I am trying to use the new unstable version of mongoose >4.0.0 to validate update queries.
say that i want to update a schema using the following query
schema.update({_id:'blah'},{a:'blah'},function(err){
//do your thing
})
so lets say i have the following schema,
var schema = new Schema({
a:{type:String}
});
schema.pre('update',function(next){
var findQuery=this._conditions; // gives {_id:'blah'}
// how do i get {a:'blah'}????
next();
});
how do i get the update query of {set:{a:'blah'}} in the pre middleware so i can do some checks before executing the update?
alternatively i know that the update query can be accessed in the post middleware, in
schema.post('update',function(){
var findQuery=this._conditions; // gives {_id:'blah'}
var updateQuery=this._update; //gives {$set:{a:'blah'}}
next();
});
but thats too late, i need this in the pre middleware to check before actually updating the db.
i tried looking through the 'this' object of the pre middleware but cannot find the updateQuery object anywhere and this._update is undefined in the pre middleware.
Is there a way to do this?
thanks
In case you're still looking for a solution that works on array operations, it looks like in newer versions of mongoose (at least 4.0.7+), this._update is defined in the pre-middleware.
I found a work around through this particular example, however it doesnt quite solve my actual problem. what you can do in mongoose version ~4.0.0 is to let the pre middleware specify to go through the model validation on update.
schema.pre('update',function(next){
this.options.runValidators = true; // make sure any changes adhere to schema
})
basically, you can then specify the validators inside the schema
var schema = new Schema({
a:{
type:String,
validate:[...] //the validation you want to run
}
});
you can choose to skip the validation on a normal save operation by using the this.isNew check inside validation functions.
this code will run validate:[...] on any $set and $unset to a in your update query.
however, it doesn't work on array operations like $push or $addToSet for some reason. so if your updating an array, it won't run the validation code at all! hence it doesn't solve the actual problem im faced with. but it can work with the example provided for anyone that comes across this particular problem
Related
I am using Mongoose 5+ and currently do not have the option of upgrading to Mongoose 6 (which seems to have fixed several issues concerning types and stuff)
I am refactoring from js to ts, and I keep hitting a wall when dealing with pre hooks. In this particular case, I want to understand how to pass generic types to the pre hook and not have typescript get mad that i am trying to access certain fields of this
So my prehook looks like this. It is using findOneAndUpdate and in this case the this is bound to the Query, which gives me some particular properties to access, such as this._update and this._conditions. I use this._update to access the information I am trying to update in this document, and I use that to modify another document in another collection before committing to the change in this document. I use this so the operation will be atomic and no changes will be committed to the DB if any of the other writes fails. However, typescript does not like me accessing values from this and outlined below are the errors i get
unitsSchema.pre('findOneAndUpdate', async function(next){
const update = this._update; //TSError: Property '_update' does not exist on type 'Query<any, any>'
const conditions = this._conditions; //Property '_conditions' does not exist on type 'Query<any, any>'
if(update.isDeleted === true){
//remove the unit from the condo model
await Condos.updateOne({_id:conditions.condoID},
{$pull:{
units:conditions._id
}}).catch(e=>next(e));
await UnitSttmt.updateMany({unitID:conditions._id},
{isDeleted:true})
.catch(e=>next(e));
}
//I even get an error here for some reason, i dont understand why here next is expecting a required argument, but not on other similar hooks
next(); // Expected 1 arguments, but got 0
}
I have tried passing it my document interface which extends mongoose.Document type and some other types too, but to no avail. Does anyone have any insight on how to get typescript to recognize the available Query paramters that exist?
Some examples I have tried
unitsSchema.pre<Query<any, UnitsDocument>>(...)
// this one obviously works but kind of defeats the purpose, but at least it gets rid of my error
unitsSchema.pre<any>(...)
also want ot mention the code works fine as javascript, it must be an error or limitation in the type declarations.. or maybe I'm just not supposed to be accessing those fields from the Query this ?
I am fairly new to MongoDB and Mongoose, I am really confused about why some of the middleware works at the document and some works on query. I am also confused about why some of the query methods return documents and some return queries. If a query is returning document it is acceptable, but why a query return query and what really it is.
Adding more to my question what is a Document function and Model or Query function, because both of them have some common methods like updateOne.
Moreover, I have gathered all these doubts from the mongoose documentation.
Tl;dr: the type of middleware most commonly defines what the this variable in a pre/post hook refers to:
Middleware Hook
'this' refers to the
methods
Document
Document
validate, save, remove, updateOne, deleteOne, init
Query
Query
count, countDocuments, deleteMany, deleteOne, estimatedDocumentCount, find, findOne, findOneAndDelete, findOneAndRemove, findOneAndReplace, findOneAndUpdate, remove, replaceOne, update, updateOne, updateMany
Aggregation
Aggregation object
aggregate
Model
Model
insertMany
Long explanation:
Middlewares are nothing, but built-in methods to interact with the database in different ways. However, as there are different ways to interact with the database, each with different advantages or preferred use-cases, they also behave differently to each other and therefor their middlewares can behave differently, even if they have the same name.
By themselves, middlewares are just shorthands/wrappers for the mongodbs native driver that's being used under the hood of mongoose. Therefor, you can usually use all middlewares, as if you were using regular methods of objects without having to care if it's a Model-, Query-, Aggregation- or Document-Middleware, as long as it does what you want it to.
However, there are a couple of use-cases where it is important to differentiate the context in which these methods are being called.
The most prominent use-case being hooks. Namely the *.pre() and the *.post() hooks. These hooks are methods that you can "inject" into your mongoose setup, so that they are being executed before or after specific events.
For example:
Let's assume I have the following Schema:
const productSchema = new Schema({
name: 'String',
version: {
type: 'Number',
default: 0
}
});
Now, let's say you always want to increase the version field with every save, so that it automatically increases the version field by 1.
The easiest way to do this would be to define a hook that takes care of this for us, so we don't have to care about this when saving an object. If we for example use .save() on the document we just created or fetched from the database, we'd just have to add the following pre-hook to the schema like this:
productSchema.pre('save', function(next) {
this.version = this.version + 1; // or this.version += 1;
next();
});
Now, whenever we call .save() on a document of this schema/model, it will always increment the version before it is actually being saved, even if we only changed the name.
However, what if we don't use the .save() or any other document-only middleware but e.g. a query middleware like findOneAndUpdate() to update an object?
Then, we won't be able to use the pre('save') hook, as .save() won't be called. In this case, we'd have to implement a similar hook for findOneAndUpdate().
Here, however, we finally come to the differences in the middlewares, as the findOneAndUpdate() hook won't allow us to do that, as it is query hook, meaning it does not have access to the actual document, but only to the query itself. So if we e.g. only change the name of the product the following middleware would not work as expected:
productSchema.pre('findOneAndUpdate', function(next) {
// this.version is undefined in the query and would therefor be NaN
this.version = this.version + 1;
next();
});
The reason for this is, that the object is directly updated in the database and not first "downloaded" to nodejs, edited and "uploaded" again. This means, that in this hook this refers to the query and not the document, meaning, we don't know what the current state of version is.
If we were to increment the version in a query like this, we'd need to update the hook as follows, so that it automatically adds the $inc operator:
productSchema.pre('findOneAndUpdate', function(next) {
this.$inc = { version: 1 };
next();
});
Alternatively, we could emulate the previous logic by manually fetching the target document and editing it using an async function. This would be less efficient in this case, as it would always call the db twice for every update, but would keep the logic consistent:
productSchema.pre('findOneAndUpdate', async function() {
const productToUpdate = await this.model.findOne(this.getQuery());
this.version = productToUpdate.version + 1;
next();
});
For a more detailed explanation, please the check the official documentation that also has a designated paragraph for the problem of having colliding naming of methods (e.g. remove() being both a Document and Query middleware method)
I wanted to update the field data only ,but my code it adding an object each time i am calling update api.I have gone through many sites and found out updateOne is the method but couldnt end up undersatnding how to implement here.I am quite new to node so any help would be appreciated.
const update=(req,res)=>{
console.log(req);
models.detailsSchema.findByIdAndUpdate(req.body.vehicleId,req.body.data,{new:true}).then((msg,err)=>{
if(err)
res.status(400).json({err})
res.status(200).json({
"resCode":"0000",
"resStatus":"Success",
"resMsg":msg
})
});
}
Looks like you're using Mongoose connected to a MongoDB instance? If that's the case, Schema.findByIdAndUpdate works on the primary key or ObjectId of the record you're trying to update. To make this code work, if my assumptions are correct, change to this:
models.detailsSchema.findByIdAndUpdate(req.body._id, req.body.data, { new:true })
Of course, you're going to want to put in some check to make sure _id is defined if this is a create/update route.
Let's say I have the following schema:
PersonSchema = {
name: String,
timesUpdated: {
type: Number,
default: 0
}
}
Every time that the given person is updated, I would want the timesUpdated field to increment by one. Now, I could use Mongoose's update middleware hook, which would be called by something like
PersonModel.update({_id: <id>}, {name: 'new name'})
and my timesUpdated field would be appropriately incremented. However, if I only wrote a hook for the update middleware, the following code would not update my timesUpdated field:
PersonModel.updateOne({_id: <id>}, {name: 'new name'})
In order for my count to be updated, I would have to write middleware for the udpateOne query. This pattern repeats for several other similar middleware hooks, such as updateMany, replaceOne, save (if you want to update a document this way), findOneAndUpdate and I'm sure many others.
I use the example of an updated count for simplicity, but I could also have used an example where some other unrelated action happens upon changing my name. Am I missing something in how hooks should be used, or is this a limitation of mongoose hooks?
Pre save hook will only be executed with following functions according to mongoose's middleware document.
init
validate
save
remove
However update functions are working directly with MongoDB, therefor there is no general use hook applies on all update functions. See related discussion on Github.
I'd suggest using a function to perform your task before/after all required calls (to update or updateOne) rather a hook, because of the limitations mentioned in the other answer and the question.
Or perhaps limit the kinds of methods that can be called to the ones that have the hook set.
Or use a hook which will always get called in the middle-ware sequence, like a validate hook.
I had a very weird issue with the way Mongoose interacted with my Node and Mongo database.
I was using express to create a basic get api route to fetch some data from my mongodb.
I had a database called test and it had a collection call "billings"
so the schema and route was pretty basic
apiRouter.route('/billing/')
.get(function(req, res) {
Billing.find(function(err, billings) {
if (err) res.send(err);
// return the bills
res.json(billings);
});
});
Where "Billing" was my mongoose schema. that simply had 1 object {test: string}
This worked fine, I got a response with all the items in my mongo db called "billings" which is only one item {test: "success"}
Next I created a collection called "historys"
I setup the exact same setup as my billings.
apiRouter.route('/historys/')
// get all the history
.get(function(req, res) {
Historys.find(function(err, historys) {
if (err) res.send(err);
// return the history
res.json(historys);
});
});
where again "Historys" was my mongoose schema. This schema was identical in setup to my billings since I didnt have any real data, the fields were the same, i just had it with a test field so the json object returned from both billings and historys should have been
{ test: "success" }
However, this time I didnt get any data back, I just got an empty object
[].
I went through my code multiple times to make sure maybe a capital got lost, or a comma somewhere etc, but the code was identical. the setup and formatting in my mongodb was identical. I went into robomongo and viewed the database and everything was named correctly.
Except, I had 2 new collections now.
My original : "Historys" AND a brand new collection "Histories"
Once i fixed my api route to go look at Histories instead of Historys, I was able to get the test data successfully. I still however cannot pull data from Historys, its like it doesnt exist yet there it was in my robomongo console when I refreshed.
I searched all my code for any mention of histories and got 0 results. Where did the system know to fix the grammar on my collection?
From the docs:
When no collection argument is passed, Mongoose produces a collection name by passing the model name to the utils.toCollectionName method. This method pluralizes the name. If you don't like this behavior, either pass a collection name or set your schemas collection name option.
So, when you did, in your schema definition, this:
mongoose.model('Historys', YourSchema);
, mongoose created the Histories collection.
When you do:
db.historys.insert({ test: "success" })
through mongodb console, if the historys collection doesn't exist, it'll be created. That's why you have the two collections in your db. Like the docs said, if you don't want mongoose to create a collection with a pluralized name based on your model, just specify the name you want.