Holochain commons

An open ideas document and a wish list for common functionality the dev community needs and possibly would like to develop.

Zome traits
Design patterns
Standalone DNA / hAPP
Potential core functionality

Zome traits

Standardised traits would allow for third party apps to better access and visualise an agents data (DNA-instances/zomes/entries) but also to interact with the data in a meaningful way. It faciltates better interopability between apps and speeds up development.

Implements

List which standard traits (and possibly trait versions) a zome uses. Possibly the trait definitions in the zome code are sufficient? But I have a sense we would like to have one more level of detail - trait id, a version number etc. The information has to be accessible not only for the app developer but for third party apps calling zome functions.

(Similar to IERC165, supportsInterface(interfaceId) https://docs.openzeppelin.com/contracts/2.x/api/introspection)

Ownable

The notion of “ownership” over a digital resource is a basic pattern many Holochain applications will need. With ownership comes the user expectance of being able to transfer that ownership, to renounce ownership, etc.

https://hackmd.io/kWfnGNR4Ta-K1h0jpK71Hw?both

Metadata

Both zome level fields and entry level fields. Standard (zome_description, …) as well as zome/app specific.

Taxonomy

Provides a list of categories for other things.

Preview

Renders a human readable preview of an entry or list of entries, possibly returns a webcomponent? Example: embed a nice looking representation of a chat entry in a humm blog post.

Editor? or Plugin?

Returns a plugin editor that can be embedded in other apps. Example: Every Humm blog post embeds a "Comments Editor" from the "HoloComments" app allowing for users to comment posts.

Timestamped

Entries carry metadata that give varying levels of proof that they happened at a certain moment in time. (cf Mixin zome(s) for entry timestamping)

ClaimsPermissioned

Actions are allowed or denied based on the possession of valid claims/credential (cf W3C Verifiable Credentials).

MembersOnly

A special application of ClaimsPermissioned that requires a valid credential to join the network.

DIDResolver

Able to take responsibility for resolving W3C Decentralised Identifiers for the data this DNA’s DHT contains. (cf Mixin zome and utility libraries for RESTful APIs and URI resolvers)

Signable

Signing: something that allows arbitrary participants to sign other entries by hash, thus indicating that they have seen and agreed with the information contained therein.

Design patterns

BlobStorage

Supports the storage and retrieval of chunked blobs and their manifests.

This could as well be a standalone DNA other DNAs can interact with.

Indexing patterns

…for browsing and retrieving other entries. I’ve seen anchors and DAGs (both have their use-cases), there are probably other flavours needed too.

Standalone DNA / hApp

Annotation

Able to annotate other data, either in the same zome/DNA, in some other DNA, or outside of Holochain entirely. Should probably be polymorphic, e.g., Annotation<BlogPost>.

Presence

Shows whether an agent is online, offline, available, busy, typing, idle, etc.

Scheduling

Shows whether an agent is available or occupied at a given date in the future.

Events

Calendars, etc. Can be composed with Scheduling to do some cool things.

Messaging

Chat, IM, DM, comments, etc.

Posting

Similar to Messaging but meant for syndication. May just be an application of Messaging.

Notification

Allows agents to subscribe to things they want to be notified on; emits notification signals to clients.

Notary

Able to witness, and guarantee the uniqueness of, events.

LinkRegistry

Zome that tracks links incoming / outgoing between the host DNA and other DNAs using XDI Link Contract schema. We would also want this as a standalone DNA that tracks links between two other DNAs.

Presence

Shows whether an agent is online, offline, available, busy, typing, idle, etc.

Identity

Able to make assertions about facets of an agent’s identity, whether in a legally recognised (e.g., driver licensing office) or an informal capacity (web of trust).

Potential core functionality

GroupAgency

Agents can form recognisable groups with persistent identifiers; group membership (= authority to act as group representative) can be verified by third parties. Related to ClaimsPermissioned. (ping @pospi, cf How will Holochain handle group agents? )

MultiNodeAgent

This DNA is capable of combining multiple agent public keys into one human representation. Similar to GroupAgency and may be able to take advantage of the same codebase.

ExistenceCheck

Simple API that checks if entries with given hashes exist in the DNA, for use by other DNAs that need to perform referential integrity checks.

Timestamping

Able to provide a timestamp for external entries, at varying levels of proof. Naturally, this can support Timestamped.

Persistent Off-Chain Storage

Provide a way to cache expensive computations and data-structures without poluting the source chain with transient data.