braid is a set of extensions that generalize HTTP from a state transfer protocol into a state synchronization protocol. braid puts the power of operational transform and CRDTs on the web, improving network performance and enabling natively peer-to-peer, collaboratively-editable, offline-first web applications. - taken from IETF internet draft
braid adds these features to HTTP:
- versioning to HTTP resources
- subscriptions to GET requests
- patches to Range Requests
- merge-types to specify OT or CRDT behavior
learn more at braid.news
the first 22 minutes of this video are also really good
braid's goal is to extend http to state sync protocol (from http to hypertext synchronization protocol), in order to do away with custom sync protocols and make state across the web more interoperable.
adopting the braid standard will make real time updates more seamless and easier to implement for developers. this is still just a small incremental improvement to the current web, however.
developers will be able to open up their state to being synced by the rest of the web. the big picture here, is that we can have a social network like twitter where each person's feed are being synced to others from their own sites instead of having to access twitter.com directly. we'd just be syncing with our network directly (followers, following). this allows for a more private form of social media.
it turns out that http is very close to being a htsp, we just need to add 5 headers to requests and responses as well as a new status code 209 Subscription.
| Header Name | Property | Description |
|---|---|---|
| Version | version-hash | Version identifier for a resource in time |
| Parents | [version-hash] | Array of version hashes, versions form a DAG |
| Merge-Type | sync-protocol | Specify a merge type to synchronize a resource |
| Patches | [patch] | Array of patches, transformations to a resource |
| Subscribe | keep-alive=(seconds) | Flag for subscription, optional (seconds) parameter |
braid does make http stateful, servers need to maintain version history and a list of subcribers to send minimal diffs to clients. how this is persisted is left up to clients and servers, braid describes a implementation agnostic format for synchronizing between peers.
the easiest strategy for accelerating adoption of the braid protocol is by implementing middleware for many server/clients in different languages. developers won't have to worry about "braidifying" their requests/responses.
wai-braid is a haskell wai middleware for transforming outgoing responses into a braid format adding the appropriate headers.