Writing a timer event (how to execute an event from time to time)

[Rogério Schneider]

Would you be kind enough to help me understanding how to write an
event which executes itself from time to time, using Nginx event
handler?

I would like to register for each request a timer to execute a given
task each 10 seconds.

I am trying this in my module handler:

static ngx_int_t ngx_http_hello_world_handler(ngx_http_request_t *r)
{
    ngx_buf_t    *b;
    ngx_chain_t   out;
    int           rc;
    ngx_event_t     *wev;

    wev = ngx_pcalloc(r->pool, sizeof(ngx_event_t));

    if (wev == NULL) {
        ngx_log_stderr(0, "wev null");
        return NGX_ERROR;
    }

    wev->handler = ngx_http_hello_world_delay_handler;
    wev->data = r;
    wev->log = r->connection->log;

    ngx_add_timer(wev, 10000);

    r->headers_out.content_type.len = sizeof("text/plain") - 1;
    r->headers_out.content_type.data = (u_char *) "text/plain";

    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));

    out.buf = b;
    out.next = NULL;

    b->pos = ngx_hello_world;
    b->last = ngx_hello_world + sizeof(ngx_hello_world);
    b->memory = 1;
    b->flush = 1;
    b->last_buf = 0;

    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = -1;

    ngx_http_clear_content_length(r);
    ngx_http_clear_accept_ranges(r);

    ngx_http_send_header(r);

    rc = ngx_http_output_filter(r, &out);

    return rc; // never got reached due to b->last_buf=0 and chunked response
}

and the delay handler:

static void ngx_http_hello_world_delay_handler(ngx_event_t *ev)
{
    ngx_buf_t    *b;
    ngx_chain_t   out;
    int           rc;
    ngx_connection_t        *c;
    ngx_http_request_t      *r;

    r = ev->data;
    c = r->connection;

    if (c->destroyed) {
        return;
    }

    out.buf = b;
    out.next = NULL;
    b->pos = ngx_hello_world;
    b->last = ngx_hello_world + sizeof(ngx_hello_world);
    b->memory = 1;
    b->flush = 1;
    b->last_buf = 0;

    rc = ngx_http_output_filter(r, &out);

    return;
}

Do you think I am missing something? I still getting segfaults just as
soon as my delay handler is called.

Regards,
-- 
Rogério Schneider
http://stockrt.github.com