// ============================================================================
// This is a Servlet sample for the G-WAN Web Server (http://www.trustleap.com)
// ----------------------------------------------------------------------------
// setheaders.c: build a complete HTTP reply -including custom response headers
// (this may be mandatory for some applications)
//
// You can insert new response headers to match your needs.
// ----------------------------------------------------------------------------
#include "gwan.h" // G-WAN exported functions
// ----------------------------------------------------------------------------
// imported functions:
// get_reply(): get a pointer on the 'reply' dynamic buffer from the server
// xbuf_init(): called after xbuf_t has been declared, to initialize struct
// xbuf_xcat(): formatted strcat() (a la printf) in a given dynamic buffer
// get_env(): get connection's 'environment' variables from the server:
// ----------------------------------------------------------------------------
// a stripped-down* version of itoa() - [*]: no checks, no ending-null
// ----------------------------------------------------------------------------
static inline void u32toa(char *p, u32 v)
{
do *p-- = '0' + (v % 10), v /= 10; while(v);
}
// ----------------------------------------------------------------------------
// Title of our HTML page
static char title[] = "Setting response headers";
// Top of our HTML page
static char top[] =
""
"%s"
""
""
"
%s
";
// ----------------------------------------------------------------------------
int main(int argc, char *argv[])
{
xbuf_t *reply = get_reply(argv);
// -------------------------------------------------------------------------
// get the current HTTP date (like "Sun, 06 Nov 1994 08:49:37 GMT")
// -------------------------------------------------------------------------
char *p = (char*)get_env(argv, SERVER_DATE);
// -------------------------------------------------------------------------
// create your custom response headers and append our HTML
// -------------------------------------------------------------------------
int position = 0;
xbuf_xcat(reply,
"HTTP/1.1 200 OK\r\n"
"Date: %s\r\n"
"Last-Modified: %s\r\n"
// << insert your custom headers here
"Content-type: text/html\r\n"
"Content-Length: %n\r\n" // make room for the HTML length
"Connection: close\r\n\r\n",
p, p,
&position); // "Sun, 06 Nov 2009 08:49:37 GMT"
int headers_size = reply->len;
// -------------------------------------------------------------------------
// save the place where to patch the empty 'Content-Length' HTTP Header
// -------------------------------------------------------------------------
p = (char*)(reply->ptr + position);
// -------------------------------------------------------------------------
// append your HTML page to the reply buffer
// -------------------------------------------------------------------------
xbuf_xcat(reply, top, title, title);
char szbody[] = " This reply was made with custom HTTP headers,"
" look at the servlet source code. ";
xbuf_ncat(reply, szbody, sizeof(szbody) - 1);
// -------------------------------------------------------------------------
// store the HTML size in the empty space of the 'Content-Length' header
// -------------------------------------------------------------------------
u32toa(p, reply->len - headers_size);
return 200; // return an HTTP code (200:'OK')
}
// ============================================================================
// End of Source Code
// ============================================================================