PurchaseOfferMarket | SubQuery Network API

# PurchaseOfferMarket

# Overview

The Purchase Offer Market Contract tracks all purchase offers for Indexers and Consumers. It allows Consumers to create/cancel purchase offers, and Indexers to accept the purchase offer to make the service agreements. It is the place Consumer publish a purchase offer for a specific deployment. And also the place indexers can search and take these purchase offers.

# Terminology

Purchase Offer: A Purchase Offer is created by the Consumer, any Indexer can accept it to make the service agreement.

# Detail

We design the date structure for Purchase Offer, It stores purchase offer related information. A Purchase Offer can accepted by multiple Indexers. Consumer transfer Token to this contract as long as the purchase offer is created. And when Indexer accept the offer, the corresponding part of the money will transfer to serviceAgrementRegistry contract first and wait rewardDistributer contract take and distribute. After Indexer accept the offer we use the planTemplate that stored in Purchase Offer structure to generate the service agreement.

Consumers can cancel their purchase offer after expire date for free, but if cancel the unexpired Purchase Offer we will charge the penalty fee.

# PurchaseOffer

struct PurchaseOffer {
  uint256 deposit;
  uint256 minimumAcceptHeight;
  uint256 minimumStakingAmount;
  uint256 planTemplateId;
  bytes32 deploymentId;
  uint256 expireDate;
  address consumer;
  bool active;
  uint16 limit;
  uint16 numAcceptedContracts;
}

# STATES

# settings

ISettings contract which stores SubQuery network contracts address

contract ISettings settings

# offers

offerId => Offer

mapping(uint256 => struct PurchaseOfferMarket.PurchaseOffer) offers

# numOffers

number of all offers

uint256 numOffers

# penaltyRate

penalty rate of consumer cancel the unexpired offer

uint256 penaltyRate

# penaltyDestination

if penalty destination address is 0x00, then burn the penalty

address penaltyDestination

# offerPoi

offerId => Indexer => _poi

mapping(uint256 => mapping(address => bytes32)) offerPoi

# EVENTS

# PurchaseOfferCreated

Emitted when Consumer create a purchase offer

event PurchaseOfferCreated(address consumer, uint256 offerId, bytes32 deploymentId, uint256 planTemplateId, uint256 deposit, uint16 limit, uint256 minimumAcceptHeight, uint256 minimumStakingAmount, uint256 expireDate)

# PurchaseOfferCancelled

Emitted when Consumer cancel a purchase offer

event PurchaseOfferCancelled(address creator, uint256 offerId, uint256 penalty)

# OfferAccepted

Emitted when Indexer accept an offer

event OfferAccepted(address indexer, uint256 offerId, uint256 agreementId)

MODIFIER

# onlyIndexer

require caller is indexer

modifier onlyIndexer()

# initialize

Initialize this contract to set penaltyRate and penaltyDestination.

function initialize(contract ISettings _settings, uint256 _penaltyRate, address _penaltyDestination) external

Name	Type	Description
_settings	contract ISettings	ISettings contract
_penaltyRate	uint256	penaltyRate that consumer cancel unexpired purchase offer
_penaltyDestination	address	penaltyDestination that consumer cancel unexpired purchase offer

# setSettings

Update setting state.

function setSettings(contract ISettings _settings) external

Name	Type	Description
_settings	contract ISettings	ISettings contract

# setPenaltyRate

allow admin the set the Penalty Rate for cancel unexpired offer.

function setPenaltyRate(uint256 _penaltyRate) external

Name	Type	Description
_penaltyRate	uint256	penalty rate to set

# setPenaltyDestination

allow admin to set the Penalty Destination address. All Penalty will transfer to this address, if penalty destination address is 0x00, then burn the penalty.

function setPenaltyDestination(address _penaltyDestination) external

Name	Type	Description
_penaltyDestination	address	penalty destination to set

# createPurchaseOffer

Allow admin to create a Purchase Offer.

function createPurchaseOffer(bytes32 _deploymentId, uint256 _planTemplateId, uint256 _deposit, uint16 _limit, uint256 _minimumAcceptHeight, uint256 _minimumStakingAmount, uint256 _expireDate) external

Name	Type	Description
_deploymentId	bytes32	deployment id
_planTemplateId	uint256	plan template id
_deposit	uint256	purchase offer value to deposit
_limit	uint16	limit indexer to accept the purchase offer
_minimumAcceptHeight	uint256	minimum block height to accept the purchase offer
_minimumStakingAmount	uint256	minimum staking amount to accept the purchase offer
_expireDate	uint256	expire date of the purchase offer in unix timestamp

# cancelPurchaseOffer

Allow Consumer to cancel their Purchase Offer. Consumer transfer all tokens to this contract when they create the offer. We will charge a Penalty to cancel unexpired Offer. And the Penalty will transfer to a configured address. If the address not configured, then we burn the Penalty.

function cancelPurchaseOffer(uint256 _offerId) external

Name	Type	Description
_offerId	uint256	purchase offer id to cancel

# acceptPurchaseOffer

Allow Indexer to accept the offer and make the service agreement. The corresponding part of the money will transfer to serviceAgrementRegistry contract and wait rewardDistributer contract take and distribute as long as Indexer accept the offer. When Indexer accept the offer we need to ensure Indexer's deployment reaches the minimumAcceptHeight, So we ask indexers to pass the latest poi value when accepting the purchase offer, and save this poi value when agreement create.

function acceptPurchaseOffer(uint256 _offerId, bytes32 _poi) external

Name	Type	Description
_offerId	uint256	purchase offer id to accept
_poi	bytes32	proof of index (hash) to accept the purchase offer

# isExpired

Return the purchase offer is expired

function isExpired(uint256 _offerId) public view returns (bool)

Name	Type	Description
_offerId	uint256	purchase offer id

Return: bool -> bool the result of is the purchase offer expired