/**
 * file: chatgpt_karbytes_27august2025_p0.txt
 * type: plain-text
 * date: 27_AUGUST_2025
 * author: karbytes
 * license: PUBLIC_DOMAIN
 */

The following is a plain-text transcript of a conversation between karbytes and ChatGPT-5 Thinking which took place between 11:59PM Pacific Standard Time on 27_AUGUST_2025 and 11:59PM Pacific Standard Time on 28_AUGUST_2025. The conversation pertains to the following SOFTWARE_ENGINEERING_PORTFOLIO item: https://karbytesforlifeblog.wordpress.com/onion_web_page_availability_logger/

* * *

karbytes:

[uploaded_file: https://raw.githubusercontent.com/karlinarayberinger/KARLINA_OBJECT_extension_pack_38/main/onion_web_page_availability_logger.html]

I noticed that my .onion web page is online but the logger web app I have running in the Tor web browser to minitor the .onion web page's availability logged that the connectivity failed several consecutive tries. (Error message: TypeError: NetworkError when attempting to fetch resource.).

ChatGPT:

[Thought for 2m 9s]

Got it—this can happen even when the .onion site loads fine in a tab. A few things in your current monitor make “false negatives” more likely, and Tor itself will occasionally drop/rotate circuits which causes brief fetch failures.

Here’s how I’d tighten it up fast:

Why you’re seeing TypeError: NetworkError…

Tor circuit churn / brief HS downtime. Short, transient failures are normal on .onion; your 60-second poll can easily catch a bad moment.

Request mode = no-cors. In your page you call fetch(..., { mode: "no-cors" }). That gives you an opaque response and hides status; in some cases Firefox/Tor will still throw a NetworkError and you can’t see details. Removing no-cors on a same-origin request makes debugging way clearer. 

HTTPS-Only / NoScript / background throttling. Tor Browser’s HTTPS-Only Mode or NoScript can block background fetches unless you’ve allowed your onion site; on mobile, background tabs can be throttled (your app has a “keep session active” button—use it when you background the tab). 

Quick checks (30 seconds each)

Confirm same-origin. Open the logger from the same .onion host (not file:/// or a clearnet mirror). Your HTML notes this is required. 

HTTPS-Only Mode: Add an exception for your onion site or temporarily disable it for testing.

NoScript: Mark your onion as “Trusted” so XHR/fetch isn’t blocked.

Console → Network: On a failure, do you see a CSP/HTTPS-Only/NoScript message (blocked) vs a request that never left (circuit issue)?

Open the polled URL (with ?t=123) in the same Tor window. If it loads while fetch fails, it’s likely a policy/JS mode issue.

Minimal code patch (drop-in)

Replace your visitPage() with this version. It:

drops no-cors for same-origin,

adds a 20s timeout,

tries HEAD then GET (some servers 405 on HEAD),

counts success only if response.ok,

retries once after 10s before declaring the minute a failure.

[html]

<script>
  const targetUrl = "http://qkbrwfubnh4knc6kkhx6uepccavpwezdf2al7w2quepe3qociegsi3yd.onion/";
  const intervalMilliseconds = 60 * 1000;
  let totalAttempts = 0, successCount = 0, failureCount = 0;
  const maxRows = 100;

  function updateStats() {
    totalAttempts++;
    const successRate = totalAttempts ? ((successCount / totalAttempts) * 100).toFixed(2) + "%" : "0%";
    document.getElementById("totalAttempts").textContent = totalAttempts;
    document.getElementById("successCount").textContent = successCount;
    document.getElementById("failureCount").textContent = failureCount;
    document.getElementById("successRate").textContent = successRate;
  }

  function logResult(isoTime, epochTime, status, notes) {
    const tbody = document.querySelector("#logTable tbody");
    if (tbody.rows.length >= maxRows) tbody.deleteRow(0);
    const tr = document.createElement("tr");
    [isoTime, epochTime, status, notes].forEach(t => {
      const td = document.createElement("td");
      td.textContent = t;
      tr.appendChild(td);
    });
    tbody.appendChild(tr);
  }

  function abortableTimeout(ms) {
    const controller = new AbortController();
    const t = setTimeout(() => controller.abort(), ms);
    return { controller, cancel: () => clearTimeout(t) };
  }

  async function tryOnce(method) {
    const { controller, cancel } = abortableTimeout(20000); // 20s
    try {
      const res = await fetch(targetUrl + "?t=" + Date.now(), {
        method,
        cache: "no-store",
        redirect: "follow",
        credentials: "omit",
        signal: controller.signal,
      });
      cancel();
      return res;
    } catch (e) {
      cancel();
      throw e;
    }
  }

  async function pingWithRetry() {
    const now = new Date();
    const isoTime = now.toISOString();
    const epochTime = now.getTime();

    try {
      // Prefer HEAD; fall back to GET if not ok (or if HEAD unsupported)
      let res;
      try {
        res = await tryOnce("HEAD");
        if (!res.ok) res = await tryOnce("GET");
      } catch {
        // wait 10s and retry once (covers circuit churn)
        await new Promise(r => setTimeout(r, 10000));
        res = await tryOnce("GET");
      }

      if (res.ok) {
        successCount++;
        logResult(isoTime, epochTime, "Success", `${res.status} ${res.statusText || ""}`.trim());
      } else {
        failureCount++;
        logResult(isoTime, epochTime, "HTTP Error", `${res.status} ${res.statusText || ""}`.trim());
      }
    } catch (err) {
      failureCount++;
      logResult(isoTime, epochTime, "Failed", `${err.name}: ${err.message}`);
    }
    updateStats();
  }

  // kick off
  pingWithRetry();
  setInterval(pingWithRetry, intervalMilliseconds);
</script>

[end html]

Optional hardening

Use a tiny endpoint just for health checks (e.g., /ping.txt with a few bytes) to avoid pulling a full page each time.

Tolerate brief outages in your metric (e.g., consider a minute “up” if any of N retries succeeds).

Second opinion monitor: run a simple torsocks curl -sS --max-time 20 <onion> cron from a VPS over Tor and compare with the browser-based log to separate Tor-client hiccups from HS issues.

If you paste in the patch above and still see consecutive NetworkErrors (and the site loads manually), the next likely culprit is HTTPS-Only/NoScript blocking fetch from JS for that origin—flip those toggles for a quick A/B test.

Want me to tailor it to log to a CSV file (downloadable) or cap the failure streaks with a visual alert?

karbytes:

I made no changes to the code and left the respective browser tab open. Now it is logging successful connection attempts again. For some reason it occasionally (like less than 4% of the time during an eight hour runtime period) logs consecutive failure results (typically between 4 and 10) before going back to logging many more success results.

ChatGPT:

[Thought for 59s]

That pattern actually looks “healthy” for Tor: brief bursts of consecutive failures (4–10 in a row) sprinkled among lots of successes are classic circuit churn / intro-point flaps on onion services. Your page can be up the whole time, but a single Tor circuit can go bad and stay bad until it rebuilds—so one client sees a small outage while others don’t.

If you want your logger to reflect service health (not just “this specific circuit right now”), here’s how to smooth out those false negatives without changing the overall cadence:

What to change (small, targeted)

Use k-of-n sub-probes per minute.
Within each 60-second window, try up to 3 quick pings spaced ~7–10 s apart. If any succeed, mark that minute “Success.” This collapses most circuit blips.

Define an incident threshold.
Only call it “Down” when you hit ≥3 consecutive failed minutes (tunable). This maps closer to user-visible downtime.

Add a little jitter.
Randomize each minute’s start by ±5–10 s so you don’t keep sampling at the exact moment a circuit rotates.

(Optional) Record latency + streaks.
Log response time and failure streak length; you’ll get real MTTR/MTBF and a clean availability %.

Drop-in snippet (keeps your one-row-per-minute log)

Paste this around your existing loop; it adds sub-probes, a failure-streak counter, and jitter. It assumes you already have logResult(...), updateStats() and targetUrl defined.

[html]

<script>
  const SUB_PROBES = 3;           // up to 3 tries within the minute
  const SUB_SPACING_MS = 8000;    // ~8s apart
  const BASE_INTERVAL_MS = 60000; // 1 minute
  const JITTER_MS = 7000;         // ±7s jitter
  const INCIDENT_OPEN_AFTER = 3;  // 3 consecutive failed minutes

  let totalAttempts = 0, successCount = 0, failureCount = 0;
  let failStreak = 0, incidentOpen = false, incidentStart = null;

  function delay(ms) { return new Promise(r => setTimeout(r, ms)); }
  function jitteredInterval() {
    const sign = Math.random() < 0.5 ? -1 : 1;
    return BASE_INTERVAL_MS + sign * Math.floor(Math.random() * JITTER_MS);
  }
  function msNow() { return Date.now(); }

  async function subProbe(method="GET", timeoutMs=20000) {
    const controller = new AbortController();
    const t = setTimeout(() => controller.abort(), timeoutMs);
    const start = msNow();
    try {
      const res = await fetch(targetUrl + "?t=" + start, {
        method, cache: "no-store", redirect: "follow", credentials: "omit",
        signal: controller.signal,
      });
      clearTimeout(t);
      return { ok: res.ok, status: res.status, rt: msNow() - start };
    } catch (e) {
      clearTimeout(t);
      return { ok: false, status: 0, rt: msNow() - start, err: e.name || "Error" };
    }
  }

  async function probeMinute() {
    const isoTime = new Date().toISOString();
    const epoch = msNow();

    let lastStatus = "Failed", notes = "All sub-probes failed";
    let bestRt = Infinity, anyOk = false, lastCode = 0;

    for (let i = 0; i < SUB_PROBES; i++) {
      // Prefer HEAD first; fall back to GET if needed
      let r = await subProbe("HEAD");
      if (!r.ok) r = await subProbe("GET");
      lastCode = r.status || 0;
      if (r.ok) {
        anyOk = true;
        bestRt = Math.min(bestRt, r.rt);
        lastStatus = "Success";
        notes = `OK ${lastCode}, bestRT=${bestRt}ms (probe ${i+1}/${SUB_PROBES})`;
        break;
      } else {
        notes = r.err ? `${r.err}` : `HTTP ${lastCode}`;
        if (i < SUB_PROBES - 1) await delay(SUB_SPACING_MS);
      }
    }

    totalAttempts++;
    if (anyOk) {
      successCount++;
      if (incidentOpen) {
        // close incident on first recovered minute
        incidentOpen = false;
        const durMin = ((epoch - incidentStart) / 60000).toFixed(1);
        // You could also append a row to a separate "incidents" table here.
      }
      failStreak = 0;
    } else {
      failureCount++;
      failStreak++;
      if (!incidentOpen && failStreak >= INCIDENT_OPEN_AFTER) {
        incidentOpen = true;
        incidentStart = epoch - (failStreak - 1) * BASE_INTERVAL_MS;
      }
    }

    const statusForRow = anyOk ? "Success" : (lastCode ? "HTTP Error" : "Failed");
    logResult(isoTime, epoch, statusForRow, notes);
    updateStats();

    // schedule next run with jitter
    setTimeout(probeMinute, jitteredInterval());
  }

  // kick off
  setTimeout(probeMinute, jitteredInterval());
</script>

[end html]

How to read the results

Availability (%): will jump up because quick, transient circuit hiccups are absorbed by sub-probes.

Incidents: only start after INCIDENT_OPEN_AFTER failed minutes in a row (tweak as you like).

Notes column: shows quickest response time seen that minute; if everything failed, you’ll see HTTP <code> or an error name like AbortError.

Extra (optional) knobs

If your target path supports it, probe a tiny /ping.txt (few bytes) to reduce load and latency.

When you notice a failure burst, manually try “New Circuit for this Site” in Tor Browser. If the tab loads instantly after that, you’ve confirmed circuit-specific flakiness rather than service downtime.

If you ever want a “second opinion,” run a cron on another box through Tor (e.g., torsocks curl --max-time 20 <your .onion>) and compare—two vantage points almost never fail simultaneously unless the service is truly down.

If you want, I can fold this into your existing HTML file exactly where it belongs and add a tiny “Incidents” table (with start/end/duration).

karbytes:

I think I'll just leave the HTML file as is (because is suits my purposes and I don't want to over complicate it). I am curious about how the Tor circuits work. How often does the circuit my app uses change (and how are the nodes for a circuit selected)?

ChatGPT:

[Thought for 2m 6s]

Great question—those “failure bursts” line up with how Tor rotates circuits and how onion-service connections are built.

How often does “your” circuit change?

Tor reuses a circuit for ~10 minutes for new connections, as long as it’s healthy. After ~10 min (the MaxCircuitDirtiness default), new TCP connections get attached to a fresh circuit; existing ones keep using the old circuit until they go idle/close. If a circuit misbehaves, Tor switches sooner. 

Tor Browser also isolates by site: each first-party domain (your .onion) gets its own circuit(s), and the “New Circuit for this Site” menu forces a fresh one for that site only. 

For an onion service specifically, each successful visit looks like:

[preformatted_text]

You → Guard → Middle → Rendezvous Point  ← Middle ← Guard ← Service

[end preformatted_text]

That’s two 3-hop circuits meeting at a rendezvous point (RP). The RP is picked by the client, and the service picks/maintains separate introduction points (IPs) that clients use to reach it. If any of these circuits flake out, Tor will build a new one—causing exactly the short failure streaks you saw. 

How are the nodes chosen?

Tor builds circuits using relays listed in the hourly consensus and applies a few rules:

Bandwidth-weighted random choice. Relays are sampled with weights so higher-capacity relays are more likely to be used. 

Safety constraints. A single circuit won’t put two relays from the same family or the same /16 (IPv4) together; and you never pick the same relay twice in a circuit. Rendezvous/intro circuits should be “Stable.” 

Role flags matter. The first hop must be a Guard; for exit traffic you need an Exit as the last hop (not used for .onion). Rendezvous and introduction circuits are built from suitable relays (no exit needed). 

What about guard nodes—do they change?

Your client sticks with the same entry guard(s) for months to reduce deanonymization risk; rotation is intentionally slow (historically on the order of a few months, with proposals to lengthen it). That’s why “New Circuit for this Site” doesn’t usually change your entry guard. 

One more rotating piece you don’t see

Your service’s descriptor is published to Hidden-Service Directories (HSDirs) that change on a schedule (default: daily time periods). The service can also rotate introduction points (faster under load/DoS). These background rotations can momentarily make lookups/introductions flaky even if the site is up. 

TL;DR: New circuits for your .onion are normally used for new connections about every 10 minutes, with immediate rebuilds on failure. Nodes are picked bandwidth-weighted with family/subnet separation and role flags. Entry guards are kept for months. Onion services add the rendezvous/intro dance on top, and their directory/intro rotation can cause brief, consecutive hiccups—exactly the pattern your logger records. 

If you want, I can tailor a compact diagram of the HS handshake and where failures typically occur, so it’s easier to map your “streaks” to the steps.

karbytes:

Can you make a text-based version of that diagram?

ChatGPT:

[Thought for 37s]

here you go—compact, text-only view of the onion-service handshake and where hiccups tend to occur:

[preformatted_text]

CLIENT (Tor Browser)                     TOR NETWORK                          ONION SERVICE
---------------------                    -----------                          -------------
                                         [HSDir(s)]  (hidden service directories)
                                               ^
(0) HS publishes descriptor (blinded ID, IPs)  |  (rotates on schedule)
                                               |
CLIENT resolves .onion -> blinded ID ----------+-------------------------------+
                                                                                |
                                                                                v
                                      +----------------------[IP1] <----+  (intro points)
                                      |                      [IP2] <----+  (HS keeps long-lived
                                      |                      [IP3] <----+   circuits to some IPs)
                                      |
                                      |                             (service side)
[App/Tab]                                                              [HS]
   |                                                                     ^
   |                                                                     |
   |                               (rendezvous leg)                      |
   |   [Guard_C] -> [Middle_C] -> [RP] <---------------- [Middle_S] <- [Guard_S]
   |                     ^                 (RP)                  ^
   |                     |                                      |
   |     (introduction leg)                                     |
   +-> [Guard_C] -> [Middle_C] -> [IPk] --(INTRODUCE1)--------->+  (via HS's intro circuit)
             \
              \----(RENDEZVOUS1 to RP with cookie)----> [RP]

Handshake steps (numbered):

[0] Service picks some Introduction Points (IP1..IPn); publishes a descriptor (with IP list & keys) to HSDirs.
[1] Client fetches the descriptor from HSDirs using the .onion address’ blinded ID.
[2] Client chooses a Rendezvous Point (RP) and builds a 3-hop circuit to it; sends RENDEZVOUS1 (with a cookie).
[3] Client builds a separate 3-hop circuit to one IP from the descriptor and sends INTRODUCE1 (carries RP info + cookie).
[4] The IP forwards the intro to the HS over HS’s existing intro circuit.
[5] HS decides to connect, builds its own 3-hop circuit to the RP, and sends RENDEZVOUS2 using the cookie.
[6] RP “stitches” the two circuits. Result: an end-to-end 6-hop path:
      Client → Guard_C → Middle_C → RP ⇄ Middle_S → Guard_S → HS
[7] Data flows over that path. New connections after ~10 min typically use a fresh client circuit; HS may rotate IPs/descriptor.

[end preformatted_text]

Where short failure streaks often come from (what your logger sees):

[1] Descriptor fetch glitches (HSDir rotation or transient lookup miss).

[2] Client→RP circuit build fails or times out; Tor retries on a new circuit.

[3–4] Chosen IP is overloaded/rotating; intro delivery fails.

[5] HS→RP circuit build fails (load or relay trouble).

Any hop flapping after [6] tears down the path; the next probe rebuilds, often succeeding.

If you want, I can also give you a minimal “legend” version you can paste into your HTML as a comment.