如何在Mongoose / MongoDB中存储文档的历史记录？

Question

I have the following Schema -

 const leadSchema = new Schema( { emails: [{ type: Email, default: null }], name: { type: String }, country: { type: String }, city: { type: String, index: true }, source: { type: Number, min: 1, max: leadConfig.sources.length, required: true }, course: { type: Schema.Types.ObjectId, ref: 'courses',required: true}, gender: { type: String, enum: leadConfig.gender }, status: {type: Schema.Types.ObjectId, ref: 'status' }, dob: Date, parent_name: String, counselor: { type: Schema.Types.ObjectId, ref: 'users', default: null }, consultant_amount: { type: Number, min: 0, default: 0 }, consultant_amount_paid: { type: Number, min: 0, default: 0 }, loan: { type: Boolean, default: false }, reported: { type: Boolean, default: false }, scholarship: { type: Number, default: 0 }, student_id: { type: Number, default: null }, next_interection_deadline: { type: Date, default: null }, session: { type: Schema.Types.ObjectId, ref: 'session' } }, { timestamps: true } ); module.exports = mongoose.model('leads', leadSchema); 

I want to store the update history of all the documents of this collection.

For Example -

If I change the name field of a lead from 'John' to 'Jane' then a record should be saved in a history table with the following schema -

 { _id:(ObjectId), collectionName:"lead" column_name:"name" oldValue - 'John', newValue - 'Jane' updateAt - Date() } 

I googled some plugins like mongoose-diff-history and it serves the purpose well but the only drawback was that it only worked with .save() method and not with mongodb updates methods.

I have been working on this problem for so many days but couldn't find a correct and efficient solution. Any solutions to this problem will be very much appreciated.

Answer 1

Have you looked into the midldeware hooks ? Usually what you want could be handled there. For example look into Mongoose hooks: http://mongoosejs.com/docs/middleware.html

You have basically "events" which allow you do intercept records just before "save" etc and do something (like in your case store/log somewhere).

Here is an example from their docs:

var schema = new Schema(..);
schema.pre('save', function(next) {
  // do stuff
  next();
})

Here is one for the 'update':

schema.pre('update', function() {
   this.update({},{ $set: { updatedAt: new Date() } });
});