IBM Blockchain Development with Hyperledger Composer

# models/sample.cto
/**
 * Defines a data model for a blind vehicle auction
 */
namespace org.acme.vehicle.auction

asset Vehicle identified by vin {
  o String vin
  o String make optional
  o String model optional
  --> Member owner
}

enum ListingState {
  o FOR_SALE
  o RESERVE_NOT_MET
  o SOLD
}

asset VehicleListing identified by listingId {
  o String listingId
  o Double reservePrice
  o String description
  o ListingState state
  o Offer[] offers optional
  --> Vehicle vehicle
}

abstract participant User identified by email {
  o String email
  o String firstName
  o String lastName
}

participant Member extends User {
  o Double balance
}

participant Auctioneer extends User {
}

transaction Offer {
  o Double bidPrice
  --> VehicleListing listing
  --> Member member
}

transaction CloseBidding {
  --> VehicleListing listing
}

# permissions.ocl

/**
 * Access Control List for the auction network.
 */
rule Auctioneer {
    description: "Allow the auctioneer full access"
    participant: "org.acme.vehicle.auction.Auctioneer"
    operation: ALL
    resource: "org.acme.vehicle.auction.*"
    action: ALLOW
}

rule Member {
    description: "Allow the member read access"
    participant: "org.acme.vehicle.auction.Member"
    operation: READ
    resource: "org.acme.vehicle.auction.*"
    action: ALLOW
}

rule VehicleOwner {
    description: "Allow the owner of a vehicle total access"
    participant(m): "org.acme.vehicle.auction.Member"
    operation: ALL
    resource(v): "org.acme.vehicle.auction.Vehicle"
    condition: (v.owner.getIdentifier() == m.getIdentifier())
    action: ALLOW
}

rule VehicleListingOwner {
    description: "Allow the owner of a vehicle total access to their vehicle listing"
    participant(m): "org.acme.vehicle.auction.Member"
    operation: ALL
    resource(v): "org.acme.vehicle.auction.VehicleListing"
    condition: (v.vehicle.owner.getIdentifier() == m.getIdentifier())
    action: ALLOW
}

rule SystemACL {
  description:  "System ACL to permit all access"
  participant: "org.hyperledger.composer.system.Participant"
  operation: ALL
  resource: "org.hyperledger.composer.system.**"
  action: ALLOW
}

rule NetworkAdminUser {
    description: "Grant business network administrators full access to user resources"
    participant: "org.hyperledger.composer.system.NetworkAdmin"
    operation: ALL
    resource: "**"
    action: ALLOW
}

rule NetworkAdminSystem {
    description: "Grant business network administrators full access to system resources"
    participant: "org.hyperledger.composer.system.NetworkAdmin"
    operation: ALL
    resource: "org.hyperledger.composer.system.**"
    action: ALLOW
}

# lib/sample.js
/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Close the bidding for a vehicle listing and choose the
 * highest bid that is over the asking price
 * @param {org.acme.vehicle.auction.CloseBidding} closeBidding - the closeBidding transaction
 * @transaction
 */
function closeBidding(closeBidding) {
    var listing = closeBidding.listing;
    if (listing.state !== 'FOR_SALE') {
        throw new Error('Listing is not FOR SALE');
    }
    // by default we mark the listing as RESERVE_NOT_MET
    listing.state = 'RESERVE_NOT_MET';
    var highestOffer = null;
    var buyer = null;
    var seller = null;
    if (listing.offers && listing.offers.length > 0) {
        // sort the bids by bidPrice
        listing.offers.sort(function(a, b) {
            return (b.bidPrice - a.bidPrice);
        });
        highestOffer = listing.offers[0];
        if (highestOffer.bidPrice >= listing.reservePrice) {
            // mark the listing as SOLD
            listing.state = 'SOLD';
            buyer = highestOffer.member;
            seller = listing.vehicle.owner;
            // update the balance of the seller
            console.log('#### seller balance before: ' + seller.balance);
            seller.balance += highestOffer.bidPrice;
            console.log('#### seller balance after: ' + seller.balance);
            // update the balance of the buyer
            console.log('#### buyer balance before: ' + buyer.balance);
            buyer.balance -= highestOffer.bidPrice;
            console.log('#### buyer balance after: ' + buyer.balance);
            // transfer the vehicle to the buyer
            listing.vehicle.owner = buyer;
            // clear the offers
            listing.offers = null;
        }
    }
    return getAssetRegistry('org.acme.vehicle.auction.Vehicle')
        .then(function(vehicleRegistry) {
            // save the vehicle
            if (highestOffer) {
                return vehicleRegistry.update(listing.vehicle);
            } else {
                return true;
            }
        })
        .then(function() {
            return getAssetRegistry('org.acme.vehicle.auction.VehicleListing')
        })
        .then(function(vehicleListingRegistry) {
            // save the vehicle listing
            return vehicleListingRegistry.update(listing);
        })
        .then(function() {
            return getParticipantRegistry('org.acme.vehicle.auction.Member')
        })
        .then(function(userRegistry) {
            // save the buyer
            if (listing.state == 'SOLD') {
                return userRegistry.updateAll([buyer, seller]);
            } else {
                return true;
            }
        });
}

/**
 * Make an Offer for a VehicleListing
 * @param {org.acme.vehicle.auction.Offer} offer - the offer
 * @transaction
 */
function makeOffer(offer) {
    var listing = offer.listing;
    if (listing.state !== 'FOR_SALE') {
        throw new Error('Listing is not FOR SALE');
    }
    if (listing.offers == null) {
        listing.offers = [];
    }
    listing.offers.push(offer);
    return getAssetRegistry('org.acme.vehicle.auction.VehicleListing')
        .then(function(vehicleListingRegistry) {
            // save the vehicle listing
            return vehicleListingRegistry.update(listing);
        });
}