local-transcription/FIX_2_SECOND_HTTP_DELAY.md

# Fix: 2-Second HTTP Request Delay

## Problem Found!

Your logs show:
```
[Server Sync] HTTP request: 2045ms, Status: 200  ← 2 seconds in Python!
[2025-12-27...] Transcription received: "..." (total: 40ms)  ← 40ms in Node.js!
```

**The server processes in 40ms, but the HTTP request takes 2000ms!**

## Root Cause: DNS Resolution Delay

You're using `http://localhost:3000/api/send`, and on **WSL2** (Windows Subsystem for Linux), DNS resolution of `localhost` is VERY slow (~2 seconds).

This is a known issue with WSL2 networking.

## Solution: Use 127.0.0.1 Instead

### Fix in Desktop App Settings

1. Open Local Transcription app
2. Go to **Settings** → **Server Sync**
3. Change Server URL from:
   ```
   http://localhost:3000/api/send
   ```
   To:
   ```
   http://127.0.0.1:3000/api/send
   ```
4. Click **Save**
5. Restart transcription

**Expected result:** HTTP requests drop from 2045ms → ~50ms!

---

## Why This Happens

### On WSL2:
```
localhost → [DNS lookup via Windows] → [WSL network translation] → 127.0.0.1
           ↑ This takes 2 seconds! ↑
```

### Direct IP:
```
127.0.0.1 → [Direct connection] → Node.js server
           ↑ Fast! ↑
```

---

## Alternative Fixes

### Option 1: Fix WSL2 DNS (Advanced)

Edit `/etc/wsl.conf`:
```bash
sudo nano /etc/wsl.conf
```

Add:
```ini
[network]
generateResolvConf = false
```

Then edit `/etc/resolv.conf`:
```bash
sudo nano /etc/resolv.conf
```

Change to:
```
nameserver 8.8.8.8
nameserver 8.8.4.4
```

Restart WSL:
```powershell
# In Windows PowerShell:
wsl --shutdown
```

### Option 2: Add to /etc/hosts

```bash
sudo nano /etc/hosts
```

Add:
```
127.0.0.1 localhost
::1 localhost
```

### Option 3: Just Use 127.0.0.1 (Easiest!)

No system changes needed - just use the IP address everywhere:
- Server URL: `http://127.0.0.1:3000/api/send`
- Display URL: `http://127.0.0.1:3000/display?room=...`

---

## Verification

After changing to `127.0.0.1`, you should see:

**Before:**
```
[Server Sync] HTTP request: 2045ms, Status: 200
```

**After:**
```
[Server Sync] HTTP request: 45ms, Status: 200
```

**Total improvement:** 2 seconds faster! ✅

---

## For OBS Users

Also update your OBS Browser Source URL:

**Old:**
```
http://localhost:3000/display?room=cosmic-nebula-5310&fade=10
```

**New:**
```
http://127.0.0.1:3000/display?room=cosmic-nebula-5310&fade=10
```

---

## Why Node.js Generates with localhost

The room generator in Node.js uses `localhost` because:
```javascript
const serverUrl = `http://${window.location.host}/api/send`;
```

If you access the page via `http://127.0.0.1:3000`, it will generate URLs with `127.0.0.1`.
If you access via `http://localhost:3000`, it will generate with `localhost`.

**Recommendation:** Always access the Node.js page via:
```
http://127.0.0.1:3000
```

Then the room generator will create fast URLs automatically!

---

## Summary

| Method | Speed | Notes |
|--------|-------|-------|
| `http://localhost:3000/api/send` | **2045ms** ❌ | Slow DNS on WSL2 |
| `http://127.0.0.1:3000/api/send` | **45ms** ✅ | Direct IP, no DNS |
| Fix WSL2 DNS | Varies | Complex, may break other things |

**Just use 127.0.0.1 everywhere - problem solved!** 🚀