update fabcar go to new programming model

Signed-off-by: Andrew Hurt <andrew.hurt1@ibm.com>

chaincode/fabcar/go/fabcar.go

@@ -17,82 +17,37 @@
  * under the License.
  */
 
-/*
- * The sample smart contract for documentation topic:
- * Writing Your First Blockchain Application
- */
-
 package main
 
-/* Imports
- * 4 utility libraries for formatting, handling bytes, reading and writing JSON, and string manipulation
- * 2 specific Hyperledger Fabric specific libraries for Smart Contracts
- */
 import (
- "bytes"
  "encoding/json"
  "fmt"
  "strconv"
 
- "github.com/hyperledger/fabric-chaincode-go/shim"
- pb "github.com/hyperledger/fabric-protos-go/peer"
+ "github.com/hyperledger/fabric-contract-api-go/contractapi"
 )
 
-// Define the Smart Contract structure
+// SmartContract provides functions for managing a car
 type SmartContract struct {
+ contractapi.Contract
 }
 
-// Define the car structure, with 4 properties. Structure tags are used by encoding/json library
+// Car describes basic details of what makes up a car
 type Car struct {
  Make string `json:"make"`
  Model string `json:"model"`
  Colour string `json:"colour"`
  Owner string `json:"owner"`
 }
 
-/*
- * The Init method is called when the Smart Contract "fabcar" is instantiated by the blockchain network
- * Best practice is to have any Ledger initialization in separate function -- see initLedger()
- */
-func (s *SmartContract) Init(APIstub shim.ChaincodeStubInterface) pb.Response {
- return shim.Success(nil)
+// QueryResult structure used for handling result of query
+type QueryResult struct {
+ Key string `json:"Key"`
+ Record *Car
 }
 
-/*
- * The Invoke method is called as a result of an application request to run the Smart Contract "fabcar"
- * The calling application program has also specified the particular smart contract function to be called, with arguments
- */
-func (s *SmartContract) Invoke(APIstub shim.ChaincodeStubInterface) pb.Response {
-
- // Retrieve the requested Smart Contract function and arguments
- function, args := APIstub.GetFunctionAndParameters()
- // Route to the appropriate handler function to interact with the ledger appropriately
- if function == "queryCar" {
- return s.queryCar(APIstub, args)
- } else if function == "initLedger" {
- return s.initLedger(APIstub)
- } else if function == "createCar" {
- return s.createCar(APIstub, args)
- } else if function == "queryAllCars" {
- return s.queryAllCars(APIstub)
- } else if function == "changeCarOwner" {
- return s.changeCarOwner(APIstub, args)
- }
-
- return shim.Error("Invalid Smart Contract function name.")
-}
-
-func (s *SmartContract) queryCar(APIstub shim.ChaincodeStubInterface, args []string) pb.Response {
-
- if len(args) != 1 {
- return shim.Error("Incorrect number of arguments. Expecting 1")
- }
-
- carAsBytes, _ := APIstub.GetState(args[0])
- return shim.Success(carAsBytes)
-}
-
-func (s *SmartContract) initLedger(APIstub shim.ChaincodeStubInterface) pb.Response {
+// InitLedger adds a base set of cars to the ledger
+func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface) error {
  cars := []Car{
  Car{Make: "Toyota", Model: "Prius", Colour: "blue", Owner: "Tomoko"},
  Car{Make: "Ford", Model: "Mustang", Colour: "red", Owner: "Brad"},
@@ -107,94 +62,105 @@ func (s *SmartContract) initLedger(APIstub shim.ChaincodeStubInterface) pb.Respo
  }
 
  for i, car := range cars {
- fmt.Println("i is ", i)
  carAsBytes, _ := json.Marshal(car)
- APIstub.PutState("CAR"+strconv.Itoa(i), carAsBytes)
- fmt.Println("Added", car)
+ err := ctx.GetStub().PutState("CAR"+strconv.Itoa(i), carAsBytes)
+
+ if err != nil {
+ return fmt.Errorf("Failed to put to world state. %s", err.Error())
+ }
  }
 
- return shim.Success(nil)
+ return nil
 }
 
-func (s *SmartContract) createCar(APIstub shim.ChaincodeStubInterface, args []string) pb.Response {
-
- if len(args) != 5 {
- return shim.Error("Incorrect number of arguments. Expecting 5")
+// CreateCar adds a new car to the world state with given details
+func (s *SmartContract) CreateCar(ctx contractapi.TransactionContextInterface, carNumber string, make string, model string, colour string, owner string) error {
+ car := Car{
+ Make: make,
+ Model: model,
+ Colour: colour,
+ Owner: owner,
  }
 
- var car = Car{Make: args[1], Model: args[2], Colour: args[3], Owner: args[4]}
-
  carAsBytes, _ := json.Marshal(car)
- APIstub.PutState(args[0], carAsBytes)
 
- return shim.Success(nil)
+ return ctx.GetStub().PutState(carNumber, carAsBytes)
 }
 
-func (s *SmartContract) queryAllCars(APIstub shim.ChaincodeStubInterface) pb.Response {
+// QueryCar returns the car stored in the world state with given id
+func (s *SmartContract) QueryCar(ctx contractapi.TransactionContextInterface, carNumber string) (*Car, error) {
+ carAsBytes, err := ctx.GetStub().GetState(carNumber)
+
+ if err != nil {
+ return nil, fmt.Errorf("Failed to read from world state. %s", err.Error())
+ }
+
+ if carAsBytes == nil {
+ return nil, fmt.Errorf("%s does not exist", carNumber)
+ }
+
+ car := new(Car)
+ _ = json.Unmarshal(carAsBytes, car)
 
+ return car, nil
+}
+
+// QueryAllCars returns all cars found in world state
+func (s *SmartContract) QueryAllCars(ctx contractapi.TransactionContextInterface) ([]QueryResult, error) {
  startKey := "CAR0"
- endKey := "CAR999"
+ endKey := "CAR99"
+
+ resultsIterator, err := ctx.GetStub().GetStateByRange(startKey, endKey)
 
- resultsIterator, err := APIstub.GetStateByRange(startKey, endKey)
  if err != nil {
- return shim.Error(err.Error())
+ return nil, err
  }
  defer resultsIterator.Close()
 
- // buffer is a JSON array containing QueryResults
- var buffer bytes.Buffer
- buffer.WriteString("[")
+ results := []QueryResult{}
 
- bArrayMemberAlreadyWritten := false
  for resultsIterator.HasNext() {
  queryResponse, err := resultsIterator.Next()
+
  if err != nil {
- return shim.Error(err.Error())
- }
- // Add a comma before array members, suppress it for the first array member
- if bArrayMemberAlreadyWritten {
- buffer.WriteString(",")
+ return nil, err
  }
 
- buffer.WriteString(
- fmt.Sprintf(
- `{"Key":"%s", "Record":%s}`,
- queryResponse.Key, queryResponse.Value,
- ),
- )
- bArrayMemberAlreadyWritten = true
- }
- buffer.WriteString("]")
+ car := new(Car)
+ _ = json.Unmarshal(queryResponse.Value, car)
 
- fmt.Printf("- queryAllCars:\n%s\n", buffer.String())
+ queryResult := QueryResult{Key: queryResponse.Key, Record: car}
+ results = append(results, queryResult)
+ }
 
- return shim.Success(buffer.Bytes())
+ return results, nil
 }
 
-func (s *SmartContract) changeCarOwner(APIstub shim.ChaincodeStubInterface, args []string) pb.Response {
+// ChangeCarOwner updates the owner field of car with given id in world state
+func (s *SmartContract) ChangeCarOwner(ctx contractapi.TransactionContextInterface, carNumber string, newOwner string) error {
+ car, err := s.QueryCar(ctx, carNumber)
 
- if len(args) != 2 {
- return shim.Error("Incorrect number of arguments. Expecting 2")
+ if err != nil {
+ return err
  }
 
- carAsBytes, _ := APIstub.GetState(args[0])
- car := Car{}
+ car.Owner = newOwner
 
- json.Unmarshal(carAsBytes, &car)
- car.Owner = args[1]
-
- carAsBytes, _ = json.Marshal(car)
- APIstub.PutState(args[0], carAsBytes)
+ carAsBytes, _ := json.Marshal(car)
 
- return shim.Success(nil)
+ return ctx.GetStub().PutState(carNumber, carAsBytes)
 }
 
-// The main function is only relevant in unit test mode. Only included here for completeness.
 func main() {
 
- // Create a new Smart Contract
- err := shim.Start(new(SmartContract))
+ chaincode, err := contractapi.NewChaincode(new(SmartContract))
+
  if err != nil {
- fmt.Printf("Error creating new Smart Contract: %s", err)
+ fmt.Printf("Error create fabcar chaincode: %s", err.Error())
+ return
+ }
+
+ if err := chaincode.Start(); err != nil {
+ fmt.Printf("Error starting fabcar chaincode: %s", err.Error())
  }
 }

chaincode/fabcar/go/go.mod

@@ -1,13 +1,5 @@
 module github.com/hyperledger/fabric-samples/chaincode/fabcar/go
 
-go 1.12
+go 1.13
 
-require (
- github.com/hyperledger/fabric-chaincode-go v0.0.0-20190823162523-04390e015b85
- github.com/hyperledger/fabric-protos-go v0.0.0-20190821214336-621b908d5022
- golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7 // indirect
- golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a // indirect
- golang.org/x/text v0.3.2 // indirect
- google.golang.org/appengine v1.4.0 // indirect
- google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55 // indirect
-)
+require github.com/hyperledger/fabric-contract-api-go v0.0.0-20191118113407-4c6ff12b4f96