JSON-RPC

@rhi-zone/fractal-json-rpc-api-projector projects a Node tree into a JSON-RPC 2.0 surface — method dispatch over HTTP or WebSocket, plus a typed client — with method names derived from the tree path (dot-joined, e.g. books.list).

What it does

projectMethods/toMethods walk the tree once into a flat JsonRpcMethod[] (name, params/result schema) plus a dispatch table keyed by that same dot-joined name. createJsonRpcHttpHandler/createJsonRpcWebSocketHandlers wrap that dispatch table in the JSON-RPC 2.0 request/response/error envelope (batch requests, notifications, the standard -32xxx error codes exported as JSON_RPC_PARSE_ERROR etc. from type-ir's json-rpc module — see Type-IR: wire formats).

Basic usage

import { api, op } from "@rhi-zone/fractal-api-tree"
import { createJsonRpcHttpHandler } from "@rhi-zone/fractal-json-rpc-api-projector"

const tree = api({
  books: api({
    list: op(() => [{ id: "1", title: "Dune" }]),
  }),
})

const handler = createJsonRpcHttpHandler(tree)
// (req: Request) => Promise<Response>
// POST { "jsonrpc": "2.0", "method": "books.list", "params": {}, "id": 1 }
// -> { "jsonrpc": "2.0", "result": [{ "id": "1", "title": "Dune" }], "id": 1 }

WebSocket

import { createJsonRpcWebSocketHandlers } from "@rhi-zone/fractal-json-rpc-api-projector"

const handlers = createJsonRpcWebSocketHandlers(tree)
// { onMessage(socket, data), ... } — wire into ws/Bun's WebSocket handlers

Typed client

import { createJsonRpcHttpClient, createJsonRpcClient, createJsonRpcHttpCall } from "@rhi-zone/fractal-json-rpc-api-projector"

const client = createJsonRpcHttpClient(tree, "http://localhost:3000/rpc")
await client.books.list() // -> JSON-RPC call to method "books.list"

// or bring your own transport function:
const call = createJsonRpcHttpCall("http://localhost:3000/rpc")
const custom = createJsonRpcClient(tree, call)

ClientError (JsonRpcClientError) wraps a JSON-RPC error response (code/message/data).

Key exports

Export	Description
toMethods(node, opts?) / projectMethods(node, opts?)	Node → JsonRpcMethod[] / full result + dispatch table
createJsonRpcHttpHandler(tree, opts?)	Fetch-compatible HTTP handler
createJsonRpcWebSocketHandlers(tree, opts?)	WebSocket message handlers
jsonRpcErrors(mapping)	Error-to-JSON-RPC-code mapping
createJsonRpcClient(tree, call)	Typed proxy client over a JsonRpcCall function
createJsonRpcHttpClient(tree, url, opts?) / createJsonRpcHttpCall(url, opts?)	HTTP-transport client / raw call function