chain.go

package main

import (
	"errors"
	"fmt"
    	"hash"

	"github.com/hyperledger/fabric/core/chaincode/shim"
)

// SimpleChaincode example simple Chaincode implementation
type SimpleChaincode struct {
}

func main() {
	err := shim.Start(new(SimpleChaincode))
	if err != nil {
		fmt.Printf("Error starting Simple chaincode: %s", err)
	}
}

// Init resets all the things
func (t *SimpleChaincode) Init(stub *shim.ChaincodeStub, function string, args []string) ([]byte, error) {
	if len(args) != 1 {
		return nil, errors.New("Incorrect number of arguments. Expecting 1")
	}

	err := stub.PutState("hello_world", []byte(args[0]))
	if err != nil {
		return nil, err
	}

	return nil, nil
}

// Invoke isur entry point to invoke a chaincode function
func (t *SimpleChaincode) Invoke(stub *shim.ChaincodeStub, function string, args []string) ([]byte, error) {
	fmt.Println("invoke is running " + function)

	// Handle different functions
	if function == "init" {
		return t.Init(stub, "init", args)
	} else if function == "write" {
		return t.write(stub, args)
	}
	fmt.Println("invoke did not find func: " + function)

	return nil, errors.New("Received unknown function invocation")
}

// Query is our entry point for queries
func (t *SimpleChaincode) Query(stub *shim.ChaincodeStub, function string, args []string) ([]byte, error) {
	fmt.Println("query is running " + function)

	// Handle different functions
	if function == "read" { //read a variable
		return t.read(stub, args)
	}
	fmt.Println("query did not find func: " + function)

	return nil, errors.New("Received unknown function query")
}

// write - invoke function to write key/value pair
func (t *SimpleChaincode) write(stub *shim.ChaincodeStub, args []string) ([]byte, error) {
	var key, value string
	var err error
	fmt.Println("running write()")

	if len(args) != 2 {
		return nil, errors.New("Incorrect number of arguments. Expecting 2. name of the key and value to set")
	}

	key = args[0] //rename for funsies
	value = args[1]
	err = stub.PutState(key, []byte(value)) //write the variable into the chaincode state
	if err != nil {
		return nil, err
	}
	return nil, nil
}

// read - query function to read key/value pair
func (t *SimpleChaincode) read(stub *shim.ChaincodeStub, args []string) ([]byte, error) {
	var key, jsonResp string
	var err error

	if len(args) != 1 {
		return nil, errors.New("Incorrect number of arguments. Expecting name of the key to query")
	}

	key = args[0]
	valAsbytes, err := stub.GetState(key)
	if err != nil {
		jsonResp = "{\"Error\":\"Failed to get state for " + key + "\"}"
		return nil, errors.New(jsonResp)
	}

	return valAsbytes, nil



// New224 creates a new SHA3-224 hash.
// Its generic security strength is 224 bits against preimage attacks,
// and 112 bits against collision attacks.
func New224() hash.Hash {
	if h := new224Asm(); h != nil {
		return h
	}
	return &state{rate: 144, outputLen: 28, dsbyte: 0x06}
}

// New256 creates a new SHA3-256 hash.
// Its generic security strength is 256 bits against preimage attacks,
// and 128 bits against collision attacks.
func New256() hash.Hash {
	if h := new256Asm(); h != nil {
		return h
	}
	return &state{rate: 136, outputLen: 32, dsbyte: 0x06}
}

// New384 creates a new SHA3-384 hash.
// Its generic security strength is 384 bits against preimage attacks,
// and 192 bits against collision attacks.
func New384() hash.Hash {
	if h := new384Asm(); h != nil {
		return h
	}
	return &state{rate: 104, outputLen: 48, dsbyte: 0x06}
}

// New512 creates a new SHA3-512 hash.
// Its generic security strength is 512 bits against preimage attacks,
// and 256 bits against collision attacks.
func New512() hash.Hash {
	if h := new512Asm(); h != nil {
		return h
	}
	return &state{rate: 72, outputLen: 64, dsbyte: 0x06}
}

// NewLegacyKeccak256 creates a new Keccak-256 hash.
//
// Only use this function if you require compatibility with an existing cryptosystem
// that uses non-standard padding. All other users should use New256 instead.
func NewLegacyKeccak256() hash.Hash { return &state{rate: 136, outputLen: 32, dsbyte: 0x01} }

// Sum224 returns the SHA3-224 digest of the data.
func Sum224(data []byte) (digest [28]byte) {
	h := New224()
	h.Write(data)
	h.Sum(digest[:0])
	return
}

// Sum256 returns the SHA3-256 digest of the data.
func Sum256(data []byte) (digest [32]byte) {
	h := New256()
	h.Write(data)
	h.Sum(digest[:0])
	return
}

// Sum384 returns the SHA3-384 digest of the data.
func Sum384(data []byte) (digest [48]byte) {
	h := New384()
	h.Write(data)
	h.Sum(digest[:0])
	return
}

// Sum512 returns the SHA3-512 digest of the data.
func Sum512(data []byte) (digest [64]byte) {
	h := New512()
	h.Write(data)
	h.Sum(digest[:0])
	return
}
}