====== Blockchain ======

===== Links =====

  * [[https://nethereum.readthedocs.io/en/latest/|Nethereum Documentation]]
  * [[https://github.com/ethereumjs/testrpc#usage|Testrpc command line options]]
  * [[https://stackoverflow.com/questions/47543679/how-do-i-compile-a-solidity-contract-with-an-import-to-standalone-byte-code|How do I compile a Solidity contract with an import to standalone byte code?]]

===== General Notes =====

  * Make sure the constructor of the contract has the correct access modifiers:
<code>
function MegaContract() public payable {
</code>

==== Security ====

To do anything that requires gas, either unlock the account beforehand with the password:

<code>
var address = "...";
var password = "...";
var web3 = new Web3();
var unlockAccountResult = await web3.Personal.UnlockAccount.SendRequestAsync(address, password, 120);
Assert.IsTrue(unlockAccountResult);
</code>

Or use the private key to create the Web3 object:

<code>
var privateKey = "...";
var web3 = new Web3(new Account(privateKey));
</code>

===== Questions =====

  * [[https://stackoverflow.com/questions/47543679/how-do-i-compile-a-solidity-contract-with-an-import-to-standalone-byte-code|How do I compile a Solidity contract with an import to standalone byte code?]]
  * How to I get the result of calling an external function with Nethereum?

===== Tool Set Install =====

  - Metamask Chrome extension.
  - (Visual Studio Code)
  - NodeJS
  - [Admin PowerShell] ''<nowiki>Set-ExecutionPolicy -ExecutionPolicy RemoteSigned</nowiki>''
  - Chocolately
  - [Admin PowerShell] ''<nowiki>choco install git -params "/GetAndUnixToolsOnPath"</nowiki>''
  - [Admin PowerShell] ''<nowiki>git config --system http.sslverify false</nowiki>''
  - [Admin PowerShell] ''<nowiki>npm install -g node-gyp</nowiki>''
  - [Admin PowerShell] ''<nowiki>npm install --global --production windows-build-tools</nowiki>''
  - [Admin PowerShell] ''<nowiki>npm install -g ethereumjs-testrpc</nowiki>''
  - [Admin PowerShell] ''<nowiki>npm install -g truffle</nowiki>''

===== Commands =====

| ''<nowiki>truffle init</nowiki>'' | Set up project. |
| ''<nowiki>testrpc</nowiki>'' | Start RPC. |
| ''<nowiki>truffle.cmd comp</nowiki>'' | Compile everything. |
| ''<nowiki>truffle.cmd migrate</nowiki>'' | Deploy everything. |
| ''<nowiki>truffle.cmd console</nowiki>'' | Console mode (to interact with contract). |
| [Truffle Console] ''<nowiki>var hw</nowiki>'' | Create a variable to reference our contract. |
| [Truffle Console] ''<nowiki>HelloWorld.deployed().then(function(deployed){hw=deployed;});</nowiki>'' | Get the reference (note that it is async). |
| [Truffle Console] ''<nowiki>hw.SayHello.call()</nowiki>'' | Call a **read-only** method on the contract. |
| [Truffle Console] ''<nowiki>hw.sendCoin('0x8...', 100)</nowiki>'' | Call a **modifying** method on the contract. |
| [Truffle Console] ''<nowiki>.exit</nowiki>'' | Exit console mode. |

===== Implementations of Ethereum blockchange =====

^ Implementation ^ Language ^ Pruning ^ Notes ^
| Geth | Go | Yes | |
| Parity | Rust | Yes | |
| EthereumJ | Java | Yes | |
| Eth | C++ | No | Reference implementation is meant for developers only. |
| PyEthApp | Python | No | |

===== Glossary =====

| ABI | Application Binary Interface. Is basically how you call functions in a contract and get data back. Like a WSDL or .h file in C. |

===== VS Code =====

Use the [[https://marketplace.visualstudio.com/items?itemName=JuanBlanco.solidity|Solidity]] extension.
  * F5 - Compilation of the current contract 
  * Ctrl + F5 - Compilation of all the contracts

===== Nethereum =====

Start with [[https://www.nuget.org/packages/Nethereum.Web3/|Nethereum.Web3]].

==== Tutorial ====

Video is [[https://www.youtube.com/watch?v=4t5Z3eX59k4|here]].

  - [VS Code] Write contract
  - [VS Code] Compile contract
  - [Command Line] Start Geth
  - [VS] Create unit test project.
  - [VS] NuGet install Nethereum.Web3 + dependencies.

===== Dev VM =====

Geth's encrypted accounts key store files can be found in ''%APPDATA%/Ethereum''.

==== Run Geth ====

  - Open a //separate// DOS ConEmu.
  - [ConEmu DOS] Run the command, ''C:\Users\TallGuy-DevVm\Dev\Geth\startgeth.bat''
  - Open a //separate// Admin PowerShell ConEmu.
  - [ConEmu PowerShell] Run the command, ''(Get-Process geth).PriorityClass = <nowiki>"BelowNormal"</nowiki>''