Delete item from CosmosDB - javascript

I'm trying to delete entries from Azure CosmosDB.
Documetation says:
/**
* Delete item
* Pass the id and partition key value to delete the item
*/
const { resource: result } = await container.item(id, category).delete();
console.log(`Deleted item with id: ${id}`);
My function to delete and items is:
// takes in an entry id to detete and deletes it with the documentation
async function findItemsToDelete(idToDelete){
const category = config.partitionKey; // partitionKey is {kind: "Hash", paths: ["/requests"]} and I've also tried just "/requests"
// the four lines below are correct
const { endpoint, key, databaseId, containerId } = config;
const client = new CosmosClient({ endpoint, key });
const database = client.database(databaseId);
const container = database.container(containerId);
// query to return item with id (random code to make sure the item exists)- not important
const querySpec = {
query: `SELECT * FROM c WHERE c.id = "${idToDelete}"`
};
const { resources: items } = await container.items
.query(querySpec)
.fetchAll();
// below is the delete code from the documentation
const { resource: result } = await container.item(idToDelete, category).delete();
// random array holding the item that was just deleted- not important
return items;
}
When I try calling this, I get an error that says: Entity with the specified id does not exist in the system. Does anyone know how to properly implement this? I know the id is correct but I believe I may be doing something wrong with the partitionKey/Category part.
I saw in this post: Cannot delete item from CosmosDB
that i may need the partition key value, but I dont know what that is or how to get it. Please let me know if you know what's going on!

Related

Override Mongoose save method to retry on `duplicate key error`

My Mongoose schema uses a custom _id value and the code I inherited does something like this
const sampleSchema = new mongoose.Schema({
_id: String,
key: String,
});
sampleSchema.statics.generateId = async function() {
let id;
do {
id = randomStringGenerator.generate({length: 8, charset: 'hex', capitalization: 'uppercase'});
} while (await this.exists({_id: id}));
return id;
};
let SampleModel = mongoose.model('Sample', sampleSchema);
A simple usage looks like this:
let mySample = new SampleModel({_id: await SampleModel.generateId(), key: 'a' });
await mySample.save();
There are at least three problems with this:
Every save will require at least two trips to the database, one to test for a unique id and one to save the document.
For this to work, it is necessary to manually call generateId() before each save. An ideal solution would handle that for me, like Mongoose does with ids of type ObjectId.
Most significantly, there is a potential race condition that will result in duplicate key error. Consider two clients running this code. Both coincidentally generate the same id at the same time, both look in the database and find the id absent, both try to write the record to the database. The second will fail.
An ideal solution would, on save, generate an id, save it to the database and on duplicate key error, generate a new id and retry. Do this in a loop until the document is stored successfully.
The trouble is, I don't know how to get Mongoose to let me do this.
Here's what I tried: Based on this SO Question, I found a rather old sample (using a very old mongoose version) of overriding the save function to accomplish something similar and based this attempt off it.
// First, change generateId() to force a collision
let ids = ['a', 'a', 'a', 'b'];
let index = 0;
let generateId = function() {
return ids[index++];
};
// Configure middleware to generate the id before a save
sampleSchema.pre('validate', function(next) {
if (this.isNew)
this._id = generateId();
next();
});
// Now override the save function
SampleModel.prototype.save_original = SampleModel.prototype.save;
SampleModel.prototype.save = function(options, callback) {
let self = this;
let retryOnDuplicate = function(err, savedDoc) {
if (err) {
if (err.code === 11000 && err.name === 'MongoError') {
self.save(options, retryOnDuplicate);
return;
}
}
if (callback) {
callback(err, savedDoc);
}
};
return self.save_original(options, retryOnDuplicate);
}
This gets me close but I'm leaking a promise and I'm not sure where.
let sampleA = new SampleModel({key: 'a'});
let sampleADoc = await sampleA.save();
console.log('sampleADoc', sampleADoc); // prints undefined, but should print the document
let sampleB = new SampleModel({key: 'b'});
let sampleBDoc = await sampleB.save();
console.log('sampleBDoc', sampleBDoc); // prints undefined, but should print the document
let all = await SampleModel.find();
console.log('all', all); // prints `[]`, but should be an array of two documents
Output
sampleADoc undefined
sampleBDoc undefined
all []
The documents eventually get written to the database, but not before the console.log calls are made.
Where am I leaking a promise? Is there an easier way to do this that addresses the three problems I outlined?
Edit 1:
Mongoose version: 5.11.15
I fixed the problem by changing the save override. The full solution looks like this:
const sampleSchema = new mongoose.Schema({
_id: String,
color: String,
});
let generateId = function() {
return randomStringGenerator.generate({length: 8, charset: 'hex', capitalization: 'uppercase'});
};
sampleSchema.pre('validate', function() {
if (this.isNew)
this._id = generateId();
});
let SampleModel = mongoose.model('Sample', sampleSchema);
SampleModel.prototype.save_original = SampleModel.prototype.save;
SampleModel.prototype.save = function(options, callback) {
let self = this;
let isDupKeyError = (error, field) => {
// Determine whether the error is a duplicate key error on the given field
return error?.code === 11000 && error?.name === 'MongoError' && error?.keyValue[field];
}
let saveWithRetries = (options, callback) => {
// save() returns undefined if used with callback or a Promise otherwise.
// https://mongoosejs.com/docs/api/document.html#document_Document-save
let promise = self.save_original(options, callback);
if (promise) {
return promise.catch((error) => {
if (isDupKeyError(error, '_id')) {
return saveWithRetries(options, callback);
}
throw error;
});
}
};
let retryCallback;
if (callback) {
retryCallback = (error, saved, rows) => {
if (isDupKeyError(error, '_id')) {
saveWithRetries(options, retryCallback);
} else {
callback(error, saved, rows);
}
}
}
return saveWithRetries(options, retryCallback);
}
This will generate an _id repeatedly until a successful save is called and addresses the three problems outlined in the original question:
The minimum trips to the database has been reduced from two to one. Of course, if there are collisions, more trips will occur but that's the exceptional case.
This implementation takes care of generating the id itself with no manual step to take before saving. This reduces complexity and removes the required knowledge of prerequisites for saving that are present in the original method.
The race condition has been addressed. It won't matter if two clients attempt to use the same key. One will succeed and the other will generate a new key and save again.
To improve this:
There ought to be a maximum number of save attempts for a single document followed by failure. In this case, you've perhaps used up all the available keys in whatever domain you're using.
The unique field may not be named _id or you might have multiple fields that require a unique generated value. The embedded helper function isDupKeyError() could be updated to look for multiple keys. Then on error you could add logic to regenerate just the failed key.

How to create a module using mongoose for sharing a changing DB connection

i've been working on an app(Node.js with MongoDB using mongoose), and the server connects to 2 different databases, 1 generic containing username and password pairs for user authentication. Then, when the user signs in, I want to connect to a different database, named after the user's userId. I managed to create a module for sharing the generic UA database, but it's more difficult with the second one, since it doesn't open with the connection, but later on, when the user signs in. I guess i got inspired by the idea of react context kind of sharing.
So far i've got something like this
const mongoose = require("mongoose");
/*
UA = User Authentication
US = User Specific
DB = DataBase
*/
const UA_DB = mongoose.createConnection(/*...*/);
);
const User = UA_DB.model("User", require("../../data-schemas/user"));
let US_DB, Order, Item, Ingredient, Place;
console.log("opened UA database");
function sendUserId(newUserId) {
userId = newUserId;
US_DB = mongoose.createConnection(/*... ${newUserId} ...*/ );
Order = US_DB.model("Order", require("../../data-schemas/order"));
Item = US_DB.model("Item", require("../../data-schemas/item"));
Ingredient = US_DB.model(
"Ingredient",
require("../../data-schemas/ingredient")
);
Place = US_DB.model("Place", require("../../data-schemas/place"));
console.log("opened US database");
}
module.exports = {
UA_DB: {
User,
},
US_DB: {
Order,
Item,
Ingredient,
Place,
},
sendUserId,
};
Now, if I hadn't made it clear, the first, UA_DB works just fine, the user signs in just fine... When it comes to the US_DB i always get undefined as values(Cannot read property 'find' of undefined). I suspect the problem could be, that the exported value doesn't update with the value of the variables. Any ideas, how this could be solved?
Well, i figured it out. Instead of using precise values I use a function to return them, and to connect to the database.UserId is stored in a token, so after verification i check whether i am already connected to the right database (with the userId variable, which stores previous values) and then return curretn values of the models now my code looks something like this
const mongoose = require("mongoose");
/*
UA = User Authentication
US = User Specific
DB = DataBase
*/
const UA_DB = mongoose.createConnection(/* ... */
);
const User = UA_DB.model("User", require("../../data-schemas/user"));
let US_DB,
Order,
Item,
Ingredient,
Place = "some default value";
console.log("opened UA database");
let userId = "";
function getUS_DBModels(newUserId) {
if (newUserId !== userId) {
userId = newUserId;
US_DB = mongoose.createConnection(`...${userId}...`
);
Order = US_DB.model("Order", require("../../data-schemas/order"));
Item = US_DB.model("Item", require("../../data-schemas/item"));
console.log("opened a US_DB connection");
Ingredient = US_DB.model(
"Ingredient",
require("../../data-schemas/ingredient")
);
Place = US_DB.model("Place", require("../../data-schemas/place"));
}
return {
Order, Item, Ingredient, Place
}
}
module.exports = {
UA_DB: {
User,
},
getUS_DBModels,
};
For anyone wondering, in different modules you can access the values like this
const dbHandler = require("./path/to/the/module");
const { Item } = dbHandler.getUS_DBModels("UserId");

Unable to add object fetched from mongoDB to normal javascript array

I am trying to create an add to cart button which fetches the data from product database using the id of specific product which I selected. I am trying to push the object found using the same Id into a normal javascript array and then to display it using ejs methods. While I was tring I found I am unable to push the data in object form.
Summary:
On 7th line I have declared an array and in that array I want to store some objects which I have fetched frome a db model.
On 15th line I am trying to push the object form into my array so that I could iterate through the objects to display them on my page using ejs. But I am unable to do that.
screenshots:
Here's the final result I'm getting even after trying to push objects in array:
empty array logged
Here are the objects I'm trying to push:
Objects
Code:
app.get("/cart", (req, res) => {
if (req.isAuthenticated()) {
const findcartdata = req.user.username;
userData.findOne({email: findcartdata}, (err, BookId) => {
// console.log(BookId.cartItemId);
const idArray = BookId.cartItemId;
var bookArray = [];
idArray.forEach((data) => {
productData.findOne({_id: data}, (err, foundBookData) =>{
// console.log(foundBookData);
if(err){
console.log(err);
}
else{
bookArray.push(foundBookData);
}
})
});
console.log(bookArray);
// res.render("cart", {
// cartBookArray: BookId.cartItemId
// })
});
} else {
res.redirect("/login");
}
})
In above code i found the user's email using passport authentication user method and using that email I wanted to add the products in a different javascript array (which I am goint to pass to my ejs file of cart and then iterate it on list) using those array of Id which I got from another model called userData. The problem is I am able to find userData of each Id but unable to store them as an array of objects.
Looks like a timing issue, your code completes before the database downloads the objects and pushes them to your array.
This should fix your issue:
// ...
const idArray = BookId.cartItemId;
var bookArray = [];
for (const data of idArray) {
const foundBookData = await productData.findOne({_id: data}).catch(console.error);
if (!foundBookData) continue;
bookArray.push(foundBookData);
}
console.log(bookArray);
// ...
By the way, make sure to make the whole function asynchronous as well, which would be done by changing this line:
userData.findOne({email: findcartdata}, async (err, BookId) => { // ...

How to create a `context.Provider`/`context.Consumer`-like structure to pass values in a bot app?

I'm trying to pass a property, that is inside the first position of an array of objects, to another module so I can use this value later. I've tried to pass it as module(args), but it keeps reading the default value which is 0. Is there a way to do this?
I tried to implement some React.context but the Bot framework Emulator is refusing it.
/////////////////Module that ll acquire the value/////////////////////////////
getCard(bot, builder, params) {
let configValues = { ...params[0] }
bot.dialog(`${configValues.path}`, function (session) {
var msg = new builder.Message(session);
const cardItem = (obj) => {
return (new builder.HeroCard(session)
.title(`${obj.title}`)
.text(`R$ ${obj.price}`)
.images([builder.CardImage.create(session, `${obj.img}`)])
.buttons([
builder.CardAction.imBack(session, `${obj.price} Item adicionado!`, 'add to cart')
// !onClick event must add the current obj.price to
// the configValues.total(Ex: configValues.total += obj.price)!
])
)
}
msg.attachmentLayout(builder.AttachmentLayout.carousel)
msg.attachments(
eval(params.map(obj => cardItem(obj)))
);
//!in here before end the dialog is where i want to update
// the configValues.total so i can show it in the -> Checkout module
session.send(msg).endDialog()
}).triggerAction({ matches: configValues.regex });
}
}
//////////////CheckOut.Module///////////////////////////////
{...}
let configValues = { ...params[0] }
let state = {
nome: "",
endereco: "",
pagamento: "",
total: configValues.total // this is the value to be read
}
bot.dialog('/intent', [
{...},
(session, results) => {
state.pagamento = results.response
session.send(
JSON.stringify(state) // here is the place to be printed
)
{...}
]
).triggerAction({ matches: /^(finalizar|checar|encerrar|confirmar pedido|terminar)/i })
Since you solved your original problem, I'll answer the one in your comment.
Your problem is here:
cartId.map((obj, i , arr) => {
// if (!obj.total) {
// obj.total.reduce(i => i += i)
// }
const newtotal = new total
newtotal.getTotals(bot, builder, obj, arr)
})
cartId contains the totals for each of your items. When you call map on it, you're passing each item individually to getTotals, which passes each item to checkout()
The reason you can't sum all of the totals and can only sum one item's total is that you pass cartId to checkout and cartId has been changed to just a single item. Instead, there's a couple of different things you could do:
Pass the whole cartId from cartItems and use something like for (var key in cartItems) in totalConstructor() and checkoutConstructor(). This is probably the easiest, but not very memory efficient.
Use BotBuilder's State Storage to store your totals array in userData, then sum that at the end. This might be more difficult to implement, but would be a much better route to go. Here's a sample that can help you get started.

Cloud Functions for Firebase: how to reference a key in a list that has been just pushed

My question is basically what to do in your cloud function, if you want to reference keys that have been generated when the client called push().
/providerApps/{UID}/ is my path to a list of appointment nodes, so each appointment node is at /providerApps/{UID}/someKey.
I need the "new item in the list", the one that was added with push(), so I thought I could order the keys and simply get the last one, but that does not work:
// (Try to) Listen for new appointments at /providerApps/{pUID}
// and store the appointment at at /clientApps/{cUID}
// cUID is in the new appointment node
exports.storeNewAppForClient = functions.database.ref("/providerApps/{UID}").onWrite(event => {
// Exit when the data is deleted.
if (!event.data.exists()) {
console.log("deletion -> exiting");
return;
}
const pUID = event.params.UID;
const params = event.params;
console.log("params: ", params);
const firstAppVal = event.data.ref.orderByKey().limitToLast(1).val();
// TypeError: event.data.ref.orderByKey(...).limitToLast(...).val is not a function
const date = firstAppVal["dateStr"];
const cUID = firstAppVal["clientUID"];
return event.data.ref.root.child("clientApps").child(cUID).child(date).set(pUID);
});
I guess I could do it on the client side with push().getKey() and allow providers to write into clientApps node, but that seems to be less elegant.
Any ideas how to do this with cloud functions?
As an illustration, my data structure looks like this:
there are provider and their clients who make appointments
Cheers
Change your trigger location to be the newly created appointment instead of the list of appointments. Then you can access the appointment data directly:
exports.storeNewAppForClient = functions.database.ref("/providerApps/{UID}/{pushId}").onWrite(event => {
// Exit when the data is deleted.
if (!event.data.exists()) {
console.log("deletion -> exiting");
return;
}
const pUID = event.params.UID;
const params = event.params;
console.log("params: ", params);
const date = event.data.child('dateStr').val();
const cUID = event.data.child('clientUID').val();
return admin.database().ref('clientApps').child(cUID).child(date).set(pUID);
});
(updated for Frank's comment)

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