nginx全局变量

yanqiufang

　　经常需要配置Nginx ，其中有许多以
$ 开头的变量，经常需要查阅nginx 所支持的变量。Nginx支持的http变量实现在ngx_http_variables.c 的 ngx_http_core_variables存储实现：
　　

ngx_http_core_variables
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_line, 0, 0, 0 },
{ ngx_string("document_root"), NULL,
ngx_http_variable_document_root, 0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
{ ngx_string("realpath_root"), NULL,
ngx_http_variable_realpath_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,
NGX_HTTP_VAR_NOCACHEABLE, 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"), NULL,
ngx_http_variable_request_body,
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_location"), NULL,
ngx_http_variable_sent_location, 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_get_size,
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_string("hostname"), NULL, ngx_http_variable_hostname,
0, 0, 0 },
{ ngx_string("pid"), NULL, ngx_http_variable_pid,
0, 0, 0 },
{ ngx_null_string, NULL, NULL, 0, 0, 0 }
};
　　


把这些变量提取下，总结如下(1.0.8版)：
　　

$args	请求中的参数;
$binary_remote_addr	远程地址的二进制表示
$body_bytes_sent	已发送的消息体字节数
$content_length	HTTP请求信息里的"Content-Length";
$content_type	请求信息里的"Content-Type";
$document_root	针对当前请求的根路径设置值;
$document_uri	与$uri相同;
$host	请求信息中的"Host"，如果请求中没有Host行，则等于设置的服务器名;
$hostname
$http_cookie	cookie 信息
$http_post
$http_referer	引用地址
$http_user_agent	客户端代理信息
$http_via	最后一个访问服务器的Ip地址。http://www.cnblogs.com/deng02/archive/2009/02/11/1387911.html
$http_x_forwarded_for	相当于网络访问路径。http://www.cnblogs.com/craig/archive/2008/11/18/1335809.html
$is_args
$limit_rate	对连接速率的限制;
$nginx_version
$pid
$query_string	与$args相同;
$realpath_root
$remote_addr	客户端地址;
$remote_port	客户端端口号;
$remote_user	客户端用户名，认证用;
$request	用户请求
$request_body
$request_body_file	发往后端的本地文件名称
$request_completion
$request_filename	当前请求的文件路径名
$request_method	请求的方法，比如"GET"、"POST"等;
$request_uri	请求的URI，带参数;
$scheme	所用的协议，比如http或者是https，比如rewrite^(.+)$$scheme://example.com$1redirect;
$sent_http_cache_control
$sent_http_connection
$sent_http_content_length
$sent_http_content_type
$sent_http_keep_alive
$sent_http_last_modified
$sent_http_location
$sent_http_transfer_encoding
$server_addr	服务器地址，如果没有用listen指明服务器地址，使用这个变量将发起一次系统调用以取得地址(造成资源浪费);
$server_name	请求到达的服务器名;
$server_port	请求到达的服务器端口号;
$server_protocol	请求的协议版本，"HTTP/1.0"或"HTTP/1.1";
$uri	请求的URI，可能和最初的值有不同，比如经过重定向之类的。