Multiformats

0.3.1.post4 verified Fri May 01 auth: no python

Python implementation of the multiformats protocols (multihash, multiaddr, multibase, multicodec, CID). Version 0.3.1.post4. Active development; releases every few months.

pip install multiformats

Common errors

error KeyError: 'sha2-256' ↓

cause The hash function is not registered because optional dependencies are missing.

fix

Install the required hash extra, e.g., pip install multiformats[sha2].

error ModuleNotFoundError: No module named 'multihash' ↓

cause Attempted to import multihash as a standalone package, but it is a submodule of multiformats.

fix

Use 'from multiformats import multihash' instead.

error TypeError: CID() got an unexpected keyword argument 'codec' ↓

cause Older code used 'codec' parameter; in v0.2.0+ the parameter is 'multicodec'.

fix

Use CID('base32', 'sha2-256', content) – the second positional argument is the multicodec name, not a keyword 'codec'.

Warnings

gotcha The package installs without optional dependencies by default. Required hash functions (e.g., SHA2, SHA3) are not available unless you install multiformats[full] or the specific extra like sha2, sha3, blake2, etc. ↓

fix Run 'pip install multiformats[full]' to get all hash implementations, or install specific extras (e.g., multiformats[sha2]).

breaking In v0.2.0, the API for creating CIDs changed. CID() now expects the multibase code as a string (e.g., 'base32'), not a number. Old code using integer codes will fail. ↓

fix Use string multibase names: CID('base32', 'sha2-256', content). See quickstart.

deprecated The multihash.decode() function returns a namedtuple; accessing fields by index is deprecated in future versions. ↓

fix Use named attributes: mh.code, mh.size, mh.digest instead of mh[0], mh[1], mh[2].

Install

pip install multiformats[full]

Imports

multihash
wrong
```
import multihash
```
correct
```
from multiformats import multihash
```
Multihash is a submodule, not a top-level package.
multiaddr
wrong
```
import multiaddr
```
correct
```
from multiformats import multiaddr
```
Multiaddr is a submodule, not a top-level package.
multibase
wrong
```
import multibase
```
correct
```
from multiformats import multibase
```
Multibase is a submodule, not a top-level package.
multicodec
wrong
```
import multicodec
```
correct
```
from multiformats import multicodec
```
Multicodec is a submodule, not a top-level package.
CID
wrong
```
from multiformats.cid import CID
```
correct
```
from multiformats import CID
```
CID is re-exported at the package level; no need to go into submodule.

Quickstart

Demonstrates basic multihash, multibase, and CID creation/decoding.

from multiformats import multihash, multibase, CID

# Create a multihash (SHA2-256, 32 bytes)
digest = b'\x12' + b'\x20' + (b'x' * 32)
mh = multihash.decode(digest)
print(f"Hash function: {mh.code}, digest size: {mh.size}")

# Encode to multibase (base58btc)
encoded = multibase.encode('base58btc', digest)
print(f"Encoded: {encoded}")

# Create a CIDv1
cid = CID('base32', 'sha2-256', b'x' * 32)
print(f"CID: {cid}")

# Validate
assert cid.version == 1