https://github.com/ipfs/go-cid

Content ID v1 implemented in go
https://github.com/ipfs/go-cid

cid ipld multiformats

Last synced: about 22 hours ago
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Content ID v1 implemented in go

• Host: GitHub
• URL: https://github.com/ipfs/go-cid
• Owner: ipfs
• License: mit
• Created: 2016-08-23T17:05:22.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-12-12T05:18:18.000Z (1 day ago)
• Last Synced: 2024-12-12T06:23:43.690Z (1 day ago)
• Topics: cid, ipld, multiformats
• Language: Go
• Homepage:
• Size: 243 KB
• Stars: 157
• Watchers: 30
• Forks: 47
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-list - go-cid
• go-awesome - go-cid - [CID spec](https://github.com/ipld/cid) Go language implementation (Open source library / Not Categorized)

README

        
go-cid

==================

[![](https://img.shields.io/badge/made%20by-Protocol%20Labs-blue.svg?style=flat-square)](http://ipn.io)

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[![GoDoc](https://godoc.org/github.com/ipfs/go-cid?status.svg)](https://godoc.org/github.com/ipfs/go-cid)

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> A package to handle content IDs in Go.

This is an implementation in Go of the [CID spec](https://github.com/ipld/cid).

It is used in `go-ipfs` and related packages to refer to a typed hunk of data.

## Lead Maintainer

[Eric Myhre](https://github.com/warpfork)

## Table of Contents

- [Install](#install)

- [Usage](#usage)

- [API](#api)

- [Contribute](#contribute)

- [License](#license)

## Install

`go-cid` is a standard Go module which can be installed with:

```sh

go get github.com/ipfs/go-cid

```

## Usage

### Running tests

Run tests with `go test` from the directory root

```sh

go test

```

### Examples

#### Parsing string input from users

```go

// Create a cid from a marshaled string

c, err := cid.Decode("bafzbeigai3eoy2ccc7ybwjfz5r3rdxqrinwi4rwytly24tdbh6yk7zslrm")

if err != nil {...}

fmt.Println("Got CID: ", c)

```

#### Creating a CID from scratch

```go

import (

  cid "github.com/ipfs/go-cid"

  mc "github.com/multiformats/go-multicodec"

  mh "github.com/multiformats/go-multihash"

)

// Create a cid manually by specifying the 'prefix' parameters

pref := cid.Prefix{

	Version: 1,

	Codec: uint64(mc.Raw),

	MhType: mh.SHA2_256,

	MhLength: -1, // default length

}

// And then feed it some data

c, err := pref.Sum([]byte("Hello World!"))

if err != nil {...}

fmt.Println("Created CID: ", c)

```

#### Check if two CIDs match

```go

// To test if two cid's are equivalent, be sure to use the 'Equals' method:

if c1.Equals(c2) {

	fmt.Println("These two refer to the same exact data!")

}

```

#### Check if some data matches a given CID

```go

// To check if some data matches a given cid, 

// Get your CIDs prefix, and use that to sum the data in question:

other, err := c.Prefix().Sum(mydata)

if err != nil {...}

if !c.Equals(other) {

	fmt.Println("This data is different.")

}

```

## Contribute

PRs are welcome!

Small note: If editing the Readme, please conform to the [standard-readme](https://github.com/RichardLitt/standard-readme) specification.

## License

MIT © Jeromy Johnson