/// <summary>
/// Private method that handles an incoming request.
/// It sets up a RequestHandlerContext instance with the data from
/// the incoming HTTP request, finds a suitable request handler to
/// produce the response, and then sends the response as an HTTP
/// response back to the client.
/// Preconditions
/// "connection is open"
/// serviceRoot != null
/// serviceRoot.Length > 8
/// "serviceRoot starts with 'http://' and ends with '/'"
/// requestRouting != null
/// </summary>
/// <param name="connection">Open TCP/IP connection</param>
/// <param name="serviceRoot">The absolute URI that is a prefix of
/// all request URIs that this web service supports. It must start
/// with "http://" and must end with "/".</param>
/// <param name="relayDomain">Host name or Internet address of the
/// relay to be used, or null if no relay is used</param>
/// <param name="requestRouting">Collection of
/// { request pattern, request handler}
/// pairs</param>
/// <param name="connectionClose">Return parameter that indicates
/// that the connection should be closed after this call. This may
/// be because the incoming request has a "Connection: close"
/// header, because the request handler has set the
/// ConnectionClose property, or because some error occurred.
/// </param>
internal static void ConsumeRequest(Stream connection,
string serviceRoot, string relayDomain,
RequestRouting requestRouting,
ref bool connectionClose)
{
Contract.Requires(connection != null);
Contract.Requires(serviceRoot != null);
Contract.Requires(serviceRoot.Length > 8);
Contract.Requires(serviceRoot.Substring(0, 7) == "http://");
Contract.Requires(serviceRoot[serviceRoot.Length - 1] != '/');
Contract.Requires(requestRouting != null);
// initialization --------------------------------------------
HttpReader reader = new HttpReader();
HttpWriter writer = new HttpWriter();
var context = new RequestHandlerContext(serviceRoot,
relayDomain);
// Both client and server may request closing the connection.
// Initially, we assume that neither one wants to close the
// connection.
context.ConnectionClose = false;
// receive request -------------------------------------------
reader.Attach(connection);
// request line
string httpMethod;
string requestUri;
string httpVersion;
reader.ReadStringToBlank(out httpMethod);
reader.ReadStringToBlank(out requestUri);
reader.ReadFieldValue(out httpVersion);
if (reader.Status != HttpStatus.BeforeContent) // error
{
reader.Detach();
connectionClose = true;
return;
}
context.RequestMethod = httpMethod;
context.RequestUri = requestUri;
// ignore version
// headers
string fieldName;
string fieldValue;
int requestContentLength = -1;
reader.ReadFieldName(out fieldName);
while (reader.Status == HttpStatus.BeforeContent)
{
reader.ReadFieldValue(out fieldValue);
if (fieldValue != null)
{
Contract.Assert(reader.Status ==
HttpStatus.BeforeContent);
if (fieldName == "Connection")
{
context.ConnectionClose =
((fieldValue == "close") ||
(fieldValue == "Close"));
}
else if (fieldName == "Content-Type")
{
context.RequestContentType = fieldValue;
}
else if (fieldName == "Content-Length")
{
if (Utilities.TryParseUInt32(fieldValue,
out requestContentLength))
{
// content length is now known
}
else
{
reader.Status = HttpStatus.SyntaxError;
reader.Detach();
connectionClose = true;
return;
}
}
}
else
{
// it's ok to skip header whose value is too long
}
Contract.Assert(reader.Status == HttpStatus.BeforeContent);
reader.ReadFieldName(out fieldName);
}
if (reader.Status != HttpStatus.InContent)
{
reader.Detach();
connectionClose = true;
return;
}
// content
if (requestContentLength > 0)
{
// receive content
var requestContent = new byte[requestContentLength];
int toRead = requestContentLength;
var read = 0;
while ((toRead > 0) && (read >= 0))
{
// already read: requestContentLength - toRead
read = reader.ReadContent(requestContent,
requestContentLength - toRead, toRead);
if (read < 0)
{
break;
} // timeout or shutdown
toRead = toRead - read;
}
try
{
char[] chars = Encoding.UTF8.GetChars(requestContent);
context.RequestContent = new string(chars);
}
catch (Exception)
{
context.RequestContentType = "text/plain";
context.RequestContent = "request content is not in UTF8 format";
Debug.Print(context.RequestContent);
// TODO signal wrong content format through HTTP status code 400 (Bad Request)?
}
}
reader.Detach();
if (reader.Status != HttpStatus.InContent)
{
connectionClose = true;
return;
}
// delegate request processing to a request handler ----------
var match = false;
foreach (Element e in requestRouting)
{
if (context.RequestMatch(e))
{
bool connClose = context.ConnectionClose;
context.ResponseStatusCode = -1; // undefined
Contract.Requires(context.ResponseContentType != null);
Contract.Requires(context.ResponseContentType == "text/plain"); // default
try
{
e.Handler(context);
}
catch (Exception h)
{
Debug.Print("exception in request handler: " + h); // TODO how to better handle handler exceptions?
throw; // rethrow, to avoid masking of errors
}
Contract.Ensures(context.ResponseStatusCode >= 100);
Contract.Ensures(context.ResponseStatusCode < 600);
Contract.Ensures(context.ResponseContentType != null);
Contract.Ensures(context.ResponseContentType.Length > 0);
// make sure that handler has not reset connectionClose flag:
Contract.Ensures((!connClose) || (context.ConnectionClose));
match = true;
break;
}
}
if (!match)
{
context.ResponseStatusCode = 404; // Not Found
context.ResponseContentType = "text/plain";
context.ResponseContent = null;
}
uint availableMemory = Debug.GC(true);
Debug.Print(context.RequestMethod + " " +
context.RequestUri + " -> " +
context.ResponseStatusCode + " [" + availableMemory + "]");
// send response ---------------------------------------------
writer.Attach(connection);
// status line
writer.WriteString("HTTP/1.1 ");
writer.WriteString(context.ResponseStatusCode.ToString());
writer.WriteLine(" "); // omit optional reason phrase
// headers
if (connectionClose) // TODO (context.ConnectionClose)
{
writer.WriteLine("Connection: close");
}
byte[] responseBuffer = null;
var responseLength = 0;
if (context.ResponseContent != null)
{
responseBuffer =
Encoding.UTF8.GetBytes(context.ResponseContent);
responseLength = responseBuffer.Length;
writer.WriteString("Content-Type: ");
writer.WriteLine(context.ResponseContentType);
}
else
{
responseLength = 0;
}
writer.WriteString("Content-Length: ");
writer.WriteLine(responseLength.ToString());
if (context.ResponseMaxAge > 0)
{
writer.WriteLine("Cache-Control: max-age=" + context.ResponseMaxAge);
}
else if (context.ResponseMaxAge == 0)
{
writer.WriteLine("Cache-Control: no-cache");
}
// content
writer.WriteBeginOfContent();
if (context.ResponseContent != null) // send content
{
writer.WriteContent(responseBuffer, 0, responseLength);
}
writer.Detach();
connectionClose = context.ConnectionClose;
}
/// <summary>
/// Private method that handles an incoming request.
/// It sets up a RequestHandlerContext instance with the data from
/// the incoming HTTP request, finds a suitable request handler to
/// produce the response, and then sends the response as an HTTP
/// response back to the client.
/// Preconditions
/// "connection is open"
/// serviceRoot != null
/// serviceRoot.Length > 8
/// "serviceRoot starts with 'http://' and ends with '/'"
/// requestRouting != null
/// </summary>
/// <param name="connection">Open TCP/IP connection</param>
/// <param name="serviceRoot">The absolute URI that is a prefix of
/// all request URIs that this web service supports. It must start
/// with "http://" and must end with "/".</param>
/// <param name="relayDomain">Host name or Internet address of the
/// relay to be used, or null if no relay is used</param>
/// <param name="requestRouting">Collection of
/// { request pattern, request handler}
/// pairs</param>
/// <param name="connectionClose">Return parameter that indicates
/// that the connection should be closed after this call. This may
/// be because the incoming request has a "Connection: close"
/// header, because the request handler has set the
/// ConnectionClose property, or because some error occurred.
/// </param>
internal static void ConsumeRequest(Stream connection,
string serviceRoot, string relayDomain,
RequestRouting requestRouting,
bool catchRequestFailures,
ref bool connectionClose)
{
Contract.Requires(connection != null);
Contract.Requires(serviceRoot != null);
Contract.Requires(serviceRoot.Length > 8);
Contract.Requires(serviceRoot.Substring(0, 7) == "http://");
Contract.Requires(serviceRoot[serviceRoot.Length - 1] != '/');
Contract.Requires(requestRouting != null);
// initialization --------------------------------------------
DebugPrint("HttpServer: ConsumeRequest - initialize");
HttpReader reader = new HttpReader();
HttpWriter writer = new HttpWriter();
var context = new RequestHandlerContext(serviceRoot,
relayDomain);
// receive request -------------------------------------------
reader.Attach(connection);
// read request line
DebugPrint("HttpServer: ConsumeRequest - read request line");
string httpMethod;
string requestUri;
string httpVersion;
reader.ReadStringToBlank(out httpMethod);
reader.ReadStringToBlank(out requestUri);
if (reader.Status == HttpStatus.RequestUriTooLong)
{
context.ResponseStatusCode = 414; // Request-URI Too Long
context.ResponseContentType = "text/plain";
context.ResponseContent = "request URI too long";
reader.Detach();
connectionClose = true;
DebugPrint("HttpServer: ConsumeRequest - request URI too long!");
return;
}
reader.ReadFieldValue(out httpVersion);
if (reader.Status != HttpStatus.BeforeContent) // error
{
reader.Detach();
connectionClose = true;
DebugPrint("HttpServer: ConsumeRequest - could not read HTTP version!");
return;
}
context.RequestMethod = httpMethod;
context.RequestUri = requestUri;
// ignore version
// headers
DebugPrint("HttpServer: ConsumeRequest - read headers");
string fieldName;
string fieldValue;
int requestContentLength = -1;
reader.ReadFieldName(out fieldName);
while (reader.Status == HttpStatus.BeforeContent)
{
reader.ReadFieldValue(out fieldValue);
if (fieldValue != null)
{
Contract.Assert(reader.Status ==
HttpStatus.BeforeContent);
if (fieldName == "Connection")
{
connectionClose =
(connectionClose ||
(fieldValue == "close") ||
(fieldValue == "Close"));
}
else if (fieldName == "Content-Type")
{
context.RequestContentType = fieldValue;
DebugPrint("HttpServer: ConsumeRequest - request Content-Type: " + fieldValue);
}
else if (fieldName == "Content-Length")
{
if (Utilities.TryParseUInt32(fieldValue,
out requestContentLength))
{
// content length is now known
DebugPrint("HttpServer: ConsumeRequest - request Content-Length: " + requestContentLength);
}
else
{
DebugPrint("HttpServer: ConsumeRequest - request syntax error");
//reader.Status = HttpStatus.SyntaxError;
reader.Detach();
connectionClose = true;
return;
}
}
}
else
{
// it's ok to skip header whose value is too long
}
Contract.Assert(reader.Status == HttpStatus.BeforeContent);
reader.ReadFieldName(out fieldName);
}
if (reader.Status != HttpStatus.InContent)
{
reader.Detach();
connectionClose = true;
return;
}
// content
DebugPrint("HttpServer: ConsumeRequest - read content");
context.RequestContentBytes = null;
if (requestContentLength > 0)
{
// receive content
context.RequestContentBytes = new byte[requestContentLength];
int toRead = requestContentLength;
var read = 0;
while ((toRead > 0) && (read >= 0))
{
// already read: requestContentLength - toRead
read = reader.ReadContent(context.RequestContentBytes,
requestContentLength - toRead, toRead);
if (read < 0) { break; } // timeout or shutdown
toRead = toRead - read;
}
}
reader.Detach();
if (reader.Status != HttpStatus.InContent)
{
connectionClose = true;
return;
}
// delegate request processing to a request handler ----------
DebugPrint("HttpServer: ConsumeRequest - call request handler");
var match = false;
foreach (RoutingElement e in requestRouting)
{
if (context.RequestMatch(e))
{
context.ConnectionClose = false;
context.ResponseStatusCode = -1; // undefined
Contract.Requires(context.ResponseContentType != null);
Contract.Requires(context.ResponseContentType == "text/plain"); // default
e.Handler(context);
if (catchRequestFailures)
{
try
{
e.Handler(context);
}
catch (Exception h)
{
DebugPrint("HttpServer: exception in request handler: " + h);
}
}
else
{
e.Handler(context);
}
Contract.Ensures(context.ResponseStatusCode >= 100);
Contract.Ensures(context.ResponseStatusCode < 600);
Contract.Ensures(context.ResponseContentType != null);
Contract.Ensures(context.ResponseContentType.Length > 0);
connectionClose = connectionClose || context.ConnectionClose;
match = true;
break;
}
}
if (!match)
{
context.ResponseStatusCode = 404; // Not Found
context.ResponseContentType = "text/plain";
context.ResponseContent = "404 error - resource not found";
DebugPrint("HttpServer: no matching request handler found");
}
Contract.Assert(context.ResponseContentType != null);
// send response ---------------------------------------------
DebugPrint("HttpServer: ConsumeRequest - send response");
writer.Attach(connection);
// status line
DebugPrint("HttpServer: ConsumeRequest - send status line");
writer.WriteString("HTTP/1.1 ");
writer.WriteString(context.ResponseStatusCode.ToString());
writer.WriteLine(" "); // omit optional reason phrase
// headers
DebugPrint("HttpServer: ConsumeRequest - send headers");
if (connectionClose)
{
writer.WriteLine("Connection: close");
}
if (context.ResponseMaxAge > 0)
{
writer.WriteLine("Cache-Control: max-age=" + context.ResponseMaxAge);
}
else if (context.ResponseMaxAge == 0)
{
writer.WriteLine("Cache-Control: no-cache");
}
writer.WriteString("Content-Type: ");
writer.WriteLine(context.ResponseContentType);
DebugPrint("HttpServer: ConsumeRequest - response Content-Type: " + context.ResponseContentType);
if (context.ResponseContent != null)
{
DebugPrint("HttpServer: ConsumeRequest - response content is text");
context.ResponseContentBytes =
Encoding.UTF8.GetBytes(context.ResponseContent);
Contract.Assert(context.ResponseContentBytes != null);
}
if (context.ResponseContentBytes != null)
{
DebugPrint("HttpServer: ConsumeRequest - content available as binary");
if (context.ResponseContentLength == -1)
{
context.ResponseContentLength = context.ResponseContentBytes.Length; // default is to take the entire buffer
}
writer.WriteString("Content-Length: ");
writer.WriteLine(context.ResponseContentLength.ToString());
DebugPrint("HttpServer: ConsumeRequest - response Content-Length: " + context.ResponseContentLength);
}
else
{
writer.WriteString("Content-Length: 0");
DebugPrint("HttpServer: ConsumeRequest - response Content-Length: 0");
}
// content
DebugPrint("HttpServer: ConsumeRequest - send content");
writer.WriteBeginOfContent();
if (context.ResponseContentBytes != null) // send content
{
writer.WriteContent(context.ResponseContentBytes, 0, context.ResponseContentLength);
}
DebugPrint("HttpServer: response sent");
writer.Detach();
uint availableMemory = Microsoft.SPOT.Debug.GC(true); // TODO define portable abstraction for free memory
Trace.TraceInformation(context.RequestMethod + " " +
context.RequestUri + " -> " +
context.ResponseStatusCode + " [" + availableMemory + "]");
}