mirror of
https://github.com/hyperledger/fabric-samples.git
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Update token_contract.go
Add ERC20 functions TotalSupply, Approve, Allowance and TransferFrom.
This commit is contained in:
wael-shama
GitHub
parent
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commit
5cf584ba27
1 changed files with 194 additions and 58 deletions
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@ -1,3 +1,14 @@
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/*******************************************************************************
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* IBM Confidential
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*
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* OCO Source Materials
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*
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* Copyright IBM Corp. 2020
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*
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* The source code for this program is not published or otherwise
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* divested of its trade secrets, irrespective of what has been
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* deposited with the U.S. Copyright Office.
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*******************************************************************************/
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package chaincode
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import (
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@ -8,19 +19,41 @@ import (
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"github.com/hyperledger/fabric-contract-api-go/contractapi"
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)
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// Define key names for options
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const totalSupplyKey = "totalSupply"
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// SmartContract provides functions for transferring tokens between accounts
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type SmartContract struct {
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contractapi.Contract
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}
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// TotalSupply - returns the total number of tokens minted
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func (s *SmartContract) TotalSupply(ctx contractapi.TransactionContextInterface) (int, error) {
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// Get ID of submitting client identity
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clientID, err := ctx.GetClientIdentity().GetID()
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if err != nil {
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return 0, fmt.Errorf("failed to get client id: %v", err)
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}
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var minterTotalSupply = "TotalSupply"
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balanceBytes, err := ctx.GetStub().GetState(minterTotalSupply)
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if err != nil {
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return 0, fmt.Errorf("failed to read from world state: %v", err)
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}
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if balanceBytes == nil {
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return 0, fmt.Errorf("the account %s does not exist", clientID)
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}
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balance, _ := strconv.Atoi(string(balanceBytes))
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return balance, nil
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}
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// Mint creates new tokens and adds them to minter's account balance
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func (s *SmartContract) Mint(ctx contractapi.TransactionContextInterface, amount int) error {
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// Check minter authorization - this sample assumes Org1 is the central banker with privilege to mint new tokens
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clientMSPID, err := ctx.GetClientIdentity().GetMSPID()
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// Check minter authorization - this sample assumes Org1 to mint new tokens
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client := ctx.GetClientIdentity()
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clientMSPID, err := client.GetMSPID()
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if err != nil {
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return fmt.Errorf("failed to get MSPID: %v", err)
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}
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@ -49,7 +82,7 @@ func (s *SmartContract) Mint(ctx contractapi.TransactionContextInterface, amount
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if currentBalanceBytes == nil {
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currentBalance = 0
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} else {
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currentBalance, _ = strconv.Atoi(string(currentBalanceBytes)) // Error handling not needed since Itoa() was used when setting the account balance, guaranteeing it was an integer.
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currentBalance, _ = strconv.Atoi(string(currentBalanceBytes))
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}
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updatedBalance := currentBalance + amount
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@ -59,26 +92,24 @@ func (s *SmartContract) Mint(ctx contractapi.TransactionContextInterface, amount
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return err
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}
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log.Printf("minter account %s balance updated from %d to %d", minter, currentBalance, updatedBalance)
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// Update the totalSupply
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totalSupplyBytes, err := ctx.GetStub().GetState(totalSupplyKey)
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var minterTotalSupply = "TotalSupply"
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currentBalanceBytes, err = ctx.GetStub().GetState(minterTotalSupply)
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if err != nil {
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return fmt.Errorf("failed to retrieve total token supply: %v", err)
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return fmt.Errorf("failed to read minter account %s from world state: %v", minter, err)
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}
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var totalSupply int
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// If no tokens have been minted, initialize the totalSupply
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if totalSupplyBytes == nil {
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totalSupply = 0
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// If minter current balance doesn't yet exist, we'll create it with a current balance of 0
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if currentBalanceBytes == nil {
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currentBalance = 0
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} else {
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totalSupply, _ = strconv.Atoi(string(totalSupplyBytes)) // Error handling not needed since Itoa() was used when setting the totalSupply, guaranteeing it was an integer.
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currentBalance, _ = strconv.Atoi(string(currentBalanceBytes))
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}
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// Add the mint amount to the total supply and update the state
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totalSupply += amount
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ctx.GetStub().PutState(totalSupplyKey, []byte(strconv.Itoa(totalSupply)))
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updatedBalance = currentBalance + amount
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err = ctx.GetStub().PutState(minterTotalSupply, []byte(strconv.Itoa(updatedBalance)))
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log.Printf("minter account %s balance updated from %d to %d", minter, currentBalance, updatedBalance)
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return nil
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}
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@ -87,8 +118,8 @@ func (s *SmartContract) Mint(ctx contractapi.TransactionContextInterface, amount
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// recipient account must be a valid clientID as returned by the ClientID() function.
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func (s *SmartContract) Transfer(ctx contractapi.TransactionContextInterface, recipient string, amount int) error {
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if amount < 0 { // transfer of 0 is allowed in ERC20, so just validate against negative amounts
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return fmt.Errorf("transfer amount cannot be negative")
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if amount <= 0 {
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return fmt.Errorf("transfer amount must be a positive integer")
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}
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// Get ID of submitting client identity
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@ -97,6 +128,10 @@ func (s *SmartContract) Transfer(ctx contractapi.TransactionContextInterface, re
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return fmt.Errorf("failed to get client id: %v", err)
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}
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if clientID == recipient {
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return fmt.Errorf("transfer recipient must be different")
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}
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clientCurrentBalanceBytes, err := ctx.GetStub().GetState(clientID)
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if err != nil {
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return fmt.Errorf("failed to read client account %s from world state: %v", clientID, err)
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@ -106,7 +141,7 @@ func (s *SmartContract) Transfer(ctx contractapi.TransactionContextInterface, re
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return fmt.Errorf("client account %s has no balance", clientID)
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}
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clientCurrentBalance, _ := strconv.Atoi(string(clientCurrentBalanceBytes)) // Error handling not needed since Itoa() was used when setting the account balance, guaranteeing it was an integer.
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clientCurrentBalance, _ := strconv.Atoi(string(clientCurrentBalanceBytes))
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if clientCurrentBalance < amount {
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return fmt.Errorf("client account %s has insufficient funds", clientID)
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@ -114,7 +149,7 @@ func (s *SmartContract) Transfer(ctx contractapi.TransactionContextInterface, re
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recipientCurrentBalanceBytes, err := ctx.GetStub().GetState(recipient)
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if err != nil {
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return fmt.Errorf("failed to read recipient account %s from world state: %v", recipient, err)
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fmt.Errorf("failed to read recipient account %s from world state: %v", recipient, err)
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}
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var recipientCurrentBalance int
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@ -122,7 +157,7 @@ func (s *SmartContract) Transfer(ctx contractapi.TransactionContextInterface, re
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if recipientCurrentBalanceBytes == nil {
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recipientCurrentBalance = 0
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} else {
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recipientCurrentBalance, _ = strconv.Atoi(string(recipientCurrentBalanceBytes)) // Error handling not needed since Itoa() was used when setting the account balance, guaranteeing it was an integer.
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recipientCurrentBalance, _ = strconv.Atoi(string(recipientCurrentBalanceBytes))
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}
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clientUpdatedBalance := clientCurrentBalance - amount
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@ -144,6 +179,131 @@ func (s *SmartContract) Transfer(ctx contractapi.TransactionContextInterface, re
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return nil
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}
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// Allowance - Returns the amount of tokens approved by the owner that can be
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// transfered to the spender's account
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func (s *SmartContract) Allowance(ctx contractapi.TransactionContextInterface, owner string, spender string) (int, error) {
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approvalKey := owner + spender
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clientApprovedBalanceBytes, err := ctx.GetStub().GetState(approvalKey)
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if err != nil {
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return 0, fmt.Errorf("failed to read client %s approval of owner %s from world state: %v", spender, owner, err)
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}
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if clientApprovedBalanceBytes == nil {
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return 0, fmt.Errorf("spender approval account %s has no balance approved to withdraw", spender)
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}
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clientApprovedBalance, _ := strconv.Atoi(string(clientApprovedBalanceBytes))
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return clientApprovedBalance, nil
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}
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// Approve - Allow `spender` to withdraw from owner account, multiple times, up to the tokens `amount`.
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// If this function is called again it overwrites the current allowance with `amount`.
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func (s *SmartContract) Approve(ctx contractapi.TransactionContextInterface, spender string, amount int) error {
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if amount <= 0 {
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return fmt.Errorf("approval amount must be a positive integer")
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}
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// Get ID of submitting client identity
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clientID, err := ctx.GetClientIdentity().GetID()
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if err != nil {
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return fmt.Errorf("failed to get client id: %v", err)
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}
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approvalKey := clientID + spender
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err = ctx.GetStub().PutState(approvalKey, []byte(strconv.Itoa(amount)))
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if err != nil {
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return err
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}
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return nil
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}
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// TransferFrom - transfers tokens from client account to recipient account.
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// recipient account must be a valid clientID as returned by the ClientID() function.
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func (s *SmartContract) TransferFrom(ctx contractapi.TransactionContextInterface, sender string, recipient string, amount int) error {
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if amount <= 0 {
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return fmt.Errorf("transfer amount must be a positive integer")
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}
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// // Get ID of submitting client identity
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clientID, err := ctx.GetClientIdentity().GetID()
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if err != nil {
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return fmt.Errorf("failed to get client id: %v", err)
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}
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clientApprovedBalance, err := s.Allowance(ctx, sender, clientID)
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if err != nil {
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return err
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}
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if clientApprovedBalance < amount {
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return fmt.Errorf("client %s approved account has insufficient funds", clientID)
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}
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// get sender Balance
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senderCurrentBalanceBytes, err := ctx.GetStub().GetState(sender)
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if err != nil {
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return fmt.Errorf("failed to read client account %s from world state: %v", sender, err)
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}
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if senderCurrentBalanceBytes == nil {
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return fmt.Errorf("sender account %s has no balance", sender)
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}
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senderCurrentBalance, _ := strconv.Atoi(string(senderCurrentBalanceBytes))
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if senderCurrentBalance < amount {
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return fmt.Errorf("client account %s has insufficient funds", sender)
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}
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// get recipient Balance
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recipientCurrentBalanceBytes, err := ctx.GetStub().GetState(recipient)
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if err != nil {
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_ = fmt.Errorf("failed to read recipient account %s from world state: %v", recipient, err)
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}
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var recipientCurrentBalance int
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// If recipient current balance doesn't yet exist, we'll create it with a current balance of 0
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if recipientCurrentBalanceBytes == nil {
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recipientCurrentBalance = 0
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} else {
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recipientCurrentBalance, _ = strconv.Atoi(string(recipientCurrentBalanceBytes))
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}
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senderUpdatedBalance := senderCurrentBalance - amount
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clientApprovedUpdatedBalance := clientApprovedBalance - amount
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recipientUpdatedBalance := recipientCurrentBalance + amount
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err = ctx.GetStub().PutState(sender, []byte(strconv.Itoa(senderUpdatedBalance)))
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if err != nil {
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return err
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}
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approvalKey := sender + clientID
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err = ctx.GetStub().PutState(approvalKey, []byte(strconv.Itoa(clientApprovedUpdatedBalance)))
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if err != nil {
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return err
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}
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err = ctx.GetStub().PutState(recipient, []byte(strconv.Itoa(recipientUpdatedBalance)))
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if err != nil {
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return err
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}
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log.Printf("sender %s balance updated from %d to %d", sender, senderCurrentBalance, senderUpdatedBalance)
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log.Printf("client %s approval balance updated from %d to %d", clientID, clientApprovedBalance, clientApprovedUpdatedBalance)
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log.Printf("recipient %s balance updated from %d to %d", recipient, recipientCurrentBalance, recipientUpdatedBalance)
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return nil
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}
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// BalanceOf returns the balance of the given account
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func (s *SmartContract) BalanceOf(ctx contractapi.TransactionContextInterface, account string) (int, error) {
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balanceBytes, err := ctx.GetStub().GetState(account)
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@ -154,13 +314,13 @@ func (s *SmartContract) BalanceOf(ctx contractapi.TransactionContextInterface, a
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return 0, fmt.Errorf("the account %s does not exist", account)
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}
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balance, _ := strconv.Atoi(string(balanceBytes)) // Error handling not needed since Itoa() was used when setting the account balance, guaranteeing it was an integer.
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balance, _ := strconv.Atoi(string(balanceBytes))
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return balance, nil
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}
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// ClientAccountBalance returns the balance of the requesting client's account
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func (s *SmartContract) ClientAccountBalance(ctx contractapi.TransactionContextInterface) (int, error) {
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// ClientBalance returns the balance of the requesting client
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func (s *SmartContract) ClientBalance(ctx contractapi.TransactionContextInterface) (int, error) {
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// Get ID of submitting client identity
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clientID, err := ctx.GetClientIdentity().GetID()
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@ -176,44 +336,20 @@ func (s *SmartContract) ClientAccountBalance(ctx contractapi.TransactionContextI
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return 0, fmt.Errorf("the account %s does not exist", clientID)
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}
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balance, _ := strconv.Atoi(string(balanceBytes)) // Error handling not needed since Itoa() was used when setting the account balance, guaranteeing it was an integer.
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balance, _ := strconv.Atoi(string(balanceBytes))
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return balance, nil
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}
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// ClientAccountID returns the id of the requesting client's account.
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// In this implementation, the client account ID is the clientId itself.
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// Users can use this function to get their own account id, which they can then give to others as the payment address
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func (s *SmartContract) ClientAccountID(ctx contractapi.TransactionContextInterface) (string, error) {
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// ClientID returns the client id of the transaction creator
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// Users can use this function to get their own client id, which they can then give to others as the payment address
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func (s *SmartContract) ClientID(ctx contractapi.TransactionContextInterface) (string, error) {
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// Get ID of submitting client identity
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clientAccountID, err := ctx.GetClientIdentity().GetID()
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clientID, err := ctx.GetClientIdentity().GetID()
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if err != nil {
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return "", fmt.Errorf("failed to get client id: %v", err)
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}
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return clientAccountID, nil
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}
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// TotalSupply returns the total token supply
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func (s *SmartContract) TotalSupply(ctx contractapi.TransactionContextInterface) (int, error) {
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// Retrieve total supply of tokens from state of smart contract
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totalSupplyBytes, err := ctx.GetStub().GetState(totalSupplyKey)
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if err != nil {
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return 0, fmt.Errorf("failed to retrieve total token supply: %v", err)
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}
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var totalSupply int
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// If no tokens have been minted, return 0
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if totalSupplyBytes == nil {
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totalSupply = 0
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} else {
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totalSupply, _ = strconv.Atoi(string(totalSupplyBytes)) // Error handling not needed since Itoa() was used when setting the totalSupply, guaranteeing it was an integer.
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}
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log.Printf("The totalSupply was queried: %d total tokens", totalSupply)
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return totalSupply, nil
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return clientID, nil
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}
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