Read Block Data in Blockchain

Q

How to Read Block Data from a Blockchain?

✍: FYIcenter.com

A

The block data from a blockchain uses a binary format. You need to use the "configtxgen -inspectBlock" command parse it to JSON format.

1. Get the newest block from the blockchain:

$ docker exec -it cli bash
root@262918fdcbc0:/opt/gopath/src/github.com/hyperledger/fabric/peer# cd
root@262918fdcbc0:~# peer channel fetch newest ./newest.block -c mychannel
root@262918fdcbc0:~# configtxgen -inspectBlock newest.block > newest.json

root@262918fdcbc0:~# more newest.json
{
  "data": {
    "data": [
      {
        "payload": {
          "data": {
            "actions": [
              {
                "header": {
                  "creator": {
"id_bytes": "LS0tLS1CRUdJTiBDRVJ...

Now you need to read the Hyperledger Fabric reference guide to figure out how transactions are stored in the block.

⇒ blockfile_000000 - Blockfiles of Blockchain

⇐ Verify Blockchain on the Channel

⇑ WYFA (Writing Your First Application)

⇑⇑ Hyperledger Tutorials

2020-02-20, 2155🔥, 0💬

Read Block Data in Blockchain
How to Read Block Data from a Blockchain? The block data from a blockchain uses a binary format. You need to use the "configtxgen -inspectBlock" command parse it to JSON format. 1. Get the newest block from the blockchain: $ docker exec -it cli bash root@262918fdcbc0:/opt/gopath/ src/github.com/hyper... 2020-02-20, ∼2156🔥, 0💬

Interact with "fabcar" Chaincode on CLI
How to Interact "fabcar" Chaincode on CLI? After you started the WYFA network properly, you will have the "fabcar" chaincode running on "mychannel" on the peer0.org1.example.com peer container. You can now interact with the "fabcar" chaincode from the CLI container as shown below. 1. Connect to CLI ... 2020-02-20, ∼1978🔥, 0💬

"fabric-nodeenv:latest not found" Error
How to resolve the "hyperledger/fabric-nodeenv:la testnot found" error? Based on discussions on the Internet, there is a something wrong in the Docker image repository for "hyperledger/fabric-nodeenv:la test"image. When you try to instantiate chaincode a Hyperledger Fabric network channel, a docker ... 2020-02-29, ∼1777🔥, 0💬

fabcar.go - The "fabcar" Chaincode
What is the fabcar.go source code file? File fabcar.go contains the source code the "fabcar" chaincode (or Smart Contract). A copy of fabcar.go file is available is the /opt/gopath/src directory on the "cli" container. You can open and read it. 1. Copy fabcar.go from cli container: $ docker cp cli:/... 2020-02-20, ∼1663🔥, 0💬

Simplest Hyperledger Fabric Network
What is the simplest Hyperledger Fabric Network? The simplest Hyperledger Fabric Network consists of 2 systems, an orderer and a peer, running 1 channel with 1 chaincode. But ledger (Blockchain and World State) is not distributed. To improve reliability, we can add a second ledger peer to the networ... 2020-02-07, ∼1503🔥, 0💬

Node.js SDK and Client Application
What is Node.js SDK and how to use it to write client applications? Hyperledger Fabric Node.js SDK is a set of libraries that allows you to write client applications to interact with chaincode in Node.js language. A Hyperledger Fabric network can be viewed as virtual operating system. Once it is up ... 2020-02-07, ∼1415🔥, 0💬

Setup Node.js for WYFA Tests
How to Setup Node.js for WYFA (Write Your First Application) Tests? Before performing any Node.js SDK tests on the WYFA network, you need to setup the Node.js on your local host. 1. Make sure Node.js is installed: $ node --version v8.10.0 2. Install required packages: $ cd hyperledger-binaries/fabri... 2020-02-07, ∼1308🔥, 0💬

Verify Blockchain on the Channel
How to Verify Blockchain on the Channel? Since all transactions (changes of assets managed by chaincodes) are stored in the blockchain shared by all peers of the channel, you can use the "peer channel" CLI command to look at them. 1. Connect to CLI container: $ docker exec -it cli bash root@262918fd... 2020-02-20, ∼1246🔥, 0💬

Verify World State in CouchDB
How to Verify World State in CouchDB container? Since peer0.org1.example.com uses the couchdb container to store the world state, you can check the current states of all assets managed by the chaincode. 1. Get database name for the chaincode "fabcar": $ curl http://localhost:5984/_all_dbs ["_replica... 2020-02-20, ∼1168🔥, 0💬

All rights in the contents of this web site are reserved by the individual author. fyicenter.com does not guarantee the truthfulness, accuracy, or reliability of any contents.