feat: endpoint for getting server restrictions

Controllers/UserContentController.cs

@@ -20,6 +20,7 @@ public class UserContentController : ControllerBase
     private readonly IConfiguration _appsettings;
     private readonly ApplicationDbContext _db;
     private readonly GeneralUseHelpers guhf;
+    List<string> _allowedExtensions = new List<string>() { ".jpg", ".jpeg", ".jfif", ".png", ".gif", ".avif", ".webp" };
 
     public UserContentController(IConfiguration appsettings, ApplicationDbContext db, GeneralUseHelpers GUHF)
     {
@@ -86,15 +87,14 @@ public class UserContentController : ControllerBase
         }
 
         // Dozwolone rozszerzenia
-        List<string> allowedExtensions = new List<string>() { ".jpg", ".jpeg", ".jfif", ".png", ".gif", ".avif", ".webp" };
         string fileExtension = Path.GetExtension(file.FileName).ToLower();
 
-        if (!allowedExtensions.Contains(fileExtension))
+        if (!_allowedExtensions.Contains(fileExtension))
         {
             return StatusCode(415, new ErrorDTO
             {
                 Status = "error",
-                Error_msg = $"Unknown file extension. Allowed: {string.Join(", ", allowedExtensions)}"
+                Error_msg = $"Unknown file extension. Allowed: {string.Join(", ", _allowedExtensions)}"
             });
         }
 
@@ -149,6 +149,34 @@ public class UserContentController : ControllerBase
         });
     }
 
+    // GET /api/v1/uc/restrictions
+    /// <summary>
+    /// [AUTHED] Get server restrictions for file upload
+    /// </summary>
+    /// <remarks>
+    /// Returns a list of allowed file extensions and mimetypes for upload.
+    /// </remarks>
+    /// <response code="200">Returned on valid request</response>
+    [HttpGet("restrictions")]
+    [Authorize]
+    [EnableCors]
+    [ProducesResponseType(200)]
+    public IActionResult GetFileUploadRestrictions()
+    {
+        return Ok(new
+        {
+            Status = "ok",
+            AllowedMimeTypes = new List<string>
+            {
+                "image/" // this could be done dynamically ~eee4
+            },
+            AllowedExtensions = _allowedExtensions,
+            MaxFileSize = int.TryParse(_appsettings.GetSection("UserContent")["MaxFileSize"], out int r)
+            ? r
+            : 5 * 1024 * 1024
+    });
+    }
+
     // DELETE /api/v1/uc/images/{id}
     /// <summary>
     /// [AUTHED] Delete an image