public static Task <FormData> ParseMultipart(Stream stream, string boundary)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
if (boundary == null)
{
throw new ArgumentNullException("boundary");
}
if (boundary.Length == 0)
{
throw new ArgumentException("Boundary cannot be empty", "boundary");
}
var form = new FormData();
boundary = "--" + boundary;
var boundaryBytes = Encoding.UTF8.GetBytes("\r\n" + boundary);
string currentLine = stream.ReadLine(Encoding.UTF8);
if (currentLine != boundary)
{
form.IsValid = false;
return(OwinConstants.TaskHelper.Completed(form));
}
while (true)
{
currentLine = stream.ReadLine(Encoding.UTF8);
// parse ContentDisposition line
var match = ContentDispositionFormDataRegex.Match(currentLine);
if (!match.Success)
{
form.IsValid = false;
return(OwinConstants.TaskHelper.Completed(form));
}
string fieldName = match.Groups[1].Value;
string fileName = match.Groups[2].Success ? match.Groups[3].Value : null;
if (fileName != null)
{
if (!ParseMultipartFile(stream, form, fieldName, fileName, boundaryBytes))
{
form.IsValid = false;
return(OwinConstants.TaskHelper.Completed(form));
}
}
else
{
if (!ParseMultipartField(stream, form, fieldName, boundaryBytes))
{
form.IsValid = false;
return(OwinConstants.TaskHelper.Completed(form));
}
}
// check end or next
currentLine = stream.ReadLine(Encoding.UTF8);
// --boundary-- end
if (currentLine == "--")
{
break;
}
// --boundary between
if (currentLine != string.Empty)
{
form.IsValid = false;
return(OwinConstants.TaskHelper.Completed(form));
}
}
return(OwinConstants.TaskHelper.Completed(form));
}
private static bool ParseMultipartField(Stream stream, FormData form, string fieldName, byte[] boundaryBytes)
{
string contentType = null;
string headerLine;
Match match;
while ((headerLine = stream.ReadLine(Encoding.UTF8)) != string.Empty)
{
// parse 'Content-" headers
match = ContentTypeFormDataRegex.Match(headerLine);
if (match.Success)
{
// nested: Content-Type: multipart/mixed; boundary=BbC04y
contentType = match.Groups[1].Value.Trim();
if (match.Groups[2].Success)
{
string fileBoundary = match.Groups[4].Value;
byte[] fileBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + fileBoundary);
byte[] temp;
if (!stream.ReadTo(fileBoundaryBytes, out temp))
{
return(false);
}
if (stream.ReadLine(Encoding.UTF8) != string.Empty)
{
return(false);
}
bool moreFiles = true;
while (moreFiles)
{
string line = stream.ReadLine(Encoding.UTF8);
match = ContentDispositionFileRegex.Match(line);
if (!match.Success)
{
return(false);
}
string filename = match.Groups[1].Value;
if (!ParseMultipartFile(stream, form, fieldName, filename, fileBoundaryBytes))
{
return(false);
}
line = stream.ReadLine(Encoding.UTF8);
if (line == "--")
{
moreFiles = false;
}
else if (line != string.Empty)
{
return(false);
}
}
// NB: CrLf already ripped here
var boundaryNoCrLf = new byte[boundaryBytes.Length - 2];
Array.Copy(boundaryBytes, 2, boundaryNoCrLf, 0, boundaryBytes.Length - 2);
if (!stream.ReadTo(boundaryNoCrLf, out temp))
{
return(false);
}
if (temp.Length != 0)
{
return(false);
}
return(true);
}
}
}
if (contentType == null)
{
contentType = "text/plain";
}
byte[] value;
if (!stream.ReadTo(boundaryBytes, out value))
{
return(false);
}
// handle charset: content-type: text/plain;charset=windows-1250
match = CharsetRegex.Match(contentType);
Encoding encoding = match.Success ? Encoding.GetEncoding(match.Groups[2].Value) : Encoding.UTF8;
form[fieldName] = encoding.GetString(value);
return(true);
}