URL Shortener API with Minimal APIs

Project roadmap

1. 01

   Create the project and model

   ~1.5h

   Create a project with dotnet new web and add EF Core with the SQLite provider. Define a ShortLink entity (Id, Code with a unique index, OriginalUrl, CreatedAt, ClickCount) and an AppDbContext. Create and apply the first migration. Done when: the database file is created with the ShortLinks table.

2. 02

   Create short links

   ~2h

   Add POST /api/links accepting { "url": "..." }. Check the URL is absolute http or https with Uri.TryCreate and at most 2,048 characters. Generate a random 7-character code from letters and digits using RandomNumberGenerator, and try again when the code already exists. Return 201 with the code and the full short URL. Done when: posting a valid URL returns a short link, and an invalid one returns 400.

3. 03

   Redirect and count clicks

   ~1.5h

   Add GET /{code}: look up the link, increase ClickCount with a single UPDATE (ExecuteUpdateAsync) so simultaneous clicks aren't lost, and return a 302 redirect to the original URL. Return 404 for unknown codes. Done when: opening a short link in the browser lands on the original page, and the click count increases.

4. 04

   Add analytics

   ~1h

   Add GET /api/links/{code}/stats returning the original URL, the creation date and the click count. Use Minimal API route groups (MapGroup) to organize the /api endpoints, and TypedResults for the responses. Done when: the stats endpoint shows the correct click count after several visits.

5. 05

   Rate limit link creation

   ~1.5h

   Add ASP.NET Core rate limiting with AddRateLimiter: a fixed-window policy partitioned by the client's IP address, allowing for example 10 new links per minute, applied only to the POST endpoint with RequireRateLimiting. Return 429 with a Retry-After header when the limit is exceeded. Done when: the 11th request within a minute gets 429, and redirects are never limited.

6. 06

   Write integration tests

   ~2h

   Create an xUnit project using WebApplicationFactory with a SQLite in-memory database. Test creating a link, the redirect (disable automatic redirects in the test client to check the 302 and Location header), click counting, stats, unknown codes, invalid URLs and rate limiting. Done when: dotnet test passes.

Resources

• DocsMinimal APIs overview
• DocsRate limiting middleware in ASP.NET Core
• DocsEF Core: ExecuteUpdate and ExecuteDelete
• DocsEF Core SQLite provider
• DocsIntegration tests in ASP.NET Core