UPCASE.C

/*++                                                                                                                              
 
Copyright (c) 1995-1996  Microsoft Corporation 
 
Module Name: 
 
    upcase.c 
 
Abstract: 
 
    This filter converts HTML response data to upper case if requested 
    by the client. The request is made by specifying an extra  
    subdirectory in the URL, which doesnt actually exist on the server, 
    but is used by the filter to indicate that upper case is desired. 
    The extra subdirectory is removed from the request before the HTTP 
    server sees the request. 
 
    When a request is received, the filter inspects the  
    subdirectories specified in the URL. If a subdirectory is 'UC' 
    or 'uc', the subdirectory is removed from the request, and the 
    filter saves in its pFilterContext field, a value indicating that 
    the response data should be converted to upper case. 
 
    When the filter entrypoint is later called for the response, it  
    checks the pFilterContext field and converts the data if  
    the mime-type of the response indicates that its an html file. 
    This avoids conversions on binary data. 
 
    An example URL entered by a user might be: 
 
        http://www.myweb.com/sales/uc/projections.htm 
 
    While the functionality of this filter is somewhat contrived, this 
    filter does a good job of demonstrating the following features of 
    filters: 
        - parsing/modifying HTTP headers (in the request) 
        - modifying data following HTTP headers (in the response) 
        - saving state to be used by the filter later 
        - adding request/response level functionality to the server 
            (instead of using a mechanism like this to convert to  
             uppercase, you may use it to do on-the-fly customized 
             translations of HTML pages (English -> French perhaps?) 
 
Author: 
 
    Kerry Schwartz (kerrys) 05-Nov-1995 
 
--*/       
 
#include <windows.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <httpfilt.h> 
 
BOOL 
WINAPI __stdcall 
GetFilterVersion( 
    HTTP_FILTER_VERSION * pVer 
    ) 
{ 
    // 
    //  Specify the types and order of notification 
    // 
 
    pVer->dwFlags = (SF_NOTIFY_NONSECURE_PORT     | 
                     SF_NOTIFY_URL_MAP            | 
                     SF_NOTIFY_SEND_RAW_DATA      | 
                     SF_NOTIFY_ORDER_DEFAULT); 
 
    pVer->dwFilterVersion = HTTP_FILTER_REVISION; 
 
    strcpy( pVer->lpszFilterDesc,  
            "Upper case conversion filter, Version 1.0"); 
 
    return TRUE; 
} 
 
DWORD 
WINAPI __stdcall 
HttpFilterProc( 
    HTTP_FILTER_CONTEXT *      pfc, 
    DWORD                      NotificationType, 
    VOID *                     pvData ) 
{ 
    CHAR *pchIn, *pPhysPath; 
    DWORD cbBuffer, cbtemp; 
    PHTTP_FILTER_URL_MAP pURLMap; 
    PHTTP_FILTER_RAW_DATA pRawData; 
     
   
    switch ( NotificationType ) 
    { 
    case SF_NOTIFY_URL_MAP: 
 
        pURLMap = (PHTTP_FILTER_URL_MAP) pvData; 
        pPhysPath = pURLMap->pszPhysicalPath; 
        pfc->pFilterContext = 0; 
 
        while (*pPhysPath) 
        { 
            if (*pPhysPath == '\\' && 
               (*(pPhysPath+1) == 'u' || *(pPhysPath+1) == 'U') && 
               (*(pPhysPath+2) == 'c' || *(pPhysPath+2) == 'C') && 
                *(pPhysPath+3) == '\\') 
            { 
                while (*(pPhysPath+3)) 
                { 
                    *pPhysPath = *(pPhysPath+3); 
                    pPhysPath++; 
                } 
                *pPhysPath = '\0'; 
                pfc->pFilterContext = (VOID *) 1; 
                break; 
            } 
            pPhysPath++; 
        } 
 
        break; 
 
    case SF_NOTIFY_SEND_RAW_DATA: 
 
        pRawData = (PHTTP_FILTER_RAW_DATA) pvData; 
 
        if (pfc->pFilterContext) 
        { 
            pchIn = (BYTE *) pRawData->pvInData; 
            cbBuffer = 0; 
            cbtemp = 0; 
 
            if (pfc->pFilterContext == (VOID *) 1)      // first block? 
            { 
                while (cbBuffer < pRawData->cbInData) 
                { 
                    if (pchIn[cbBuffer] == '\n' && 
                        pchIn[cbBuffer+2] == '\n') 
                    { 
                        cbBuffer +=3; 
                        break; 
                    } 
                    cbBuffer++; 
                } 
             
                while (cbtemp < cbBuffer) 
                { 
                    if (pchIn[cbtemp] == '/' && pchIn[cbtemp+1] == 'h' && 
                        pchIn[cbtemp+2] == 't' && pchIn[cbtemp+3] == 'm') 
                    { 
                        pfc->pFilterContext = (VOID *) 2; 
                        break; 
                    } 
                    cbtemp++; 
                } 
                if (cbtemp == cbBuffer) 
                    pfc->pFilterContext = 0;        // not an html file 
            } 
             
            if (pfc->pFilterContext) 
            { 
                while (cbBuffer < pRawData->cbInData) 
                { 
                    pchIn[cbBuffer] =  
                        (pchIn[cbBuffer]>='a' && pchIn[cbBuffer]<='z') ?  
                (pchIn[cbBuffer]-'a'+'A') : pchIn[cbBuffer]; 
                    cbBuffer++; 
                } 
             
            } 
        } 
        break; 
            
    default: 
        break;         
    } 
 
    return SF_STATUS_REQ_NEXT_NOTIFICATION; 
}