github.com/leonlxy/hyperledger@v1.0.0-alpha.0.20170427033203-34922035d248/core/scc/samplesyscc/samplesyscc.go (about)

     1  /*
     2  Copyright IBM Corp. 2016 All Rights Reserved.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8  		 http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package samplesyscc
    18  
    19  import (
    20  	"github.com/hyperledger/fabric/core/chaincode/shim"
    21  	pb "github.com/hyperledger/fabric/protos/peer"
    22  )
    23  
    24  // SampleSysCC example simple Chaincode implementation
    25  type SampleSysCC struct {
    26  }
    27  
    28  // Init initializes the sample system chaincode by storing the key and value
    29  // arguments passed in as parameters
    30  func (t *SampleSysCC) Init(stub shim.ChaincodeStubInterface) pb.Response {
    31  	//as system chaincodes do not take part in consensus and are part of the system,
    32  	//best practice to do nothing (or very little) in Init.
    33  
    34  	return shim.Success(nil)
    35  }
    36  
    37  // Invoke gets the supplied key and if it exists, updates the key with the newly
    38  // supplied value.
    39  func (t *SampleSysCC) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
    40  	f, args := stub.GetFunctionAndParameters()
    41  
    42  	switch f {
    43  	case "putval":
    44  		if len(args) != 2 {
    45  			return shim.Error("need 2 args (key and a value)")
    46  		}
    47  
    48  		// Initialize the chaincode
    49  		key := args[0]
    50  		val := args[1]
    51  
    52  		_, err := stub.GetState(key)
    53  		if err != nil {
    54  			jsonResp := "{\"Error\":\"Failed to get val for " + key + "\"}"
    55  			return shim.Error(jsonResp)
    56  		}
    57  
    58  		// Write the state to the ledger
    59  		err = stub.PutState(key, []byte(val))
    60  		if err != nil {
    61  			return shim.Error(err.Error())
    62  		}
    63  
    64  		return shim.Success(nil)
    65  	case "getval":
    66  		var err error
    67  
    68  		if len(args) != 1 {
    69  			return shim.Error("Incorrect number of arguments. Expecting key to query")
    70  		}
    71  
    72  		key := args[0]
    73  
    74  		// Get the state from the ledger
    75  		valbytes, err := stub.GetState(key)
    76  		if err != nil {
    77  			jsonResp := "{\"Error\":\"Failed to get state for " + key + "\"}"
    78  			return shim.Error(jsonResp)
    79  		}
    80  
    81  		if valbytes == nil {
    82  			jsonResp := "{\"Error\":\"Nil val for " + key + "\"}"
    83  			return shim.Error(jsonResp)
    84  		}
    85  
    86  		return shim.Success(valbytes)
    87  	default:
    88  		jsonResp := "{\"Error\":\"Unknown functon " + f + "\"}"
    89  		return shim.Error(jsonResp)
    90  	}
    91  }