private static void ValidateAndCorrectHeaders(HeaderSection hs)
{
// https://tools.ietf.org/html/rfc7230#section-5.4
// Since the Host field - value is critical information for handling a
// request, a user agent SHOULD generate Host as the first header field
// following the request - line.
HeaderField hostToCorrect = null;
foreach (var f in hs.Fields)
{
// if we find host
if (f.Name == "Host")
{
// if host is not first
if (hs.Fields.First().Name != "Host")
{
// then correct host
hostToCorrect = f;
break;
}
}
}
if (hostToCorrect != null)
{
hs.Fields.Remove(hostToCorrect);
hs.Fields.Insert(0, hostToCorrect);
}
// https://tools.ietf.org/html/rfc7230#section-3.3.2
// If a message is received that has multiple Content-Length header
// fields with field-values consisting of the same decimal value, or a
// single Content-Length header field with a field value containing a
// list of identical decimal values(e.g., "Content-Length: 42, 42"),
// indicating that duplicate Content-Length header fields have been
// generated or combined by an upstream message processor, then the
// recipient MUST either reject the message as invalid or replace the
// duplicated field - values with a single valid Content - Length field
// containing that decimal value prior to determining the message body
// length or forwarding the message.
var allParts = new HashSet <string>();
foreach (var field in hs.Fields)
{
if (field.Name == "Content-Length")
{
var parts = field.Value.Trim().Split(',');
foreach (var part in parts)
{
allParts.Add(part.Trim());
}
}
}
if (allParts.Count > 0) // then has Content-Length field
{
if (allParts.Count > 1)
{
throw new InvalidDataException("Invalid Content-Length.");
}
hs.Fields.RemoveAll(x => x.Name == "Content-Length");
hs.Fields.Add(new HeaderField("Content-Length", allParts.First()));
}
}