Merge pull request #1406 from SteamRE/content-length-fallback

Support downloading manifests/chunks with missing Content-Length
SteamRE · Aug 26, 2024 · eee6330 · eee6330
2 parents 6164937 + 1cdf7a7
commit eee6330
Showing 1 changed file with 51 additions and 23 deletions.
diff --git a/SteamKit2/SteamKit2/Steam/CDN/Client.cs b/SteamKit2/SteamKit2/Steam/CDN/Client.cs
@@ -100,30 +100,45 @@ public async Task<DepotManifest> DownloadManifestAsync( uint depotId, ulong mani
                     throw new SteamKitWebRequestException( $"Response status code does not indicate success: {response.StatusCode:D} ({response.ReasonPhrase}).", response );
                 }
 
-                if ( !response.Content.Headers.ContentLength.HasValue )
-                {
-                    throw new SteamKitWebRequestException( "Response does not have Content-Length", response );
-                }
-
                 cts.CancelAfter( ResponseBodyTimeout );
 
-                var contentLength = ( int )response.Content.Headers.ContentLength;
-                var buffer = ArrayPool<byte>.Shared.Rent( contentLength );
+                var contentLength = -1;
+                byte[]? buffer = null;
+
+                if ( response.Content.Headers.ContentLength.HasValue )
+                {
+                    contentLength = ( int )response.Content.Headers.ContentLength;
+                    buffer = ArrayPool<byte>.Shared.Rent( contentLength );
+                }
+                else
+                {
+                    DebugLog.WriteLine( nameof( CDN ), $"Manifest response does not have Content-Length, falling back to unbuffered read." );
+                }
 
                 try
                 {
-                    using var ms = new MemoryStream( buffer, 0, contentLength );
+                    MemoryStream ms;
 
-                    // Stream the http response into the rented buffer
-                    await response.Content.CopyToAsync( ms, cts.Token );
+                    if ( buffer != null )
+                    {
+                        ms = new MemoryStream( buffer, 0, contentLength );
 
-                    if ( ms.Position != contentLength )
+                        // Stream the http response into the rented buffer
+                        await response.Content.CopyToAsync( ms, cts.Token );
+
+                        if ( ms.Position != contentLength )
+                        {
+                            throw new InvalidDataException( $"Length mismatch after downloading depot manifest! (was {ms.Position}, but should be {contentLength})" );
+                        }
+
+                        ms.Position = 0;
+                    }
+                    else
                     {
-                        throw new InvalidDataException( $"Length mismatch after downloading depot manifest! (was {ms.Position}, but should be {contentLength})" );
+                        var data = await response.Content.ReadAsByteArrayAsync();
+                        ms = new MemoryStream( data );
                     }
 
-                    ms.Position = 0;
-
                     // Decompress the zipped manifest data
                     using var zip = new ZipArchive( ms );
                     var entries = zip.Entries;
@@ -132,10 +147,15 @@ public async Task<DepotManifest> DownloadManifestAsync( uint depotId, ulong mani
 
                     using var zipEntryStream = entries[ 0 ].Open();
                     depotManifest = DepotManifest.Deserialize( zipEntryStream );
+
+                    ms.Dispose();
                 }
                 finally
                 {
-                    ArrayPool<byte>.Shared.Return( buffer );
+                    if ( buffer != null )
+                    {
+                        ArrayPool<byte>.Shared.Return( buffer );
+                    }
                 }
             }
             catch ( Exception ex )
@@ -224,17 +244,25 @@ public async Task<int> DownloadDepotChunkAsync( uint depotId, DepotManifest.Chun
                     throw new SteamKitWebRequestException( $"Response status code does not indicate success: {response.StatusCode:D} ({response.ReasonPhrase}).", response );
                 }
 
-                if ( !response.Content.Headers.ContentLength.HasValue )
-                {
-                    throw new SteamKitWebRequestException( "Response does not have Content-Length", response );
-                }
+                var contentLength = ( int )chunk.CompressedLength;
 
-                var contentLength = ( int )response.Content.Headers.ContentLength;
+                if ( response.Content.Headers.ContentLength.HasValue )
+                {
+                    contentLength = ( int )response.Content.Headers.ContentLength;
 
-                // assert that lengths match only if the chunk has a length assigned.
-                if ( chunk.CompressedLength > 0 && contentLength != chunk.CompressedLength )
+                    // assert that lengths match only if the chunk has a length assigned.
+                    if ( chunk.CompressedLength > 0 && contentLength != chunk.CompressedLength )
+                    {
+                        throw new InvalidDataException( $"Content-Length mismatch for depot chunk! (was {contentLength}, but should be {chunk.CompressedLength})" );
+                    }
+                }
+                else if ( contentLength > 0 )
+                {
+                    DebugLog.WriteLine( nameof( CDN ), $"Response does not have Content-Length, falling back to chunk.CompressedLength." );
+                }
+                else
                 {
-                    throw new InvalidDataException( $"Content-Length mismatch for depot chunk! (was {contentLength}, but should be {chunk.CompressedLength})" );
+                    throw new SteamKitWebRequestException( "Response does not have Content-Length and chunk.CompressedLength is not set.", response );
                 }
 
                 cts.CancelAfter( ResponseBodyTimeout );