Applicazione di esempio del server HTTP
L'applicazione di esempio seguente illustra come usare l'API server HTTP per eseguire attività sul lato server. Il file "precomp.h" incluso nel primo esempio include tutte le intestazioni necessarie per eseguire gli esempi, ad esempio:
#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")
Principali e Preliminari
#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;
}
Inizializzare il servizio HTTP
//
// 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;
}
Registrare gli URL in ascolto
//
// 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 ++;
}
}
Chiamare la routine per ricevere una richiesta
DoReceiveRequests(hReqQueue);
Pulire l'API server HTTP
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;
Ricevere una richiesta
/*******************************************************************++
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
);
Gestire la richiesta HTTP
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;
}
Inviare una risposta HTTP
/*******************************************************************++
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;
}
Inviare una risposta HTTP POST
#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;
}
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