Updated scanner to infer when it has reached the end of results.

JSMR.Infrastructure/Http/ApiClient.cs

@@ -10,9 +10,12 @@ public abstract class ApiClient(IHttpService http, ILogger logger, JsonSerialize
 {
     protected async Task<T> GetJsonAsync<T>(string url, CancellationToken cancellationToken = default)
     {
-        string response = await http.GetStringAsync(url, cancellationToken);
+        HttpStringResponse response = await http.GetAsync(url, cancellationToken);
 
-        return JsonSerializer.Deserialize<T>(response, json)
+        if (response.Content is null)
+            throw new Exception("No content to deserialize");
+
+        return JsonSerializer.Deserialize<T>(response.Content, json)
             ?? throw new InvalidOperationException($"Failed to deserialize JSON to {typeof(T).Name} from {url}.");
     }
 

JSMR.Infrastructure/Http/HtmlLoadResult.cs

@@ -0,0 +1,12 @@
+using HtmlAgilityPack;
+using System.Net;
+
+namespace JSMR.Infrastructure.Http;
+
+public sealed class HtmlLoadResult
+{
+    public required HttpStatusCode StatusCode { get; init; }
+    public HtmlDocument? Document { get; init; }
+
+    public bool IsSuccessStatusCode => (int)StatusCode is >= 200 and <= 299;
+}

JSMR.Infrastructure/Http/HtmlLoader.cs

@@ -4,13 +4,26 @@ namespace JSMR.Infrastructure.Http;
 
 public class HtmlLoader(IHttpService httpService) : IHtmlLoader
 {
-    public async Task<HtmlDocument> GetHtmlDocumentAsync(string url, CancellationToken cancellationToken)
+    public async Task<HtmlLoadResult> GetHtmlDocumentAsync(string url, CancellationToken cancellationToken)
     {
-        string html = await httpService.GetStringAsync(url, cancellationToken);
+        HttpStringResponse response = await httpService.GetAsync(url, cancellationToken);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            return new HtmlLoadResult
+            {
+                StatusCode = response.StatusCode,
+                Document = null
+            };
+        }
 
         HtmlDocument document = new();
-        document.LoadHtml(html);
+        document.LoadHtml(response.Content ?? string.Empty);
 
-        return document;
+        return new HtmlLoadResult
+        {
+            StatusCode = response.StatusCode,
+            Document = document
+        };
     }
 }

JSMR.Infrastructure/Http/HttpService.cs

@@ -2,10 +2,10 @@
 
 public class HttpService(HttpClient httpClient) : IHttpService
 {
-    public Task<string> GetStringAsync(string url, CancellationToken cancellationToken)
-        => GetStringAsync(url, new Dictionary<string, string>(), cancellationToken);
+    public Task<HttpStringResponse> GetAsync(string url, CancellationToken cancellationToken)
+        => GetAsync(url, new Dictionary<string, string>(), cancellationToken);
 
-    public async Task<string> GetStringAsync(string url, IDictionary<string, string> headers, CancellationToken cancellationToken)
+    public async Task<HttpStringResponse> GetAsync(string url, IDictionary<string, string> headers, CancellationToken cancellationToken)
     {
         using HttpRequestMessage request = new(HttpMethod.Get, url);
 
@@ -14,11 +14,18 @@ public class HttpService(HttpClient httpClient) : IHttpService
             request.Headers.TryAddWithoutValidation(header.Key, header.Value);
         }
 
-        httpClient.DefaultRequestHeaders.UserAgent.ParseAdd("JSMR/1.0");
+        request.Headers.UserAgent.ParseAdd("JSMR/1.0");
 
-        using HttpResponseMessage response = await httpClient.SendAsync(request, cancellationToken);
-        response.EnsureSuccessStatusCode();
+        using HttpResponseMessage response = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
 
-        return await response.Content.ReadAsStringAsync(cancellationToken);
+        string? content = response.Content is null
+            ? null
+            : await response.Content.ReadAsStringAsync(cancellationToken);
+
+        return new HttpStringResponse
+        {
+            StatusCode = response.StatusCode,
+            Content = content
+        };
     }
 }

JSMR.Infrastructure/Http/HttpStringResponse.cs

@@ -0,0 +1,11 @@
+using System.Net;
+
+namespace JSMR.Infrastructure.Http;
+
+public sealed class HttpStringResponse
+{
+    public required HttpStatusCode StatusCode { get; init; }
+    public string? Content { get; init; }
+
+    public bool IsSuccessStatusCode => (int)StatusCode is >= 200 and <= 299;
+}

JSMR.Infrastructure/Http/IHtmlLoader.cs

@@ -1,8 +1,6 @@
-using HtmlAgilityPack;
-
-namespace JSMR.Infrastructure.Http;
+namespace JSMR.Infrastructure.Http;
 
 public interface IHtmlLoader
 {
-    Task<HtmlDocument> GetHtmlDocumentAsync(string url, CancellationToken cancellationToken);
+    Task<HtmlLoadResult> GetHtmlDocumentAsync(string url, CancellationToken cancellationToken);
 }

JSMR.Infrastructure/Http/IHttpService.cs

@@ -2,6 +2,6 @@
 
 public interface IHttpService
 {
-    Task<string> GetStringAsync(string url, CancellationToken cancellationToken);
-    Task<string> GetStringAsync(string url, IDictionary<string, string> headers, CancellationToken cancellationToken);
+    Task<HttpStringResponse> GetAsync(string url, CancellationToken cancellationToken);
+    Task<HttpStringResponse> GetAsync(string url, IDictionary<string, string> headers, CancellationToken cancellationToken);
 }

JSMR.Infrastructure/Scanning/VoiceWorksScanner.cs

@@ -8,6 +8,7 @@ using JSMR.Infrastructure.Http;
 using JSMR.Infrastructure.Scanning.Extensions;
 using JSMR.Infrastructure.Scanning.Models;
 using System.Globalization;
+using System.Net;
 using System.Text.RegularExpressions;
 
 namespace JSMR.Infrastructure.Scanning;
@@ -20,24 +21,46 @@ public abstract class VoiceWorksScanner(IHtmlLoader htmlLoader) : IVoiceWorksSca
     protected abstract DateOnly? GetEstimatedReleaseDate(string expectedDate);
     protected abstract DateOnly? GetSalesDate(string salesDate);
 
-    public async Task<IReadOnlyList<DLSiteWork>> ScanPageAsync(VoiceWorkScanOptions options, CancellationToken cancellationToken = default)
+    public async Task<VoiceWorkScanResult> ScanPageAsync(VoiceWorkScanOptions options, CancellationToken cancellationToken = default)
     {
-        DLSiteHtmlDocument document = await GetDLSiteHtmlCollectionAsync(options, cancellationToken);
+        string url = GetUrl(options);
+        HtmlLoadResult result = await htmlLoader.GetHtmlDocumentAsync(url, cancellationToken);
+
+        // Expected boundary: past the last search page
+        if (result.StatusCode == HttpStatusCode.NotFound)
+        {
+            return new VoiceWorkScanResult(
+                Works: [],
+                EndOfResults: true
+            );
+        }
+
+        // Unexpected non-success response
+        if (!result.IsSuccessStatusCode || result.Document is null)
+        {
+            throw new HttpRequestException(
+                $"Unexpected response status code {(int)result.StatusCode} ({result.StatusCode}) while scanning {url}");
+        }
+
+        DLSiteHtmlDocument document = new(result.Document);
         DLSiteHtmlNode[] nodes = document.GetDLSiteNodes();
 
+        // Defensive fallback in case DLsite changes from 404 to 200 with empty page
+        if (nodes.Length == 0)
+        {
+            return new VoiceWorkScanResult(
+                Works: [],
+                EndOfResults: true
+            );
+        }
+
         DLSiteWork[] works = GetDLSiteWorks(nodes, options);
         works.InferAndUpdateExpectedDates();
 
-        return works;
-    }
-
-    private async Task<DLSiteHtmlDocument> GetDLSiteHtmlCollectionAsync(VoiceWorkScanOptions options, CancellationToken cancellationToken)
-    {
-        string url = GetUrl(options);
-
-        HtmlDocument document = await htmlLoader.GetHtmlDocumentAsync(url, cancellationToken);
-
-        return new DLSiteHtmlDocument(document);
+        return new VoiceWorkScanResult(
+            Works: works,
+            EndOfResults: false
+        );
     }
 
     protected string GetUrl(VoiceWorkScanOptions options)