reader-api/CHAPTER_SAVE_DEBUG.md

🐛 Chapter Save Debugging Guide

Vấn Đề Đã Fix

✅ Fix 1: Ownership Check (Line 932)

• Vấn đề: MOD không thể tạo chapter cho truyện mặc định (uploaderId = NULL)
• Fix: Thêm OR uploaderId IS NULL vào WHERE clause
• Dòng: 932, 1002

✅ Fix 2: Input Validation

• Vấn đề: Content có thể trống, number có thể âm
• Fix: Thêm validation trước insert
• Dòng: 920-927, 997-1004

✅ Fix 3: Data Consistency Logging

• Vấn đề: Nếu MongoDB insert succeed nhưng PostgreSQL fail → dữ liệu inconsistent
• Fix: Thêm separate error handling và logging [CRITICAL]
• Dòng: 956-974

---

🔍 Testing Checklist

A. Network Debugging (Browser DevTools)

1. Mở DevTools: F12 → Network tab
2. Ấn "Lưu chương"
3. Kiểm tra request POST /api/mod/chuong:
   • ✅ Status code: 201 = success, 4xx/5xx = error
   • ✅ Response body: Phần lấy id, number, title
   • ❌ Status 403: Ownership issue
   • ❌ Status 400: Duplicate or validation error
   • ❌ Status 500: Server error (check [CRITICAL] logs)

B. MongoDB Verification

# Access MongoDB
mongosh  # hoặc mongo

# Switch to database
use reader_db  # (thay bằng tên DB thực tế)

# List recent chapters
db.chapters.find({}, {novelId: 1, number: 1, title: 1, createdAt: 1})
  .sort({_id: -1})
  .limit(5)

# Check specific novel
db.chapters.countDocuments({novelId: "YOUR_NOVEL_ID"})

# Check for duplicates (race condition)
db.chapters.find({novelId: "YOUR_NOVEL_ID", number: 1})

C. PostgreSQL Verification

# Access PostgreSQL
psql  # hoặc your database client

# Check novel total chapters count
SELECT id, title, "totalChapters" FROM "Novel" WHERE id = 'YOUR_NOVEL_ID';

# Verify it matches MongoDB count
-- MongoDB should have same count as "totalChapters"

D. Server Log Analysis

Look for these patterns in backend logs:

✅ Success:
[timestamp] POST /mod/chuong - Status 201
[timestamp] Inserted chapter id: xxx

❌ Issues:
[CRITICAL] ⚠️ INCONSISTENT STATE: Chapter inserted in MongoDB...
[timestamp] Lỗi MongoDB: [error message]
[timestamp] Ownership check failed: 403

---

🚀 Common Scenarios & Solutions

Scenario 1: Network Shows 201 But Chapter Not Visible

Cause: Chapter saved but not refreshed in UI Solution:

• Press F5 to refresh page
• Check MongoDB to confirm chapter exists
• Check if fetchChapters() was called after save

Scenario 2: Network Shows 403 Forbidden

Cause: Novel ownership check failed Solution:

• Verify you are MOD or ADMIN user
• Verify novel exists in PostgreSQL:

  SELECT id, title, "uploaderId" FROM "Novel" WHERE id = 'YOUR_ID';
  

• If uploaderId is NULL (default), ensure you're MOD user

Scenario 3: Network Shows 400 Bad Request

Causes:

• Chapter number already exists
• Title or content empty
• Chapter number ≤ 0

Solution: Check response detail message and fix input

Scenario 4: Network Shows 500 Server Error

Cause: MongoDB or PostgreSQL failure Solution:

• Check server logs for [CRITICAL] message
• If MongoDB failed: Check MongoDB connection
• If PostgreSQL failed: Check PostgreSQL connection
• Contact admin with error message

---

🔧 Advanced Debug Commands

Check MongoDB Connection Status

# From backend terminal
python3 -c "
import asyncio
from app.database import mongo_db

async def check():
    await mongo_db.command('ping')
    print('✓ MongoDB Connected!')

asyncio.run(check())
"

Check PostgreSQL Connection Status

# From backend terminal
python3 -c "
import asyncio
from sqlalchemy.ext.asyncio import create_async_engine
from app.database import SessionLocal

async def check():
    async with SessionLocal() as session:
        result = await session.execute('SELECT 1')
        print('✓ PostgreSQL Connected!')

asyncio.run(check())
"

Manually Sync Total Chapters

# If totalChapters is out of sync
mongosh
use reader_db

# Get count
db.chapters.countDocuments({novelId: "YOUR_NOVEL_ID"})

# Then update PostgreSQL manually:
# psql
UPDATE "Novel" SET "totalChapters" = 123 WHERE id = 'YOUR_NOVEL_ID';

---

📋 Test Cases

Test 1: Basic Chapter Save

1. Create novel
2. Save chapter #1
3. ✅ Should appear in chapter list
4. ✅ totalChapters should be 1

Test 2: Sequential Chapters

1. Save chapters 1, 2, 3
2. ✅ All should appear with correct numbers
3. ✅ Next chapter field should suggest 4

Test 3: Duplicate Prevention

1. Save chapter #5
2. Try to save chapter #5 again
3. ✅ Should show "Chương 5 đã tồn tại"

Test 4: Default Novel (MOD Permission)

1. Verify a novel with uploaderId = NULL exists
2. As MOD user, save chapter to that novel
3. ✅ Should succeed (not 403 Forbidden)

Test 5: No Empty Content

1. Try to save chapter with empty title
2. ✅ Should show "Tiêu đề chương không được trống"
3. Try to save chapter with empty content
4. ✅ Should show "Nội dung chương không được trống"

---

🆘 Still Having Issues?

1. Run checklist A, B, C above and collect outputs
2. Screenshot of Network tab response
3. MongoDB output from find()
4. Server log output (especially [CRITICAL] lines)
5. Share these with: [your-dev-contact]

---

📊 Monitoring

Health Check Script

#!/bin/bash
# save as monitor-save.sh

echo "=== Chapter Save System Health Check ==="
echo ""
echo "1. MongoDB Connection:"
# mongosh check here

echo ""
echo "2. PostgreSQL Connection:"
# psql check here

echo ""
echo "3. Backend API:"
curl -s http://localhost:8000/docs | head -20

echo ""
echo "=== Done ==="

Run: bash monitor-save.sh