envio/src/sources/RpcWebSocketHeightStream.res.mjs

A latency and sync speed optimized, developer friendly blockchain data indexer.

// Generated by ReScript, PLEASE EDIT WITH CARE

import * as Rpc from "./Rpc.res.mjs";
import * as Utils from "../Utils.res.mjs";
import * as Logging from "../Logging.res.mjs";
import * as Prometheus from "../Prometheus.res.mjs";
import * as Primitive_option from "@rescript/runtime/lib/es6/Primitive_option.js";
import * as S$RescriptSchema from "rescript-schema/src/S.res.mjs";
import * as Primitive_exceptions from "@rescript/runtime/lib/es6/Primitive_exceptions.js";

let subscribeRequestJson = JSON.stringify({
  jsonrpc: "2.0",
  id: 1,
  method: "eth_subscribe",
  params: ["newHeads"]
});

let wsMessageSchema = S$RescriptSchema.union([
  S$RescriptSchema.object(s => {
    s.f("method", S$RescriptSchema.literal("eth_subscription"));
    return {
      TAG: "NewHead",
      _0: s.f("params", S$RescriptSchema.object(s => s.f("result", S$RescriptSchema.object(s => s.f("number", Rpc.hexIntSchema)))))
    };
  }),
  S$RescriptSchema.object(s => ({
    TAG: "SubscriptionConfirmed",
    _0: s.f("result", S$RescriptSchema.string)
  })),
  S$RescriptSchema.object(s => {
    s.f("error", S$RescriptSchema.unknown);
    return "ErrorResponse";
  })
]);

function subscribe(wsUrl, chainId, onHeight) {
  let wsRef = {
    contents: undefined
  };
  let isUnsubscribed = {
    contents: false
  };
  let errorCount = {
    contents: 0
  };
  let staleTimeoutId = {
    contents: undefined
  };
  let clearStaleTimeout = () => {
    let id = staleTimeoutId.contents;
    if (id !== undefined) {
      clearTimeout(Primitive_option.valFromOption(id));
      staleTimeoutId.contents = undefined;
      return;
    }
  };
  let resetStaleTimeout = () => {
    clearStaleTimeout();
    staleTimeoutId.contents = Primitive_option.some(setTimeout(() => {
      let ws = wsRef.contents;
      if (ws !== undefined) {
        Primitive_option.valFromOption(ws).close();
        return;
      }
    }, 60000));
  };
  let scheduleReconnect = () => {
    if (!(!isUnsubscribed.contents && errorCount.contents < 9)) {
      return;
    }
    let duration = 125 * (Math.pow(2.0, errorCount.contents) | 0) | 0;
    setTimeout(() => {
      if (!isUnsubscribed.contents) {
        return startConnection();
      }
    }, duration);
  };
  let startConnection = () => {
    if (isUnsubscribed.contents || errorCount.contents >= 9) {
      return;
    }
    let ws = new WebSocket(wsUrl);
    wsRef.contents = Primitive_option.some(ws);
    ws.onopen = () => {
      ws.send(subscribeRequestJson);
      resetStaleTimeout();
    };
    ws.onmessage = event => {
      try {
        let blockNumber = S$RescriptSchema.parseOrThrow(JSON.parse(event.data), wsMessageSchema);
        if (typeof blockNumber !== "object") {
          if (errorCount.contents < 9) {
            errorCount.contents = errorCount.contents + 1 | 0;
          }
          let ws = wsRef.contents;
          if (ws !== undefined) {
            Primitive_option.valFromOption(ws).close();
            return;
          } else {
            return;
          }
        }
        if (blockNumber.TAG !== "NewHead") {
          return resetStaleTimeout();
        }
        errorCount.contents = 0;
        resetStaleTimeout();
        Prometheus.SourceRequestCount.increment("WebSocket", chainId, "eth_subscribe");
        return onHeight(blockNumber._0);
      } catch (raw_e) {
        let e = Primitive_exceptions.internalToException(raw_e);
        if (e.RE_EXN_ID === S$RescriptSchema.Raised) {
          return Logging.warn({
            msg: "WebSocket height stream received unrecognized message",
            chainId: chainId,
            data: event.data
          });
        }
        if (e.RE_EXN_ID === "JsExn") {
          return Logging.warn({
            msg: "WebSocket height stream failed to parse message",
            chainId: chainId,
            err: Utils.prettifyExn(e),
            data: event.data
          });
        }
        Logging.error({
          msg: "Unexpected error in WebSocket height stream message handler",
          chainId: chainId,
          err: Utils.prettifyExn(e),
          data: event.data
        });
        throw e;
      }
    };
    ws.onerror = _error => {
      if (errorCount.contents < 9) {
        errorCount.contents = errorCount.contents + 1 | 0;
      }
      let ws = wsRef.contents;
      if (ws === undefined) {
        return;
      }
      let ws$1 = Primitive_option.valFromOption(ws);
      if (ws$1.readyState === 1) {
        ws$1.close();
        return;
      }
    };
    ws.onclose = () => {
      wsRef.contents = undefined;
      clearStaleTimeout();
      scheduleReconnect();
    };
  };
  startConnection();
  return () => {
    isUnsubscribed.contents = true;
    clearStaleTimeout();
    let ws = wsRef.contents;
    if (ws !== undefined) {
      Primitive_option.valFromOption(ws).close();
      return;
    }
  };
}

let retryCount = 9;

let baseDuration = 125;

let staleTimeMillis = 60000;

export {
  retryCount,
  baseDuration,
  staleTimeMillis,
  subscribeRequestJson,
  wsMessageSchema,
  subscribe,
}
/* subscribeRequestJson Not a pure module */