Http_conn.h#ifndef HTTPCONNECTION_H
#define HTTPCONNECTION_H
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/epoll.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <sys/stat.h>
#include <string.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <stdarg.h>
#include <errno.h>
#include "locker.h"
class http_conn
{
public:
/*文件名的最大长度*/
static const int FILENAME_LEN = 200;
/*读缓冲区的大小*/
static const int READ_BUFFER_SIZE = 2048;
/*写缓冲区的大小*/
static const int WRITE_BUFFER_SIZE = 1024;
/*HTTP请求方法,但我们仅支持GET*/
enum METHOD { GET = 0, POST, HEAD, PUT, DELETE, TRACE, OPTIONS, CONNECT, PATCH };
/*解析客户请求时,主状态机所处的状态*/
enum CHECK_STATE { CHECK_STATE_REQUESTLINE = 0, CHECK_STATE_HEADER, CHECK_STATE_CONTENT };
/*服务器处理HTTP请求的可能结果*/
enum HTTP_CODE { NO_REQUEST, GET_REQUEST, BAD_REQUEST, NO_RESOURCE, FORBIDDEN_REQUEST, FILE_REQUEST, INTERNAL_ERROR, CLOSED_CONNECTION };
/*行的读取状态*/
enum LINE_STATUS { LINE_OK = 0, LINE_BAD, LINE_OPEN };
public:
http_conn(){}
~http_conn(){}
public:
/*初始化新接受的连接*/
void init( int sockfd, const sockaddr_in& addr );
/*关闭连接*/
void close_conn( bool real_close = true );
/*处理客户请求*/
void process();
/*非阻塞读操作*/
bool read();
/*非阻塞写操作*/
bool write();
private:
/*初始化连接*/
void init();
/*解析HTTP请求*/
HTTP_CODE process_read();
/*填充HTTP应答*/
bool process_write( HTTP_CODE ret );
/*下面一组函数被process_read调用以解析HTTP请求*/
HTTP_CODE parse_request_line( char* text );
HTTP_CODE parse_headers( char* text );
HTTP_CODE parse_content( char* text );
HTTP_CODE do_request();
char* get_line() { return m_read_buf + m_start_line; }
LINE_STATUS parse_line();
/*下面这一组函数被process_write调用以填充HTTP应答*/
void unmap();
bool add_response( const char* format, ... );
bool add_content( const char* content );
bool add_status_line( int status, const char* title );
bool add_headers( int content_length );
bool add_content_length( int content_length );
bool add_linger();
bool add_blank_line();
public:
/*所有socket上的事件都被注册到同一个epoll内核事件表中,所以将epoll文件描述符设置为静态*/
static int m_epollfd;
/*统计用户数量*/
static int m_user_count;
private:
/*该HTTP连接的socket和对方的socket地址*/
int m_sockfd;
sockaddr_in m_address;
/*读缓冲区*/
char m_read_buf[ READ_BUFFER_SIZE ];
/*标识读缓冲中已经读入的客户数据的最后一个字节的下一个位置*/
int m_read_idx;
/*当前正在分析的字符在读缓冲区中的位置*/
int m_checked_idx;
/*当前正在解析的行的起始位置*/
int m_start_line;
/*写缓冲区*/
char m_write_buf[ WRITE_BUFFER_SIZE ];
/*写缓冲区中待发送的字节数*/
int m_write_idx;
/*主状态机当前所处的状态*/
CHECK_STATE m_check_state;
/*请求方法*/
METHOD m_method;
/*客户请求的目标文件的完整路径,其内容等于doc_root + m_url,doc_root是网站根目录*/
char m_real_file[ FILENAME_LEN ];
/*客户请求的目标文件的文件名*/
char* m_url;
/*HTTP协议版本号,我们仅支持HTTP/1.1*/
char* m_version;
/*主机名*/
char* m_host;
/*HTTP请求的消息体的长度*/
int m_content_length;
/*HTTP请求是否要求保持连接*/
bool m_linger;
/*客户请求的目标文件被mmap到内存中的起始位置*/
char* m_file_address;
/*目标文件的状态,通过它我们可以判断文件是否存在,是否为目录,是否可读,并获取文件大小等*/
struct stat m_file_stat;
/*我们将采用writev来执行写操作,所以定义下面两个成员,其中m_iv_count表示被写内存
*块的数量*/
struct iovec m_iv[2];
int m_iv_count;
};
#endif
http_conn.cpp
#include "http_conn.h"
/*定义HTTP响应的一些状态信息*/
const char* ok_200_title = "OK";
const char* error_400_title = "Bad Request";
const char* error_400_form = "Your request has bad syntax or is inherently impossible to satisfy.\n";
const char* error_403_title = "Forbidden";
const char* error_403_form = "You do not have permission to get file from this server.\n";
const char* error_404_title = "Not Found";
const char* error_404_form = "The requested file was not found on this server.\n";
const char* error_500_title = "Internal Error";
const char* error_500_form = "There was an unusual problem serving the requested file.\n";
/*网站的根目录*/
const char* doc_root = "/var/www/html";
int setnonblocking( int fd )
{
int old_option = fcntl( fd, F_GETFL );
int new_option = old_option | O_NONBLOCK;
fcntl( fd, F_SETFL, new_option );
return old_option;
}
void addfd( int epollfd, int fd, bool one_shot )
{
epoll_event event;
event.data.fd = fd;
event.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
if( one_shot )
{
event.events |= EPOLLONESHOT;
}
epoll_ctl( epollfd, EPOLL_CTL_ADD, fd, &event );
setnonblocking( fd );
}
void removefd( int epollfd, int fd )
{
epoll_ctl( epollfd, EPOLL_CTL_DEL, fd, 0 );
close( fd );
}
void modfd( int epollfd, int fd, int ev )
{
epoll_event event;
event.data.fd = fd;
event.events = ev | EPOLLET | EPOLLONESHOT | EPOLLRDHUP;
epoll_ctl( epollfd, EPOLL_CTL_MOD, fd, &event );
}
int http_conn::m_user_count = 0;
int http_conn::m_epollfd = -1;
void http_conn::close_conn( bool real_close )
{
if( real_close && ( m_sockfd != -1 ) )
{
//modfd( m_epollfd, m_sockfd, EPOLLIN );
removefd( m_epollfd, m_sockfd );
m_sockfd = -1;
m_user_count--;/*关闭一个连接时,将客户总数减1*/
}
}
void http_conn::init( int sockfd, const sockaddr_in& addr )
{
m_sockfd = sockfd;
m_address = addr;
int error = 0;
socklen_t len = sizeof( error );
getsockopt( m_sockfd, SOL_SOCKET, SO_ERROR, &error, &len );
/*如下两行是为了避免TIME_WAIT状态,仅用于调试,实际使用时应该去掉*/
int reuse = 1;
setsockopt( m_sockfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof( reuse ) );
addfd( m_epollfd, sockfd, true );
m_user_count++;
init();
}
void http_conn::init()
{
m_check_state = CHECK_STATE_REQUESTLINE;
m_linger = false;
m_method = GET;
m_url = 0;
m_version = 0;
m_content_length = 0;
m_host = 0;
m_start_line = 0;
m_checked_idx = 0;
m_read_idx = 0;
m_write_idx = 0;
memset( m_read_buf, '\0', READ_BUFFER_SIZE );
memset( m_write_buf, '\0', WRITE_BUFFER_SIZE );
memset( m_real_file, '\0', FILENAME_LEN );
}
/*从状态机*/
http_conn::LINE_STATUS http_conn::parse_line()
{
char temp;
for ( ; m_checked_idx < m_read_idx; ++m_checked_idx )
{
temp = m_read_buf[ m_checked_idx ];
if ( temp == '\r' )
{
if ( ( m_checked_idx + 1 ) == m_read_idx )
{
return LINE_OPEN;
}
else if ( m_read_buf[ m_checked_idx + 1 ] == '\n' )
{
m_read_buf[ m_checked_idx++ ] = '\0';
m_read_buf[ m_checked_idx++ ] = '\0';
return LINE_OK;
}
return LINE_BAD;
}
else if( temp == '\n' )
{
if( ( m_checked_idx > 1 ) && ( m_read_buf[ m_checked_idx - 1 ] == '\r' ) )
{
m_read_buf[ m_checked_idx-1 ] = '\0';
m_read_buf[ m_checked_idx++ ] = '\0';
return LINE_OK;
}
return LINE_BAD;
}
}
return LINE_OPEN;
}
/*循环读取客户数据,直到无数据可读或者对方关闭连接*/
bool http_conn::read()
{
if( m_read_idx >= READ_BUFFER_SIZE )
{
return false;
}
int bytes_read = 0;
while( true )
{
bytes_read = recv( m_sockfd, m_read_buf + m_read_idx, READ_BUFFER_SIZE - m_read_idx, 0 );
if ( bytes_read == -1 )
{
if( errno == EAGAIN || errno == EWOULDBLOCK )
{
break;
}
return false;
}
else if ( bytes_read == 0 )
{
return false;
}
m_read_idx += bytes_read;
}
return true;
}
/*解析HTTP请求行,获得请求方法,目标URL,以及HTTP版本号*/
http_conn::HTTP_CODE http_conn::parse_request_line( char* text )
{
m_url = strpbrk( text, " \t" );
if ( ! m_url )
{
return BAD_REQUEST;
}
*m_url++ = '\0';
char* method = text;
if ( strcasecmp( method, "GET" ) == 0 )
{
m_method = GET;
}
else
{
return BAD_REQUEST;
}
m_url += strspn( m_url, " \t" );
m_version = strpbrk( m_url, " \t" );
if ( ! m_version )
{
return BAD_REQUEST;
}
*m_version++ = '\0';
m_version += strspn( m_version, " \t" );
if ( strcasecmp( m_version, "HTTP/1.1" ) != 0 )
{
return BAD_REQUEST;
}
if ( strncasecmp( m_url, "http://", 7 ) == 0 )
{
m_url += 7;
m_url = strchr( m_url, '/' );
}
if ( ! m_url || m_url[ 0 ] != '/' )
{
return BAD_REQUEST;
}
m_check_state = CHECK_STATE_HEADER;
return NO_REQUEST;
}
/*解析HTTP请求的一个头部信息*/
http_conn::HTTP_CODE http_conn::parse_headers( char* text )
{
/*遇到空行,表示头部字段解析完毕*/
if( text[ 0 ] == '\0' )
{
if ( m_method == HEAD )
{
return GET_REQUEST;
}
/*如果HTTP请求有消息体,则还需要读取m_content_length字节的消息体,状态
*机转移到CHECK_STATE_CONTENT状态*/
if ( m_content_length != 0 )
{
m_check_state = CHECK_STATE_CONTENT;
return NO_REQUEST;
}
/*是否说明我们已经得到了一个完整的HTTP请求*/
return GET_REQUEST;
}
/*处理Connection头部字段*/
else if ( strncasecmp( text, "Connection:", 11 ) == 0 )
{
text += 11;
text += strspn( text, " \t" );
if ( strcasecmp( text, "keep-alive" ) == 0 )
{
m_linger = true;
}
}
/*处理Content-Length头部字段*/
else if ( strncasecmp( text, "Content-Length:", 15 ) == 0 )
{
text += 15;
text += strspn( text, " \t" );
m_content_length = atol( text );
}
/*处理Host头部字段*/
else if ( strncasecmp( text, "Host:", 5 ) == 0 )
{
text += 5;
text += strspn( text, " \t" );
m_host = text;
}
else
{
printf( "oop! unknow header %s\n", text );
}
return NO_REQUEST;
}
/*没有真正解析HTTP请求的消息体,只是判断它是否被完整地读入了*/
http_conn::HTTP_CODE http_conn::parse_content( char* text )
{
if ( m_read_idx >= ( m_content_length + m_checked_idx ) )
{
text[ m_content_length ] = '\0';
return GET_REQUEST;
}
return NO_REQUEST;
}
/*主机态机*/
http_conn::HTTP_CODE http_conn::process_read()
{
LINE_STATUS line_status = LINE_OK;
HTTP_CODE ret = NO_REQUEST;
char* text = 0;
while ( ( ( m_check_state == CHECK_STATE_CONTENT ) && ( line_status == LINE_OK ) )
|| ( ( line_status = parse_line() ) == LINE_OK ) )
{
text = get_line();
m_start_line = m_checked_idx;
printf( "got 1 http line: %s\n", text );
switch ( m_check_state )
{
case CHECK_STATE_REQUESTLINE:
{
ret = parse_request_line( text );
if ( ret == BAD_REQUEST )
{
return BAD_REQUEST;
}
break;
}
case CHECK_STATE_HEADER:
{
ret = parse_headers( text );
if ( ret == BAD_REQUEST )
{
return BAD_REQUEST;
}
else if ( ret == GET_REQUEST )
{
return do_request();
}
break;
}
case CHECK_STATE_CONTENT:
{
ret = parse_content( text );
if ( ret == GET_REQUEST )
{
return do_request();
}
line_status = LINE_OPEN;
break;
}
default:
{
return INTERNAL_ERROR;
}
}
}
return NO_REQUEST;
}
/*当得到一个完整,正确的HTTP请求时,我们就分析目标文件的属性。如果目标文件存在,对
* 所有用户可读,且不是目录,则使用mmap将其映射到内存地址m_file_address处,并告诉调用者
* 获取文件成功*/
http_conn::HTTP_CODE http_conn::do_request()
{
strcpy( m_real_file, doc_root );
int len = strlen( doc_root );
strncpy( m_real_file + len, m_url, FILENAME_LEN - len - 1 );
if ( stat( m_real_file, &m_file_stat ) < 0 )
{
return NO_RESOURCE;
}
if ( ! ( m_file_stat.st_mode & S_IROTH ) )
{
return FORBIDDEN_REQUEST;
}
if ( S_ISDIR( m_file_stat.st_mode ) )
{
return BAD_REQUEST;
}
int fd = open( m_real_file, O_RDONLY );
m_file_address = ( char* )mmap( 0, m_file_stat.st_size, PROT_READ, MAP_PRIVATE, fd, 0 );
close( fd );
return FILE_REQUEST;
}
/*对内存映射区执行munmap操作*/
void http_conn::unmap()
{
if( m_file_address )
{
munmap( m_file_address, m_file_stat.st_size );
m_file_address = 0;
}
}
/*写HTTP响应*/
bool http_conn::write()
{
int temp = 0;
int bytes_have_send = 0;
int bytes_to_send = m_write_idx;
if ( bytes_to_send == 0 )
{
modfd( m_epollfd, m_sockfd, EPOLLIN );
init();
return true;
}
while( 1 )
{
temp = writev( m_sockfd, m_iv, m_iv_count );
if ( temp <= -1 )
{
/*如果TCP写缓冲没有空间,则等待下一轮EPOLLOUT事件,虽然在此期间,服务器无法
* 立即接收到同一个客户的下一请求,但这可以保鲜盒增连接的完整性*/
if( errno == EAGAIN )
{
modfd( m_epollfd, m_sockfd, EPOLLOUT );
return true;
}
unmap();
return false;
}
bytes_to_send -= temp;
bytes_have_send += temp;
if ( bytes_to_send <= bytes_have_send )
{
/*发送HTTP响应成功,根据HTTP请求中的Connection字段是否立即关闭连接*/
unmap();
if( m_linger )
{
init();
modfd( m_epollfd, m_sockfd, EPOLLIN );
return true;
}
else
{
modfd( m_epollfd, m_sockfd, EPOLLIN );
return false;
}
}
}
}
/*往写缓冲区写入待发送数据*/
bool http_conn::add_response( const char* format, ... )
{
if( m_write_idx >= WRITE_BUFFER_SIZE )
{
return false;
}
va_list arg_list;
va_start( arg_list, format );
int len = vsnprintf( m_write_buf + m_write_idx, WRITE_BUFFER_SIZE - 1 - m_write_idx, format, arg_list );
if( len >= ( WRITE_BUFFER_SIZE - 1 - m_write_idx ) )
{
return false;
}
m_write_idx += len;
va_end( arg_list );
return true;
}
bool http_conn::add_status_line( int status, const char* title )
{
return add_response( "%s %d %s\r\n", "HTTP/1.1", status, title );
}
bool http_conn::add_headers( int content_len )
{
add_content_length( content_len );
add_linger();
add_blank_line();
}
bool http_conn::add_content_length( int content_len )
{
return add_response( "Content-Length: %d\r\n", content_len );
}
bool http_conn::add_linger()
{
return add_response( "Connection: %s\r\n", ( m_linger == true ) ? "keep-alive" : "close" );
}
bool http_conn::add_blank_line()
{
return add_response( "%s", "\r\n" );
}
bool http_conn::add_content( const char* content )
{
return add_response( "%s", content );
}
/*根据服务器处理HTTP请求的结果,决定返回给客户的内容*/
bool http_conn::process_write( HTTP_CODE ret )
{
switch ( ret )
{
case INTERNAL_ERROR:
{
add_status_line( 500, error_500_title );
add_headers( strlen( error_500_form ) );
if ( ! add_content( error_500_form ) )
{
return false;
}
break;
}
case BAD_REQUEST:
{
add_status_line( 400, error_400_title );
add_headers( strlen( error_400_form ) );
if ( ! add_content( error_400_form ) )
{
return false;
}
break;
}
case NO_RESOURCE:
{
add_status_line( 404, error_404_title );
add_headers( strlen( error_404_form ) );
if ( ! add_content( error_404_form ) )
{
return false;
}
break;
}
case FORBIDDEN_REQUEST:
{
add_status_line( 403, error_403_title );
add_headers( strlen( error_403_form ) );
if ( ! add_content( error_403_form ) )
{
return false;
}
break;
}
case FILE_REQUEST:
{
add_status_line( 200, ok_200_title );
if ( m_file_stat.st_size != 0 )
{
add_headers( m_file_stat.st_size );
m_iv[ 0 ].iov_base = m_write_buf;
m_iv[ 0 ].iov_len = m_write_idx;
m_iv[ 1 ].iov_base = m_file_address;
m_iv[ 1 ].iov_len = m_file_stat.st_size;
m_iv_count = 2;
return true;
}
else
{
const char* ok_string = "<html><body></body></html>";
add_headers( strlen( ok_string ) );
if ( ! add_content( ok_string ) )
{
return false;
}
}
}
default:
{
return false;
}
}
m_iv[ 0 ].iov_base = m_write_buf;
m_iv[ 0 ].iov_len = m_write_idx;
m_iv_count = 1;
return true;
}
/*由线程池中工作线程调用,这是处理HTTP请求的入口函数*/
void http_conn::process()
{
HTTP_CODE read_ret = process_read();
if ( read_ret == NO_REQUEST )
{
modfd( m_epollfd, m_sockfd, EPOLLIN );
return;
}
bool write_ret = process_write( read_ret );
if ( ! write_ret )
{
close_conn();
}
modfd( m_epollfd, m_sockfd, EPOLLOUT );
}
main.cpp
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <cassert>
#include <sys/epoll.h>
#include "locker.h"
#include "threadpool.h"
#include "http_conn.h"
#define MAX_FD 65536
#define MAX_EVENT_NUMBER 10000
extern int addfd( int epollfd, int fd, bool one_shot );
extern int removefd( int epollfd, int fd );
void addsig( int sig, void( handler )(int), bool restart = true )
{
struct sigaction sa;
memset( &sa, '\0', sizeof( sa ) );
sa.sa_handler = handler;
if( restart )
{
sa.sa_flags |= SA_RESTART;
}
sigfillset( &sa.sa_mask );
assert( sigaction( sig, &sa, NULL ) != -1 );
}
void show_error( int connfd, const char* info )
{
printf( "%s", info );
send( connfd, info, strlen( info ), 0 );
close( connfd );
}
int main( int argc, char* argv[] )
{
if( argc <= 2 )
{
printf( "usage: %s ip_address port_number\n", basename( argv[0] ) );
return 1;
}
const char* ip = argv[1];
int port = atoi( argv[2] );
/*忽略SIGPIPE信号*/
addsig( SIGPIPE, SIG_IGN );
/*创建线程池*/
threadpool< http_conn >* pool = NULL;
try
{
pool = new threadpool< http_conn >;
}
catch( ... )
{
return 1;
}
/*预先为每个可能的客户连接分配一个http_conn对象*/
http_conn* users = new http_conn[ MAX_FD ];
assert( users );
int user_count = 0;
int listenfd = socket( PF_INET, SOCK_STREAM, 0 );
assert( listenfd >= 0 );
struct linger tmp = { 1, 0 };
setsockopt( listenfd, SOL_SOCKET, SO_LINGER, &tmp, sizeof( tmp ) );
int ret = 0;
struct sockaddr_in address;
bzero( &address, sizeof( address ) );
address.sin_family = AF_INET;
inet_pton( AF_INET, ip, &address.sin_addr );
address.sin_port = htons( port );
ret = bind( listenfd, ( struct sockaddr* )&address, sizeof( address ) );
assert( ret >= 0 );
ret = listen( listenfd, 5 );
assert( ret >= 0 );
epoll_event events[ MAX_EVENT_NUMBER ];
int epollfd = epoll_create( 5 );
assert( epollfd != -1 );
addfd( epollfd, listenfd, false );
http_conn::m_epollfd = epollfd;
while( true )
{
int number = epoll_wait( epollfd, events, MAX_EVENT_NUMBER, -1 );
if ( ( number < 0 ) && ( errno != EINTR ) )
{
printf( "epoll failure\n" );
break;
}
for ( int i = 0; i < number; i++ )
{
int sockfd = events[i].data.fd;
if( sockfd == listenfd )
{
struct sockaddr_in client_address;
socklen_t client_addrlength = sizeof( client_address );
int connfd = accept( listenfd, ( struct sockaddr* )&client_address, &client_addrlength );
if ( connfd < 0 )
{
printf( "errno is: %d\n", errno );
continue;
}
if( http_conn::m_user_count >= MAX_FD )
{
show_error( connfd, "Internal server busy" );
continue;
}
/*初始化客户连接*/
users[connfd].init( connfd, client_address );
}
else if( events[i].events & ( EPOLLRDHUP | EPOLLHUP | EPOLLERR ) )
{
/*如果有异常,直接关闭客户连接*/
users[sockfd].close_conn();
}
else if( events[i].events & EPOLLIN )
{
/*根据读的结果,决定是将任何添加到线程池,还是关闭连接*/
if( users[sockfd].read() )
{
pool->append( users + sockfd );
}
else
{
users[sockfd].close_conn();
}
}
else if( events[i].events & EPOLLOUT )
{
/*根据写的结果,决定是否关闭连接*/
if( !users[sockfd].write() )
{
users[sockfd].close_conn();
}
}
else
{}
}
}
close( epollfd );
close( listenfd );
delete [] users;
delete pool;
return 0;
}
本文详细介绍了一个简单的HTTP服务器的实现过程,包括HTTP请求的解析、HTTP响应的构建以及服务器的架构设计。通过具体代码展示了如何处理客户端请求并返回相应的内容。
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