High-concurrency server design-FastCGI Design

FastCGI is indispensable in server development. Its usage is as follows:

while( FCGI_Accept() >= 0 ){                printf( "Content-type: text/plain \r\n"                "Content-Length: %d\r\n"                "Connection: close\r\n\r\n%s\r\n", strlen( buffer ), buffer );        }

The facgcgi header file has the following macros:

#undef  fprintf#definefprintf  FCGI_fprintf#undef  printf#defineprintf   FCGI_printf

We can see that the printf function has been macro-switched, and the printf in the program is no longer a standard output. In this way, there is a problem. If you want to debug and print the information to stdout, it will not work.

In actual development, various problems may occur, and sometimes some information needs to be printed. At this time, you can modify the fcgi_stdio.h header file and change it to the following:

#undef  _fprintf#define _fprintf  FCGI_fprintf#undef  _printf#define_printf   FCGI_printf

The corresponding macro should also be replaced in the corresponding place in the program.

FastCGI can be parsed using this function:

char *getenv(const char *name) 

There are several types of parameters:

Content_type

Content_type	Request type
Content_length	Body segment length
QUERY_STRING	Request string

Take the following HTTP request message as an example:

GET /s?ie=utf-8&bs=%E8%BF%99%E6%98%AF&f=8&rsv_bp=1&rsv_spt=3&wd=%E6%9C%8D%E5%8A%A1%E5%99%A8%E5%BC%80%E5%8F%91&rsv_sug3=11&rsv_sug=0&rsv_sug4=609&rsv_sug1=2&inputT=32681 HTTP/1.1Host: www.baidu.comConnection: keep-aliveContent-Type: text/html;charset=utf-8Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31Referer: http://www.baidu.com/s?wd=%E8%BF%99%E6%98%AF&rsv_bp=0&ch=&tn=baidu&bar=&rsv_spt=3&ie=utf-8&rsv_sug3=4&rsv_sug=0&rsv_sug4=240&rsv_sug1=3&inputT=2835Accept-Encoding: gzip,deflate,sdchAccept-Language: zh-CN,zh;q=0.8Accept-Charset: GBK,utf-8;q=0.7,*;q=0.3Cookie: BAIDUID=A83324E58AE26486E46FC49ED127891B:FG=1; BDSVRTM=163; H_PS_PSSID=1439_2448_2454_2256_1788_2249; WWW_ST=1369271667063

Content_type corresponds to row 5th, and QUERY_STRING corresponds to the first row.

FastCGI is not object-oriented, and all tasks are completed in the main loop, including parsing, processing, and response.

In actual development, to improve efficiency, developers do not have to worry about the underlying layer. I encapsulate it into a class: fcgi_net_duty

#ifndef __FCGI_NET_H__#define __FCGI_NET_H__#define FCGI_NET_OK           0#define FCGI_NET_ERROR        1#define FCGI_NET_PARAM_ERROR  2enum fcgi_net_type{        FCGI_NET_TEXT = 0,        FCGI_NET_APP_STREAM,        FCGI_NET_IMAGE,};class fcgi_net_duty{public:        fcgi_net_duty();        ~fcgi_net_duty();        void do_request();protected:        void  do_prev();        void  do_cast();        virtual void  do_handle();        void  do_write();        void  do_finish();        int get_req_int( const char* param, int *value );                int get_req_ll( const char* param, long long *value );        int get_req_str( const char* param, const char **value );        int get_cookie_int( const char* param, int *value );        int get_cookie_ll( const char* param, long long *value );        int get_cookie_str( const char* param, const char **value );private:        std::map< const char*, const char* > m_req;        std::map< const char*, const char* > m_cookie;        int rtn;                int content_type;        int content_length;        char* content_buf;};

Put the main loop in the do_request Function

Fcgi_net_duty.cpp

void fcgi_net_duty::do_request(){        while( FCGI_Accept() >= 0 ){                do_prev();                do_cast();                do_handle();                do_write();                do_finish();        }}

Subclass only needs to care about the corresponding business. Each business can be completed by a subclass. For example, there are three existing businesses: busi1, bui2, and busi3. Let's take one of them as an example:

Fcig_busi1.h

#ifndef __FCGI_BUSI1_H__#define __FCGI_BUSI1_H__class fcgi_busi1 : public fcgi_net_duty{public:         fcgi_busi1();        ~fcgi_busi1();        void do_handle();};#endif //__FCGI_BUSI1_H__

Fcgi_busi1.cpp

void fcgi_busi1::do_handle(){        const char* busi1;        int flag;        rtn = FCGI_NET_ERROR;        flag = get_req_str( "busi1", &busi1 );        if( flag ){                rtn = FCGI_NET_PARAM_ERROR;                return;        }        sprintf( content_buf, "%s","your busi is ok" );        rtn = FCGI_NET_OK;}int main(){        fcgi_busi1 busi1;        busi1.do_request();}

Corresponding makefile:

INC=-I./ LIB=-L/usr/lib64 -lfcgiCPPFLAGS=-g -w $(INC)CC=g++BUSI1=./build/busi1BUSI2=./build/busi2BUSI3=./build/busi3all: $(BUSI1) $(BUSI2) $(BUSI3)$(BUSI1): ./fcgi_net_duty.o ./fcgi_busi1.o        $(CC) -O $@ $^ $(LIB)$(BUSI2): ./fcgi_net_duty.o ./fcgi_busi2.o        $(CC) -O $@ $^ $(LIB)$(BUSI3): ./fcgi_net_duty.o ./fcgi_busi3.o        $(CC) -O $@ $^ $(LIB)

Okay. Now a lightweight FastCGI development framework has been built. In real-world development, a member can develop network processing, and others can specialize in corresponding business processing, my philosophy is to let professional people do professional things, so that they can better improve their professional skills.