Hyperledger fabric: Querying implicit data collection

Question

I am seeing this when querying data from implicit private data collection. Please see code snippet below.

When I query individual key (using QueryBidPrivate/GetPrivateData), I get corresponding data. But if I query the complete collection (using GetPrivateDataByRange(collection, "", "")), I get nothing from the Iterator.

peer chaincode query -C mychannel -n govtcontract -c '{"function":"QueryBidPrivate","Args":["100", "1035"]}' {"bidamt":100,"biddate":"2022-05-04","contractid":"1035","salt":"4567ab4567","vendorid":"100"}

peer chaincode query -C mychannel -n govtcontract -c '{"function":"ListAllBids","Args":[]}'

No output

Is there anything I am missing here ?

// ListAllBids returns all Bids details from private state
func (s *SmartContract) ListAllBids(ctx contractapi.TransactionContextInterface) ([]VendorBid, error) {
 
        // Get client org id and verify it matches peer org id.
        // In this scenario, client is only authorized to read/write private data from its own peer.
        clientOrgID, err := getClientOrgID(ctx, true)
        if err != nil {
                return nil, fmt.Errorf("failed to get verified OrgID: %s", err.Error())
        }
 
        collection := "_implicit_org_" + clientOrgID
 
        BidIterator, err := ctx.GetStub().GetPrivateDataByRange(collection, "", "")
        if err != nil {
                logger.Infof("ListAllBids error: %s", err.Error())
                return nil, fmt.Errorf("failed to read bid list : %s", err.Error())
        }
        if BidIterator == nil {
                logger.Infof("ListAllBids : null iterator ")
                return nil, fmt.Errorf("bid private details does not exist ")
        }
        defer BidIterator.Close()
        logger.Infof("ListAllBids in govtcontract: no error")
 
        var allbids []VendorBid
        myMSPID, err := ctx.GetClientIdentity().GetMSPID()
        logger.Infof("myMSPID: %s", myMSPID)
        for BidIterator.HasNext() {
                logger.Infof("Iterator has element: ")
 
                entrybid, err := BidIterator.Next()
                if err != nil {
                        return nil, err
                }
 
                var bidvar VendorBid
                err = json.Unmarshal(entrybid.Value, &bidvar)
                if err != nil {
                        return nil, err
                }
 
                allbids = append(allbids, bidvar)
                logger.Infof("Iterator element: %s", entrybid.Value)
 
        }
        
 
        return allbids, nil
 
}

=========================================

// QueryBidPrivate returns the Bid details from owner's private data collection
func (s *SmartContract) QueryBidPrivate(ctx contractapi.TransactionContextInterface, vendorId string, contractId string) (string, error) {
 
        // Get client org id and verify it matches peer org id.
        // In this scenario, client is only authorized to read/write private data from its own peer.
        clientOrgID, err := getClientOrgID(ctx, true)
        if err != nil {
                return "", fmt.Errorf("failed to get verified OrgID: %s", err.Error())
        }
 
        collection := "_implicit_org_" + clientOrgID
 
        bidconkey, err := ctx.GetStub().CreateCompositeKey(vendorId, []string{contractId})
 
        bidDetails, err := ctx.GetStub().GetPrivateData(collection, bidconkey)
        if err != nil {
                return "", fmt.Errorf("failed to read bid private properties from client org's collection: %s", err.Error())
        }
        if bidDetails == nil {
                return "", fmt.Errorf("bid private details does not exist in client org's collection: %s", contractId)
        }
 
        return string(bidDetails), nil
}

Answer 1

I faced the same error in the smart contract. The issue here is because of storing data on the composite key. Instead of below code :

         for BidIterator.HasNext() {
            logger.Infof("Iterator has element: ")

            entrybid, err := BidIterator.Next()
            if err != nil {
                    return nil, err
            }

            var bidvar VendorBid
            err = json.Unmarshal(entrybid.Value, &bidvar)
            if err != nil {
                    return nil, err
            }

            allbids = append(allbids, bidvar)
            logger.Infof("Iterator element: %s", entrybid.Value)

    }

Use the below function

    func constructQueryResponseFromIterator(resultsIterator    shim.StateQueryIteratorInterface) 

(*bytes.Buffer, error) {

// buffer is a JSON array containing QueryResults
var buffer bytes.Buffer
buffer.WriteString("[")

bArrayMemberAlreadyWritten := false
for resultsIterator.HasNext() {
    queryResponse, err := resultsIterator.Next()
    if err != nil {
        return nil, err
    }
    // Add a comma before array members, suppress it for the first array member
    if bArrayMemberAlreadyWritten == true {
        buffer.WriteString(",")
    }
    buffer.WriteString("{")
    //buffer.WriteString("{\"Key\":")
    //buffer.WriteString("\"")
    //buffer.WriteString(queryResponse.Key)
    //buffer.WriteString("\"")

    buffer.WriteString(", \"Record\":")
    // Record is a JSON object, so we write as-is
    buffer.WriteString(string(queryResponse.Value))
    buffer.WriteString("}")
    bArrayMemberAlreadyWritten = true
}
buffer.WriteString("]")

return &buffer, nil

}