Skip to content

Latest commit

 

History

History

Chapter06

README.md

Chapter 6, Diving into Blockchain: Proof of Existence

This chapter introduces the decentralized application development using MultiChain blockchain framework by implementing a use case — Proof of Existence.

Scripts present here could be used to create and deploy web server to create a REST API. Full project with front end integration could be found here.

Quick Start

Getting started with MultiChain

  • Installation (ubuntu distro) More installation instructions for Mac/Windows/Linux can be found at: www.multichain.com/download-install/

    • Change directory to tmp folder:

      cd /tmp

    • Download the MultiChain bundle:

      wget https://www.multichain.com/download/multichain-1.0.6.tar.gz

    • Exctract the tar file:

      tar -xvzf multichain-1.0.6.tar.gz

    • Change directory to the extracted folder:

      cd multichain-1.0.6

    • Move few files to /usr/local/bin:

      mv multichaind multichain-cli multichain-util /usr/local/bin

  • Create a chain

    multichain-util create testchain -default-rpc-port=4416

  • Configure multichain node

    Copy the file ./multichain.conf to ~/.multichain/testchain/ to setup required rpc user and password to communicate from POE server

  • Instantiate the chain by creating a process

    multichaind testchain –daemon

  • Check the chain with getinfo

    multichain-cli testchain getinfo

    It should throw the following output

    `{"method":"getinfo","params":[],"id":1,"chain_name":"chain1"}

    {

     "version": "1.0.2", 

 "nodeversion": 10002901, 

 "protocolversion": 10009, 

 "chainname": "chain1", 

 "description": "MultiChain testchain", 

 "protocol": "multichain", 

 "port": 4273, 

 ...

 "balance": 0, 

 "walletdbversion": 2, 

 ...

    } `

  • Create a stream

    multichain-cli testchain create stream poe false

  • Subscribe to the stream

    multichain-cli testchain subscribe poe

  • You should be able to publish stream item if everything went well

    multichain-cli testchain publish poe key1 73747265616d2064617461

Deploying the Proof of Existence application

  • Install dependencies

    pip install -r requirements.txt

  • Start python webserver

    python poe_server.py

Using Docker

You can also run the docker containers for both MultiChain node and POE server if you do not want to play around with the commands. Windows/Mac users can also run this docker instances.

Docker engine and Docker compose installation instructions can be found here.

Following command will setup both MultiChain node and the POE server to interact.

docker-compose up

HTTP API

Publish document
curl -X POST -F 'name=user' -F '[email protected]' -F 'message=some message' -F 'digest=86abfbd5f1a9e928935cdee9b2fd1bc2d43254b40d996e262026e9d668555613' http://localhost:8000/publish
Verify document
curl http://localhost:8000/verify?digest=86abfbd5f1a9e928935cdee9b2fd1bc2d43254b40d996e262026e9d668555613
Fetch latest document info
curl http://localhost:8000/details?count=3