NotificationWebsite

This project was developed as a test assignment as part of the selection for an internship

Implement a web application on ASP .NET Core that allows creating users in the application with subsequent automatic sending of emails to users on a schedule.

The application must read parameters from the json file of the application settings.

The parameters must specify:

• Task execution schedule as a cron expression
• Path to the folder with email templates

The application must contain a background service that will perform the following procedure with a specified schedule:

• Get a list of emails of application users
• Send an email to all users using a specified template

Within the application, it is also necessary to implement a REST API for saving users with the following endpoint: POST /api/users - creating a new user

The request body must contain email, name and age.

Email validation:

• Compliance with email format
• Uniqueness within the application

Name validation:

• Name length must not exceed 20 characters
• Cannot be null

Age validation:

• Age must be between 18 and 100 years old

The application must send a welcome email upon registration.

The application must support at least 2 email templates:

• Welcome email
• Informational email

Ability to insert variables into the template (username, email, etc.) The User model must contain the following fields:

• Id – unique user identifier
• Email – email
• Name – username
• Age – age
• Timestamp – Creation date (in UTC format)

Storage all users in the InMemory Database.

Requirements:

• .NET 8 platform
• Application type - web application with REST API
• Support for Windows and Linux-style paths
• The application must have at least 2 email templates
• User creation must be validated
• The application must correctly handle errors that occur during operation, displaying understandable messages to the user. If an error occurs while sending a message to the mail, the program must process and display the error, and then wait for the next attempt according to the schedule

Additional conditions of the task:

• Implement logging in the application using the standard ILogger mechanism:
• Error logging
• Request logging
• Logging the progress of sending mail
• Logging the process of creating a user

Implement receiving a list of users, as well as sending a POST request to send a letter along the path:

• POST /api/users/{id}/email
• When sending a letter via a request, it is sent to the user's mail instantly, without waiting

Examples of letters:

The content of the letter when creating a new user in the system:

• Welcome to our system {{Name}}
• Your email {{Email}}
• Random image from the Internet (you can use https://http.cat/{status_code}, with any existing status code)

Contents of the information letter:

• We inform you {{Name}}
• Time passed since the user was created: {{ Time }}
• Random image from the Internet (you can use https://http.dog/{status_code}.jpg, with any existing status code) Where Time is the calculated time unit of the difference, the current DateTime and Timestamp in utc