Fix GZippedString decompress

Scraper/Extensions.cs

@@ -6,4 +6,16 @@ public static class Extensions
     {
         Console.Out.WriteLine(str);
     }
+    
+    public static byte[] ReadAllToByteArray(this Stream stream)
+    {
+        var bytes = new List<byte>();
+
+        int b;
+
+        // -1 is a special value that mark the end of the stream
+        while ((b = stream.ReadByte()) != -1) bytes.Add((byte)b);
+
+        return bytes.ToArray();
+    }
 }

Scraper/GZippedString.cs

@@ -24,31 +24,43 @@ public class GZippedString : IXmlSerializable
     private string CompressString(string text)
     {
         byte[] buffer = Encoding.UTF8.GetBytes(text);
+        
         var memoryStream = new MemoryStream();
         using (var gZipStream = new GZipStream(memoryStream, CompressionMode.Compress, true))
             gZipStream.Write(buffer, 0, buffer.Length);
+        
         memoryStream.Position = 0;
         var compressedData = new byte[memoryStream.Length];
         memoryStream.Read(compressedData, 0, compressedData.Length);
+        
         var gZipBuffer = new byte[compressedData.Length + 4];
-        Buffer.BlockCopy(compressedData, 0, gZipBuffer, 4, compressedData.Length);
+        Buffer.BlockCopy(compressedData, 0, gZipBuffer, 4, compressedData.Length);  // bytes 4.. are the gzip content
-        Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gZipBuffer, 0, 4);
+        
+        Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gZipBuffer, 0, 4); // bytes 0..3 are the length of the uncompressed string
+        
         return Convert.ToBase64String(gZipBuffer);
     }
 		
     private string DecompressString(string compressedText)
     {
         byte[] gZipBuffer = Convert.FromBase64String(compressedText);
-        using (var memoryStream = new MemoryStream())
+        
+        using var memoryStream = new MemoryStream();
+        
+        int dataLength = BitConverter.ToInt32(gZipBuffer[..4], 0);
+            
+        memoryStream.Write(gZipBuffer, 4, gZipBuffer.Length - 4);
+        memoryStream.Position = 0;
+            
+        byte[] buffer = null;
+
+        using (var gZipStream = new GZipStream(memoryStream, CompressionMode.Decompress))
         {
-            int dataLength = BitConverter.ToInt32(gZipBuffer, 0);
+            buffer = gZipStream.ReadAllToByteArray();
-            memoryStream.Write(gZipBuffer, 4, gZipBuffer.Length - 4);
+            if (dataLength != buffer.Length) throw new Exception("not enough data in gzip");
-            var buffer = new byte[dataLength];
-            memoryStream.Position = 0;
-            using (var gZipStream = new GZipStream(memoryStream, CompressionMode.Decompress))
-                gZipStream.Read(buffer, 0, buffer.Length);
-            return Encoding.UTF8.GetString(buffer);
         }
+            
+        return Encoding.UTF8.GetString(buffer);
     }
 
     public static implicit operator GZippedString(string v) => new GZippedString{Value = v};