examples

README

Emulator Examples

This package contains code samples that interact with the Flow Emulator.

• Running the emulator with the Flow CLI
  • Installation
  • Starting the server
• Running the examples
  • Get Blocks
  • Get Accounts
  • Get Events
  • Get Collection
  • Execute Script
  • Send Transaction
  • Create Account
  • Add Account Key
  • Deploy Contract
  • Transaction Arguments
  • Transaction Signing
    • Single Party, Single Signature
    • Single Party, Multiple Signatures
    • Multiple Parties
    • Multiple Parties, Two authorizers
    • Multiple Parties, Multiple Signatures
    • Verify Signature
      • User Signature
      • User Signature Verify All
      • User Signature Verify Any
    • Verify Events
    • Create Account
    • Add Account Key
    • Deploy Contract
    • Query Events
    • Transaction Arguments
    • Transaction Signing
      • Single Party, Single Signature
      • Single Party, Multiple Signatures
      • Multiple Parties
      • Multiple Parties, Two authorizers
      • Multiple Parties, Multiple Signatures

Running the emulator with the Flow CLI

The emulator is bundled with the Flow CLI, a command-line interface for working with Flow.

Installation

Follow these steps to install the Flow CLI.

Starting the server

Start the emulator by running the following command in this directory:

flow emulator start -v

The -v flag enables verbose log output, which is useful for testing

Running the examples

In a separate process, run any of the example programs below. Watch the emulator logs to see transaction output.

Get Blocks

Get blocks by ID, height or latest on Flow.

make get-blocks

Get Accounts

Get accounts by address in specific block on Flow

make get-accounts

Get Events

Get events emitted by transactions.

make get-events

Get Collection

Get collections by ID.

make get-collection

Execute Script

Execute cadence script.

make send-transactions

Send Transaction

Send a transaction.

make send-transactions

Create Account

Create a new account on Flow.

make create-account

Add Account Key

Add a key to an existing account.

make add-account-key

Deploy Contract

Deploy a Cadence smart contract.

make deploy-contract

Transaction Arguments

Submit a transaction with Cadence arguments.

make transaction-arguments

Transaction Signing

Single Party, Single Signature

Sign a transaction with a single account.

make single-party

Single Party, Multiple Signatures

Sign a transaction with a single account using multiple signatures.

make single-party-multisig

Multiple Parties

Sign a transaction with multiple accounts.

make multi-party

Multiple Parties, Two authorizers

Sign a transaction with multiple accounts and authorize for both of them.

make multi-party-two-authorizers

Multiple Parties, Multiple Signatures

Sign a transaction with multiple accounts using multiple signatures.

make multi-party-multisig

Verify Signature

User Signature

Sign an arbitrary user message.

make user-signature

User Signature Verify all

Sign an arbitrary user message and verify it by using the public keys on an account respecting the weights of each key.

make user-signature-verify-all

User Signature Verify any

Sign an arbitrary user message and verify it by using the public keys on an account. Return success if any public key on the account can sign the message.

make user-signature-verify-all

Verify Events

Verify events emitted in a block.

make verify-events

Documentation

Index

• Variables
• func CreateAccount(flowClient access.Client, publicKeys []*flow.AccountKey) *flow.Account
• func CreateAccountWithContracts(flowClient access.Client, publicKeys []*flow.AccountKey, ...) *flow.Account
• func First[T any](arr []T, f func(e T) bool) (T, error)
• func FundAccountInEmulator(flowClient access.Client, address flow.Address, amount float64)
• func GetReferenceBlockId(flowClient access.Client) flow.Identifier
• func Handle(err error)
• func NewFlowGRPCClient() *grpc.Client
• func Print[T any](object T)
• func RandomAccount(flowClient access.Client) (flow.Address, *flow.AccountKey, crypto.Signer)
• func RandomPrivateKey() crypto.PrivateKey
• func RandomTransaction(flowClient access.Client) *flow.Transaction
• func ReadFile(name string) string
• func ServiceAccount(flowClient access.Client) (flow.Address, *flow.AccountKey, crypto.Signer)
• func WaitForSeal(ctx context.Context, c access.Client, id flow.Identifier) *flow.TransactionResult

Variables

var Config *config.Config

Functions

func CreateAccount

func CreateAccount(flowClient access.Client, publicKeys []*flow.AccountKey) *flow.Account

func CreateAccountWithContracts

func CreateAccountWithContracts(flowClient access.Client, publicKeys []*flow.AccountKey, contracts []templates.Contract) *flow.Account

func First

func First[T any](arr []T, f func(e T) bool) (T, error)

func FundAccountInEmulator

func FundAccountInEmulator(flowClient access.Client, address flow.Address, amount float64)

FundAccountInEmulator Mints FLOW to an account. Minting only works in an emulator environment.

func GetReferenceBlockId

func GetReferenceBlockId(flowClient access.Client) flow.Identifier

func Handle

func Handle(err error)

func NewFlowGRPCClient

func NewFlowGRPCClient() *grpc.Client

func Print

func Print[T any](object T)

func RandomAccount

func RandomAccount(flowClient access.Client) (flow.Address, *flow.AccountKey, crypto.Signer)

func RandomPrivateKey

func RandomPrivateKey() crypto.PrivateKey

RandomPrivateKey returns a randomly generated ECDSA P-256 private key.

func RandomTransaction

func RandomTransaction(flowClient access.Client) *flow.Transaction

func ReadFile

func ReadFile(name string) string

func ServiceAccount

func ServiceAccount(flowClient access.Client) (flow.Address, *flow.AccountKey, crypto.Signer)

func WaitForSeal

func WaitForSeal(ctx context.Context, c access.Client, id flow.Identifier) *flow.TransactionResult