ngx_http_auto_keepalive.c

/*
 *
 * Copyright (c) 2013 Shang Yuanchun <idealities@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <nginx.h>
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>

typedef struct {
    ngx_flag_t    keepalive_autoclose;     /* auto disable keepalive */
    ngx_str_t     autoclose_filetypes;     /* file types to auto disable keepalive */
} ngx_http_auto_keepalive_loc_conf_t;

static void *create_http_auto_keepalive_loc_conf(ngx_conf_t *cf);
static char *merge_http_auto_keepalive_loc_conf(ngx_conf_t *cf,
                void *parent, void *child);

static ngx_int_t ngx_http_auto_keepalive_init(ngx_conf_t *cf);
static ngx_int_t ngx_http_auto_keepalive_handler(ngx_http_request_t *r);

static ngx_inline u_char *ngx_strrlchr(
                          u_char *p, u_char *last, u_char c)
{
    last--;
    while (last >= p) {

        if (*last == c) {
            return last;
        }

        last--;
    }

    return NULL;
}

static ngx_command_t ngx_http_auto_keepalive_commands[] = {

    { ngx_string("keepalive_autoclose"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|
      NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,    /* set  */
      NGX_HTTP_LOC_CONF_OFFSET,  /* conf */
      0,                         /* offset */
      NULL                       /* post   */
    },
    { ngx_string("autoclose_filetypes"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|
      NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,          /* set  */
      NGX_HTTP_LOC_CONF_OFFSET,       /* conf */
      offsetof(ngx_http_auto_keepalive_loc_conf_t,
               autoclose_filetypes),  /* offset */
      NULL                            /* post   */
    },

    ngx_null_command
};

static ngx_http_module_t ngx_http_auto_keepalive_module_ctx = {
    NULL,                          /* preconfiguration  */
    ngx_http_auto_keepalive_init,  /* postconfiguration */

    NULL,                          /* create_main_conf */
    NULL,                          /* init_main_conf   */

    NULL,                          /* create_srv_conf  */
    NULL,                          /* merge_srv_conf   */

    create_http_auto_keepalive_loc_conf,
    merge_http_auto_keepalive_loc_conf
};

ngx_module_t ngx_http_auto_keepalive_module = {
    NGX_MODULE_V1,
    &ngx_http_auto_keepalive_module_ctx,  /* module context  */
    ngx_http_auto_keepalive_commands,     /* module commands */
    NGX_HTTP_MODULE,                      /* module type     */
    NULL,                                 /* init master     */
    NULL,                                 /* init module     */
    NULL,                                 /* init process    */
    NULL,                                 /* init thread     */
    NULL,                                 /* exit thread     */
    NULL,                                 /* exit process    */
    NULL,                                 /* exit master     */
    NGX_MODULE_V1_PADDING
};

static void *create_http_auto_keepalive_loc_conf(ngx_conf_t *cf)
{
    ngx_http_auto_keepalive_loc_conf_t *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_auto_keepalive_loc_conf_t));
    if (conf == NULL) {
#if defined nginx_version && nginx_version >= 8011
        return NULL;
#else
        return NGX_CONF_ERROR;
#endif
    }

    conf->keepalive_autoclose = NGX_CONF_UNSET;

    return conf;
}

static char *merge_http_auto_keepalive_loc_conf(ngx_conf_t *cf,
                void *parent, void *child)
{
    ngx_http_auto_keepalive_loc_conf_t *prev = parent;
    ngx_http_auto_keepalive_loc_conf_t *conf = child;

    ngx_conf_merge_value(conf->keepalive_autoclose,
                         prev->keepalive_autoclose,
                         0);
    ngx_conf_merge_str_value(conf->autoclose_filetypes,
                             prev->autoclose_filetypes,
                             ".iso .tar .bz2 .gz .zip .rar");

    return NGX_CONF_OK;
}

static ngx_int_t ngx_http_auto_keepalive_init(ngx_conf_t *cf)
{
    ngx_http_handler_pt       *handler = NULL;
    ngx_http_core_main_conf_t *cmcf    = NULL;

    cmcf     = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
    handler  = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
    if (handler == NULL) {
        return NGX_ERROR;
    }
    *handler = ngx_http_auto_keepalive_handler;

    return NGX_OK;
}

static ngx_int_t ngx_http_auto_keepalive_handler(ngx_http_request_t *r)
{
    ngx_http_auto_keepalive_loc_conf_t  *conf;
    u_char *ext;

    conf = ngx_http_get_module_loc_conf(r, ngx_http_auto_keepalive_module);
    if (conf->keepalive_autoclose && r->headers_in.referer) {
        /*
         * if keepalive_autoclose is enabled, and the request is for
         * specific file type and has referer, then it will auto
         * disable keep-alive.
         */
        ext = (u_char *)ngx_strrlchr(r->uri.data, r->uri.data+r->uri.len, '.');
        if (ext
            && ngx_strstrn(conf->autoclose_filetypes.data,
                           (char *)ext, (r->uri.data + r->uri.len) - ext))
        {

            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "Request for specific file types, keepalive_autoclose triggered");
            r->keepalive = 0;
        }
    }

    return NGX_OK;
}