Handling duplicate posts when syncing data between WordPress and MongoDB

1. Unique Index on MongoDB Field

Create a unique index on the MongoDB field that you are using to store the post IDs. This ensures that MongoDB will prevent duplicate entries from being inserted into the collection.

javascript
const RecordSchema = new mongoose.Schema({
  name: { type: String, required: true, unique: true }
});

2. Check for Duplicate IDs

Before inserting a new document into MongoDB, check if the ID already exists in the collection. If it does, update the existing document instead of inserting a new one.

javascript
const Record = mongoose.model('Record', RecordSchema);

// Check for duplicate ID
Record.findOne({ name: 'John' }, (err, doc) => {
  if (err || doc) {
    // Update existing document
    Record.updateOne({ name: 'John' }, { $set: { name: 'John' } }, (err, res) => {
      if (err) {
        console.error(err);
      }
    });
  } else {
    // Insert new document
    const newRecord = new Record({ name: 'John' });
    newRecord.save((err, doc) => {
      if (err) {
        console.error(err);
      }
    });
  }
});

3. Use a Custom ObjectId

Generate a custom ObjectId that includes a prefix or a unique identifier for each sub-register. This ensures that duplicate IDs are less likely to occur.

javascript
const mongoose = require('mongoose');
const ObjectId = mongoose.Types.ObjectId;

// Generate a custom ObjectId
const customId = new ObjectId().toString();
customId = customId.substring(0, 8) + 'myPrefix' + customId.substring(8);

// Use the custom ID in your MongoDB schema
const RecordSchema = new mongoose.Schema({
  _id: { type: String, default: customId },
  name: { type: String, required: true }
});

4. Use a UUID

Use a UUID (Universally Unique Identifier) to ensure that each document has a unique ID. You can use a library like `uuid` to generate UUIDs.

javascript
const uuid = require('uuid');

// Generate a UUID
const uuidId = uuid.v4();

// Use the UUID in your MongoDB schema
const RecordSchema = new mongoose.Schema({
  _id: { type: String, default: uuidId },
  name: { type: String, required: true }
});

5. Handle Duplicate IDs in Error Handler

If a duplicate ID is encountered, handle it in your error handler by generating a new ID and updating the existing document.

javascript
const Record = mongoose.model('Record', RecordSchema);

// Handle duplicate ID error
Record.on('error', (err) => {
  if (err.name === 'MongoError' && err.code === 11000) {
    // Generate a new ID
    const newId = uuid.v4();
    // Update the existing document
    Record.updateOne({ _id: err.value }, { _id: newId }, (err, res) => {
      if (err) {
        console.error(err);
      }
    });
  }
});

These strategies can help you handle duplicate posts when syncing data between WordPress and MongoDB.