view src/http/modules/ngx_http_ssi_filter_module.h @ 7514:319242d2ddc9

Upstream: background cache update before cache send (ticket #1782). In case of filter finalization, essential request fields like r->uri, r->args etc could be changed, which affected the cache update subrequest. Also, after filter finalization r->cache could be set to NULL, leading to null pointer dereference in ngx_http_upstream_cache_background_update(). The fix is to create background cache update subrequest before sending the cached response. Since initial introduction in 1aeaae6e9446 (1.11.10) background cache update subrequest was created after sending the cached response because otherwise it blocked the parent request output. In 9552758a786e (1.13.1) background subrequests were introduced to eliminate the delay before sending the final part of the cached response. This also made it possible to create the background cache update subrequest before sending the response. Note that creating the subrequest earlier does not change the fact that in case of filter finalization the background cache update subrequest will likely not have enough time to successfully update the cache entry. Filter finalization leads to the main request termination as soon the current iteration of request processing is complete.
author Roman Arutyunyan <arut@nginx.com>
date Mon, 03 Jun 2019 20:33:26 +0300
parents d620f497c50f
children 49e7db44b57c
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_HTTP_SSI_FILTER_H_INCLUDED_
#define _NGX_HTTP_SSI_FILTER_H_INCLUDED_


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


#define NGX_HTTP_SSI_MAX_PARAMS       16

#define NGX_HTTP_SSI_COMMAND_LEN      32
#define NGX_HTTP_SSI_PARAM_LEN        32
#define NGX_HTTP_SSI_PARAMS_N         4


#define NGX_HTTP_SSI_COND_IF          1
#define NGX_HTTP_SSI_COND_ELSE        2


#define NGX_HTTP_SSI_NO_ENCODING      0
#define NGX_HTTP_SSI_URL_ENCODING     1
#define NGX_HTTP_SSI_ENTITY_ENCODING  2


typedef struct {
    ngx_hash_t                hash;
    ngx_hash_keys_arrays_t    commands;
} ngx_http_ssi_main_conf_t;


typedef struct {
    ngx_buf_t                *buf;

    u_char                   *pos;
    u_char                   *copy_start;
    u_char                   *copy_end;

    ngx_uint_t                key;
    ngx_str_t                 command;
    ngx_array_t               params;
    ngx_table_elt_t          *param;
    ngx_table_elt_t           params_array[NGX_HTTP_SSI_PARAMS_N];

    ngx_chain_t              *in;
    ngx_chain_t              *out;
    ngx_chain_t             **last_out;
    ngx_chain_t              *busy;
    ngx_chain_t              *free;

    ngx_uint_t                state;
    ngx_uint_t                saved_state;
    size_t                    saved;
    size_t                    looked;

    size_t                    value_len;

    ngx_list_t               *variables;
    ngx_array_t              *blocks;

#if (NGX_PCRE)
    ngx_uint_t                ncaptures;
    int                      *captures;
    u_char                   *captures_data;
#endif

    unsigned                  conditional:2;
    unsigned                  encoding:2;
    unsigned                  block:1;
    unsigned                  output:1;
    unsigned                  output_chosen:1;

    ngx_http_request_t       *wait;
    void                     *value_buf;
    ngx_str_t                 timefmt;
    ngx_str_t                 errmsg;
} ngx_http_ssi_ctx_t;


typedef ngx_int_t (*ngx_http_ssi_command_pt) (ngx_http_request_t *r,
    ngx_http_ssi_ctx_t *ctx, ngx_str_t **);


typedef struct {
    ngx_str_t                 name;
    ngx_uint_t                index;

    unsigned                  mandatory:1;
    unsigned                  multiple:1;
} ngx_http_ssi_param_t;


typedef struct {
    ngx_str_t                 name;
    ngx_http_ssi_command_pt   handler;
    ngx_http_ssi_param_t     *params;

    unsigned                  conditional:2;
    unsigned                  block:1;
    unsigned                  flush:1;
} ngx_http_ssi_command_t;


extern ngx_module_t  ngx_http_ssi_filter_module;


#endif /* _NGX_HTTP_SSI_FILTER_H_INCLUDED_ */