Instructions:

Write a web app that models a user as described below and provides the operations listed below. The user collection must be named users.

---

User:

Here are the properties of a User.

User Properties

Property	Data Type	Required?
name	String	Yes
age	Number	Yes
email	String	Yes
phoneNumber	Number	No

---

> CRUD Operations:

1. These will be supported via GET requests.

2. The request data will be provided as query parameters.

3. The URLs must be /create, /retrieve, /update and /delete

---

Create:

A user will be created by sending a GET request for the path /create

Request Parameters for Create: Here are the query parameters for the request.

Name	Always present?	Notes
name	Yes
age	Yes
email	Yes
phoneNumber	No	phoneNumber will only have the numeric characters 0 through 0, and will not contain any spaces, hyphens or non-numeric characters. It will also not start with a 0

> Response Body for Create:

The response body will be JSON object for the document created in MongoDB.

> Example:

Request:

http://localhost:3000/create?name=Cher Gray&age=27&email=cher@example.com&phoneNumber=8114482

NOTE: URLs containing certain special characters such as spaces need to be encoded. Most browsers do the encoding for you, so that you can type a URL with spaces in it and the browser does the necessary encoding when sending the HTTP request, but in case you use a tool for sending HTTP request that does not perform percent-encoding, be aware to this.

Response:

NOTE: The property "_v" is a version number added by Mongoose. It is OK to include this property in the response, but this is your choice and you can also decide to exclude it from the response. It is perfectly fine if the order of properties in the response you see doesn't match the order of properties in these examples.

{ "phoneNumber": 8114482, "_id": "60e435e0e2d67f620c534a84", "name": "Cher Gray", "age": 27, "email": "cher@example.com", "__v": 0 }

---

Retrieve:

Users will be retrieved by sending a GET request for the path /retrieve

Request Parameters for Retrieve:

Here are the query parameters for the request:

Name	Always Present?
name	No
age	No
email	No
phoneNumber	No
_id	No

A retrieve request can contain zero or more query parameters.

1. If the request has no query parameters, then all the documents should be returned.

2. If the request has one query parameter, then only the documents matching that query parameter should be returned.

3. If the request has more than one query parameter, then only the documents that match every query parameter should be returned.

a. In other words, when querying the database, all the values from the query parameters must be AND-ed together.

> Response Body for Retrieve:

An array of JSON objects corresponding to the documents matching the query parameters. The array will be empty if no document matches the query parameters.

> Example:

Request

http://localhost:3000/retrieve?_id=60e435e0e2d67f620c534a84

Response

[ { "phoneNumber": 8114482, "_id": "60e435e0e2d67f620c534a84", "name": "Cher Gray", "age": 27, "email": "cher@example.com", "__v": 0 } ]

---

Update

A user will be updated by sending a GET request for the path /update

Request Parameters for Update:

Here are the query parameters for the request:

Name	Always Present?
name	No
age	No
email	No
phoneNumber	No
_id	Yes

- Every request for /update will always contain _id as a request parameter.

- The _id of a document is immutable and cannot be changed.

- In addition to _id, a request will contain at least one other query parameter. However, a request may contain more than one query parameter.

-For example, a request may contain the query parameters _id, name, phoneNumber.

- The required behavior is that if any property is not specified in the query parameters, then the value of that property must not be updated.For example, if a request contains the query parameters _id, age, phoneNumber, the app must update the document with this specified value of _id

-To set the age property of the document to the value in the query parameter and the phoneNumber to the value in the query parameter, regardless of whether or not the document previously had a value for this property.

- But must leave the properties name and email of the document unmodified.

> Response Body for Update:

If a matching document was found, then the response body must be a JSON object with a property updateCount and value either 0 or 1.

The value of updateCount must be 1 if any property of the matching document was changed.

{ "updateCount" : 1}

The value of updateCount must be 0 if no property of the matching document was changed.

{ "updateCount": 0}

If no document was found with the specified value of _id, the response must be as follows:

{ "Error" : "Not found"}

> Example:

Request

http://localhost:3000/update?_id=60e435e0e2d67f620c534a84&age=28&phoneNumber=12193456

Response

{ "updateCount": 1 }

---

A user will be deleted by sending a GET request for the path /delete

Here are the query parameters for the request:

Name	Always Present?
name	No
age	No
email	No
phoneNumber	No
_id	Yes

A delete request will have exactly one of the above query parameters.

> For example:

- If the request has the _id query parameter and there is a document with this _id value, it should be deleted.

- If the request has the name query parameter, you should delete all the documents in which the value of the name property is exactly the same as the value in the query parameter.

- Similarly, if the request has the query parameter email, age or phoneNumber, then all documents matching the value of email, age or phoneNumber must be removed.

> Response Body for Delete

An JSON object specifying how many documents were deleted as shown below:

{ "deletedCount": 2}

If no documents were deleted, the response must be:

{ "deletedCount": 0}

> Example:

Request

http://localhost:3000/delete?age=27

Response

{ "deletedCount": 3 }

---

Separate Model Code from Controller Code:

- Your model code must be separate from your controller code.

- You cannot import the mongoose package in your controller code.

- You cannot import the express packages in your model code.

- Your model code can be in as many files as you want.

- Similarly, your controller code can be in as many files as you want.

- However, the model code and the controller code must be in separate files.

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Hints:

- You can assume that the value of the query parameters (e.g., phoneNumber, age) will be of the correct data type and you don't need to validate the values.

- To delete multiple users that match a filter, you can use the method deleteMany: https://mongoosejs.com/docs/api.html#model_Model-deleteMany

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REQUIREMENTS:

> You must not hardcode the MongoDB connect string in your JavaScript code. You must use the variable MONGODB_CONNECT_STRING in the file .env to connect to the MongoDB server. Before testing your app, we will change the value of this variable to point to our own MongoDB server.

> Your code must include a .env file with 2 variables

- PORT with value 3000, which is the port on which the Express server will receive HTTP requests, and

- MONGODB_CONNECT_STRING with the connect string that must be used to connect to the MongoDB server.

> In the zip file, you must include all the code for your application, except the node_modules directory.