update

Author: BrennanConroy

src/Http/WebUtilities/src/MultipartBoundary.cs

@@ -10,11 +10,11 @@ internal sealed class MultipartBoundary
     private readonly byte[] _boundaryBytes;
     private bool _expectLeadingCrlf;
 
-    public MultipartBoundary(string boundary, bool expectLeadingCrlf = true)
+    public MultipartBoundary(string boundary)
     {
         ArgumentNullException.ThrowIfNull(boundary);
 
-        _expectLeadingCrlf = expectLeadingCrlf;
+        _expectLeadingCrlf = false;
         _boundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary);
 
         FinalBoundaryLength = BoundaryBytes.Length + 2; // Include the final '--' terminator.

src/Http/WebUtilities/src/MultipartReader.cs

@@ -56,7 +56,7 @@ public MultipartReader(string boundary, Stream stream, int bufferSize)
         }
         _stream = new BufferedReadStream(stream, bufferSize);
         boundary = HeaderUtilities.RemoveQuotes(new StringSegment(boundary)).ToString();
-        _boundary = new MultipartBoundary(boundary, false);
+        _boundary = new MultipartBoundary(boundary);
     }
 
     /// <summary>
@@ -83,12 +83,9 @@ public MultipartReader(string boundary, Stream stream, int bufferSize)
     /// <returns></returns>
     public async Task<MultipartSection?> ReadNextSectionAsync(CancellationToken cancellationToken = new CancellationToken())
     {
-        if (_currentStream == null)
-        {
-            // Only occurs on first call
-            // This stream will drain any preamble data and remove the first boundary marker.
-            _currentStream = new MultipartReaderStream(_stream, _boundary) { LengthLimit = HeadersLengthLimit };
-        }
+        // Only occurs on first call
+        // This stream will drain any preamble data and remove the first boundary marker.
+        _currentStream ??= new MultipartReaderStream(_stream, _boundary) { LengthLimit = HeadersLengthLimit };
 
         // Drain the prior section.
         await _currentStream.DrainAsync(cancellationToken);

src/Http/WebUtilities/src/MultipartReaderStream.cs

@@ -145,16 +145,18 @@ private int UpdatePosition(int read)
         if (_observedLength < _position)
         {
             _observedLength = _position;
-            if (LengthLimit.HasValue && _observedLength > LengthLimit.GetValueOrDefault())
+            if (LengthLimit.HasValue &&
+                LengthLimit.GetValueOrDefault() is var lengthLimit &&
+                _observedLength > lengthLimit)
             {
                 // If we hit the limit before the first boundary then we're using the header length limit, not the body length limit.
                 if (_boundary.BeforeFirstBoundary())
                 {
-                    throw new InvalidDataException($"Multipart header length limit {LengthLimit.GetValueOrDefault()} exceeded. Too much data before the first boundary.");
+                    throw new InvalidDataException($"Multipart header length limit {lengthLimit} exceeded. Too much data before the first boundary.");
                 }
                 else
                 {
-                    throw new InvalidDataException($"Multipart body length limit {LengthLimit.GetValueOrDefault()} exceeded.");
+                    throw new InvalidDataException($"Multipart body length limit {lengthLimit} exceeded.");
                 }
             }
         }