Class Cid

Identifies some content, e.g. a Content ID.

Inheritance

Object

Cid

Implements

IEquatable<Cid>

Inherited Members

Object.Equals(Object, Object)

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Namespace: Ipfs

Assembly: Ipfs.Core.dll

Syntax

[JsonConverter(typeof(Cid.CidJsonConverter))]
public class Cid : IEquatable<Cid>

Remarks

A Cid is a self-describing content-addressed identifier for distributed systems.

Initially, IPFS used a MultiHash as the CID and this is still supported as Version 0. Version 1 adds a self describing structure to the multi-hash, see the spec.

note

The Algorithm must be "sha2-256" for a version 0 CID.

Fields

DefaultContentType

The default ContentType.

Declaration

public const string DefaultContentType = "dag-pb"

Field Value

Type	Description
String

Properties

ContentType

The content type or format of the data being addressed.

Declaration

public string ContentType { get; set; }

Property Value

Type	Description
String	dag-pb, dag-cbor, eth-block, etc. Defaults to "dag-pb".

Remarks

Sets Version to 1, when setting a value that is not equal to "dag-pb".

See Also

MultiCodec

Encoding

The MultiBase encoding of the CID.

Declaration

public string Encoding { get; set; }

Property Value

Type	Description
String	base58btc, base32, base64, etc. Defaults to DefaultAlgorithmName.

Remarks

Sets Version to 1, when setting a value that is not equal to "base58btc".

See Also

MultiBase

Hash

The cryptographic hash of the content being addressed.

Declaration

public MultiHash Hash { get; set; }

Property Value

Type	Description
MultiHash	The MultiHash of the content being addressed.

Remarks

Sets Version to 1, when setting a hashing algorithm that is not equal to "sha2-256".

note

If the Algorithm equals identity, then the Digest is also the content. This is commonly referred to as 'CID inlining'.

Version

The version of the CID.

Declaration

public int Version { get; set; }

Property Value

Type	Description
Int32	0 or 1.

Remarks

When the Version is 0 and the following properties are not matched, then the version is upgraded to version 1 when any of the properties is set.

• ContentType equals "dag-pb"
• Encoding equals "base58btc"
• Hash algorithm name equals "sha2-256"

The default Encoding is "base32" when the Version is not zero.

Methods

Decode(String)

Converts the specified String to an equivalent Cid object.

Declaration

public static Cid Decode(string input)

Parameters

Type	Name	Description
String	input	The Encode() string.

Returns

Type	Description
Cid	A new Cid that is equivalent to input.

Exceptions

Type	Condition
FormatException	When the input can not be decoded.

See Also

Encode()

Encode()

Converts the CID to its equivalent string representation.

Declaration

public string Encode()

Returns

Type	Description
String	The string representation of the Cid.

Remarks

For Version 0, this is equalivalent to the ToBase58() of the Hash.

See Also

Decode(String)

Equals(Cid)

Declaration

public bool Equals(Cid that)

Parameters

Type	Name	Description
Cid	that

Returns

Type	Description
Boolean

Equals(Object)

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
Object	obj

Returns

Type	Description
Boolean

Overrides

Object.Equals(Object)

GetHashCode()

Declaration

public override int GetHashCode()

Returns

Type	Description
Int32

Overrides

Object.GetHashCode()

Read(CodedInputStream)

Reads the binary representation of the CID from the specified Google.Protobuf.CodedInputStream.

Declaration

public static Cid Read(CodedInputStream stream)

Parameters

Type	Name	Description
Google.Protobuf.CodedInputStream	stream	The Google.Protobuf.CodedInputStream to read from.

Returns

Type	Description
Cid	A new Cid.

Read(Byte[])

Reads the binary representation of the CID from the specified byte array.

Declaration

public static Cid Read(byte[] buffer)

Parameters

Type	Name	Description
Byte[]	buffer	The souce of a CID.

Returns

Type	Description
Cid	A new Cid.

Remarks

The buffer does NOT start with a varint length prefix.

Read(Stream)

Reads the binary representation of the CID from the specified Stream.

Declaration

public static Cid Read(Stream stream)

Parameters

Type	Name	Description
Stream	stream	The Stream to read from.

Returns

Type	Description
Cid	A new Cid.

ToArray()

Returns the binary representation of the CID as a byte array.

Declaration

public byte[] ToArray()

Returns

Type	Description
Byte[]	A new buffer containing the CID.

Remarks

The buffer does NOT start with a varint length prefix.

ToString()

Returns the string representation of the CID in the general format.

Declaration

public override string ToString()

Returns

Type	Description
String	e.g. "QmXg9Pp2ytZ14xgmQjYEiHjVjMFXzCVVEcRTWJBmLgR39V"

Overrides

Object.ToString()

ToString(String)

Returns a string representation of the CID according to the provided format specifier.

Declaration

public string ToString(string format)

Parameters

Type	Name	Description
String	format	A single format specifier that indicates how to format the value of the CID. Can be "G" or "L".

Returns

Type	Description
String	The CID in the specified format.

Remarks

The "G" format specifier is the same as calling Encode().

Specifier	return value
G	QmXg9Pp2ytZ14xgmQjYEiHjVjMFXzCVVEcRTWJBmLgR39V
L	base58btc cidv0 dag-pb sha2-256 Qm...

Exceptions

Type	Condition
FormatException	format is not valid.

Write(CodedOutputStream)

Writes the binary representation of the CID to the specified Google.Protobuf.CodedOutputStream.

Declaration

public void Write(CodedOutputStream stream)

Parameters

Type	Name	Description
Google.Protobuf.CodedOutputStream	stream	The Google.Protobuf.CodedOutputStream to write to.

Write(Stream)

Writes the binary representation of the CID to the specified Stream.

Declaration

public void Write(Stream stream)

Parameters

Type	Name	Description
Stream	stream	The Stream to write to.

Operators

Equality(Cid, Cid)

Value equality.

Declaration

public static bool operator ==(Cid a, Cid b)

Parameters

Type	Name	Description
Cid	a
Cid	b

Returns

Type	Description
Boolean

Implicit(Cid to String)

Implicit casting of a Cid to a String.

Declaration

public static implicit operator string (Cid id)

Parameters

Type	Name	Description
Cid	id	A Cid.

Returns

Type	Description
String	A new String.

Remarks

Equivalent to

Cid.Encode()

Implicit(MultiHash to Cid)

Implicit casting of a MultiHash to a Cid.

Declaration

public static implicit operator Cid(MultiHash hash)

Parameters

Type	Name	Description
MultiHash	hash	A MultiHash.

Returns

Type	Description
Cid	A new Cid based on the hash. A Version 0 CID is returned if the hash is "sha2-356"; otherwise Version 1.

Implicit(String to Cid)

Implicit casting of a String to a Cid.

Declaration

public static implicit operator Cid(string s)

Parameters

Type	Name	Description
String	s	A string encoded Cid.

Returns

Type	Description
Cid	A new Cid.

Remarks

Equivalent to

 Cid.Decode(s)

Inequality(Cid, Cid)

Value inequality.

Declaration

public static bool operator !=(Cid a, Cid b)

Parameters

Type	Name	Description
Cid	a
Cid	b

Returns

Type	Description
Boolean

Implements

System.IEquatable<T>

See Also

https://github.com/ipld/cid