大量查询无结果-Hyeperledger Fabric v1.0

Question

I'm trying to perform a rich query in the chaincode. Every peer has CouchDB and I have follow example in marble source code. But I don't get any result (no error), just an empty array.

When I run the same query in CouchDB directly there is no issue and I get one or more results.

This is the chaincode source code I use:

if len(args) == 3 && args[1] == "complex" {
    fmt.Printf("Query complex
")

    if isJSON(args[2]) {

        fmt.Printf("Complex query: %s
", args[2])

        resultsIterator, err := stub.GetQueryResult(args[2])
        if err != nil {
            jsonResp := "{\"Error\":\"Not able to make the query, see error: " + err.Error() + "\"}"
            return shim.Error(jsonResp)
        }
        defer resultsIterator.Close()

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

        bArrayMemberAlreadyWritten := false
        for resultsIterator.HasNext() {
            queryResponse, err := resultsIterator.Next()
            if err != nil {
                jsonResp := "{\"Error\":\"Not able to make the query, see error: " + err.Error() + "\"}"
                return shim.Error(jsonResp)
            }
            // Add a comma before array members, suppress it for the first array member
            if bArrayMemberAlreadyWritten == true {
                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("]")

        fmt.Printf("Query Response: %s
", buffer.String())

        return shim.Success(buffer.Bytes())
    }

    jsonResp := "{\"Error\":\"The query is not a valid JSON\"}"
    return shim.Error(jsonResp)
}

Answer 1

The problem is has to do with the 'data.' metadata envelope that Fabric injects into the document that is persisted into CouchDB state database. From the chaincode author's perspective, there is no 'data' envelope, and as such the 'data' envelope should be excluded from any queries that are passed in. The Fabric will inject the 'data' envelope, both upon save and upon query. If you utilize the Fauxton UI for trial queries directly against CouchDB (without the benefit of the Fabric injection code), you will need to include the 'data' envelope. Just remember to exclude the 'data' envelope when writing chaincode queries.

See the example queries that correspond to the marbles02 example, note that there is no data envelope provided.