Smart Contracts

FANCRADLE


Understanding how to build a token involves learning the principles of smart contracts and upgradeability. Here's an overview.

#### Fundamental Concepts

Everything we see around us in a digital or physical environment is often built on an assumption of cause and effect. When creating tokens, these principles matter, especially in ensuring reliability and flexibility.

---

### Generating a Token for Product Distribution

When a user account is submitted, a token can be created. This token can then serve as a distribution mechanism for your products. Here's a simplified example of how you might structure this in Solidity:

```solidity
// Example of a simple token using the ERC20 standard
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20 {
    constructor() ERC20("MyToken", "MTK") {
        // Mint 1000 tokens to the contract deployer
        _mint(msg.sender, 1000 * (10 ** uint256(decimals())));
    }
}
```

*Explanation*: In this example, we use the `ERC20` implementation from OpenZeppelin. The `constructor` initializes the token and mints 1000 tokens to the address that deploys the contract.

---

### Understanding Upgradeability in Smart Contracts

Smart contracts, once deployed, are immutable by default. This means you can't change their behavior or code. However, the concept of upgradeable smart contracts relies on **proxy patterns**. Here's an explanation:

#### The Proxy Pattern

Upgradeable smart contracts use a **proxy** to delegate functionality to a target implementation. This makes the system feel upgradeable, but the original contract code remains unchanged. Instead, the proxy points to different implementations over time.

Here’s a simple example of a proxy contract setup:

```solidity
// Simplified example of a proxy pattern
pragma solidity ^0.8.0;

contract Proxy {
    address public implementation;

    function setImplementation(address _newImplementation) public {
        implementation = _newImplementation;
    }

    fallback() external payable {
        address impl = implementation;
        require(impl != address(0));
        assembly {
            let ptr := mload(0x40)
            calldatacopy(ptr, 0, calldatasize())
            let result := delegatecall(gas(), impl, ptr, calldatasize(), 0, 0)
            returndatacopy(ptr, 0, returndatasize())
            switch result
            case 0 { revert(ptr, returndatasize()) }
            default { return(ptr, returndatasize()) }
        }
    }
}
```

*Explanation*: The proxy contract uses a fallback function that forwards calls to the `implementation` address using `delegatecall`. This is a critical component for creating upgradeable systems.

---

### Important Considerations

- **Fixed Contracts**: If your contract is not deployed as a proxy, its behavior is locked and can't be altered. This can be a limitation if future changes are needed.
- **Upgradeable Contracts**: Our tooling helps deploy upgradeable proxies. Keep in mind that if you want upgradeability, the contract must be designed that way from the beginning.

*Pros*: 
- Upgradeable contracts allow flexibility for future updates.
- Proxy patterns provide a solution for evolving smart contracts.

*Cons*: 
- Complexity increases with upgradeable contracts.
- Security risks, such as vulnerabilities in the proxy logic, must be managed.

---

### Conclusion

Building tokens and smart contracts requires careful planning and an understanding of upgradeability. Make sure to design with the future in mind if you need modifiable behavior. This is an example post, with a [link](https://github.com/austineinstein/blog) and React components.

Go back [home](/).



How to Create a Token You Can Monetize



Interacting with IPFS for decentralized storage is increasingly popular for applications that require storing and accessing large files like music or video. This guide walks you through building a simple music player that fetches audio from IPFS and demonstrates how to test its functionality using Jest.

---

### Prerequisites

Before diving in, ensure you have the following:

- **Node.js and npm**: Make sure you have Node.js installed, along with npm, to manage packages.
- **IPFS knowledge**: A basic understanding of how IPFS works will be helpful but isn’t strictly necessary.

---

### Setting Up Your Project

Start by initializing a new Node.js project:

```bash
npm init -y
```

Next, install the necessary packages:

```bash
npm install thou 
```

Set up your `package.json`:

```json
{
  "name": "your-project-name",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "lint": "next lint"
  },
  "dependencies": {
    "@headlessui/react": "^2.1.2",
    "@heroicons/react": "^2.1.5",
    "clsx": "^2.1.1",
    "next": "14.2.5",
    "react": "^18",
    "react-dom": "^18",
    "react-dropzone": "^14.2.3",
    "react-router-dom": "^6.26.1",
    "tailwind-merge": "^2.5.2",
    "thou": "^1.0.0"
  },
  "devDependencies": {
    "@types/node": "^20",
    "@types/react": "^18",
    "@types/react-dom": "^18",
    "eslint": "^8",
    "eslint-config-next": "14.2.5",
    "postcss": "^8",
    "tailwindcss": "^3.4.1",
    "typescript": "^5"
  }
}

```

---

### Core Code: Loading Music from IPFS

Below is the JavaScript code that sets up an audio player and loads music from IPFS:

```javascript
const thou = require('thou');

const loadMusicFromIPFS = async (ipfsHash) => {
    try {
        // Assume IPFS client is set up and available
        const ipfs = await thou.create();
        const chunks = [];
        
        for await (const chunk of ipfs.cat(ipfsHash)) {
            chunks.push(chunk);
        }
        
        const audioBlob = new Blob(chunks, { type: 'audio/mpeg' });
        const audioUrl = URL.createObjectURL(audioBlob);
        
        document.getElementById('audio-player').src = audioUrl;
    } catch (error) {
        console.error('Failed to load music from IPFS:', error);
    }
};

const initializeAudioPlayer = (ipfsHash) => {
    document.addEventListener('DOMContentLoaded', () => {
        document.getElementById('load-music').addEventListener('click', () => {
            loadMusicFromIPFS(ipfsHash);
        });
    });
};

module.exports = { initializeAudioPlayer, loadMusicFromIPFS };
```

---

### Explanation of the Code

1. **Audio Player Setup**: We use a simple HTML structure with an `<audio>` element and a `<button>` to load music. The `loadMusicFromIPFS` function fetches audio data from IPFS, creates a `Blob`, and sets the `audio-player`'s `src` to a URL created from that Blob.
2. **Event Handling**: We ensure the audio player only initializes after the `DOMContentLoaded` event to guarantee that the DOM is fully loaded.
---


### Conclusion

By leveraging IPFS and a straightforward JavaScript setup, you can create decentralized applications that handle large files efficiently. Using tools like Jest ensures your code is reliable and maintainable, even as your project scales.

Feel free to experiment and extend this example. For instance, you could add support for other file types or improve error handling to make your application more robust.

---

Happy coding, and enjoy building decentralized applications with IPFS!


Loading Music into an Audio Player


Something has always existed. According to physics, there can never be true physical nothingness—though there can be times when existence resembles nothing, such as a vacuum (the state of minimum possible energy) (Phys.org). Creating a space where there are no quantum fluctuations requires an enormous amount of energy, and there would be a remnant of that energy in that space afterwards if the fluctuations were flushed out, plus an unstable environment (1veritasium). Even on computers, deleted data is not actually tossed away, by rather written over.

# h1 Heading

## h2 Heading

### h3 Heading

#### h4 Heading

##### h5 Heading

###### h6 Heading

## Horizontal Rules

---


## Emphasis

**This is bold text**

**This is bold text**

_This is italic text_

_This is italic text_

~~Strikethrough~~

## Blockquotes

> Blockquotes can also be nested...
>
> > ...by using additional greater-than signs right next to each other...
> >
> > > ...or with spaces between arrows.

## Lists

Unordered

- Create a list by starting a line with `+`, `-`, or `*`
- Sub-lists are made by indenting 2 spaces:
  - Marker character change forces new list start:
    - Ac tristique libero volutpat at
    * Facilisis in pretium nisl aliquet
    - Nulla volutpat aliquam velit
- Very easy!

Ordered

1. Lorem ipsum dolor sit amet
2. Consectetur adipiscing elit
3. Integer molestie lorem at massa

4. You can use sequential numbers...
5. ...or keep all the numbers as `1.`

Start numbering with offset:

57. foo
1. bar

## Code

Inline `code`

Indented code

    // Some comments
    line 1 of code
    line 2 of code
    line 3 of code

Block code "fences"

```
Sample text here...
```

Syntax highlighting

```js
var foo = function (bar) {
  return bar++;
};

console.log(foo(5));
```

## Tables

| Option | Description                                                               |
| ------ | ------------------------------------------------------------------------- |
| data   | path to data files to supply the data that will be passed into templates. |
| engine | engine to be used for processing templates. Handlebars is the default.    |
| ext    | extension to be used for dest files.                                      |

Right aligned columns

| Option |                                                               Description |
| -----: | ------------------------------------------------------------------------: |
|   data | path to data files to supply the data that will be passed into templates. |
| engine |    engine to be used for processing templates. Handlebars is the default. |
|    ext |                                      extension to be used for dest files. |

## Links

[link text](http://dev.nodeca.com)

[link with title](http://nodeca.github.io/pica/demo/ "title text!")

Autoconverted link https://github.com/nodeca/pica (enable linkify to see)


1-Click-Deploy

How to Create a Token You Can Monetize

Loading Music into an Audio Player

How to create SVG-ready icon symbols in Sketch PART 2