ngx_http_variables.c

Nginx是一个高性能的HTTP和反向代理服务器

/*
 * Copyright (C) Igor Sysoev
 */


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


static ngx_int_t ngx_http_variable_request(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static void ngx_http_variable_request_set(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static void ngx_http_variable_request_set_size(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_header(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_headers(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_variable_unknown_header_in(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_unknown_header_out(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_variable_host(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_binary_remote_addr(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_remote_addr(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_remote_port(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_server_addr(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_server_port(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_scheme(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_is_args(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_document_root(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_request_filename(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_server_name(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_request_method(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_remote_user(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_body_bytes_sent(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_request_completion(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_request_body_file(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_variable_sent_content_type(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_sent_content_length(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_sent_last_modified(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_sent_connection(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_sent_keep_alive(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_variable_sent_transfer_encoding(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

static ngx_int_t ngx_http_variable_nginx_version(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);

/*
 * TODO:
 *     Apache CGI: AUTH_TYPE, PATH_INFO (null), PATH_TRANSLATED
 *                 REMOTE_HOST (null), REMOTE_IDENT (null),
 *                 SERVER_SOFTWARE
 *
 *     Apache SSI: DOCUMENT_NAME, LAST_MODIFIED, USER_NAME (file owner)
 */

/*
 * the $http_host, $http_user_agent, $http_referer, $http_via,
 * and $http_x_forwarded_for variables may be handled by generic
 * ngx_http_variable_unknown_header_in(), but for perfomance reasons
 * they are handled using dedicated entries
 */

static ngx_http_variable_t  ngx_http_core_variables[] = {

    { ngx_string("http_host"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.host), 0, 0 },

    { ngx_string("http_user_agent"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.user_agent), 0, 0 },

    { ngx_string("http_referer"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.referer), 0, 0 },

#if (NGX_HTTP_GZIP)
    { ngx_string("http_via"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.via), 0, 0 },
#endif

#if (NGX_HTTP_PROXY || NGX_HTTP_REALIP)
    { ngx_string("http_x_forwarded_for"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.x_forwarded_for), 0, 0 },
#endif

    { ngx_string("http_cookie"), NULL, ngx_http_variable_headers,
      offsetof(ngx_http_request_t, headers_in.cookies), 0, 0 },

    { ngx_string("content_length"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.content_length), 0, 0 },

    { ngx_string("content_type"), NULL, ngx_http_variable_header,
      offsetof(ngx_http_request_t, headers_in.content_type), 0, 0 },

    { ngx_string("host"), NULL, ngx_http_variable_host, 0, 0, 0 },

    { ngx_string("binary_remote_addr"), NULL,
      ngx_http_variable_binary_remote_addr, 0, 0, 0 },

    { ngx_string("remote_addr"), NULL, ngx_http_variable_remote_addr, 0, 0, 0 },

    { ngx_string("remote_port"), NULL, ngx_http_variable_remote_port, 0, 0, 0 },

    { ngx_string("server_addr"), NULL, ngx_http_variable_server_addr, 0, 0, 0 },

    { ngx_string("server_port"), NULL, ngx_http_variable_server_port, 0, 0, 0 },

    { ngx_string("server_protocol"), NULL, ngx_http_variable_request,
      offsetof(ngx_http_request_t, http_protocol), 0, 0 },

    { ngx_string("scheme"), NULL, ngx_http_variable_scheme, 0, 0, 0 },

    { ngx_string("request_uri"), NULL, ngx_http_variable_request,
      offsetof(ngx_http_request_t, unparsed_uri), 0, 0 },

    { ngx_string("uri"), NULL, ngx_http_variable_request,
      offsetof(ngx_http_request_t, uri),
      NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("document_uri"), NULL, ngx_http_variable_request,
      offsetof(ngx_http_request_t, uri),
      NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("request"), NULL, ngx_http_variable_request,
      offsetof(ngx_http_request_t, request_line), 0, 0 },

    { ngx_string("document_root"), NULL,
      ngx_http_variable_document_root, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("query_string"), NULL, ngx_http_variable_request,
      offsetof(ngx_http_request_t, args),
      NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("args"),
      ngx_http_variable_request_set,
      ngx_http_variable_request,
      offsetof(ngx_http_request_t, args),
      NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("is_args"), NULL, ngx_http_variable_is_args,
      0, NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("request_filename"), NULL,
      ngx_http_variable_request_filename, 0,
      NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("server_name"), NULL, ngx_http_variable_server_name, 0, 0, 0 },

    { ngx_string("request_method"), NULL,
      ngx_http_variable_request_method, 0, 0, 0 },

    { ngx_string("remote_user"), NULL, ngx_http_variable_remote_user, 0, 0, 0 },

    { ngx_string("body_bytes_sent"), NULL, ngx_http_variable_body_bytes_sent,
      0, 0, 0 },

    { ngx_string("request_completion"), NULL,
      ngx_http_variable_request_completion,
      0, 0, 0 },

    { ngx_string("request_body_file"), NULL,
      ngx_http_variable_request_body_file,
      0, 0, 0 },

    { ngx_string("sent_http_content_type"), NULL,
      ngx_http_variable_sent_content_type, 0, 0, 0 },

    { ngx_string("sent_http_content_length"), NULL,
      ngx_http_variable_sent_content_length, 0, 0, 0 },

    { ngx_string("sent_http_last_modified"), NULL,
      ngx_http_variable_sent_last_modified, 0, 0, 0 },

    { ngx_string("sent_http_connection"), NULL,
      ngx_http_variable_sent_connection, 0, 0, 0 },

    { ngx_string("sent_http_keep_alive"), NULL,
      ngx_http_variable_sent_keep_alive, 0, 0, 0 },

    { ngx_string("sent_http_transfer_encoding"), NULL,
      ngx_http_variable_sent_transfer_encoding, 0, 0, 0 },

    { ngx_string("sent_http_cache_control"), NULL, ngx_http_variable_headers,
      offsetof(ngx_http_request_t, headers_out.cache_control), 0, 0 },

    { ngx_string("limit_rate"), ngx_http_variable_request_set_size,
      ngx_http_variable_request,
      offsetof(ngx_http_request_t, limit_rate),
      NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("nginx_version"), NULL, ngx_http_variable_nginx_version,
      0, 0, 0 },

    { ngx_null_string, NULL, NULL, 0, 0, 0 }
};


ngx_http_variable_value_t  ngx_http_variable_null_value =
    ngx_http_variable("");
ngx_http_variable_value_t  ngx_http_variable_true_value =
    ngx_http_variable("1");


ngx_http_variable_t *
ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
{
    ngx_int_t                   rc;
    ngx_uint_t                  i;
    ngx_hash_key_t             *key;
    ngx_http_variable_t        *v;
    ngx_http_core_main_conf_t  *cmcf;

    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

    key = cmcf->variables_keys->keys.elts;
    for (i = 0; i < cmcf->variables_keys->keys.nelts; i++) {
        if (name->len != key[i].key.len
            || ngx_strncasecmp(name->data, key[i].key.data, name->len) != 0)
        {
            continue;
        }

        v = key[i].value;

        if (!(v->flags & NGX_HTTP_VAR_CHANGEABLE)) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "the duplicate \"%V\" variable", name);
            return NULL;
        }

        return v;
    }

    v = ngx_palloc(cf->pool, sizeof(ngx_http_variable_t));
    if (v == NULL) {
        return NULL;
    }

    v->name.len = name->len;
    v->name.data = ngx_palloc(cf->pool, name->len);
    if (v->name.data == NULL) {
        return NULL;
    }

    for (i = 0; i < name->len; i++) {
        v->name.data[i] = ngx_tolower(name->data[i]);
    }

    v->set_handler = NULL;
    v->get_handler = NULL;
    v->data = 0;
    v->flags = flags;
    v->index = 0;

    rc = ngx_hash_add_key(cmcf->variables_keys, &v->name, v, 0);

    if (rc == NGX_ERROR) {
        return NULL;
    }

    if (rc == NGX_BUSY) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "conflicting variable name \"%V\"", name);
        return NULL;
    }

    return v;
}


ngx_int_t
ngx_http_get_variable_index(ngx_conf_t *cf, ngx_str_t *name)
{
    ngx_uint_t                  i;
    ngx_http_variable_t        *v;
    ngx_http_core_main_conf_t  *cmcf;

    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

    v = cmcf->variables.elts;

    if (v == NULL) {
        if (ngx_array_init(&cmcf->variables, cf->pool, 4,
                           sizeof(ngx_http_variable_t)) == NGX_ERROR)
        {
            return NGX_ERROR;
        }

    } else {
        for (i = 0; i < cmcf->variables.nelts; i++) {
            if (name->len != v[i].name.len
                || ngx_strncasecmp(name->data, v[i].name.data, name->len) != 0)
            {
                continue;
            }

            return i;
        }
    }

    v = ngx_array_push(&cmcf->variables);
    if (v == NULL) {
        return NGX_ERROR;
    }

    v->name.len = name->len;
    v->name.data = ngx_palloc(cf->pool, name->len);
    if (v->name.data == NULL) {
        return NGX_ERROR;
    }

    for (i = 0; i < name->len; i++) {
        v->name.data[i] = ngx_tolower(name->data[i]);
    }

    v->set_handler = NULL;
    v->get_handler = NULL;
    v->data = 0;
    v->flags = 0;
    v->index = cmcf->variables.nelts - 1;

    return cmcf->variables.nelts - 1;
}


ngx_http_variable_value_t *
ngx_http_get_indexed_variable(ngx_http_request_t *r, ngx_uint_t index)
{
    ngx_http_variable_t        *v;
    ngx_http_core_main_conf_t  *cmcf;

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    if (cmcf->variables.nelts <= index) {
        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
                      "unknown variable index: %d", index);
        return NULL;
    }

    if (r->variables[index].not_found || r->variables[index].valid) {
        return &r->variables[index];
    }

    v = cmcf->variables.elts;

    if (v[index].get_handler(r, &r->variables[index], v[index].data)
        == NGX_OK)
    {
        if (v[index].flags & NGX_HTTP_VAR_NOCACHEABLE) {
            r->variables[index].no_cacheable = 1;
        }

        return &r->variables[index];
    }

    r->variables[index].valid = 0;
    r->variables[index].not_found = 1;

    return NULL;
}


ngx_http_variable_value_t *
ngx_http_get_flushed_variable(ngx_http_request_t *r, ngx_uint_t index)
{
    ngx_http_variable_value_t  *v;

    v = &r->variables[index];

    if (v->valid) {
        if (!v->no_cacheable) {
            return v;
        }

        v->valid = 0;
        v->not_found = 0;
    }

    return ngx_http_get_indexed_variable(r, index);
}


ngx_http_variable_value_t *
ngx_http_get_variable(ngx_http_request_t *r, ngx_str_t *name, ngx_uint_t key,
    ngx_uint_t nowarn)
{
    ngx_http_variable_t        *v;
    ngx_http_variable_value_t  *vv;
    ngx_http_core_main_conf_t  *cmcf;

    cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);

    v = ngx_hash_find(&cmcf->variables_hash, key, name->data, name->len);

    if (v) {
        if (v->flags & NGX_HTTP_VAR_INDEXED) {
            return ngx_http_get_indexed_variable(r, v->index);

        } else {

            vv = ngx_palloc(r->pool, sizeof(ngx_http_variable_value_t));

            if (vv && v->get_handler(r, vv, v->data) == NGX_OK) {
                return vv;
            }

            return NULL;
        }
    }

    vv = ngx_palloc(r->pool, sizeof(ngx_http_variable_value_t));
    if (vv == NULL) {
        return NULL;
    }

    if (ngx_strncmp(name->data, "http_", 5) == 0) {

        if (ngx_http_variable_unknown_header_in(r, vv, (uintptr_t) name)
            == NGX_OK)
        {
            return vv;
        }

        return NULL;
    }

    if (ngx_strncmp(name->data, "sent_http_", 10) == 0) {

        if (ngx_http_variable_unknown_header_out(r, vv, (uintptr_t) name)
            == NGX_OK)
        {
            return vv;
        }

        return NULL;
    }

    if (ngx_strncmp(name->data, "upstream_http_", 10) == 0) {

        if (ngx_http_upstream_header_variable(r, vv, (uintptr_t) name)
            == NGX_OK)
        {
            return vv;
        }

        return NULL;
    }