken from 0xf233dcee88fe0abe import FlowToken from 0x1654653399040a61 import FungibleTokenMetadataViews from 0xf233dcee88fe0abe import ScopedFTProviders from 0x1e4aa0b87d10b141 import EVM from 0xe467b9dd11fa00df import FlowEVMBridgeUtils from 0x1e4aa0b87d10b141 import FlowEVMBridge from 0x1e4aa0b87d10b141 import FlowEVMBridgeConfig from 0x1e4aa0b87d10b141 /// This transaction bridges fungible tokens from EVM to Cadence assuming it has already been onboarded to the /// FlowEVMBridge. The full amount to be transferred is sourced from EVM, so it's assumed the signer has sufficient /// balance of the ERC20 to bridging into Cadence. Also know that the recipient Flow account must have a Receiver /// capable of receiving the bridged tokens accessible via published Capability at the token's standard path. /// /// NOTE: The ERC20 must have first been onboarded to the bridge. This can be checked via the method /// FlowEVMBridge.evmAddressRequiresOnboarding(address: self.evmContractAddress) /// /// @param vaultIdentifier: The Cadence type identifier of the FungibleToken Vault to bridge /// - e.g. vault.getType().identifier /// @param amount: The amount of tokens to bridge from EVM and transfer to the recipient /// @param recipient: The Flow account address to receive the bridged tokens /// transaction(vaultIdentifier: String, amount: UInt256, recipient: Address) { let vaultType: Type let receiver: &{FungibleToken.Receiver} let scopedProvider: @ScopedFTProviders.ScopedFTProvider let coa: auth(EVM.Bridge) &EVM.CadenceOwnedAccount prepare(signer: auth(BorrowValue, CopyValue, IssueStorageCapabilityController, PublishCapability, SaveValue, UnpublishCapability) &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") /* --- Construct the Vault type --- */ // // Construct the Vault type from the provided identifier self.vaultType = CompositeType(vaultIdentifier) ?? panic("Could not construct Vault type from identifier: ".concat(vaultIdentifier)) // Parse the Vault identifier into its components let tokenContractAddress = FlowEVMBridgeUtils.getContractAddress(fromType: self.vaultType) ?? panic("Could not get contract address from identifier: ".concat(vaultIdentifier)) let tokenContractName = FlowEVMBridgeUtils.getContractName(fromType: self.vaultType) ?? panic("Could not get contract name from identifier: ".concat(vaultIdentifier)) /* --- Reference the signer's Vault --- */ // // Borrow a reference to the FungibleToken Vault, configuring if necessary let viewResolver = getAccount(tokenContractAddress).contracts.borrow<&{ViewResolver}>(name: tokenContractName) ?? panic("Could not borrow ViewResolver from FungibleToken contract") let vaultData = viewResolver.resolveContractView( resourceType: self.vaultType, viewType: Type() ) as! FungibleTokenMetadataViews.FTVaultData? ?? panic("Could not resolve FTVaultData view") // If the vault does not exist, create it and publish according to the contract's defined configuration if signer.storage.borrow<&{FungibleToken.Vault}>(from: vaultData.storagePath) == nil { signer.storage.save(<-vaultData.createEmptyVault(), to: vaultData.storagePath) signer.capabilities.unpublish(vaultData.receiverPath) signer.capabilities.unpublish(vaultData.metadataPath) let receiverCap = signer.capabilities.storage.issue<&{FungibleToken.Vault}>(vaultData.storagePath) let metadataCap = signer.capabilities.storage.issue<&{FungibleToken.Vault}>(vaultData.storagePath) signer.capabilities.publish(receiverCap, at: vaultData.receiverPath) signer.capabilities.publish(metadataCap, at: vaultData.metadataPath) } self.receiver = getAccount(recipient).capabilities.borrow<&{FungibleToken.Receiver}>(vaultData.receiverPath) ?? panic("Could not borrow Vault from recipient's account") /* --- Configure a ScopedFTProvider --- */ // // Calculate the bridge fee - bridging from EVM consumes no storage, so flat fee let approxFee = FlowEVMBridgeUtils.calculateBridgeFee(bytes: 400_000) // 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 request let vault: @{FungibleToken.Vault} <- self.coa.withdrawTokens( type: self.vaultType, amount: amount, feeProvider: &self.scopedProvider as auth(FungibleToken.Withdraw) &{FungibleToken.Provider} ) // Ensure the bridged vault is the correct type assert(vault.getType() == self.vaultType, message: "Bridged vault type mismatch") // Deposit the bridged token into the signer's vault self.receiver.deposit(from: <-vault) // Destroy the ScopedFTProvider destroy self.scopedProvider } }

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