change: simplify didcore components, did-exchange protocol

[Patrik-Stas]

The changes in this PR are primarily stemming by removing generics on DidDocument and Service data structures. This change trickles-up significantly all the way to did-exchange implementation. This enable many simplifications and removal of lots of code. Some other improvements has been done on the way as well.

I recommend start looking at the PR from top down to understand public API effect of the changes.

Demo

• aries/aries_vcx/tests/test_did_exchange.rs is the top-most level of changes

Simplified DidExchangeRequester

• Now has single method construct_request which simple accepts a Did as input - can be any resolvable DID. This means it's also possible to establish didcomm any 2 entities which have DID - be it did:peer, did:sov or any other DID.
• Trimmed down support for invitations - we do not support OOB invitations with service objects "embedded" into the invitation. This Aries design was objected in Out of band - proposing change ( services VS from ) aries-rfcs#802. We can implemented later if desired by any vcx users, but solution is ugly - it would be needed to convert Service object to Did Document which doesn't make sense.

These changes also lead to internals simplification where bunch of transformation code could been removed

Simplified DidExchangeResponder

• Just like requester (invitee), DidExchangeRequester(inviter) needs to provide their pairwise PeerDid for the counterparty upon constructing Response message. This means that currently the responder always rotates their DID, regardless of what kind of DID they used in invitation. Making rotation optional will be addressed in the future.
• Removes required argument invitation_id from receive_request method signature. Also, don't keep this information in SM state - the responder might receive request which is not constructed on basis of any invitation - but rather simply on basis of knowing responder's public DID. Invitation might not exist in a first place, so it doesn't make sense to store its ID.

DidCore

Removed generics

The main goal of the PR was simplification of DidCore components - mainly removing generic type parameters from DidDocument<E> and Service<E>. This lead to many changes, but in scope of DidCore components:

• Instance of DidDocument can represent any valid Did Document with any extra fields. Instance of Service can represent any Service object, with any extra fields.
• In practice, in didcomm we usually use certain extra fields on Service object - such as routingKeys, recipientKeys, accept etc. Given the "extra" typing we dropped, the current typing design has following considerations:
  1. When resolving did document, we don't know what extra field we might find. We don't know what resolver will return for a particular DID. We don't know what fields the applications build on top of did_doc crate wants to support, work with. Hence it's up to applications to decide either work with DidDocument/Service as their are, or convert these to custom types in runtime, if typed environment for extra fields is needed.
  2. We also provide fully typed version of common didcomm Services - such as struct ServiceDidCommV1, struct ServiceDidCommV2. These tend to be useful when the user wants to construct particular service type themselves. Equally, as mentioned in the previous point i., user can also choose to convert Serviceto more explicit types such asServiceDidCommV1upon resolution. However, in practical terms so far inaries_vcx`, this was not really needed.

New features

• Implement new util methods on DidDocument such as get_service_of_type, get_key_agreement_of_type to support data lookups within did documents.

Refactoring

• Remove custom url wrapper for url::Url crate in did_doc crate
• Refactoring around did:peer:2 de/abbreviation

Error handling

• Refactoring of errors to reduce number of variants, for example DidDocumentBuilderError now has only single KeyDecodingError variant, which itself hold further more details about particular decoding issue
• Introduce new error types in did_doc crate, such as JsonWebKeyError, MultibaseWrapperError, KeyDecodingError and others to avoid misusing DidDocumentBuilderError in contexts where we are not in fact using did document builder.

Other changes

Testing

• introduce pretty_assertions https://github.com/rust-pretty-assertions/rust-pretty-assertions#usage as dev dependency to some of the crates and tests

Logging

• Derive Display for more structs

Refactoring

• aries-vcx-agent did-exchange service is generating invitation with did:peer as value of services, rather than inlining service object.
• Make DidPeer<Numalgo2> --- DDO user friendlier. Instead of calling "util" function resolve_numalgo2(did PublicKeyEncoding::Base58) this is now done did.to_did_doc(PublicKeyEncoding::Base58)
• Didcomm v1 refactoring (EncryptionEnvelope)
  • added new constructor which takes in 2 DidDocument structures. Noteworthy is that key_agreement is used for encryption rather than recipientKeys "extra field". The thing is, peer:did:2 doesn't even define how recipientKeys should be abbreviated, I believe it assumes it wouldn't be used anymore.

Fix

• did:peer:3 validation regex did not allow DIDs which contains Service only. But all fields in Did Document are optional - except id, did:peer:3.S.* is valid DID too.

Note

• This PR contains intermediary refactoring work done in Remove didcore generics, update did-exchange #1097

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 1125 lines in your changes are missing coverage. Please review.

Project coverage is 0.05%. Comparing base (74ab042) to head (053055e).

Files	Patch %	Lines
did_core/did_doc/src/schema/legacy.rs	0.00%	104 Missing ⚠️
...peer_did/numalgos/numalgo2/service_abbreviation.rs	0.00%	95 Missing ⚠️
aries/aries_vcx/tests/test_did_exchange.rs	0.00%	93 Missing ⚠️
did_core/did_doc/src/schema/service/mod.rs	0.00%	72 Missing ⚠️
...rc/protocols/did_exchange/state_machine/helpers.rs	0.00%	67 Missing ⚠️
...core/did_doc/src/schema/service/typed/didcommv1.rs	0.00%	60 Missing ⚠️
aries/aries_vcx/src/utils/didcomm_utils.rs	0.00%	53 Missing ⚠️
...did_peer/src/peer_did/numalgos/numalgo2/helpers.rs	0.00%	47 Missing ⚠️
did_core/did_doc/src/schema/service/typed/mod.rs	0.00%	43 Missing ⚠️
aries/aries_vcx/src/protocols/did_exchange/mod.rs	0.00%	41 Missing ⚠️
... and 46 more

Additional details and impacted files

@@          Coverage Diff           @@
##            main   #1075    +/-   ##
======================================
  Coverage   0.05%   0.05%            
======================================
  Files        473     476     +3     
  Lines      24239   24137   -102     
  Branches    4492    4498     +6     
======================================
  Hits          13      13            
+ Misses     24226   24124   -102     

Flag	Coverage Δ
unittests-aries-vcx	0.05% <0.00%> (+<0.01%)	⬆️

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[Patrik-Stas]

aries-vcx -- aries-vcx AATH did-exchange tests passing

[gmulhearn]

Skimmed thru aries changes. nice stuff