Source Code
The source code for this example is in the qos.c file in the plugins/nsapi/examples subdirectory of the server root directory.
#include "nspr.h"
#include "base/pblock.h"
#include "frame/log.h"
#include "frame/http.h"
/*-----------------------------------------------------------------
decode : internal function used for parsing of QOS values in pblock
-------------------------------------------------------------------
void decode(const char* val, PRInt32* var, pblock* pb)
{
char* pbval;
if ( (!var) || (!val) || (!pb) )
return;
pbval = pblock_findval(val, pb);
if (!pbval)
return;
*var = atoi(pbval);
}
/*----------------------------------------------------------------
qos_error_sample
This function is meant to be an error handler for an HTTP 503 error
code, which is returned by qos_handler when QOS limits are exceeded
and enforced.
This sample function just prints out a message about which
limits were exceeded.
------------------------------------------------------------------
NSAPI_PUBLIC int qos_error_sample(pblock *pb, Session *sn, Request *rq)
{
char error[1024] = "";
char* err_header = "<HTML><HEAD><TITLE>Unable to service request
</TITLE></HEAD><BODY>";
char* err_footer = "</BODY></HTML>";
PRBool ours = PR_FALSE;
PRInt32 vs_bw = 0, vs_bwlim = 0, vs_bw_ef = 0,
vs_conn = 0, vs_connlim = 0, vs_conn_ef = 0,
vsc_bw = 0, vsc_bwlim = 0, vsc_bw_ef = 0,
vsc_conn = 0, vsc_connlim = 0, vsc_conn_ef = 0,
srv_bw = 0, srv_bwlim = 0, srv_bw_ef = 0,
srv_conn = 0, srv_connlim = 0, srv_conn_ef = 0;
pblock* apb = rq->vars;
decode("vs_bandwidth", &vs_bw, apb);
decode("vs_connections", &vs_conn, apb);
decode("vs_bandwidth_limit", &vs_bwlim, apb);
decode("vs_bandwidth_enforced", &vs_bw_ef, apb);
decode("vs_connections_limit", &vs_connlim, apb);
decode("vs_connections_enforced", &vs_conn_ef, apb);
decode("vsclass_bandwidth", &vsc_bw, apb);
decode("vsclass_connections", &vsc_conn, apb);
decode("vsclass_bandwidth_limit", &vsc_bwlim, apb);
decode("vsclass_bandwidth_enforced", &vsc_bw_ef, apb);
decode("vsclass_connections_limit", &vsc_connlim, apb);
decode("vsclass_connections_enforced", &vsc_conn_ef, apb);
decode("server_bandwidth", &srv_bw, apb);
decode("server_connections", &srv_conn, apb);
decode("server_bandwidth_limit", &srv_bwlim, apb);
decode("server_bandwidth_enforced", &srv_bw_ef, apb);
decode("server_connections_limit", &srv_connlim, apb);
decode("server_connections_enforced", &srv_conn_ef, apb);
if ((vs_bwlim) && (vs_bw>vs_bwlim))
{
/* VS bandwidth limit was exceeded, display it */
ours = PR_TRUE;
sprintf(error, "<P>Virtual server bandwidth limit of %d .
Current VS bandwidth : %d . <P>",
vs_bwlim, vs_bw);
};
if ((vs_connlim) && (vs_conn>vs_connlim))
{
/* VS connection limit was exceeded, display it */
ours = PR_TRUE;
sprintf(error, "<P>Virtual server connection limit of %d .
Current VS connections : %d . <P>",
vs_connlim, vs_conn);
};
if ((vsc_bwlim) && (vsc_bw>vsc_bwlim))
{
/* VSCLASS bandwidth limit was exceeded, display it */
ours = PR_TRUE;
sprintf(error, "<P>Virtual server class bandwidth limit of %d .
Current VSCLASS bandwidth : %d . <P>",
vsc_bwlim, vsc_bw);
};
if ((vsc_connlim) && (vsc_conn>vsc_connlim))
{
/* VSCLASS connection limit was exceeded, display it */
ours = PR_TRUE;
sprintf(error, "<P>Virtual server class connection limit of %d .
Current VSCLASS connections : %d . <P>",
vsc_connlim, vsc_conn);
};
if ((srv_bwlim) && (srv_bw>srv_bwlim))
{
/* SERVER bandwidth limit was exceeded, display it */
ours = PR_TRUE;
sprintf(error, "<P>Global bandwidth limit of %d .
Current bandwidth : %d . <P>",
srv_bwlim, srv_bw);
};
if ((srv_connlim) && (srv_conn>srv_connlim))
{
/* SERVER connection limit was exceeded, display it */
ours = PR_TRUE;
sprintf(error, "<P>Global connection limit of %d .
Current connections : %d . <P>",
srv_connlim, srv_conn);
};
if (ours)
{
/* this was really a QOS failure, therefore send the error page */
pb_param *pp = pblock_remove ("content-type", rq->srvhdrs);
if (pp != NULL)
param_free (pp);
pblock_nvinsert ("content-type", "text/html", rq->srvhdrs);
protocol_start_response(sn, rq);
net_write(sn->csd, err_header, strlen(err_header));
net_write(sn->csd, error, strlen(error));
net_write(sn->csd, err_footer, strlen(err_footer));
return REQ_PROCEED;
}
else
{
/* this 503 didn't come from a QOS SAF failure,
let someone else handle it */
return REQ_PROCEED;
};
}
/*---------------------------------------------------------------
qos_handler_sample
This is an NSAPI AuthTrans function.
It examines the QOS values in the request and compares them to the
QOS limits.
It does several things:
1) It will log errors if the QOS limits are exceeded.
2) It will return REQ_ABORTED with a 503 error code if the QOS limits
are exceeded, and the QOS limits are set to be enforced. Otherwise
it will return REQ_PROCEED.
------------------------------------------------------------------
NSAPI_PUBLIC int qos_handler_sample(pblock *pb, Session *sn, Request *rq)
{
PRBool ok = PR_TRUE;
PRInt32 vs_bw = 0, vs_bwlim = 0, vs_bw_ef = 0,
vs_conn = 0, vs_connlim = 0, vs_conn_ef = 0,
vsc_bw = 0, vsc_bwlim = 0, vsc_bw_ef = 0,
vsc_conn = 0, vsc_connlim = 0, vsc_conn_ef = 0,
srv_bw = 0, srv_bwlim = 0, srv_bw_ef = 0,
srv_conn = 0, srv_connlim = 0, srv_conn_ef = 0;
pblock* apb = rq->vars;
decode("vs_bandwidth", &vs_bw, apb);
decode("vs_connections", &vs_conn, apb);
decode("vs_bandwidth_limit", &vs_bwlim, apb);
decode("vs_bandwidth_enforced", &vs_bw_ef, apb);
decode("vs_connections_limit", &vs_connlim, apb);
decode("vs_connections_enforced", &vs_conn_ef, apb);
decode("vsclass_bandwidth", &vsc_bw, apb);
decode("vsclass_connections", &vsc_conn, apb);
decode("vsclass_bandwidth_limit", &vsc_bwlim, apb);
decode("vsclass_bandwidth_enforced", &vsc_bw_ef, apb);
decode("vsclass_connections_limit", &vsc_connlim, apb);
decode("vsclass_connections_enforced", &vsc_conn_ef, apb);
decode("server_bandwidth", &srv_bw, apb);
decode("server_connections", &srv_conn, apb);
decode("server_bandwidth_limit", &srv_bwlim, apb);
decode("server_bandwidth_enforced", &srv_bw_ef, apb);
decode("server_connections_limit", &srv_connlim, apb);
decode("server_connections_enforced", &srv_conn_ef, apb);
if ((vs_bwlim) && (vs_bw>vs_bwlim))
{
/* bandwidth limit was exceeded, log it */
ereport(LOG_FAILURE, "Virtual server bandwidth limit of %d exceeded.
Current VS bandwidth : %d", &vs_bwlim, vs_bw);
if (vs_bw_ef)
{
/* and enforce it */
ok = PR_FALSE;
};
};
if ((vs_connlim) && (vs_conn>vs_connlim))
{
/* connection limit was exceeded, log it */
ereport(LOG_FAILURE, "Virtual server connection limit of %d exceeded.
Current VS connections : %d", &vs_connlim, vs_conn);
if (vs_conn_ef)
{
/* and enforce it */
ok = PR_FALSE;
};
};
if ((vsc_bwlim) && (vsc_bw>vsc_bwlim))
{
/* bandwidth limit was exceeded, log it */
ereport(LOG_FAILURE, "Virtual server class bandwidth limit of %d exceeded.
Current VSCLASS bandwidth : %d", &vsc_bwlim, vsc_bw);
if (vsc_bw_ef)
{
/* and enforce it */
ok = PR_FALSE;
};
};
if ((vsc_connlim) && (vsc_conn>vsc_connlim))
{
/* connection limit was exceeded, log it */
ereport(LOG_FAILURE, "Virtual server class connection limit of %d exceeded.
Current VSCLASS connections : %d", &vsc_connlim, vsc_conn);
if (vsc_conn_ef)
{
/* and enforce it */
ok = PR_FALSE;
};
};
if ((srv_bwlim) && (srv_bw>srv_bwlim))
{
/* bandwidth limit was exceeded, log it */
ereport(LOG_FAILURE, "Global bandwidth limit of %d exceeded.
Current global bandwidth : %d", &srv_bwlim, srv_bw);
if (srv_bw_ef)
{
/* and enforce it */
ok = PR_FALSE;
};
};
if ((srv_connlim) && (srv_conn>srv_connlim))
{
/* connection limit was exceeded, log it */
ereport(LOG_FAILURE, "Global connection limit of %d exceeded.
Current global connections : %d", &srv_connlim, srv_conn);
if (srv_conn_ef)
{
/* and enforce it */
ok = PR_FALSE;
};
};
if (ok)
{
return REQ_PROCEED;
}
else
{
/* one of the limits was exceeded
therefore, we set HTTP error 503 "server too busy" */
protocol_status(sn, rq, PROTOCOL_SERVICE_UNAVAILABLE, NULL);
return REQ_ABORTED;
};
}
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