Proof of Existence Part 2 — Creating data stream to store hash of the file and metadata in blockchain network.

Step 1: First we would create a new blockchain named chain1. On the first server, run this command:

multichain-util create chain1

Step 2 : Initialize the blockchain, including mining the genesis block. multichaind chain1 -daemon

Step 3 : Get info of blockchain run command (multichain-cli chain1).

sourabhsethi8888@mutichain-instance-1:~$ multichain-cli chain1

MultiChain Core RPC client build 1.0 alpha 26 protocol 10006


Interactive mode

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

{
    "version" : "1.0 alpha 26",
    "protocolversion" : 10006,
    "chainname" : "chain1",
    "description" : "MultiChain chain1",
    "protocol" : "multichain",
    "port" : 9565,
    "setupblocks" : 60,
    "nodeaddress" : "chain1@10.142.0.4:9565",
    "burnaddress" : "1XXXXXXWZzXXXXXXYBXXXXXXbVXXXXXXWsKJr3",
    "incomingpaused" : false,
    "miningpaused" : false,
    "walletversion" : 60000,
    "balance" : 0.00000000,
    "walletdbversion" : 2,
    "reindex" : false,
    "blocks" : 15549,
    "timeoffset" : 0,
    "connections" : 0,
    "proxy" : "",
    "difficulty" : 0.00001526,
    "testnet" : false,
    "keypoololdest" : 1530472920,
    "keypoolsize" : 2,
    "paytxfee" : 0.00000000,
    "relayfee" : 0.00000000,
    "errors" : ""
}
chain1:

Step 4: Create stream POE in chain1.

Now let’s create a stream POE, which can be used for general data storage and retrieval.

chain1: create stream poe false    
{"method":"create","params":["stream","poe",false],"id":1,"chain_name":"chain1"}

922ce92090a540222ccd2cb9349d7fc34fd83570938b9e500102543189667f95
chain1:

The false means the stream can only be written to by those with explicit permissions. Let’s see its permissions:

chain1: listpermissions poe.*    
{"method":"listpermissions","params":["poe.*"],"id":1,"chain_name":"chain1"}

[
    {
        "address" : "1HGMosmcKEPUnwD2DzNUfQ46HCA9Th4mBZCZEF",
        "for" : {
            "type" : "stream",
            "name" : "poe",
            "streamref" : "15591-267-11410"
        },
        "type" : "admin",
        "startblock" : 0,
        "endblock" : 4294967295
    },
    {
        "address" : "1HGMosmcKEPUnwD2DzNUfQ46HCA9Th4mBZCZEF",
        "for" : {
            "type" : "stream",
            "name" : "poe",
            "streamref" : "15591-267-11410"
        },
        "type" : "activate",
        "startblock" : 0,
        "endblock" : 4294967295
    },
    {
        "address" : "1HGMosmcKEPUnwD2DzNUfQ46HCA9Th4mBZCZEF",
        "for" : {
            "type" : "stream",
            "name" : "poe",
            "streamref" : "15591-267-11410"
        },
        "type" : "write",
        "startblock" : 0,
        "endblock" : 4294967295
    }
]
chain1:

subscribe poe

chain1: subscribe poe
{"method":"subscribe","params":["poe"],"id":1,"chain_name":"chain1"}

Step 5: So for now, only the first server has the ability to write to the stream, as well as administrate it. Let’s publish something to it, with key key1:

chain1: publish poe key1 73747265616d2064617461
{"method":"publish","params":["poe","key1","73747265616d2064617461"],"id":1,"chain_name":"chain1"}

744f9a635f6fb34ee9fa58245341d6d9799574c94fa2c5dc960e7961b80d9f81
chain1:

Step 6: Now let’s query the stream’s contents in many different ways.

liststreamitems poe

chain1: liststreamitems poe
{"method":"liststreamitems","params":["poe"],"id":1,"chain_name":"chain1"}

[
    {
        "publishers" : [
            "1HGMosmcKEPUnwD2DzNUfQ46HCA9Th4mBZCZEF"
        ],
        "key" : "key1",
        "data" : "922ce92090a540222ccd2cb9349d7fc34fd83570938b9e500102543189667f95",
        "confirmations" : 22,
        "blocktime" : 1530693688,
        "txid" : "525cc31b4de0627f19a9bea627fad933252d8ccecdf7a7a04cbf9a3486686f78"
    },
    {
        "publishers" : [
            "1HGMosmcKEPUnwD2DzNUfQ46HCA9Th4mBZCZEF"
        ],
        "key" : "key1",
        "data" : "73747265616d2064617461",
        "confirmations" : 6,
        "blocktime" : 1530693893,
        "txid" : "744f9a635f6fb34ee9fa58245341d6d9799574c94fa2c5dc960e7961b80d9f81"
    }
]
chain1:
chain1: liststreamkeys poe
{"method":"liststreamkeys","params":["poe"],"id":1,"chain_name":"chain1"}

[
    {
        "key" : "key1",
        "items" : 2,
        "confirmed" : 2
    }
]
chain1: liststreampublishers poe
{"method":"liststreampublishers","params":["poe"],"id":1,"chain_name":"chain1"}

[
    {
        "publisher" : "1HGMosmcKEPUnwD2DzNUfQ46HCA9Th4mBZCZEF",
        "items" : 2,
        "confirmed" : 2
    }
]
chain1:

Conclusion : One would be able to understand the Streams in multichain network to store the data in blockchain.