Blockchain - Read Block Data in Blockchain

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, 375👍, 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, 496👍, 0💬

blockfile_000000 - Blockfiles of Blockchain
What is blockfile_000000 Blockfiles of Blockchain? Blocks of a blockchain are stored in physical files. Since they are very static once created, there is no need to store them in database. Hyperledger Fabric combines multiple blocks into a single blockfile, and stores it in the /var/hyperledger/prod... 2020-02-07, 491👍, 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, 389👍, 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, 376👍, 0💬

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