✨ Link scrapping for preview

DysonNetwork.Sphere/Connection/WebReader/WebReaderController.cs

@@ -0,0 +1,110 @@
+using DysonNetwork.Sphere.Permission;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.RateLimiting;
+
+namespace DysonNetwork.Sphere.Connection.WebReader;
+
+/// <summary>
+/// Controller for web scraping and link preview services
+/// </summary>
+[ApiController]
+[Route("/scrap")]
+[EnableRateLimiting("fixed")]
+public class WebReaderController(WebReaderService reader, ILogger<WebReaderController> logger)
+    : ControllerBase
+{
+    /// <summary>
+    /// Retrieves a preview for the provided URL
+    /// </summary>
+    /// <param name="url">URL-encoded link to generate preview for</param>
+    /// <returns>Link preview data including title, description, and image</returns>
+    [HttpGet("link")]
+    public async Task<ActionResult<LinkEmbed>> ScrapLink([FromQuery] string url)
+    {
+        if (string.IsNullOrEmpty(url))
+        {
+            return BadRequest(new { error = "URL parameter is required" });
+        }
+
+        try
+        {
+            // Ensure URL is properly decoded
+            var decodedUrl = UrlDecoder.Decode(url);
+
+            // Validate URL format
+            if (!Uri.TryCreate(decodedUrl, UriKind.Absolute, out _))
+            {
+                return BadRequest(new { error = "Invalid URL format" });
+            }
+
+            var linkEmbed = await reader.GetLinkPreviewAsync(decodedUrl);
+            return Ok(linkEmbed);
+        }
+        catch (WebReaderException ex)
+        {
+            logger.LogWarning(ex, "Error scraping link: {Url}", url);
+            return BadRequest(new { error = ex.Message });
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex, "Unexpected error scraping link: {Url}", url);
+            return StatusCode(StatusCodes.Status500InternalServerError, 
+                new { error = "An unexpected error occurred while processing the link" });
+        }
+    }
+
+    /// <summary>
+    /// Force invalidates the cache for a specific URL
+    /// </summary>
+    [HttpDelete("link/cache")]
+    [Authorize]
+    [RequiredPermission("maintenance", "cache.scrap")]
+    public async Task<IActionResult> InvalidateCache([FromQuery] string url)
+    {
+        if (string.IsNullOrEmpty(url))
+        {
+            return BadRequest(new { error = "URL parameter is required" });
+        }
+
+        await reader.InvalidateCacheForUrlAsync(url);
+        return Ok(new { message = "Cache invalidated for URL" });
+    }
+
+    /// <summary>
+    /// Force invalidates all cached link previews
+    /// </summary>
+    [HttpDelete("cache/all")]
+    [Authorize]
+    [RequiredPermission("maintenance", "cache.scrap")]
+    public async Task<IActionResult> InvalidateAllCache()
+    {
+        await reader.InvalidateAllCachedPreviewsAsync();
+        return Ok(new { message = "All link preview caches invalidated" });
+    }
+}
+
+/// <summary>
+/// Helper class for URL decoding
+/// </summary>
+public static class UrlDecoder
+{
+    public static string Decode(string url)
+    {
+        // First check if URL is already decoded
+        if (!url.Contains('%') && !url.Contains('+'))
+        {   
+            return url;
+        }
+
+        try
+        {
+            return System.Net.WebUtility.UrlDecode(url);
+        }
+        catch
+        {
+            // If decoding fails, return the original string
+            return url;
+        }
+    }
+}