Source code for aries_cloudagent.connections.models.diddoc.util

DIDDoc utility methods.

Copyright 2017-2019 Government of Canada
Public Services and Procurement Canada -

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from base58 import b58decode
from urllib.parse import urlparse

[docs]def resource(ref: str, delimiter: str = None) -> str: """ Extract the resource for an identifier. Given a (URI) reference, return up to its delimiter (exclusively), or all of it if there is none. Args: ref: reference delimiter: delimiter character (default None maps to '#', or ';' introduces identifiers) """ return ref.split(delimiter if delimiter else "#")[0]
[docs]def canon_did(uri: str) -> str: """ Convert a URI into a DID if need be, left-stripping 'did:sov:' if present. Args: uri: input URI or DID Raises: ValueError: for invalid input. """ if ok_did(uri): return uri if uri.startswith("did:sov:"): rv = uri[8:] if ok_did(rv): return rv raise ValueError( "Bad specification {} does not correspond to a sovrin DID".format(uri) )
[docs]def canon_ref(did: str, ref: str, delimiter: str = None): """ Given a reference in a DID document, return it in its canonical form of a URI. Args: did: DID acting as the identifier of the DID document ref: reference to canonicalize, either a DID or a fragment pointing to a location in the DID doc delimiter: delimiter character marking fragment (default '#') or introducing identifier (';') against DID resource """ if not ok_did(did): raise ValueError("Bad DID {} cannot act as DID document identifier".format(did)) if ok_did(ref): # e.g., LjgpST2rjsoxYegQDRm7EL return "did:sov:{}".format(did) if ok_did(resource(ref, delimiter)): # e.g., LjgpST2rjsoxYegQDRm7EL#keys-1 return "did:sov:{}".format(ref) if ref.startswith( "did:sov:" ): # e.g., did:sov:LjgpST2rjsoxYegQDRm7EL, did:sov:LjgpST2rjsoxYegQDRm7EL#3 rv = ref[8:] if ok_did(resource(rv, delimiter)): return ref raise ValueError("Bad URI {} does not correspond to a sovrin DID".format(ref)) if urlparse(ref).scheme: # e.g., return ref return "did:sov:{}{}{}".format(did, delimiter if delimiter else "#", ref) # e.g., 3
[docs]def ok_did(token: str) -> bool: """ Whether input token looks like a valid decentralized identifier. Args: token: candidate string Returns: whether input token looks like a valid schema identifier """ try: return len(b58decode(token)) == 16 if token else False except ValueError: return False