Effect CommunityEC
Effect Community•16mo ago•
5 replies
fucory

Implementing JSON-RPC with Effect-TS RPC Package: Defining and Converting Request Shapes

I'm struggling to figure out the best way to implement json-rpc with the rpc package https://github.com/Effect-TS/effect/tree/main/packages/rpc

What I want to do is define the shape of a request

export class JsonRpcRequest extends Class<JsonRpcRequest>("JsonRpcRequest")({
  jsonrpc: optional(String),
  method: String,
  params: Union(Struct({}), Array(String)),
  id: optional(Union(String, Number))
}) {}

export class GetBlockByNumberJsonRpcRequest extends JsonRpcRequest.extend<GetBlockByNumberJsonRpcRequest>("GetBlockByNumberJsonRpcRequest")({
  method: Literal(identifier),
  params: Tuple(Union(HexString, Literal("latest")), Boolean)
}) {}


However reading source code of the rpc package it seems to be hardcoded to only accept requests that have a _tag property. So next step I thought was to define a way to convert between the two

export class GetBlockByNumber extends Schema.TaggedRequest<GetBlockByNumber>()(
  identifier,
  {
    failure: Schema.Never, 
    success: JsonRpcBlock, 
    payload: {
      blockTag: Union(BlockTag, BigIntFromSelf),
      fullTransactionObjects: Boolean,
    },
  }
) {}

export const JsonRpcToTaggedRequest = Schema.transform(
  GetBlockByNumberJsonRpcRequest,
  GetBlockByNumber,
  {
    strict: true,
    decode: ({ params }) => {
      const [blockTag, fullTransactionObjects] = params
      return new GetBlockByNumber({
        blockTag: decodeUnknownSync(JsonRpcBlockTagToBlockTag)(blockTag),
        fullTransactionObjects,
      })
    },
    encode: ({ blockTag, fullTransactionObjects }) => new GetBlockByNumberJsonRpcRequest({
      jsonrpc: "2.0",
      method: "eth_getBlockByNumber",
      params: [typeof blockTag === 'bigint' ? numberToHex(blockTag) : blockTag, fullTransactionObjects],
    })
  }
)


But I still can't quite figure out how to get all the pieces to click in place. It generally feels like there must be an easier way I'm missing.
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