go-cid
A package to handle content IDs in Go.
This is an implementation in Go of the CID spec.
It is used in go-ipfs and related packages to refer to a typed hunk of data.
Lead Maintainer
Table of Contents
Install
go-cid is a standard Go module which can be installed with:
go get github.com/ipfs/go-cidUsage
Running tests
Run tests with go test from the directory root
go testExamples
Parsing string input from users
// 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
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
// 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
// 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 specification.
License
MIT © Jeromy Johnson