just-short-it/Pages/Index.cshtml.cs

using System.Text;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Caching.Distributed;

namespace JustShortIt.Pages;

public class IndexModel : PageModel {
    private ILogger<IndexModel> Logger { get; }
    private IDistributedCache Db { get; set; }

    // Bound property
    public string? Id { get; set; }
    public string? ErrorMessage { get; set; }

    public IndexModel(ILogger<IndexModel> logger, IDistributedCache distributedCache) {
        Logger = logger;
        Db = distributedCache;
    }

    public async Task<IActionResult> OnGetAsync(string? id) {
        Id = id;

        if (Id is not null) {
            string? data = await Db.GetStringAsync(Id);
            if (data is not null) return Redirect(data);

            ErrorMessage = "Redirect ID not found, it may have been deleted or expired";
        }

        return Page();
    }
}