URL shortener using ruby on rails and redis

Feature Requirements:

1. URL Shortening:

   • The user should be able to provide a long URL, and the application should generate a unique, short URL.
   • The short URL should be stored in Redis, with the long URL as the value.
   • The short URL should be generated based on a unique, sequential ID or a random string.

2. URL Redirection:

   • When a user visits the short URL, the application should retrieve the corresponding long URL from Redis and redirect the user to the long URL.

3. Custom URLs:

   • The user should be able to specify a custom short URL instead of using the automatically generated one.
   • The custom short URL should also be stored in Redis, with the long URL as the value.
   • The application should validate the uniqueness of the custom short URL.

4. URL Expiration:

   • The user should be able to set an expiration time for the short URL.
   • The application should automatically remove the short URL and its associated long URL from Redis when the expiration time is reached.

5. URL Analytics:

   • The application should track the number of times each short URL is accessed.
   • The user should be able to view the access statistics for their short URLs.

6. User Management:

   • The application should allow users to register and log in.
   • Each user should have their own set of short URLs, which they can manage (create, view, edit, delete).

Edge Cases and Considerations:

1. Duplicate Short URLs:

   • If a user tries to create a short URL that already exists, the application should handle the conflict gracefully.
   • The application should either generate a new short URL or return an error message and ask the user to choose a different short URL.

2. Invalid URL Input:

   • The application should validate the input URL to ensure it is a valid URL format before attempting to shorten it.
   • If the input URL is invalid, the application should return an error message and ask the user to provide a valid URL.

3. URL Encoding:

   • The application should handle URL encoding correctly when storing and retrieving the long URLs from Redis.
   • This is important to ensure that the redirected URL preserves the original formatting and parameters.

4. Rate Limiting:

   • To prevent abuse and excessive URL shortening, the application should implement rate limiting for each user or IP address.
   • The rate limiting can be implemented using Redis counters and expiration.

5. Concurrency and Race Conditions:

   • When multiple users attempt to create the same short URL simultaneously, the application should handle the race condition gracefully.
   • This can be achieved by using Redis transactions or other concurrency control mechanisms.

6. Scalability and High Availability:

   • As the application grows, the Redis database may become a bottleneck.
   • The application should be designed to scale horizontally by using a Redis cluster or sharding the data across multiple Redis instances.
   • Additionally, the application should be highly available by implementing failover and recovery mechanisms.

7. Security Considerations:

   • The application should prevent users from creating short URLs that could be used for malicious purposes, such as phishing or redirecting to harmful content.
   • The application should also implement proper input validation and sanitization to prevent SQL injection or other security vulnerabilities.

By considering these feature requirements and edge cases, you can build a robust and scalable URL shortener using Ruby and Redis that provides a great user experience and ensures the security and reliability of the application.