Blockchain Stuffs

Some useful documentations that I've been reading about blockchain and smart-contracts

• https://blockgeeks.com/guides/ethereum/
• https://blockgeeks.com/guides/smart-contracts/
• https://remix.readthedocs.io/en/latest/quickstart_javascript_vm.html
• https://medium.com/aigang-network/how-ethereum-contract-can-communicate-with-external-data-source-2e32616ea180
• https://medium.com/@qmqlegal/what-you-need-to-know-about-blockchain-54df3291f834
• http://solidity.readthedocs.io/en/develop/security-considerations.html
• https://hackernoon.com/ethereum-development-walkthrough-part-2-truffle-ganache-geth-and-mist-8d6320e12269
• http://solidity.readthedocs.io/en/develop/miscellaneous.html?highlight=pure#modifiers
• http://remix.ethereum.org
• https://docs.oraclize.it/#background

Solidity tutorials

• https://learnxinyminutes.com/docs/solidity/
• https://blockgeeks.com/guides/solidity/

Plattaforms

• Namecoin
• Ethereum

Installing npm, Truffle, and remix-ide

First steps

Run the following commands to install npm and nodejs

apt-get updade && \
apt-get install npm nodejs -y

Now as explained in https://stackoverflow.com/questions/30713136/strange-npm-behavior-when-installing-packages-like-grunt we have to create a symbolic link to the nodejs binary.

sudo ln -s /usr/bin/nodejs /usr/bin/node

Configuring npm environment

This step was based on https://docs.npmjs.com/getting-started/fixing-npm-permissions. To avoid permissions erros on npm you must run the following commands:

• Back-up your computer before you start.

• Make a directory for global installations:

 mkdir ~/.npm-global

• Configure npm to use the new directory path:

npm config set prefix '~/.npm-global'

• Open or create a ~/.profile file and add this line:

export PATH=~/.npm-global/bin:$PATH

• Back on the command line, update your system variables:

source ~/.profile

• Test: Download a package globally without using sudo.

In case of versioning erros, follow this tutorial https://stackoverflow.com/questions/8191459/how-do-i-update-node-js

Installing remix-ide and Truffle

Simple!!! Just execute:

npm install truffle -g
npm install remix-ide -g

Your first Dapp

• https://truffleframework.com/tutorials/pet-shop

Interacting with your contracts

• https://truffleframework.com/docs/truffle/getting-started/interacting-with-your-contracts

Installing Web3.js API

npm i web3

In case of erros such like: github.com[0: 192.30.253.113]: errno=Conexão recusada

See: https://stackoverflow.com/questions/1722807/how-to-convert-git-urls-to-http-urls

Some interesting discussion topics

• Memory vs Storage
• Optimizing your Solidity contract’s gas usage

Web3 APIs

• Web3 Javascript API
• Web3 Python API

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