166a3a6880
When reading from an io.Reader that has no data, the io.EOF error should not be wrapped in ErrInvalidCid. This is not an invalid CID, and is not the same as a partial read which is indicated by io.ErrUnexpectedEOF. This fix is needed because existing code that uses CidFromReader may check for the end of an input stream by `if err == io.EOF` instead of the preferred `if errors.Is(err, io.EOF)`, and that code break at runtime after upgrading to go-cid v0.4.0.
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-cid
Usage
Running tests
Run tests with go test from the directory root
go test
Examples
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