Interaction

This module provides an ADT (Abstract Data Type) that represents the underlying data required by the send function. It provides function in which to modify the interaction.

Types of interactions

Currently the Access Node recognizes 7 different types of interactions.

• Script executes a script, can be used to query Flow
• Transaction executes a transaction
• GetTransaction requests the status of a supplied transaction
• GetAccount requests a supplied account
• GetEvents requests events of a supplied type
• GetLatestBlock requests the latest block
• Ping requests a pong

Internal Properties

The interaction is a monomorphic data structure, that merges the 7 types of interactions together. Internally it has a bunch of properties, but not everything needs to be included for each of the 7 interaction types.

• tag (all) Int -- a marker that represents the type of the interaction
• status (all) Int -- a marker that represents the status of the interaction
• reason (all) String -- used to supply more information/feedback when a status is bad
• payload (script, transaction)
  • code (script, transaction) UInt8Array -- encoded cadence code
  • ref (transaction) UInt8Array -- encoded id of an existing block (used for timeout)
  • nonce (transaction) Int -- all transactions in Flow need to be unique
  • limit (transaction) Int -- how much payer is willing to spend
• bounds (getEvents)
  • start (getEvebts) Int [?-> UInt8Array] -- events after this
  • end (getEvents) Int [?-> UInt8Array] -- events before this
• acct (getAccount) UInt8Array -- encoded version of an account
• authz (transaction) Array<{acct:UInt8Array, signature:UInt8Array}> -- list of accounts and signatures authorizing a transaction
• payer (transaction) {acct:UInt8Array, signature: UInt8Array} -- which account is paying for the transaction and their authorization
• eventType (getEvents) String [?->UInt8Array] -- the type of events to query against
• txId (getTransaction) UInt8Array -- encoded id of the transaction to query against
• isSealed (getLatestBlock) Boolean -- determines if the criteria for the latest block is sealed or FIND_CORRECT_STATE_NAME
• assigns (all) {[String]:Any} -- a pocket to hold things in while building and resolving

Exposed Constants

Tags

Status

Exposed Functions

• Constructor
  • interaction/0
  • isInteraction/1
• Control
  • Ok/1
  • isOk/1
  • Bad/2
  • isBad/1
  • why/1
• Tags
  • Unknown
    • makeUnknown/1
    • isUnknown/1
  • Script
    • makeScript/1
    • isScript/1
  • Transaction
    • makeTransaction/1
    • isTransaction/1
  • GetTransaction
    • makeGetTransaction/1
    • isGetTransaction/1
  • GetAccount
    • makeGetAccount/1
    • isGetAccount/1
  • GetEvents
    • makeGetEvents/1
    • isGetEvents/1
  • GetLatestBlock
    • makeGetLatestBlock/1
    • isGetLatestBlock/1
  • Ping
    • makePing/1
    • isPing/1
• Assigns
  • get/3
  • put/2
  • update/2
  • destroy/1
• Composition
  • pipe/2
  • pipe/1

interaction/0

Constructs an empty interaction.

import {interaction} from "@onflow/interaction"

const emptyInteraction = interaction()

isInteraction/1

returns true if the value passed to it is an interaction

import {interaction, isInteraction} from "@onflow/interaction"

const ix = interaction()

isInteraction(ix) // true
isInteraction("i am a string") // false

Ok/1 and isOk/1

Sets the status of an interaction to OK

import {interaction, Ok, isOk} from "@onflow/interaction"

isOk(Ok(interaction())) // true

Bad/2, isBad/1 and why/1

Sets the status of an interaction to BAD, can also add a reason as to why its bad.

import {interaction, Bad, why} from "@onflow/interaction"

const ix = Bad(interaction, "You were supposed to do the thing")
isBad(ix) // true
why(ix) // "You were supposed to do the thing"

makeUnknown/1 and isUnknown/1

tags an interaction as Unknown

import {interaction, makeUnknown, isUnknown} from "@onflow/interaction"

isUnknown(makeUnknown(interaction())) // true

makeScript/1 and isScript/1

tags an interaction as a Script interaction

import {interaction, makeScript, isScript} from "@onflow/interaction"

isScript(makeScript(interaction())) // true

makeTransaction/1 and isTransaction/1

tags an interaction as a Transaction interaction

import {interaction, makeTransaction, isTransaction} from "@onflow/interaction"

isTransaction(makeTransaction(interaction())) // true

makeGetTransaction/1 and isGetTransaction/1

tags an interaction as a GetTransaction interaction

import {interaction, makeGetTransaction, isGetTransaction} from "@onflow/interaction"

isGetTransaction(makeGetTransaction(interaction())) // true

makeGetAccount/1 and isGetAccount/1

tags an interaction as a GetAccount interaction

import {interaction, makeGetAccount, isGetAccount} from "@onflow/interaction"

isGetAccount(makeGetAccount(interaction())) // true

makeGetEvents/1 and isGetEvents/1

tags an interaction as a GetEvents interaction

import {interaction, makeGetEvents, isGetEvents} from "@onflow/interaction"

isGetEvents(makeGetEvents(interaction())) // true

makeGetLatestBlock/1 and isGetLatestBlock/1

tags an interaction as a GetLatestBlock interaction

import {interaction, makeGetLatestBlock, isGetLatestBlock} from "@onflow/interaction"

isGetLatestBlock(makeGetLatestBlock(interaction())) // true

makePing/1 and isPing/1

tags an interaction as a Ping interaction

import {interaction, makePing, isPing} from "@onflow/interaction"

isPing(makePing(interaction())) // true

get/3, put/2, update/2 and destory/1

crud operations for the assigns pocket inside the interaction. They are specifically designed to be used with pipe.

import {interaction, get, put, update, destory} from "@onflow/interaction"

let ix = interaction()
get(ix, "count", 0) // 0

ix = put("count", 0)(ix)
get(ix, "count", 0) // 0

ix = update("count", count => count + 1)(ix)
get(ix, "count", 0) // 1

ix = destory("count")(ix)
get(ix, "count", 0) // 0

pipe/2

asynchronously composes transform functions and applys them to an interaction.

import {interaction, pipe, put, update} from "@onflow/interaction"

const ix = await pipe(interaction(), [
  put("a", 5),
  put("b", 6),
  update("sum", (_, ix) => get(ix, "a", 0) + get(ix, "b", 0))
])

get(ix, "sum", 0) // 11

pipe/1

gets passed an array of transform functions, returning a function that takes an interaction to apply the transform functions to asynchronously.

import {interaction, pipe, put, update} from "@onflow/interaction"

const run = await pipe([
  put("a", 5),
  put("b", 6),
  update("sum", (_, ix) => get(ix, "a", 0) + get(ix, "b", 0))
])

const ix = run(interaction())

get(ix, "sum", 0) // 11

// Pipes can also be composed

const p1 = pipe([
  put("a", 1),
  put("b", 2),
])

const p2 = pipe([
  put("c", 3),
  put("d", 4),
])

const calc = update("sum", (_, ix) => ["a", "b", "c", "d"].reduce((acc, d) => acc + get(ix, d, 0), 0))

const ix = await pipe(interaction(), [p1, p2, calc])
get(ix, "sum", 0) // 10

// Pipes can be stoped

import { Bad, Ok, isBad, why } from "@onflow/interaction"

const countCantBeGreaterThan = value => ix => 
  get(ix, "count", 0) > value
    ? Bad(ix, `Was greater than ${value}`)
    : Ok(ix)

const setCount = count => put("count", count)

const incCountBy = amount => update("count", (count) => count + amount)

const ix = await pipe(interaction(), [
  setCount(5),                // count: 5
  countCantBeGreaterThan(10), // Ok
  incCountBy(3),              // count: 8
  countCantBeGreaterThan(10), // Ok
  incCountBy(5),              // count: 13
  countCantBeGreaterThan(10), // Bad
  incCountBy(9),              // never called
])

isBad(ix) // true
why(ix) // "Was greater than 10"