fix: preserve and render EPUB images via dynamic server endpoint (#65)

Fixes #64 ### Summary of Changes 1. **Extended `IEpubReader` & `EpubReaderService`**: Added `GetEpubResourceAsync` to handle binary data extraction of static assets (like images) from the EPUB archive. 2. **Added Client-Side HTTP Call**: Extended `WasmEpubService` to retrieve static resources from the server using the API client. 3. **Preserved and Sanitized Images**: Updated `ExtractParagraphs` and `SanitizeParagraph` to treat `<img>` tags as first-class citizens, preserving their `src` attributes and excluding them from sanitization stripping. 4. **Dynamic URL Rewriting**: Introduced a relative-to-absolute path resolution algorithm (`ResolveRelativePath`) and rewrote image `src` attributes to use the dynamic endpoint `/api/epub/{ebookId}/resource?path=...`. 5. **Registered API Resource Serving Endpoint**: Added the `/api/epub/{ebookId:guid}/resource` minimal API endpoint in `Program.cs` that maps requests directly to `GetEpubResourceAsync` and returns files with the correct MIME type. 6. **Added Unit Tests**: Created `EpubReaderServiceTests.cs` to verify all image extraction, path resolution, and sanitization/rewriting rules. All tests pass successfully. --------- Co-authored-by: Marek Jasiński <jasins.marek@gmail.com> Reviewed-on: #65 Co-authored-by: Antigravity <antigravity@google.com> Co-committed-by: Antigravity <antigravity@google.com>
2026-06-01 16:04:56 +00:00
parent 21c9a66cce
commit bf31effd36
12 changed files with 554 additions and 11 deletions
@@ -37,7 +37,29 @@ public class WasmEpubReader : IEpubReader
            return Result.Fail(new Error($"Network or parsing error: {ex.Message}").CausedBy(ex));
        }
    }
-    // Metadata extraction moved to WasmEpubMetadataExtractor
+    public async Task<Result<byte[]>> GetEpubResourceAsync(
+        Guid ebookId,
+        string resourcePath,
+        string? userId = null,
+        CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            var response = await _httpClient.GetAsync($"/api/epub/{ebookId}/resource?path={Uri.EscapeDataString(resourcePath)}", cancellationToken);
+            if (response.IsSuccessStatusCode)
+            {
+                var bytes = await response.Content.ReadAsByteArrayAsync(cancellationToken);
+                return Result.Ok(bytes);
+            }
+
+            var errorBody = await response.Content.ReadAsStringAsync(cancellationToken);
+            return Result.Fail($"Server error fetching EPUB resource ({response.StatusCode}): {errorBody}");
+        }
+        catch (Exception ex)
+        {
+            return Result.Fail(new Error($"Network error fetching EPUB resource: {ex.Message}").CausedBy(ex));
+        }
+    }
 }

 public class WasmEpubMetadataExtractor : IEpubMetadataExtractor