HM Land Registry Digital Street Proof of Concept - CorDapp

This is a CorDapp for demonstrating a simple transfer of ownership on Corda, including smart contracts and digital signatures.

Directory Structure

Directory	Description
/config	contains log4j configs
/cordapp-common	module defining common/reusable pieces of code
/cordapp-contracts-states	module defining states, contracts, data Models and ORM schemas
/cordapp-flows	module defining corda flows
/gradle	contains the gradle wrapper, which allows the use of gradle without installing it yourself and worrying about which version is required
/lib	contains the quasar jar which rewrites our CorDapp’s flows to be checkpointable
/src	contains end to end integration test of CorDapp

Running the nodes from the terminal

Pre-requisites

Please refer to the Getting set up instructions.

You will also need a running instance of Title API within the Digital Street development Environment

Building the CorDapp

Note: The HMLR CorDapp depends on land title data from the external Title API service. The API URL has to be set as a gradle property (as shown in the commands below), or by modifying gradle.properties.

• Open a terminal window in the digital-street-cordapp directory
• Build the test nodes with our CorDapp using the following command:
  • Unix/Mac OSX: ./gradlew deployNodes -PtitleApiUrl=http://localhost:8005/v1/titles/
  • Windows: gradlew.bat deployNodes -PtitleApiUrl=http://localhost:8005/v1/titles/

Running the CorDapp

Start the nodes by running the following command from the root of the digital-street-cordapp folder

• Unix/Mac OSX: kotlin-source/build/nodes/runnodes
• Windows: call kotlin-source\build\nodes\runnodes.bat

This will start 6 Corda Nodes

• HMLR
• Conveyancer1
• Conveyancer2
• Lender1
• SettlingParty
• Notary

Running the Unit tests

Note: The flow-tests depends on land title data from the external Title API service. The API URL has to be set as a gradle property (as shown in the commands below), or by modifying gradle.properties.

Note: Instructions for running JUnit tests from an IDE.

• Open a terminal window in the digital-street-cordapp directory
• Run the test cases using the following command
  • Unix/Mac OSX: ./gradlew test -PtitleApiUrl=http://localhost:8005/v1/titles/
  • Windows: gradlew.bat test -PtitleApiUrl=http://localhost:8005/v1/titles/

Running the end to end Integration test

Note: The flow-tests depends on land title data from the external Title API service. The API URL has to be set as a gradle property (as shown in the commands below), or by modifying gradle.properties.

• Open a terminal window in the digital-street-cordapp directory
• Run the integration test case using the following command
  • Unix/Mac OSX: ./gradlew clean integrationTest --info -PtitleApiUrl=http://localhost:8005/v1/titles/
  • Windows: gradlew.bat clean integrationTest --info -PtitleApiUrl=http://localhost:8005/v1/titles/

End-to-End CorDapp flow description

The integration test script covers the end to end journey of the CorDapp as described below:

STEP: 1

• A Seller's Conveyancer requests HMLR a particular land title which the seller owns

• This will create a transaction with RequestIssuanceState between the HMLR and the Conveyancer node

       ----------------------------
       |                          |
       |                          |
       | RequestIssuanceState     |
       |                          |
       |    - titleID             |
       |    - titleIssuer         |
       |    - seller              |
       |    - sellerConveyancer   |
       |    - status              |
       |                          |
       |                          |
       ----------------------------
  

STEP: 2

• HMLR will then automatically issue a land title on the Corda ledger by invoking a sub-flow

• This will create a transaction with new LandTitleState, ProposedChargesAndRestrictionState being issued on the HMLR, Seller's Conveyancer and Seller's Lender nodes

       ---------------------------------
       |                               |
       |                               |
       |  LandTitleState               |
       |                               |
       |    - titleID                  |
       |    - landTitleProperties      |
       |    - titleIssuer              |
       |    - titleType                |
       |    - lastSoldValue            |
       |    - status                   |
       |                               |
       ---------------------------------
   
       ---------------------------------------
       |                                     |
       |                                     |
       |  ProposedChargesAndRestrictionsState|
       |                                     |
       |    - titleID                        |
       |    - ownerConveyancer               |
       |    - buyerConveyancer               |
       |    - restrictions                   |
       |    - charges                        |
       |    - status                         |
       |                                     |  
       |                                     |
       |                                     | 
       ---------------------------------------
  
       ---------------------------------------
       |                                     |
       |                                     |
       |  ProposedChargesAndRestrictionsState|
       |                                     |
       |    - titleID                        |
       |    - ownerConveyancer               |
       |    - buyerConveyancer               |
       |    - restrictions                   |
       |    - charges                        |
       |    - status                         |
       |                                     |  
       |                                     |
       |                                     |
       ---------------------------------------
  

STEP: 3

• The Seller's Conveyancer would then request seller's lender to provide consent for discharge
• This will update the ProposedChargesAndRestrictionState with status = REQUEST_TO_ADD_CONSENT_FOR_DISCHARGE

STEP: 4

• The Seller's Lender would then provide consent for discharge
• This will update the ProposedChargesAndRestrictionState with status = CONSENT_FOR_DISCHARGE

STEP: 5

• The Seller's Conveyancer would then create a Sales contract with the Buyer's Conveyancer

• This will create a transaction with new LandAgreementState, PaymentConfirmationState issued on both conveyancer's nodes and SettlingParty node

       ---------------------------------                     
       |                               |       
       |                               |
       |  LandAgreementState           |
       |                               |
       |    - titleID                  |
       |    - buyer                    |            
       |    - seller                   |                          
       |    - buyerConveyancer         |
       |    - sellerconveyacner        |
       |    - creationDate             |
       |    - completionDate           |
       |    - contractRate             |
       |    - purchasePrice            |
       |    - deposit                  |
       |    - contentsPrice            |
       |    - balance                  |
       |    - titleStateLinearId       |
       |    - specificIncumbrances     |
       |    - titleGuarantee           |
       |    - status                   |
       |                               |
       ---------------------------------
       
       ----------------------------------
       |                                |
       |                                |
       |  PaymentConfirmationState      |
       |                                |
       |    - titleID                   |
       |    - seller                    |
       |    - buyer                     |
       |    - purchasePrice             |
       |    - landAgreementStateLinearId|
       |    - settlingParty             |
       |    - buyerConveyancer          | 
       |    - status                    |
       |                                | 
       ----------------------------------
  
  
       ----------------------------------
       |                                |
       |                                |
       |  PaymentConfirmationState      |
       |                                |
       |    - titleID                   |
       |    - seller                    |
       |    - buyer                     |
       |    - purchasePrice             |
       |    - landAgreementStateLinearId|
       |    - settlingParty             |
       |    - buyerConveyancer          |
       |    - status                    |
       |                                |
       ----------------------------------
  

STEP: 6

• The Buyer's conveyancer would then provide consent to add a new charge to the land title
• This will update the ProposedChargesAndRestrictionState with new charge details and status = CONSENT_FOR_NEW_CHARGE

STEP: 7

• The Buyer's conveyancer approves the sales contract
• This will update the LandAgreementState with status = APPROVED

STEP: 8

• The Seller signs the sales contract
• A Smart Contract will verify the seller's signature
• This will update the LandAgreementState with status = SIGNED

STEP: 9

• The Settling Party would then provide confirmation of payment they received from buyer in their escrow account offline
• This will update the PaymentConfirmationState with status = CONFIRM_PAYMENT_RECEIVED_IN_ESCROW

STEP: 10

• The Buyer signs the sales contract
• A Smart Contract will verify the buyer's signature
• This will update the LandAgreementState with status = COMPLETED

STEP: 11

• The land gets transferred to the buyer on the completion date if all the constraints in the Smart Contract are met

JUnit test prerequisites

• Sets up the test working directory (after each clean) using the following command:
  • Unix/Mac OSX: ./gradlew copyConfig -PtitleApiUrl=http://localhost:8005/v1/titles/
  • Windows: gradlew.bat copyConfig -PtitleApiUrl=http://localhost:8005/v1/titles/
• Add -javaagent:../../lib/quasar.jar as a VM option.
• Set the working directory to build/tests.