Example #1
0
// Query has two functions
// get - takes one argument, a key, and returns the value for the key
// keys - returns all keys stored in this chaincode
func (t *SimpleChaincode) Query(stub shim.ChaincodeStubInterface, function string, args []string) ([]byte, error) {

	switch function {

	case "get":
		if len(args) < 1 {
			return nil, errors.New("get operation must include one argument, a key")
		}
		key := args[0]
		value, err := stub.GetState(key)
		if err != nil {
			return nil, fmt.Errorf("get operation failed. Error accessing state: %s", err)
		}
		return value, nil

	case "keys":

		keysIter, err := stub.RangeQueryState("", "")
		if err != nil {
			return nil, fmt.Errorf("keys operation failed. Error accessing state: %s", err)
		}
		defer keysIter.Close()

		var keys []string
		for keysIter.HasNext() {
			key, _, iterErr := keysIter.Next()
			if iterErr != nil {
				return nil, fmt.Errorf("keys operation failed. Error accessing state: %s", err)
			}
			keys = append(keys, key)
		}

		jsonKeys, err := json.Marshal(keys)
		if err != nil {
			return nil, fmt.Errorf("keys operation failed. Error marshaling JSON: %s", err)
		}

		return jsonKeys, nil

	default:
		return nil, errors.New("Unsupported operation")
	}
}
Example #2
0
// Invoke has two functions
// put - takes two arguements, a key and value, and stores them in the state
// remove - takes one argument, a key, and removes if from the state
func (t *SimpleChaincode) Invoke(stub shim.ChaincodeStubInterface) ([]byte, error) {
	function, args := stub.GetFunctionAndParameters()
	switch function {
	case "put":
		if len(args) < 2 {
			return nil, errors.New("put operation must include two arguments, a key and value")
		}
		key := args[0]
		value := args[1]

		err := stub.PutState(key, []byte(value))
		if err != nil {
			fmt.Printf("Error putting state %s", err)
			return nil, fmt.Errorf("put operation failed. Error updating state: %s", err)
		}
		return nil, nil

	case "remove":
		if len(args) < 1 {
			return nil, errors.New("remove operation must include one argument, a key")
		}
		key := args[0]

		err := stub.DelState(key)
		if err != nil {
			return nil, fmt.Errorf("remove operation failed. Error updating state: %s", err)
		}
		return nil, nil

	case "get":
		if len(args) < 1 {
			return nil, errors.New("get operation must include one argument, a key")
		}
		key := args[0]
		value, err := stub.GetState(key)
		if err != nil {
			return nil, fmt.Errorf("get operation failed. Error accessing state: %s", err)
		}
		return value, nil

	case "keys":
		keysIter, err := stub.RangeQueryState("", "")
		if err != nil {
			return nil, fmt.Errorf("keys operation failed. Error accessing state: %s", err)
		}
		defer keysIter.Close()

		var keys []string
		for keysIter.HasNext() {
			key, _, iterErr := keysIter.Next()
			if iterErr != nil {
				return nil, fmt.Errorf("keys operation failed. Error accessing state: %s", err)
			}
			keys = append(keys, key)
		}

		jsonKeys, err := json.Marshal(keys)
		if err != nil {
			return nil, fmt.Errorf("keys operation failed. Error marshaling JSON: %s", err)
		}

		return jsonKeys, nil

	default:
		return nil, errors.New("Unsupported operation")
	}
}