Random Comment with little to no meaning

asset-transfer-basic/chaincode-go/chaincode/smartcontract.go

@@ -44,7 +44,7 @@ type SmartContract struct {
 // Insert struct field in alphabetic order => to achieve determinism across languages
 // golang keeps the order when marshal to json but doesn't order automatically
 
-var schemas []Schema
+var lastSchemaHash String 
 
 type Data struct {
 	Contributor     string   `json:"Contributor"`
@@ -56,80 +56,118 @@ type Data struct {
 }
 
 type Schema struct {
-	Contributor     string   `json:"Contributor"`
+	Version           int `json:"Version"`
-	ContributorId   string   `json:"ContributorId"`
+	Hash              string `json:"Hash"`
-	ContentHash     string   `json:"ContentHash"`
+	JsonSchemaContent map[string]interface{}
-	Id              string   `json:"Id"`
-	Owners          []string `json:"Owners"`
-	JsonFileContent map[string]interface{}
 }
 
 // InitLedger adds a base set of Data entries to the ledger
-func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface, pathSchema string, pathFirstJsonFile string) error {
+func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface, InitSchema string, InitData string) error {
 
 	// We use the function jsonReader in order to read the content of the shcema Json File. The schema Json file is composed by us and inserted into
 	// the docker container of the commited chaincode (For now)
-	schemaJsonFileContent, error_schema := s.JsonReader(ctx, pathSchema)
+	schemaJsonFileContent, error_schema := s.JsonReader(ctx, InitSchema)
-	firstJsonFileContent, error_file := s.JsonReader(ctx, pathFirstJsonFile)
+	firstJsonFileContent, error_file := s.JsonReader(ctx, InitData)
 
 	if error_schema != nil {
 		return fmt.Errorf("failed to read shcema.json file: %v", error_schema)
 	} else if error_file != nil {
 		return fmt.Errorf("failed to read 1st json files: %v", error_file)
 	} else {
-		fmt.Printf("Schema Content: %v", schemaJsonFileContent)
-		fmt.Printf("Test Json file Content: %v", firstJsonFileContent)
 		
-		dataEntries := []Data{
+		firstJsonFileHash = Hash(InitData)
-			{Contributor: "pepitoperes@email.com", ContributorId: "ABC123", ContentHash: "ZXCVBNM", Id: "00000", Owners: []string{"CIA", "DEA", "FBI"}, JsonFileContent: firstJsonFileContent},
+		schemaJsonFileHash = Hash(InitSchema)
+		lastSchemaHash = schemaJsonFileHash
+
+		data := Data{
+			Contributor: "pepitoperes@email.com", 
+			ContributorId: "ABC123", 
+			ContentHash: firstJsonFileHash, 
+			Id: "00000", 
+			Owners: []string{"CIA", "DEA", "FBI"}, 
+			JsonFileContent: firstJsonFileContent,
 		}
 
 		//This is the definition of the Schema that we should use for validate all the JSON files from now on.
-		initSchema := Schema{Contributor: "pepitoperes@email.com", ContributorId: "ABC123", ContentHash: "ZXCVBNM", Id: "00000", Owners: []string{"CIA", "DEA", "FBI"}, JsonFileContent: schemaJsonFileContent}
+		
-		schemas = append(schemas, initSchema)
+		initSchema := Schema{
-
+			Version: "1.0",
-		for _, data := range schemas {
+			Hash: schemaJsonFileHash,
-			assetJSON, err := json.Marshal(data)
+			JsonSchemaContent: schemaJsonFileContent,
-			if err != nil {
-				return err
-			}
-
-			err = ctx.GetStub().PutState(data.Id, assetJSON)
-			if err != nil {
-				return fmt.Errorf("failed to put to world state. %v", err)
-			}
 		}
 
-		for _, data := range dataEntries {
+		
-			assetJSON, err := json.Marshal(data)
+		assetJSON, err := json.Marshal(data)
-			if err != nil {
+		if err != nil {
-				return err
+			return err
-			}
-
-			err = ctx.GetStub().PutState(data.Id, assetJSON)
-			if err != nil {
-				return fmt.Errorf("failed to put to world state. %v", err)
-			}
 		}
 
+		err = ctx.GetStub().PutState(data.ContentHash, assetJSON)
+		if err != nil {
+			return fmt.Errorf("failed to put to world state. %v", err)
+		}
+		
+
+	
+		assetJSON, err := json.Marshal(initSchema)
+		if err != nil {
+			return err
+		}
+
+		err = ctx.GetStub().PutState(initSchema.Hash, assetJSON)
+		if err != nil {
+			return fmt.Errorf("failed to put to world state. %v", err)
+		}
+		
+
 	}
 	return nil
 }
 
-func (s *SmartContract) JsonReader(ctx contractapi.TransactionContextInterface, path string) (map[string]interface{}, error) {
+func (s *SmartContract) LastSchemaHash() (string) {
+	return lastSchemaHash
+}
 
-	content, err := ioutil.ReadFile(path)
+func (s *SmartContract) Hash(doc string) string, err {
-	if err != nil {
+	result = isJSON(doc)
-		log.Fatal("Error when opening file: ", err)
+	if !result{
+		return "HASH CRASH", fmt.Errorf("String passed as parameter is not in JSON format")
+	} else{
+		var v interface{}
+		err = json.Unmarshal([]byte(doc), &v)
+		if err != nil{
+			return "HASH CRASH", fmt.Errorf("Unable to unmarshal Json String passed as parameter. No hash calculation can be completed: %v", err)
+		} else {
+			cdoc, err := json.Marshal(v)
+			if err != nil{
+				return "HASH CRASH", fmt.Errorf("Unable to re-marshal interface into json format. No hash calculation can be completed: %v", err)
+			} else{
+				sum := sha256.Sum256(cdoc)
+				return hex.EncodeToString(sum[0:]), nil
+			}
 	}
+}
+
+func (smct *SmartContract) isJSON(s string) bool {
+	var js interface{}
+	return json.Unmarshal([]byte(s), &js) == nil
+}
+
+func (s *SmartContract) JsonReader(ctx contractapi.TransactionContextInterface, content string) (map[string]interface{}, error) {
 
-	// Now let's unmarshall the data into `payload`
 	var payload map[string]interface{}
-	err = json.Unmarshal(content, &payload)
+	IsJson := isJSON(content)
-	if err != nil {
+
-		log.Fatal("Error during Unmarshal(): ", err)
+	if !content {
+		return payload, log.Fatal("The String passed is not in JSON format. Check the string: %v", IsJson)
+	} else {
+		// Now let's unmarshall the data into `payload`
+		err = json.Unmarshal(IsJson, &payload)
+		if err != nil {
+			log.Fatal("Error during Unmarshal() of string into type Interface: %v", err)
+		}
+		return payload, nil
 	}
-	return payload, nil
 }
 
 // GetAllAssets returns all assets found in world state
@@ -160,8 +198,17 @@ func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface
 	return dataSamples, nil
 }
 
+func (s *SmartContract) SchemaExists(ctx contractapi.TransactionContextInterface, Hash string) (bool, error) {
+	assetJSON, err := ctx.GetStub().GetState(Hash)
+	if err != nil {
+		return false, fmt.Errorf("failed to read from world state: %v", err)
+	}
+
+	return assetJSON != nil, nil
+}
+
 func (s *SmartContract) CreateNewSchema(ctx contractapi.TransactionContextInterface,
-	Contributor string, ContributorId string, ContentHash string, Id string, AbsolutePathToJsonFile string) error {
+	version string, newSchemaContent string) error {
 
 	// We assume this new schema is different from what existed previously
 	//exists, err := s.AssetExists(ctx, Id)
@@ -172,21 +219,24 @@ func (s *SmartContract) CreateNewSchema(ctx contractapi.TransactionContextInterf
 	//	return fmt.Errorf("the asset %s already exists", Id)
 	//}
 
-	jsonFileContent, err := s.JsonReader(ctx, AbsolutePathToJsonFile)
+	jsonFileContent, err := s.JsonReader(ctx, newSchemaContent)
 	if err != nil {
 		return err
 	} else {
-		newSchema := Schema{
+		// Verify that an schema with exact same structure doesn't exist yet.
-			Contributor:     Contributor,
+		hashContent = Hash(newSchemaContent)
-			ContributorId:   ContributorId,
+		exists, err = SchemaExists(hashContent)
-			ContentHash:     ContentHash,
+		if exists{
-			Id:              Id,
+			return fmt.Errorf("Schema already exists: %v", err)
-			Owners:          []string{"DOE", "DOS", "DOJ"},
+		} else {
-			JsonFileContent: jsonFileContent,
+			lastSchemaHash = hashContent
+			newSchema := Schema{
+				Version:           version,
+				Hash:              hashContent,
+				JsonSchemaContent: jsonFileContent,
+			}
 		}
 		
-		schemas = append(schemas, newSchema)
-
 		return nil
 		}
 	}
@@ -194,7 +244,7 @@ func (s *SmartContract) CreateNewSchema(ctx contractapi.TransactionContextInterf
 
 // GetAllSchemas returns all schemas found in world state
 
-func (s *SmartContract) GetAllSchemas(ctx contractapi.TransactionContextInterface) ([]Schema, error) {
+//func (s *SmartContract) GetAllSchemas(ctx contractapi.TransactionContextInterface) ([]Schema, error) {
 	// range query with empty string for startKey and endKey does an
 	// open-ended query of all schemas in the chaincode namespace.
 	//resultsIterator, err := ctx.GetStub().GetStateByRange("", "")
@@ -218,8 +268,8 @@ func (s *SmartContract) GetAllSchemas(ctx contractapi.TransactionContextInterfac
 	//	schemaSamples = append(schemaSamples, &schm)
 	//}
 
-	return schemas, nil
+	//return schemas, nil
-}
+//}
 
 // AssetExists returns true when asset with given ID exists in world state
 func (s *SmartContract) AssetExists(ctx contractapi.TransactionContextInterface, Id string) (bool, error) {
@@ -233,7 +283,7 @@ func (s *SmartContract) AssetExists(ctx contractapi.TransactionContextInterface,
 
 // JSON Validation
 
-func (s *SmartContract) ValidJson(ctx contractapi.TransactionContextInterface, AbsolutePathToJsonFile string) (bool, error) {
+func (s *SmartContract) ValidJson(ctx contractapi.TransactionContextInterface, JsonContent string) (bool, error) {
 
 	//schemaLoader := gojsonschema.NewReferenceLoader("file:///Users/fernando/Projects/OSC-IS/fabric-samples/test-network/JsonSchemaValidationTests/Schema.json")
 	//documentLoader := gojsonschema.NewReferenceLoader("file:////Users/fernando/Projects/OSC-IS/fabric-samples/test-network/JsonSchemaValidationTests/testFile.json")
@@ -243,9 +293,13 @@ func (s *SmartContract) ValidJson(ctx contractapi.TransactionContextInterface, A
 
 	// PATH Needs to be absolute path (From root '/'). Add something that takes care of that.
 
-	m := schemas[len(schemas) - 1].JsonFileContent
+	//m := schemas[len(schemas) - 1].JsonFileContent
-	schemaLoader := gojsonschema.NewGoLoader(m)
+
-	documentLoader := gojsonschema.NewReferenceLoader("file://" + AbsolutePathToJsonFile)
+	CurrentSchemaHash = LastSchemaHash()
+	schema = ReadSchema(CurrentSchemaHash)
+
+	schemaLoader := gojsonschema.NewGoLoader(schema.JsonSchemaContent)
+	documentLoader := gojsonschema.NewStringLoader(JsonContent)
 
 	result, err := gojsonschema.Validate(schemaLoader, documentLoader)
 
@@ -266,9 +320,10 @@ func (s *SmartContract) ValidJson(ctx contractapi.TransactionContextInterface, A
 
 // CreateDataSample issues a new Data Sample to the world state with given details.
 func (s *SmartContract) CreateDataSample(ctx contractapi.TransactionContextInterface,
-	Contributor string, ContributorId string, ContentHash string, Id string, AbsolutePathToJsonFile string) error {
+	Contributor string, ContributorId string, Id string, JsonFileContent string) error {
-
+	
-	exists, err := s.AssetExists(ctx, Id)
+	ContentHash = Hash(JsonFileContent)
+	exists, err := s.AssetExists(ctx, ContentHash)
 	if err != nil {
 		return err
 	}
@@ -276,14 +331,14 @@ func (s *SmartContract) CreateDataSample(ctx contractapi.TransactionContextInter
 		return fmt.Errorf("the asset %s already exists", Id)
 	}
 
-	valid, err := s.ValidJson(ctx, AbsolutePathToJsonFile)
+	valid, err := s.ValidJson(ctx, JsonFileContent)
 	if err != nil {
 		return err
 	}
 	if !valid {
 		return fmt.Errorf("the json file provided is not valid")
 	} else {
-		jsonFileContent, err := s.JsonReader(ctx, AbsolutePathToJsonFile)
+		jsonFileContent, err := s.JsonReader(ctx, JsonFileContent)
 		if err != nil {
 			return err
 		} else {
@@ -301,7 +356,7 @@ func (s *SmartContract) CreateDataSample(ctx contractapi.TransactionContextInter
 				return err
 
 			}
-			return ctx.GetStub().PutState(Id, assetJSON)
+			return ctx.GetStub().PutState(ContentHash, assetJSON)
 			}
 		}
 
@@ -365,6 +420,24 @@ func (s *SmartContract) ReadAsset(ctx contractapi.TransactionContextInterface, I
 	return &data, nil
 }
 
+func (s *SmartContract) ReadSchema(ctx contractapi.TransactionContextInterface, hash string) (*Schema, error) {
+	assetJSON, err := ctx.GetStub().GetState(hash)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read from world state: %v", err)
+	}
+	if assetJSON == nil {
+		return nil, fmt.Errorf("the schema with hash %s does not exist", hash)
+	}
+
+	var schema Schema
+	err = json.Unmarshal(assetJSON, &schema)
+	if err != nil {
+		return nil, err
+	}
+
+	return &scehma, nil
+}
+
 // TransferAsset updates the owner field of asset with given id in world state, and returns the old owner.
 func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, Id string, newOwners []string) ([]string, error) {
 	data, err := s.ReadAsset(ctx, Id)

asset-transfer-basic/chaincode-go/chaincode/smartcontractBACKUP4.go.txt

@@ -0,0 +1,464 @@
+package chaincode
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/hyperledger/fabric-contract-api-go/contractapi"
+	"github.com/xeipuuv/gojsonschema"
+
+	"io/ioutil"
+	"log"
+)
+
+// SmartContract provides functions for managing an Asset
+type SmartContract struct {
+	contractapi.Contract
+}
+
+// Asset describes basic details of what makes up a simple asset
+// Insert struct field in alphabetic order => to achieve determinism across languages
+// golang keeps the order when marshal to json but doesn't order automatically
+
+/*type Data struct {
+	docType          string `json:"docType"`
+	id               string `json:"id"`
+	title            string `json:"title"`
+	description      string `json:"description"`
+	Type             string `json:"Type"`
+	DOI              string `json:"DOI"`
+	url              string `json:"url"`
+	manifest         string `json:"manifest"`
+	footprint        string `json:"footprint"`
+	keywords         string `json:"keywords"`
+	otherDataIdName  string `json:"otherDataIdName"`
+	otherDataIdValue string `json:"otherDataIdValue"`
+	fundingAgencies  string `json:"fundingAgencies"`
+	acknowledgment   string `json:"acknowledgment"`
+	noteForChange    string `json:"noteForChange"`
+	contributor      string `json:"contributor"`
+	contributor_id   string `json:"contributor_id"`
+}*/
+
+// Asset describes basic details of what makes up a simple asset
+// Insert struct field in alphabetic order => to achieve determinism across languages
+// golang keeps the order when marshal to json but doesn't order automatically
+
+var schemas []Schema
+
+type Data struct {
+	Contributor     string   `json:"Contributor"`
+	ContributorId   string   `json:"ContributorId"`
+	ContentHash     string   `json:"ContentHash"`
+	Id              string   `json:"Id"`
+	Owners          []string `json:"Owners"`
+	JsonFileContent map[string]interface{}
+}
+
+type Schema struct {
+	Contributor     string   `json:"Contributor"`
+	ContributorId   string   `json:"ContributorId"`
+	ContentHash     string   `json:"ContentHash"`
+	Id              string   `json:"Id"`
+	Owners          []string `json:"Owners"`
+	JsonFileContent map[string]interface{}
+}
+
+// InitLedger adds a base set of Data entries to the ledger
+func (s *SmartContract) InitLedger(ctx contractapi.TransactionContextInterface, pathSchema string, pathFirstJsonFile string) error {
+
+	// We use the function jsonReader in order to read the content of the shcema Json File. The schema Json file is composed by us and inserted into
+	// the docker container of the commited chaincode (For now)
+	schemaJsonFileContent, error_schema := s.JsonReader(ctx, pathSchema)
+	firstJsonFileContent, error_file := s.JsonReader(ctx, pathFirstJsonFile)
+
+	if error_schema != nil {
+		return fmt.Errorf("failed to read shcema.json file: %v", error_schema)
+	} else if error_file != nil {
+		return fmt.Errorf("failed to read 1st json files: %v", error_file)
+	} else {
+		fmt.Printf("Schema Content: %v", schemaJsonFileContent)
+		fmt.Printf("Test Json file Content: %v", firstJsonFileContent)
+		
+		dataEntries := []Data{
+			{Contributor: "pepitoperes@email.com", ContributorId: "ABC123", ContentHash: "ZXCVBNM", Id: "00000", Owners: []string{"CIA", "DEA", "FBI"}, JsonFileContent: firstJsonFileContent},
+		}
+
+		//This is the definition of the Schema that we should use for validate all the JSON files from now on.
+		initSchema := Schema{Contributor: "pepitoperes@email.com", ContributorId: "ABC123", ContentHash: "ZXCVBNM", Id: "00000", Owners: []string{"CIA", "DEA", "FBI"}, JsonFileContent: schemaJsonFileContent}
+		schemas = append(schemas, initSchema)
+
+		for _, data := range schemas {
+			assetJSON, err := json.Marshal(data)
+			if err != nil {
+				return err
+			}
+
+			err = ctx.GetStub().PutState(data.Id, assetJSON)
+			if err != nil {
+				return fmt.Errorf("failed to put to world state. %v", err)
+			}
+		}
+
+		for _, data := range dataEntries {
+			assetJSON, err := json.Marshal(data)
+			if err != nil {
+				return err
+			}
+
+			err = ctx.GetStub().PutState(data.Id, assetJSON)
+			if err != nil {
+				return fmt.Errorf("failed to put to world state. %v", err)
+			}
+		}
+
+	}
+	return nil
+}
+
+func (s *SmartContract) JsonReader(ctx contractapi.TransactionContextInterface, path string) (map[string]interface{}, error) {
+
+	content, err := ioutil.ReadFile(path)
+	if err != nil {
+		log.Fatal("Error when opening file: ", err)
+	}
+
+	// Now let's unmarshall the data into `payload`
+	var payload map[string]interface{}
+	err = json.Unmarshal(content, &payload)
+	if err != nil {
+		log.Fatal("Error during Unmarshal(): ", err)
+	}
+	return payload, nil
+}
+
+// GetAllAssets returns all assets found in world state
+func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface) ([]*Data, error) {
+	// range query with empty string for startKey and endKey does an
+	// open-ended query of all assets in the chaincode namespace.
+	resultsIterator, err := ctx.GetStub().GetStateByRange("", "")
+	if err != nil {
+		return nil, err
+	}
+	defer resultsIterator.Close()
+
+	var dataSamples []*Data
+	for resultsIterator.HasNext() {
+		queryResponse, err := resultsIterator.Next()
+		if err != nil {
+			return nil, err
+		}
+
+		var data Data
+		err = json.Unmarshal(queryResponse.Value, &data)
+		if err != nil {
+			return nil, err
+		}
+		dataSamples = append(dataSamples, &data)
+	}
+
+	return dataSamples, nil
+}
+
+func (s *SmartContract) CreateNewSchema(ctx contractapi.TransactionContextInterface,
+	Contributor string, ContributorId string, ContentHash string, Id string, AbsolutePathToJsonFile string) error {
+
+	// We assume this new schema is different from what existed previously
+	//exists, err := s.AssetExists(ctx, Id)
+	//if err != nil {
+	//	return err
+	//}
+	//if exists {
+	//	return fmt.Errorf("the asset %s already exists", Id)
+	//}
+
+	jsonFileContent, err := s.JsonReader(ctx, AbsolutePathToJsonFile)
+	if err != nil {
+		return err
+	} else {
+		newSchema := Schema{
+			Contributor:     Contributor,
+			ContributorId:   ContributorId,
+			ContentHash:     ContentHash,
+			Id:              Id,
+			Owners:          []string{"DOE", "DOS", "DOJ"},
+			JsonFileContent: jsonFileContent,
+		}
+		
+		schemas = append(schemas, newSchema)
+
+		return nil
+		}
+	}
+
+
+// GetAllSchemas returns all schemas found in world state
+
+func (s *SmartContract) GetAllSchemas(ctx contractapi.TransactionContextInterface) ([]Schema, error) {
+	// range query with empty string for startKey and endKey does an
+	// open-ended query of all schemas in the chaincode namespace.
+	//resultsIterator, err := ctx.GetStub().GetStateByRange("", "")
+	//if err != nil {
+	//	return nil, err
+	//}
+	//defer resultsIterator.Close()
+
+	//var schemaSamples []*Schema
+	//for resultsIterator.HasNext() {
+	//	queryResponse, err := resultsIterator.Next()
+	//	if err != nil {
+	//		return nil, err
+	//	}
+
+	//	var schm Schema
+	//	err = json.Unmarshal(queryResponse.Value, &schm)
+	//	if err != nil {
+	//		return nil, err
+	//	}
+	//	schemaSamples = append(schemaSamples, &schm)
+	//}
+
+	return schemas, nil
+}
+
+// AssetExists returns true when asset with given ID exists in world state
+func (s *SmartContract) AssetExists(ctx contractapi.TransactionContextInterface, Id string) (bool, error) {
+	assetJSON, err := ctx.GetStub().GetState(Id)
+	if err != nil {
+		return false, fmt.Errorf("failed to read from world state: %v", err)
+	}
+
+	return assetJSON != nil, nil
+}
+
+// JSON Validation
+
+func (s *SmartContract) ValidJson(ctx contractapi.TransactionContextInterface, AbsolutePathToJsonFile string) (bool, error) {
+
+	//schemaLoader := gojsonschema.NewReferenceLoader("file:///Users/fernando/Projects/OSC-IS/fabric-samples/test-network/JsonSchemaValidationTests/Schema.json")
+	//documentLoader := gojsonschema.NewReferenceLoader("file:////Users/fernando/Projects/OSC-IS/fabric-samples/test-network/JsonSchemaValidationTests/testFile.json")
+
+	//schemaLoader := gojsonschema.NewReferenceLoader("file:///home/chaincode/Schema.json")
+	//documentLoader := gojsonschema.NewReferenceLoader("file:////home/chaincode/testFile.json")
+
+	// PATH Needs to be absolute path (From root '/'). Add something that takes care of that.
+
+	m := schemas[len(schemas) - 1].JsonFileContent
+	schemaLoader := gojsonschema.NewGoLoader(m)
+	documentLoader := gojsonschema.NewReferenceLoader("file://" + AbsolutePathToJsonFile)
+
+	result, err := gojsonschema.Validate(schemaLoader, documentLoader)
+
+	if err != nil {
+		panic(err.Error())
+	}
+
+	if result.Valid() {
+		fmt.Printf("The document is valid\n")
+	} else {
+		fmt.Printf("The document is not valid. see errors :\n")
+		for _, desc := range result.Errors() {
+			fmt.Printf("- %s\n", desc)
+		}
+	}
+	return result.Valid(), nil
+}
+
+// CreateDataSample issues a new Data Sample to the world state with given details.
+func (s *SmartContract) CreateDataSample(ctx contractapi.TransactionContextInterface,
+	Contributor string, ContributorId string, ContentHash string, Id string, AbsolutePathToJsonFile string) error {
+
+	exists, err := s.AssetExists(ctx, Id)
+	if err != nil {
+		return err
+	}
+	if exists {
+		return fmt.Errorf("the asset %s already exists", Id)
+	}
+
+	valid, err := s.ValidJson(ctx, AbsolutePathToJsonFile)
+	if err != nil {
+		return err
+	}
+	if !valid {
+		return fmt.Errorf("the json file provided is not valid")
+	} else {
+		jsonFileContent, err := s.JsonReader(ctx, AbsolutePathToJsonFile)
+		if err != nil {
+			return err
+		} else {
+			data := Data{
+				Contributor:     Contributor,
+				ContributorId:   ContributorId,
+				ContentHash:     ContentHash,
+				Id:              Id,
+				Owners:          []string{"DOE", "DOS", "DOJ"},
+				JsonFileContent: jsonFileContent,
+			}
+
+			assetJSON, err := json.Marshal(data)
+			if err != nil {
+				return err
+
+			}
+			return ctx.GetStub().PutState(Id, assetJSON)
+			}
+		}
+
+}
+// UpdateAsset updates an existing asset in the world state with provided parameters.
+func (s *SmartContract) UpdateAsset(ctx contractapi.TransactionContextInterface,
+	Contributor string, ContributorId string, ContentHash string, Id string) error {
+	exists, err := s.AssetExists(ctx, Id)
+	if err != nil {
+		return err
+	}
+	if !exists {
+		return fmt.Errorf("the asset %s does not exist", Id)
+	}
+
+	// overwriting original asset with new asset
+
+	data := Data{
+		Contributor:   Contributor,
+		ContributorId: ContributorId,
+		ContentHash:   ContentHash,
+		Id:            Id,
+		Owners:        []string{"DOE", "DOS", "DOJ"},
+	}
+
+	assetJSON, err := json.Marshal(data)
+	if err != nil {
+		return err
+	}
+
+	return ctx.GetStub().PutState(Id, assetJSON)
+}
+
+func (s *SmartContract) DeleteAsset(ctx contractapi.TransactionContextInterface, Id string) error {
+	exists, err := s.AssetExists(ctx, Id)
+	if err != nil {
+		return err
+	}
+	if !exists {
+		return fmt.Errorf("the asset %s does not exist", Id)
+	}
+
+	return ctx.GetStub().DelState(Id)
+}
+
+func (s *SmartContract) ReadAsset(ctx contractapi.TransactionContextInterface, Id string) (*Data, error) {
+	assetJSON, err := ctx.GetStub().GetState(Id)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read from world state: %v", err)
+	}
+	if assetJSON == nil {
+		return nil, fmt.Errorf("the asset %s does not exist", Id)
+	}
+
+	var data Data
+	err = json.Unmarshal(assetJSON, &data)
+	if err != nil {
+		return nil, err
+	}
+
+	return &data, nil
+}
+
+// TransferAsset updates the owner field of asset with given id in world state, and returns the old owner.
+func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, Id string, newOwners []string) ([]string, error) {
+	data, err := s.ReadAsset(ctx, Id)
+	if err != nil {
+		return []string{}, err
+	}
+
+	data.Owners = newOwners
+
+	assetJSON, err := json.Marshal(data)
+	if err != nil {
+		return []string{}, err
+	}
+
+	err = ctx.GetStub().PutState(Id, assetJSON)
+	if err != nil {
+		return []string{}, err
+	}
+
+	return data.Owners, nil
+}
+
+/*
+
+
+// ReadAsset returns the asset stored in the world state with given id.
+func (s *SmartContract) ReadAsset(ctx contractapi.TransactionContextInterface, id string) (*Asset, error) {
+	assetJSON, err := ctx.GetStub().GetState(id)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read from world state: %v", err)
+	}
+	if assetJSON == nil {
+		return nil, fmt.Errorf("the asset %s does not exist", id)
+	}
+
+	var asset Asset
+	err = json.Unmarshal(assetJSON, &asset)
+	if err != nil {
+		return nil, err
+	}
+
+	return &asset, nil
+}
+
+
+
+// TransferAsset updates the owner field of asset with given id in world state, and returns the old owner.
+func (s *SmartContract) TransferAsset(ctx contractapi.TransactionContextInterface, id string, newOwner string) (string, error) {
+	asset, err := s.ReadAsset(ctx, id)
+	if err != nil {
+		return "", err
+	}
+
+	oldOwner := asset.Owner
+	asset.Owner = newOwner
+
+	assetJSON, err := json.Marshal(asset)
+	if err != nil {
+		return "", err
+	}
+
+	err = ctx.GetStub().PutState(id, assetJSON)
+	if err != nil {
+		return "", err
+	}
+
+	return oldOwner, nil
+}
+
+// GetAllAssets returns all assets found in world state
+func (s *SmartContract) GetAllAssets(ctx contractapi.TransactionContextInterface) ([]*Asset, error) {
+	// range query with empty string for startKey and endKey does an
+	// open-ended query of all assets in the chaincode namespace.
+	resultsIterator, err := ctx.GetStub().GetStateByRange("", "")
+	if err != nil {
+		return nil, err
+	}
+	defer resultsIterator.Close()
+
+	var assets []*Asset
+	for resultsIterator.HasNext() {
+		queryResponse, err := resultsIterator.Next()
+		if err != nil {
+			return nil, err
+		}
+
+		var asset Asset
+		err = json.Unmarshal(queryResponse.Value, &asset)
+		if err != nil {
+			return nil, err
+		}
+		assets = append(assets, &asset)
+	}
+
+	return assets, nil
+}
+*/