DataStore_Assessment

Problem Statement

Build a file-based key-value data store that supports the basic CRD (create, read, and delete) operations. This data store is meant to be used as a local storage for one single process on one laptop. The data store must be exposed as a library to clients that can instantiate a class and work with the data store.

About

1. This Project uses NodeJS, which can be found here
2. Used Express JS Framework to create the API, more

Setup

1. Download or Clone this Repository
2. Run this command npm install , This will install all the dependencies.
3. To run the application all you have to type is npm start or npm start <absolute_path_datastore>

How to Use it as a Library

This Application only allows three functions those are:

1. Create
2. Read
3. Delete

Create

This function only supports POST method, this method only accepts JSON format. The Key should always be a string capped at 32chars and value is always JSON capped at 16KB. Create cannot be invoked for an existing key. If key is already present in the datastore then appropriate message is shown.

This Method can be imported from CRD library as

const CRD = require("./CRD/CRD");
CRD.Create(key_to_be_inserted, data_path_of_your_datastore);

Read

This function only supports GET method, this method accepts key from the user and searches for the key in the DataStore and returns the value for the key, if not found then appropriate message is shown. If any value has Time-To-Live property, Once the Time-To-Live for a key has expired, the key will no longer be available for Read or Delete operations.

This Method can be imported from CRD library as

const CRD = require("./CRD/CRD");
CRD.Read(key_to_be_searched, data_path_of_your_datastore);

Delete

This function only supports DELETE method, this method accepts key from the user and searches for the key in the DataStore and deletes the value for the key, if not found then appropriate message is shown.. If any value has Time-To-Live property, Once the Time-To-Live for a key has expired, the key will no longer be available for Read or Delete operations.

This Method can be imported from CRD library.

const CRD = require("./CRD/CRD");
CRD.Delete(key_to_be_deleted, data_path_of_your_datastore);

How to use it as an API

API supports three function those are

1. GET => This method is used to read the data from datastore using the key.
2. POST => This method is used to create and store data into datastore.
3. DELETE => This method is used to delete the data from datastore using the key.

Note:

The following are not allowed in the application

1. Use appropriate method for CRD, that is GET is used for Read function, POST is used for Create function and DELETE is used for Delete function. if any other method is used it will show you the help page.
2. Please use a valid directory of your datastore.
3. If an absolute path is given then the file name should have .json extension.

Create using API

This API gives you flexibility to use the API in two ways, those are:

1. http://localhost:3000/create/<JSON_Data>
2. http://localhost:3000/create?key=<JSON_Data>

Either of the above options can be used. If any incorrect way is used then it will automatically direct you to the help page.

Read using API

This API gives you flexibility to use the API in two ways, those are:

1. http://localhost:3000/read/<The_key_to_be_read>
2. http://localhost:3000/read?key=<The_key_to_be_read>

Either of the above options can be used. If any incorrect way is used then it will automatically direct you to the help page.

Delete using API

This API gives you flexibility to use the API in two ways, those are:

1. http://localhost:3000/delete/<The_key_to_be_deleted>
2. http://localhost:3000/delete?key=<The_key_to_be_deleted>

Either of the above options can be used. If any incorrect way is used then it will automatically direct you to the help page.