envio/src/sources/HyperSyncHeightStream.res.mjs

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

// Generated by ReScript, PLEASE EDIT WITH CARE

import * as Utils from "../Utils.res.mjs";
import * as Logging from "../Logging.res.mjs";
import * as Prometheus from "../Prometheus.res.mjs";
import * as Stdlib_Int from "@rescript/runtime/lib/es6/Stdlib_Int.js";
import * as Eventsource from "eventsource";
import * as Primitive_int from "@rescript/runtime/lib/es6/Primitive_int.js";
import * as Primitive_option from "@rescript/runtime/lib/es6/Primitive_option.js";

function subscribe(hyperSyncUrl, apiToken, chainId, onHeight) {
  let eventsourceRef = {
    contents: undefined
  };
  let errorCount = {
    contents: 0
  };
  let timeoutIdRef = {
    contents: setTimeout(() => {}, 0)
  };
  let updateTimeoutId = () => {
    clearTimeout(timeoutIdRef.contents);
    let newTimeoutId = setTimeout(() => {
      Logging.trace({
        msg: "Timeout fired for height stream",
        chainId: chainId,
        url: hyperSyncUrl,
        staleTimeMillis: 15000
      });
      refreshEventSource();
    }, 15000);
    timeoutIdRef.contents = newTimeoutId;
  };
  let scheduleReconnect = () => {
    clearTimeout(timeoutIdRef.contents);
    let delay = 50 * (Math.pow(2.0, errorCount.contents) | 0) | 0;
    timeoutIdRef.contents = setTimeout(() => refreshEventSource(), Primitive_int.min(delay, 60000));
  };
  let refreshEventSource = () => {
    let es = eventsourceRef.contents;
    if (es !== undefined) {
      Primitive_option.valFromOption(es).close();
    }
    let userAgent = `hyperindex/` + Utils.EnvioPackage.value.version;
    let es$1 = new Eventsource.EventSource(hyperSyncUrl + `/height/sse`, {
      fetch: (url, args) => {
        let newrecord = {...args};
        return fetch(url, (newrecord.headers = Object.fromEntries([
          [
            "Authorization",
            `Bearer ` + apiToken
          ],
          [
            "User-Agent",
            userAgent
          ]
        ]), newrecord));
      }
    });
    eventsourceRef.contents = Primitive_option.some(es$1);
    updateTimeoutId();
    es$1.onopen = () => {
      errorCount.contents = 0;
      Logging.trace({
        msg: "SSE connection opened for height stream",
        chainId: chainId,
        url: hyperSyncUrl
      });
    };
    es$1.onerror = error => {
      errorCount.contents = errorCount.contents + 1 | 0;
      Logging.trace({
        msg: "EventSource error on height stream, reconnecting",
        chainId: chainId,
        url: hyperSyncUrl,
        status: error.status,
        error: error.message,
        errorCount: errorCount.contents
      });
      scheduleReconnect();
    };
    es$1.addEventListener("ping", _event => updateTimeoutId());
    es$1.addEventListener("height", event => {
      let height = Stdlib_Int.fromString(event.data, undefined);
      if (height !== undefined) {
        Prometheus.SourceRequestCount.increment("HyperSync", chainId, "heightStream");
        updateTimeoutId();
        return onHeight(height);
      } else {
        return Logging.trace({
          msg: "Height was not a number in event.data",
          chainId: chainId,
          data: event.data
        });
      }
    });
  };
  refreshEventSource();
  return () => {
    clearTimeout(timeoutIdRef.contents);
    let es = eventsourceRef.contents;
    if (es !== undefined) {
      Primitive_option.valFromOption(es).close();
      return;
    }
  };
}

export {
  subscribe,
}
/* Utils Not a pure module */