✨ Web articles and feed

DysonNetwork.Sphere/Connection/WebReader/WebFeedService.cs

@@ -0,0 +1,91 @@
+using System.Security.Claims;
+using System.ServiceModel.Syndication;
+using System.Xml;
+using DysonNetwork.Sphere.Account;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+
+namespace DysonNetwork.Sphere.Connection.WebReader;
+
+public class WebFeedService(
+    AppDatabase database,
+    IHttpClientFactory httpClientFactory,
+    ILogger<WebFeedService> logger,
+    AccountService accountService
+)
+{
+    public async Task<WebFeed> CreateWebFeedAsync(WebFeedController.CreateWebFeedRequest dto, ClaimsPrincipal claims)
+    {
+        if (claims.Identity?.Name == null)
+        {
+            throw new UnauthorizedAccessException();
+        }
+
+        var account = await accountService.LookupAccount(claims.Identity.Name);
+        if (account == null)
+        {
+            throw new UnauthorizedAccessException();
+        }
+
+        var feed = new WebFeed
+        {
+            Url = dto.Url,
+            Title = dto.Title,
+            Description = dto.Description,
+            PublisherId = account.Id,
+        };
+
+        database.Set<WebFeed>().Add(feed);
+        await database.SaveChangesAsync();
+
+        return feed;
+    }
+
+    public async Task ScrapeFeedAsync(WebFeed feed, CancellationToken cancellationToken = default)
+    {
+        var httpClient = httpClientFactory.CreateClient();
+        var response = await httpClient.GetAsync(feed.Url, cancellationToken);
+        response.EnsureSuccessStatusCode();
+
+        await using var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
+        using var reader = XmlReader.Create(stream);
+        var syndicationFeed = SyndicationFeed.Load(reader);
+
+        if (syndicationFeed == null)
+        {
+            logger.LogWarning("Could not parse syndication feed for {FeedUrl}", feed.Url);
+            return;
+        }
+
+        foreach (var item in syndicationFeed.Items)
+        {
+            var itemUrl = item.Links.FirstOrDefault()?.Uri.ToString();
+            if (string.IsNullOrEmpty(itemUrl))
+            {
+                continue;
+            }
+
+            var articleExists = await database.Set<WebArticle>()
+                .AnyAsync(a => a.FeedId == feed.Id && a.Url == itemUrl, cancellationToken);
+
+            if (articleExists)
+            {
+                continue;
+            }
+
+            var newArticle = new WebArticle
+            {
+                FeedId = feed.Id,
+                Title = item.Title.Text,
+                Url = itemUrl,
+                Author = item.Authors.FirstOrDefault()?.Name,
+                Content = (item.Content as TextSyndicationContent)?.Text ?? item.Summary.Text,
+                PublishedAt = item.PublishDate.UtcDateTime,
+            };
+
+            database.Set<WebArticle>().Add(newArticle);
+        }
+
+        await database.SaveChangesAsync(cancellationToken);
+    }
+}