fastcgi协议解析(nginx)

Posted 2020-10-10 阮減显

 

请求
nginx ->[

{(post data) +> (NGX_HTTP_FASTCGI_STDIN)} * N +>

{(environment variables) +> (NGX_HTTP_FASTCGI_PARAMS)} * N  +>  

(角色和连接设置) +>

(NGX_HTTP_FASTCGI_BEGIN_REQUEST)

] -> fastCGI

NGX_HTTP_FASTCGI_BEGIN_REQUEST : 第一个发送出去的 ngx_http_fastcgi_header_t
角色和连接设置 : ngx_http_fastcgi_begin_request_t结构体
NGX_HTTP_FASTCGI_PARAMS : 环境变量 ,可能有N个
environment variables : 环境变量具体数据包括请求的url use_agent 等等,可能有N个,长度由NGX_HTTP_FASTCGI_PARAMS中的content_length_*指定
NGX_HTTP_FASTCGI_STDIN : 提交的数据 ,可能有N个,
post data : post 上来的数据,可能有N个,长度由NGX_HTTP_FASTCGI_STDIN中的content_length_*指定

 

数据结构

#define NGX_HTTP_FASTCGI_BEGIN_REQUEST  1
#define NGX_HTTP_FASTCGI_ABORT_REQUEST  2
#define NGX_HTTP_FASTCGI_END_REQUEST    3
#define NGX_HTTP_FASTCGI_PARAMS         4
#define NGX_HTTP_FASTCGI_STDIN          5
#define NGX_HTTP_FASTCGI_STDOUT         6
#define NGX_HTTP_FASTCGI_STDERR         7
#define NGX_HTTP_FASTCGI_DATA           8

typedef struct {
    u_char  version; //标识FastCGI协议版本 一般为 1
    u_char  type;  //参考上面的宏定义  NGX_HTTP_FASTCGI_*
    u_char  request_id_hi;  //请求id
    u_char  request_id_lo;
    u_char  content_length_hi; //请求内容长度
    u_char  content_length_lo;
    u_char  padding_length; //填充长度
    u_char  reserved;
} ngx_http_fastcgi_header_t;



typedef struct {
    u_char  role_hi; //角色id
    u_char  role_lo;
    u_char  flags; // 0 请求完毕后关闭连接 1 请求接收后保持连接
    u_char  reserved[5];
} ngx_http_fastcgi_begin_request_t;

 

fastCGI 接收请求样例

		memcpy(&fh,recvBuf+0,sizeof(ngx_http_fastcgi_header_t));//FCGI_BEGIN_REQUEST
		memcpy(&fb,recvBuf+sizeof(ngx_http_fastcgi_header_t),sizeof(ngx_http_fastcgi_begin_request_t));
		memcpy(&fp,recvBuf+sizeof(ngx_http_fastcgi_header_t)+sizeof(ngx_http_fastcgi_begin_request_t),sizeof(ngx_http_fastcgi_header_t));//FCGI_PARAMS
		
		int paramLen = fp.contentLengthB1*256+fp.contentLengthB0; //816
		char paramBuf[1024];
		memcpy(paramBuf,recvBuf+sizeof(ngx_http_fastcgi_header_t)*2+sizeof(ngx_http_fastcgi_begin_request_t),paramLen);//environment variables
		
		memcpy(&fp,recvBuf+sizeof(ngx_http_fastcgi_header_t)*2+sizeof(ngx_http_fastcgi_begin_request_t)+paramLen,sizeof(ngx_http_fastcgi_header_t));//FCGI_PARAMS
		memcpy(&fp,recvBuf+sizeof(ngx_http_fastcgi_header_t)*3+sizeof(ngx_http_fastcgi_begin_request_t)+paramLen,sizeof(ngx_http_fastcgi_header_t));//FCGI_STDIN

 

响应

fastCGI ->[

(NGX_HTTP_FASTCGI_END_REQUEST) +>

{(response error data) +> (NGX_HTTP_FASTCGI_STDERR)} * N  +>  

{(response data) +> (NGX_HTTP_FASTCGI_STDOUT)} * N +>

] -> NGINX

NGX_HTTP_FASTCGI_STDOUT : 输出的正常内容，可能有N个
response data : 相应的数据，长度由NGX_HTTP_FASTCGI_STDOUT中的content_length_*指
NGX_HTTP_FASTCGI_STDERR : 输出的报错内容，可能有N个
response error data : 相应的数据，长度由NGX_HTTP_FASTCGI_STDERR中的content_length_*指
NGX_HTTP_FASTCGI_END_REQUEST : 标识本次响应结束

 

 

 

fastCGI 接收样例

 

		char sendBuf[1024];
		char response[]="HTTP/1.1 200 OK\r\nContent-Type:text/html\r\nContent-Length: 7\r\n\r\nWelcome";
		
		fStdout.version=1;
		fStdout.type=6;//FCGI_STDOUT
		fStdout.requestIdB1=0;
		fStdout.requestIdB0=1;
		
		fStdout.contentLengthB1=0;
		fStdout.contentLengthB0=strlen(response);
		fStdout.paddingLength=0;
		fStdout.reserved=0;
		
		fStderr=fStdout;
		fStderr.type=7;//FCGI_STDERR
		fStderr.contentLengthB0=0;

		fEnd = fStderr;
		fEnd.type=3;//FCGI_END_REQUEST
		
		memcpy(sendBuf,&fStdout,sizeof(ngx_http_fastcgi_header_t));
		memcpy(sendBuf+sizeof(ngx_http_fastcgi_header_t),response,strlen(response));
		memcpy(sendBuf+sizeof(ngx_http_fastcgi_header_t)+strlen(response),&fStderr,sizeof(ngx_http_fastcgi_header_t));
		memcpy(sendBuf+sizeof(ngx_http_fastcgi_header_t)*2+strlen(response),&fEnd,sizeof(ngx_http_fastcgi_header_t));

		send(sockConnection, sendBuf, sizeof(ngx_http_fastcgi_header_t)*3+strlen(response),0);