class 10.txt

test network:

2 orgs
 
1 order


Async process:
--------------

client 1 ----> request to read a file from File system

client 2 ----> request to open a DB for update operation

client 3 ----> request to start a web server

client 4 ----> print logs



server:
-------

1 - req1 ---> client ---> read file
2 - req2 ---> open the db
3 - req1 ---> send the file to client1
4 - req3 ---> to start another web server
5 - req2 ---> notofies to client saying
6 - req3 ---> start the new web req from clinet3

Event loop ----> node js



java:
------
 import java.*
 class Helloworld
  {
    system.out.printl("helloworld")
  }

compile to bytecode ---> java

C:
----


#include <stdio>

 main ()
 func 
{ 

 printl ('helloworld')

}

compile ---> run


node js:
----------

console.log ("helloworld");

 node helloworld.js


java:

 import java.*

nodejs:

 command to import http omodule

var http = require('http')



create webserver:
------------------

1. import http module

2. var for http

3. var for port

4. create serve using http.createServe

5. start the server on port



promises and async/await:
--------------------------

 promise ---> client

 a. resolve ---> consider file read is success
 b. reject  ---> 


async/await --->


File system ----> fs

var fs = require('fs') 

 fs.createfile
 fs.openfile
 fs.writefile
 fs.readfile
 fs.closefile


http.createServer
http.closeServer


to handle apis with http is time consuming for devs and for processing

express is a framework developed on top of http to handle

1. effective api calls
2. easy database integrations
3. effective handlers
4. fast processing time


C R U D

post/get/put/delete

get---->

app.get('/'



ledger:
---------
1. asset 1 -> 5000
2. asset 1 -> 15000

world state:
------------

1. asset 1 -> 5000 + delta ----> 5000 + 15000 ---> 20,000


work flows:
-----------

1. transaction
2. digital signature verification
3. completed by both parties involved in the txn



Corda network:
--------------

 5 banks who wish to join a corda network for a DLT credit/Letter of credit 

peers ----> 5 banks

miners/validators/ordering service ----> Doesnt use 

Notary service ----> central node which will validate txn


1. identity process ---> which generates required pub/priv keys, identity certificates
   
2. Network map service ---->

 txn1 ----> user1 (bank1) ----> user2 (bank2)

Routing tables:
 [bank1 ---> 100.20.16.140/DNS
   bank2 ---> 100.21.16.150
   . bank5 ---> 100.25.17.123]

3. notary service --->  {123 9 10 11 15 16}

 bank1 , bank2 ---> 1 2 3

 bank2, bank3 ---> 9 10 11 

 bank3 , bank4 ---> 15 16



Corda is used for only finanical based apps ----> (standard version (minimal , 1000tps) and enterprise versin) ---> costly
 per txn basis --->

Fabric ---> almost all apps ---> open source (free)




(openzeplin, alchemy, moralis, chainlink)

Ethereum: solidity, web3.js, ethers.js, truffle, hardhat, openzeppline contract specifications (erc20, erc721, erc1155) ---> "2"


(enterprises)
Fabric: java/nodejs/golang, network commands, linux, docker, kubernetes ---> "1"

Corda: java/kotlin

IOTA

Algorand

PolkaDot

Solana

Hedera hashgraph