HTTP Server Sample Application
The following sample application shows how to use the HTTP Server API to perform server-side tasks. The "precomp.h" file included in the first example includes all the headers necessary to run the samples, for example:
#ifndef UNICODE
#define UNICODE
#endif
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0600
#endif
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#include <http.h>
#include <stdio.h>
#pragma comment(lib, "httpapi.lib")
Main and Preliminaries
#include "precomp.h"
//
// Macros.
//
#define INITIALIZE_HTTP_RESPONSE( resp, status, reason ) \
do \
{ \
RtlZeroMemory( (resp), sizeof(*(resp)) ); \
(resp)->StatusCode = (status); \
(resp)->pReason = (reason); \
(resp)->ReasonLength = (USHORT) strlen(reason); \
} while (FALSE)
#define ADD_KNOWN_HEADER(Response, HeaderId, RawValue) \
do \
{ \
(Response).Headers.KnownHeaders[(HeaderId)].pRawValue = \
(RawValue);\
(Response).Headers.KnownHeaders[(HeaderId)].RawValueLength = \
(USHORT) strlen(RawValue); \
} while(FALSE)
#define ALLOC_MEM(cb) HeapAlloc(GetProcessHeap(), 0, (cb))
#define FREE_MEM(ptr) HeapFree(GetProcessHeap(), 0, (ptr))
//
// Prototypes.
//
DWORD DoReceiveRequests(HANDLE hReqQueue);
DWORD
SendHttpResponse(
IN HANDLE hReqQueue,
IN PHTTP_REQUEST pRequest,
IN USHORT StatusCode,
IN PSTR pReason,
IN PSTR pEntity
);
DWORD
SendHttpPostResponse(
IN HANDLE hReqQueue,
IN PHTTP_REQUEST pRequest
);
/*******************************************************************++
Routine Description:
main routine
Arguments:
argc - # of command line arguments.
argv - Arguments.
Return Value:
Success/Failure
--*******************************************************************/
int __cdecl wmain(
int argc,
wchar_t * argv[]
)
{
ULONG retCode;
HANDLE hReqQueue = NULL;
int UrlAdded = 0;
HTTPAPI_VERSION HttpApiVersion = HTTPAPI_VERSION_1;
if (argc < 2)
{
wprintf(L"%ws: <Url1> [Url2] ... \n", argv[0]);
return -1;
}
Initialize the HTTP Service
//
// Initialize HTTP Server APIs
//
retCode = HttpInitialize(
HttpApiVersion,
HTTP_INITIALIZE_SERVER, // Flags
NULL // Reserved
);
if (retCode != NO_ERROR)
{
wprintf(L"HttpInitialize failed with %lu \n", retCode);
return retCode;
}
//
// Create a Request Queue Handle
//
retCode = HttpCreateHttpHandle(
&hReqQueue, // Req Queue
0 // Reserved
);
if (retCode != NO_ERROR)
{
wprintf(L"HttpCreateHttpHandle failed with %lu \n", retCode);
goto CleanUp;
}
Register the URLs to Listen On
//
// The command line arguments represent URIs that to
// listen on. Call HttpAddUrl for each URI.
//
// The URI is a fully qualified URI and must include the
// terminating (/) character.
//
for (int i = 1; i < argc; i++)
{
wprintf(L"listening for requests on the following url: %s\n", argv[i]);
retCode = HttpAddUrl(
hReqQueue, // Req Queue
argv[i], // Fully qualified URL
NULL // Reserved
);
if (retCode != NO_ERROR)
{
wprintf(L"HttpAddUrl failed with %lu \n", retCode);
goto CleanUp;
}
else
{
//
// Track the currently added URLs.
//
UrlAdded ++;
}
}
Call the Routine to Receive a Request
DoReceiveRequests(hReqQueue);
Cleanup the HTTP Server API
CleanUp:
//
// Call HttpRemoveUrl for all added URLs.
//
for(int i=1; i<=UrlAdded; i++)
{
HttpRemoveUrl(
hReqQueue, // Req Queue
argv[i] // Fully qualified URL
);
}
//
// Close the Request Queue handle.
//
if(hReqQueue)
{
CloseHandle(hReqQueue);
}
//
// Call HttpTerminate.
//
HttpTerminate(HTTP_INITIALIZE_SERVER, NULL);
return retCode;
Receive a Request
/*******************************************************************++
Routine Description:
The function to receive a request. This function calls the
corresponding function to handle the response.
Arguments:
hReqQueue - Handle to the request queue
Return Value:
Success/Failure.
--*******************************************************************/
DWORD DoReceiveRequests(
IN HANDLE hReqQueue
)
{
ULONG result;
HTTP_REQUEST_ID requestId;
DWORD bytesRead;
PHTTP_REQUEST pRequest;
PCHAR pRequestBuffer;
ULONG RequestBufferLength;
//
// Allocate a 2 KB buffer. This size should work for most
// requests. The buffer size can be increased if required. Space
// is also required for an HTTP_REQUEST structure.
//
RequestBufferLength = sizeof(HTTP_REQUEST) + 2048;
pRequestBuffer = (PCHAR) ALLOC_MEM( RequestBufferLength );
if (pRequestBuffer == NULL)
{
return ERROR_NOT_ENOUGH_MEMORY;
}
pRequest = (PHTTP_REQUEST)pRequestBuffer;
//
// Wait for a new request. This is indicated by a NULL
// request ID.
//
HTTP_SET_NULL_ID( &requestId );
for(;;)
{
RtlZeroMemory(pRequest, RequestBufferLength);
result = HttpReceiveHttpRequest(
hReqQueue, // Req Queue
requestId, // Req ID
0, // Flags
pRequest, // HTTP request buffer
RequestBufferLength,// req buffer length
&bytesRead, // bytes received
NULL // LPOVERLAPPED
);
Handle the HTTP Request
if(NO_ERROR == result)
{
//
// Worked!
//
switch(pRequest->Verb)
{
case HttpVerbGET:
wprintf(L"Got a GET request for %ws \n",
pRequest->CookedUrl.pFullUrl);
result = SendHttpResponse(
hReqQueue,
pRequest,
200,
PSTR("OK"),
PSTR("Hey! You hit the server \r\n")
);
break;
case HttpVerbPOST:
wprintf(L"Got a POST request for %ws \n",
pRequest->CookedUrl.pFullUrl);
result= SendHttpPostResponse(hReqQueue, pRequest);
break;
default:
wprintf(L"Got a unknown request for %ws \n",
pRequest->CookedUrl.pFullUrl);
result = SendHttpResponse(
hReqQueue,
pRequest,
503,
PSTR("Not Implemented"),
NULL
);
break;
}
if(result != NO_ERROR)
{
break;
}
//
// Reset the Request ID to handle the next request.
//
HTTP_SET_NULL_ID( &requestId );
}
else if(result == ERROR_MORE_DATA)
{
//
// The input buffer was too small to hold the request
// headers. Increase the buffer size and call the
// API again.
//
// When calling the API again, handle the request
// that failed by passing a RequestID.
//
// This RequestID is read from the old buffer.
//
requestId = pRequest->RequestId;
//
// Free the old buffer and allocate a new buffer.
//
RequestBufferLength = bytesRead;
FREE_MEM( pRequestBuffer );
pRequestBuffer = (PCHAR) ALLOC_MEM( RequestBufferLength );
if (pRequestBuffer == NULL)
{
result = ERROR_NOT_ENOUGH_MEMORY;
break;
}
pRequest = (PHTTP_REQUEST)pRequestBuffer;
}
else if(ERROR_CONNECTION_INVALID == result &&
!HTTP_IS_NULL_ID(&requestId))
{
// The TCP connection was corrupted by the peer when
// attempting to handle a request with more buffer.
// Continue to the next request.
HTTP_SET_NULL_ID( &requestId );
}
else
{
break;
}
}
if(pRequestBuffer)
{
FREE_MEM( pRequestBuffer );
}
return result;
}
Send an HTTP Response
/*******************************************************************++
Routine Description:
The routine sends a HTTP response
Arguments:
hReqQueue - Handle to the request queue
pRequest - The parsed HTTP request
StatusCode - Response Status Code
pReason - Response reason phrase
pEntityString - Response entity body
Return Value:
Success/Failure.
--*******************************************************************/
DWORD SendHttpResponse(
IN HANDLE hReqQueue,
IN PHTTP_REQUEST pRequest,
IN USHORT StatusCode,
IN PSTR pReason,
IN PSTR pEntityString
)
{
HTTP_RESPONSE response;
HTTP_DATA_CHUNK dataChunk;
DWORD result;
DWORD bytesSent;
//
// Initialize the HTTP response structure.
//
INITIALIZE_HTTP_RESPONSE(&response, StatusCode, pReason);
//
// Add a known header.
//
ADD_KNOWN_HEADER(response, HttpHeaderContentType, "text/html");
if(pEntityString)
{
//
// Add an entity chunk.
//
dataChunk.DataChunkType = HttpDataChunkFromMemory;
dataChunk.FromMemory.pBuffer = pEntityString;
dataChunk.FromMemory.BufferLength =
(ULONG) strlen(pEntityString);
response.EntityChunkCount = 1;
response.pEntityChunks = &dataChunk;
}
//
// Because the entity body is sent in one call, it is not
// required to specify the Content-Length.
//
result = HttpSendHttpResponse(
hReqQueue, // ReqQueueHandle
pRequest->RequestId, // Request ID
0, // Flags
&response, // HTTP response
NULL, // pReserved1
&bytesSent, // bytes sent (OPTIONAL)
NULL, // pReserved2 (must be NULL)
0, // Reserved3 (must be 0)
NULL, // LPOVERLAPPED(OPTIONAL)
NULL // pReserved4 (must be NULL)
);
if(result != NO_ERROR)
{
wprintf(L"HttpSendHttpResponse failed with %lu \n", result);
}
return result;
}
Send an HTTP POST Response
#define MAX_ULONG_STR ((ULONG) sizeof("4294967295"))
/*******************************************************************++
Routine Description:
The routine sends a HTTP response after reading the entity body.
Arguments:
hReqQueue - Handle to the request queue.
pRequest - The parsed HTTP request.
Return Value:
Success/Failure.
--*******************************************************************/
DWORD SendHttpPostResponse(
IN HANDLE hReqQueue,
IN PHTTP_REQUEST pRequest
)
{
HTTP_RESPONSE response;
DWORD result;
DWORD bytesSent;
PUCHAR pEntityBuffer;
ULONG EntityBufferLength;
ULONG BytesRead;
ULONG TempFileBytesWritten;
HANDLE hTempFile;
TCHAR szTempName[MAX_PATH + 1];
CHAR szContentLength[MAX_ULONG_STR];
HTTP_DATA_CHUNK dataChunk;
ULONG TotalBytesRead = 0;
BytesRead = 0;
hTempFile = INVALID_HANDLE_VALUE;
//
// Allocate space for an entity buffer. Buffer can be increased
// on demand.
//
EntityBufferLength = 2048;
pEntityBuffer = (PUCHAR) ALLOC_MEM( EntityBufferLength );
if (pEntityBuffer == NULL)
{
result = ERROR_NOT_ENOUGH_MEMORY;
wprintf(L"Insufficient resources \n");
goto Done;
}
//
// Initialize the HTTP response structure.
//
INITIALIZE_HTTP_RESPONSE(&response, 200, "OK");
//
// For POST, echo back the entity from the
// client
//
// NOTE: If the HTTP_RECEIVE_REQUEST_FLAG_COPY_BODY flag had been
// passed with HttpReceiveHttpRequest(), the entity would
// have been a part of HTTP_REQUEST (using the pEntityChunks
// field). Because that flag was not passed, there are no
// o entity bodies in HTTP_REQUEST.
//
if(pRequest->Flags & HTTP_REQUEST_FLAG_MORE_ENTITY_BODY_EXISTS)
{
// The entity body is sent over multiple calls. Collect
// these in a file and send back. Create a temporary
// file.
//
if(GetTempFileName(
L".",
L"New",
0,
szTempName
) == 0)
{
result = GetLastError();
wprintf(L"GetTempFileName failed with %lu \n", result);
goto Done;
}
hTempFile = CreateFile(
szTempName,
GENERIC_READ | GENERIC_WRITE,
0, // Do not share.
NULL, // No security descriptor.
CREATE_ALWAYS, // Overrwrite existing.
FILE_ATTRIBUTE_NORMAL, // Normal file.
NULL
);
if(hTempFile == INVALID_HANDLE_VALUE)
{
result = GetLastError();
wprintf(L"Cannot create temporary file. Error %lu \n",
result);
goto Done;
}
do
{
//
// Read the entity chunk from the request.
//
BytesRead = 0;
result = HttpReceiveRequestEntityBody(
hReqQueue,
pRequest->RequestId,
0,
pEntityBuffer,
EntityBufferLength,
&BytesRead,
NULL
);
switch(result)
{
case NO_ERROR:
if(BytesRead != 0)
{
TotalBytesRead += BytesRead;
WriteFile(
hTempFile,
pEntityBuffer,
BytesRead,
&TempFileBytesWritten,
NULL
);
}
break;
case ERROR_HANDLE_EOF:
//
// The last request entity body has been read.
// Send back a response.
//
// To illustrate entity sends via
// HttpSendResponseEntityBody, the response will
// be sent over multiple calls. To do this,
// pass the HTTP_SEND_RESPONSE_FLAG_MORE_DATA
// flag.
if(BytesRead != 0)
{
TotalBytesRead += BytesRead;
WriteFile(
hTempFile,
pEntityBuffer,
BytesRead,
&TempFileBytesWritten,
NULL
);
}
//
// Because the response is sent over multiple
// API calls, add a content-length.
//
// Alternatively, the response could have been
// sent using chunked transfer encoding, by
// passimg "Transfer-Encoding: Chunked".
//
// NOTE: Because the TotalBytesread in a ULONG
// are accumulated, this will not work
// for entity bodies larger than 4 GB.
// For support of large entity bodies,
// use a ULONGLONG.
//
sprintf_s(szContentLength, MAX_ULONG_STR, "%lu", TotalBytesRead);
ADD_KNOWN_HEADER(
response,
HttpHeaderContentLength,
szContentLength
);
result =
HttpSendHttpResponse(
hReqQueue, // ReqQueueHandle
pRequest->RequestId, // Request ID
HTTP_SEND_RESPONSE_FLAG_MORE_DATA,
&response, // HTTP response
NULL, // pReserved1
&bytesSent, // bytes sent-optional
NULL, // pReserved2
0, // Reserved3
NULL, // LPOVERLAPPED
NULL // pReserved4
);
if(result != NO_ERROR)
{
wprintf(
L"HttpSendHttpResponse failed with %lu \n",
result
);
goto Done;
}
//
// Send entity body from a file handle.
//
dataChunk.DataChunkType =
HttpDataChunkFromFileHandle;
dataChunk.FromFileHandle.
ByteRange.StartingOffset.QuadPart = 0;
dataChunk.FromFileHandle.
ByteRange.Length.QuadPart =
HTTP_BYTE_RANGE_TO_EOF;
dataChunk.FromFileHandle.FileHandle = hTempFile;
result = HttpSendResponseEntityBody(
hReqQueue,
pRequest->RequestId,
0, // This is the last send.
1, // Entity Chunk Count.
&dataChunk,
NULL,
NULL,
0,
NULL,
NULL
);
if(result != NO_ERROR)
{
wprintf(
L"HttpSendResponseEntityBody failed %lu\n",
result
);
}
goto Done;
break;
default:
wprintf(
L"HttpReceiveRequestEntityBody failed with %lu \n",
result);
goto Done;
}
} while(TRUE);
}
else
{
// This request does not have an entity body.
//
result = HttpSendHttpResponse(
hReqQueue, // ReqQueueHandle
pRequest->RequestId, // Request ID
0,
&response, // HTTP response
NULL, // pReserved1
&bytesSent, // bytes sent (optional)
NULL, // pReserved2
0, // Reserved3
NULL, // LPOVERLAPPED
NULL // pReserved4
);
if(result != NO_ERROR)
{
wprintf(L"HttpSendHttpResponse failed with %lu \n",
result);
}
}
Done:
if(pEntityBuffer)
{
FREE_MEM(pEntityBuffer);
}
if(INVALID_HANDLE_VALUE != hTempFile)
{
CloseHandle(hTempFile);
DeleteFile(szTempName);
}
return result;
}