文章17 ngx_http_request_t结构体详解欢迎转载，转载请注明http://blog.csdn.net/yankai0219/article/detai
文章17 ngx_http_request_t结构体详解
欢迎转载，转载请注明http://blog.csdn.net/yankai0219/article/details/8220621
由于本人能力有限，对于这些结构体的成员变量的解释，肯定有所差池，还请大家指出，大家共同学习主要内容：0.序一、ngx_http_request_t结构体解释二、ngx_http_request_body_t结构体三ngx_http_headers_in_t结构体四附录：里面用到的一些函数五一些没有搞清楚的成员变量
0.序在nginx中我们指的是http请求，具体到nginx中的数据结构是ngx_http_request_t。ngx_http_request_t是对一个http请求的封装。 我们知道，一个http请求，包含请求行、请求头、请求体、响应行、响应头、响应体。nginx中http代表http请求的数据结构是ngx_http_request_t。一个http请求，包含请求行、请求头、请求体、响应行、响应头、响应体。
http请求是典型的请求-响应类型的的网络协议，而http是文件协议，所以我们在分析请求行与请求头，以及输出响应行与响应头，往往是一行一行的进行处理。如果我们自己来写一个http服务器，通常在一个连接建立好后，客户端会发送请求过来。然后我们读取一行数据，分析出请求行中包含的method、uri、http_version信息。然后再一行一行处理请求头，并根据请求method与请求头的信息来决定是否有请求体以及请求体的长度，然后再去读取请求体。得到请求后，我们处理请求产生需要输出的数据，然后再生成响应行，响应头以及响应体。在将响应发送给客户端之后，一个完整的请求就处理完了。当然这是最简单的webserver的处理方式，其实nginx也是这样做的，只是有一些小小的区别，比如，当请求头读取完成后，就开始进行请求的处理了。nginx通过ngx_http_request_t来保存解析请求与输出响应相关的数据。
这短短的一段话蕴含的太多内容。首先一个http请求包含请求消息与响应消息。请求消息包括请求行、请求头、请求体。响应消息包括响应行、响应头、响应体。其次，在nginx中，ngx_http_request_t代表一个http请求，即ngx_http_request_t中包含了所有http请求的内容。
再次，关于message-body的存在与否，是与HTTP协议有关。最后，得到请求后，我们处理请求产生需要输出的数据，再生成响应行、响应头、响应体。
另外，提到nginx的区别，当请求头读取完成后，就开始进行请求的处理。是因为nginx采用异步处理。在读取请求头后，就进行请求的处理，而对于message-body的处理则异步进行。、http://hi.baidu.com/toughie/item/aa8990c1314a5d78cfd4f843http://tengine.taobao.org/book/chapter_2.html#request
一、ngx_http_request_t结构体解释
struct ngx_http_request_s { uint32_t signature; /* "HTTP" *//*与连接有关的内容*/ ngx_connection_t * connection;/*以下四个保存的是模块所对应的上下文结构体的指针。其中ctx对应于自定义的上下文结构体指针main_conf对应于main的上下文结构体指针loc_conf对应于loc的上下文结构体指针src_conf对应于srv的上下文结构体指针*/
void ** ctx;
void ** main_conf;
void ** srv_conf;
void ** loc_conf; /*读写事件的函数指针*/ ngx_http_event_handler_pt read_event_handler; ngx_http_event_handler_pt write_event_handler;
#if (NGX_HTTP_CACHE) ngx_http_cache_t * cache;
#endif/*与upstream模块相关的结构体*/ ngx_http_upstream_t * upstream; ngx_array_t * upstream_states; /* of ngx_http_upstream_state_t */
ngx_pool_t * pool; ngx_buf_t * header_in;// 会保存一些消息体的内容
ngx_http_headers_in_t headers_in; //代表请求头部 // 请求的header结构体 ngx_http_headers_out_t headers_out;//代表响应头部
ngx_http_request_body_t * request_body;//代表请求头部.
r-> request_body-> bufs中存放的请求体中的数据 time_t lingering_time; time_t start_sec; ngx_msec_t start_msec;
/*从method到http_protocol都是请求行中信息*/ ngx_uint_t method; ngx_uint_t http_version;//http版本
ngx_str_t request_line;//请求行 ngx_str_t uri; ngx_str_t args; ngx_str_t exten; ngx_str_t unparsed_uri;
ngx_str_t method_name; ngx_str_t http_protocol;
/* out;作用未知*/ ngx_chain_t * out;/*接下来从main到posted_requests都是与主请求和子请求有关的内容/ ngx_http_request_t * main;//这个表示主的request，也就是当前的request链中最上面的那个request，通过这个域我们就能判断当前的request是不是subrequest。 ngx_http_request_t * parent;//这个表示当前的request的父request。 //subrequest就是子请求，也就是在当前的一个请求中nginx再生成一个请求。ngx_http_postponed_request_t * postponed;//先来看postponed，这个域用来缓存父request的数据（也就是将要发送数据的request) ngx_http_post_subrequest_t * post_subrequest;//这个域保存了子请求的post request，它也就是保存了需要被发送的request. ngx_http_posted_request_t * posted_requests;//这个保存了所有的需要处理的request链表，也就是说它即包含子请求也包含父请求/* virtual hosts based on the address:port r->virtual_names = addr_conf->virtual_names*/ ngx_http_virtual_names_t * virtual_names;
ngx_int_t phase_handler; ngx_http_handler_pt content_handler; ngx_uint_t access_code;/* variables 包含了所有的变量*/ ngx_http_variable_value_t * variables;
#if (NGX_PCRE) ngx_uint_t ncaptures;
int * captures; u_char * captures_data;
#endif size_t limit_rate;
/* used to learn the
Apache compatible response length without a header */ size_t header_size;
off_t request_length;
ngx_uint_t err_status;
/*http_connection作用未知*/ ngx_http_connection_t * http_connection;
ngx_http_log_handler_pt log_handler;
ngx_http_cleanup_t * cleanup;
unsigned subrequests:8;
unsigned count:8;
unsigned blocked:8;
unsigned aio:1;
unsigned http_state:4;
/* URI with "/." and on Win32 with "//" */
unsigned complex_uri:1;
/* URI with "%" */
unsigned quoted_uri:1;
/* URI with "+" */
unsigned plus_in_uri:1;
/* URI with " " */
unsigned space_in_uri:1;
unsigned invalid_header:1;// 一个标示位，标示header是否有效，不正常的结束视为无效
unsigned add_uri_to_alias:1;
unsigned valid_location:1;
unsigned valid_unparsed_uri:1;
unsigned uri_changed:1;
unsigned uri_changes:4;/*下面这两个参数就会设定为每个body都存放到临时文件里，并且这个临时文件在请求结束后不会被删除：
r->request_body_in_persistent_file = 1;
r->request_body_in_file_only = 1;
*/
unsigned request_body_in_single_buf:1;
unsigned request_body_in_file_only:1;
unsigned request_body_in_persistent_file:1;
unsigned request_body_in_clean_file:1;
unsigned request_body_file_group_access:1;
unsigned request_body_file_log_level:3;
unsigned subrequest_in_memory:1;
unsigned waited:1;
#if (NGX_HTTP_CACHE)
unsigned cached:1;
#endif#if (NGX_HTTP_GZIP)
unsigned gzip_tested:1;
unsigned gzip_ok:1;
unsigned gzip_vary:1;
#endif unsigned proxy:1;
unsigned bypass_cache:1;
unsigned no_cache:1;
/* * instead of using the request context data in * ngx_http_limit_conn_module and ngx_http_limit_req_module * we use the single bits in the request structure */
unsigned limit_conn_set:1;
unsigned limit_req_set:1;
#if 0
unsigned cacheable:1;
#endif unsigned pipeline:1;
unsigned plain_http:1;
unsigned chunked:1;
unsigned header_only:1;
unsigned keepalive:1;
unsigned lingering_close:1;
unsigned discard_body:1;
unsigned internal:1;
unsigned error_page:1;
unsigned ignore_content_encoding:1;
unsigned filter_finalize:1;
unsigned post_action:1;
unsigned request_complete:1;
unsigned request_output:1;
unsigned header_sent:1;
unsigned expect_tested:1;
unsigned root_tested:1;
unsigned done:1;
unsigned logged:1;
unsigned buffered:4;
unsigned main_filter_need_in_memory:1;
unsigned filter_need_in_memory:1;
unsigned filter_need_temporary:1;
unsigned allow_ranges:1;
#if (NGX_STAT_STUB)
unsigned stat_reading:1;
unsigned stat_writing:1;
#endif /* used to parse HTTP headers *//*通过打印，不能获得header_name_start内容通过打印，可以获得header_start内容：为cookie内容+空行，也就是header_start内容包含cookie，但不仅仅包含cookie。*/
ngx_uint_t state;
ngx_uint_t header_hash; ngx_uint_t lowcase_index; u_char lowcase_header[NGX_HTTP_LC_HEADER_LEN];
u_char * header_name_start; u_char * header_name_end; u_char * header_start; u_char * header_end;
/* * a memory that can be reused after parsing a request line * via ngx_http_ephemeral_t *//* used to parse HTTP 请求行的消息** 通过打印，可以知道接下来这部分内容都是关于HTTP请求行的，通过这些指针可以方便找到所需的请求行中的内容，比如 r-> method_end+1,r-> http_protocol .data-1 之间就是URI。*/
u_char * uri_start; u_char * uri_end; u_char * uri_ext; u_char * args_start; u_char * request_start; u_char * request_end; u_char * method_end; u_char * schema_start; u_char * schema_end; u_char * host_start; u_char * host_end; u_char * port_start; u_char * port_end;
unsigned http_minor:16;
unsigned http_major:16;};测试中所添加函数内容：
#if 1
printf( "***ngx_http_upload_handler server :%s\t length is %d\n",out_headers_in.server. data,out_headers_in.server .len); yk_print_ngx_str_t ("server is " ,r->headers_in. server.data ,r->headers_in. server.len ); yk_print_ngx_str_t ("request_line is " ,r->request_line. data,r->request_line .len); yk_print_ngx_str_t ("
uri is ",r->uri .data,r-> uri.len ); yk_print_ngx_str_t ("
args is ",r->args .data,r-> args.len ); yk_print_ngx_str_t ("method_name is " ,r->method_name. data,r->method_name .len); yk_print_ngx_str_t ("unparsed_uri is " ,r->unparsed_uri. data,r->unparsed_uri .len);
yk_print_start2end( "r->uri_start",r->uri_start ,r->uri_end); yk_print_start2end( "r->request_start",r->request_start ,r->request_end); yk_print_start2end( "r->schema_start",r->schema_start ,r->schema_start); yk_print_start2end( "r->host_start",r->host_start ,r->host_start); //
printf("uri_ext is %s \t method_end is %s \t ",r->uri_ext,r->method_end);
yk_print_start2end( "
uri is",r-> method_end+1,r->http_protocol .data-1); /*这句话可以将
uri完整无错的打印出来*/ yk_print_start2end( "method_name start-end is" ,r->method_name. data,r->method_end +1);/*这句话可以将method完整无错的打印出来*/ //yk_print_start2end("header_name_start is",r->header_name_start,r->header_name_end); yk_print_start2end( "header_start is",r->header_start ,r->header_end);
#endif
ngx_http_request_t 中header_in作用：会保存一些消息体的内容，在用户名密码登陆的时候
二、ngx_http_request_body_t结构体typedef struct { ngx_temp_file_t * temp_file; ngx_chain_t * bufs;/*消息体都保存在这个chain里面*/ ngx_buf_t * buf; /*用作临时存储的buf，在ngx_http_read_client_request_body和ngx_http_do_read_client_request_body中用得到*/ off_t rest; ngx_chain_t * to_write; ngx_http_client_body_handler_pt post_handler;} ngx_http_request_body_t;通过下面的语句可以打印bufs中内容。/*below is edited by yankai*/ yankai_cl = r->request_body->bufs; yankai_sum_rb_bufs = 0; for (; yankai_cl; yankai_cl = yankai_cl->next){ yankai_sum_rb_bufs += (size_t)ngx_buf_size(yankai_cl->buf); } printf( "###yankai_sum_rb_bufs in ngx_http_upload_body_handler mm is %d\n",yankai_sum_rb_bufs);
三ngx_http_headers_in_t结构体typedef struct { ngx_list_t headers;
ngx_table_elt_t * host; ngx_table_elt_t * connection; ngx_table_elt_t * if_modified_since; ngx_table_elt_t * if_unmodified_since; ngx_table_elt_t * user_agent; ngx_table_elt_t * referer; ngx_table_elt_t * content_length; ngx_table_elt_t * content_type;
ngx_table_elt_t * range; ngx_table_elt_t * if_range;
ngx_table_elt_t * transfer_encoding; ngx_table_elt_t * expect;
#if (NGX_HTTP_GZIP) ngx_table_elt_t * accept_encoding; ngx_table_elt_t * via;
#endif ngx_table_elt_t * authorization;
ngx_table_elt_t * keep_alive;
#if (NGX_HTTP_X_FORWARDED_FOR) ngx_table_elt_t * x_forwarded_for;
#endif#if (NGX_HTTP_REALIP) ngx_table_elt_t *x_real_ip;
#endif#if (NGX_HTTP_HEADERS) ngx_table_elt_t *accept; ngx_table_elt_t *accept_language;
#endif#if (NGX_HTTP_DAV) ngx_table_elt_t *depth; ngx_table_elt_t *destination; ngx_table_elt_t *overwrite; ngx_table_elt_t *date;
#endif ngx_str_t user; ngx_str_t passwd;
ngx_array_t cookies;
ngx_str_t server;
off_t content_length_n; time_t keep_alive_n;
unsigned connection_type:2;
unsigned msie:1;
unsigned msie6:1;
unsigned opera:1;
unsigned gecko:1;
unsigned chrome:1;
unsigned safari:1;
unsigned konqueror:1;} ngx_http_headers_in_t;说明：ngx_http_headers_in_t是包含请求头中所有内容，
1）ngx_table_elt_t 都是RFC2616中提到的请求头域的内容
2）user、passwd未知
3）cookie里面保存的是cookie的内容，可以通过下面的代码打印出来
#if 0 /*six line code source :http://lijinxing17.blog.163.com/blog/static/34977708201062710583500/*/ ngx_table_elt_t ** cookies = NULL; ngx_uint_t i; printf( "Cookie count: %d\n" , r->headers_in.cookies.nelts); cookies = r->headers_in.cookies.elts;
for ( i = 0 ; i < r->headers_in.cookies.nelts; i++) { printf( "Cookie line %d: %s\n" , i, cookies[i]->value.data); }
#endif
四附录：里面用到的一些函数/**函数功能：知道字符串的其实地址和中止地址，输出该字符串*/
void yk_print_start2end(
char * description,u_char * start,u_char *end){
printf("%s\t" ,description); u_char * ptemp;
for(ptemp = start; ptemp != end; ptemp++)
printf("%c" ,*ptemp);
printf( "\n");}/**函数功能：知道字符串的其实地址和中止地址，输出该字符串*/
void yk_print_ngx_str_t(
char * description,u_char * data,
int len){
printf("%s\t" ,description); u_char * ptemp;
for(ptemp = data; ptemp != (data + len); ptemp++)
printf("%c" ,*ptemp);
printf("\n" );}
打印cookie内容
#if 0 /*six line code source :http://lijinxing17.blog.163.com/blog/static/34977708201062710583500/*/ ngx_table_elt_t ** cookies = NULL; ngx_uint_t i; printf( "Cookie count: %d\n" , r->headers_in.cookies.nelts); cookies = r->headers_in.cookies.elts;
for ( i = 0 ; i < r->headers_in.cookies.nelts; i++) { printf( "Cookie line %d: %s\n" , i, cookies[i]->value.data); }
#endif五、一些没有搞清楚的成员变量ngx_http_headers_int_t结构体中user passwd headers
ngx_connection_t *connection
ngx_http_connection_t *http_connection
