#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <ctype.h>
#include <strings.h>
#include <string.h>
#include <sys/stat.h>
#include <pthread.h>
#include <sys/wait.h>
#include <stdlib.h>
#define ISspace
(x
) isspace
((int
)(x
))
#define
SERVER_STRING "
Server: jdbhttpd/0.1.0\r\n"
void* accept_request
(void *
);
void bad_request
(int
);
void cat
(int, FILE *
);
void cannot_execute
(int
);
void error_die
(const char *
);
void execute_cgi
(int, const char *, const char *, const char *
);
int get_line
(int, char *, int
);
void headers
(int, const char *
);
void not_found
(int
);
void
serve_file
(int, const char *
);
int startup
(unsigned short *
);
void unimplemented
(int
);
/**********************************************************************/
/* A request has caused a call to accept
() on the
server port to
* return. Process the request appropriately.
* Parameters: the socket connected to the
client */
/**********************************************************************/
void* accept_request
(void *p
client)
{
printf
("accept_request\n"
);
int
client = *
(int*
)p
client;
char buf[65536];
int numchars;
char method[255];
char url[255];
char path[512];
size_t i, j;
struct stat st;
int cgi = 0; /* becomes true if
server decides this is a CGI program */
char *query_string = NULL;
/*得到请求的第一行*/
numchars = get_line
(client, buf, sizeof
(buf
));
i = 0; j = 0;
/*把客户端的请求方法存到 method 数组*/
while
(!ISspace
(buf[j]
) &&
(i < sizeof
(method
) - 1
))
{
method[i] = buf[j];
i++; j++;
}
method[i] = '\0';
/*如果既不是 GET 又不是 POST 则无法处理 */
if
(strcasecmp
(method, "GET"
) && strcasecmp
(method, "POST"
))
{
unimplemented
(client);
return NULL;
}
/* POST 的时候开启 cgi */
if
(strcasecmp
(method, "POST"
) == 0
)
cgi = 1;
/*读取 url 地址*/
i = 0;
while
(ISspace
(buf[j]
) &&
(j < sizeof
(buf
)))
j++;
while
(!ISspace
(buf[j]
) &&
(i < sizeof
(url
) - 1
) &&
(j < sizeof
(buf
)))
{
/*存下 url */
url[i] = buf[j];
i++; j++;
}
url[i] = '\0';
/*处理 GET 方法*/
if
(strcasecmp
(method, "GET"
) == 0
)
{
/* 待处理请求为 url */
query_string = url;
while
((*query_string != '?'
) &&
(*query_string != '\0'
))
query_string++;
/* GET 方法特点，? 后面为参数*/
if
(*query_string == '?'
)
{
/*开启 cgi */
cgi = 1;
*query_string = '\0';
query_string++;
}
}
/*格式化 url 到 path 数组，html 文件都在
web 中*/
sprintf
(path, "
web%s", url
);
/*默认情况为 index.html */
if
(path[strlen
(path
) - 1] == '/'
)
strcat
(path, "Index.html"
);
/*根据路径找到对应文件 */
if
(stat
(path, &st
) == -1
) {
/*把所有 headers 的信息都丢弃*/
while
((numchars > 0
) && strcmp
("\n", buf
)) /* read & discard headers */
numchars = get_line
(client, buf, sizeof
(buf
));
/*回应客户端找不到*/
not_found
(client);
}
else
{
/*如果是个目录，则默认使用该目录下 index.html 文件*/
if
((st.st_mode & S_IFMT
) == S_IFDIR
)
strcat
(path, "/Index.html"
);
if
((st.st_mode & S_IXUSR
) ||
(st.st_mode & S_IXGRP
) ||
(st.st_mode & S_IXOTH
) )
cgi = 1;
/*不是 cgi,直接把
服务器文件返回，否则执行 cgi */
if
(!cgi
)
serve_file
(client, path
);
else
execute_cgi
(client, path, method, query_string
);
}
/*断开与客户端的连接（HTTP 特点：无连接）*/
close
(client);
return NULL;
}
/**********************************************************************/
/* Inform the
client that a request it has made has a problem.
* Parameters:
client socket */
/**********************************************************************/
void bad_request
(int
client)
{
printf
("bad_request\n"
);
char buf[65536];
/*回应客户端错误的 HTTP 请求 */
sprintf
(buf, "HTTP/1.0 400 BAD REQUEST\r\n"
);
send
(client, buf, sizeof
(buf
), 0
);
sprintf
(buf, "Content-type: text/html\r\n"
);
send
(client, buf, sizeof
(buf
), 0
);
sprintf
(buf, "\r\n"
);
send
(client, buf, sizeof
(buf
), 0
);
sprintf
(buf, "<P>Your
browser sent a bad request, "
);
send
(client, buf, sizeof
(buf
), 0
);
sprintf
(buf, "such as a POST without a Content-Length.\r\n"
);
send
(client, buf, sizeof
(buf
), 0
);
}
/**********************************************************************/
/* Put the entire contents of a file out on a socket. This function
* is named after the UNIX "cat" command, because it might have been
* easier just to do something like pipe, fork, and exec
("cat"
).
* Parameters: the
client socket descriptor
* FILE pointer for the file to cat */
/**********************************************************************/
void cat
(int
client, FILE *resource
)
{
printf
("cat\n"
);
char buf[65536];
/*读取文件中的所有数据写到 socket */
fgets
(buf, sizeof
(buf
), resource
);
while
(!feof
(resource
))
{
send
(client, buf, strlen
(buf
), 0
);
fgets
(buf, sizeof
(buf
), resource
);
}
}
/**********************************************************************/
/* Inform the
client that a CGI script could not be executed.
* Parameter: the
client socket descriptor. */
/**********************************************************************/
void cannot_execute
(int
client)
{
printf
("cannot_execute\n"
);
char buf[65536];
/* 回应客户端 cgi 无法执行*/
sprintf
(buf, "HTTP/1.0 500 Internal
Server Error\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "Content-type: text/html\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "<P>Error prohibited CGI execution.\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
}
/**********************************************************************/
/* Print out an error message with perror
() (for system errors; based
* on value of errno, which indicates system call errors
) and exit the
* program indicating an error. */
/**********************************************************************/
void error_die
(const char *sc
)
{
/*出错信息处理 */
printf
("error_die\n"
);
perror
(sc
);
exit
(1
);
}
/**********************************************************************/
/* Execute a CGI script. Will need to set environment variables as
* appropriate.
* Parameters:
client socket descriptor
* path to the CGI script */
/**********************************************************************/
void execute_cgi
(int
client, const char *path, const char *method, const char *query_string
)
{
printf
("execute_cgi\n"
);
char buf[65536];
int cgi_output[2];
int cgi_input[2];
pid_t pid;
int status;
int i;
char c;
int numchars = 1;
int content_length = -1;
buf[0] = 'A'; buf[1] = '\0';
if
(strcasecmp
(method, "GET"
) == 0
)
/*把所有的 HTTP header 读取并丢弃*/
while
((numchars > 0
) && strcmp
("\n", buf
)) /* read & discard headers */
numchars = get_line
(client, buf, sizeof
(buf
));
else /* POST */
{
/* 对 POST 的 HTTP 请求中找出 content_length */
numchars = get_line
(client, buf, sizeof
(buf
));
while
((numchars > 0
) && strcmp
("\n", buf
))
{
/*利用 \0 进行分隔 */
buf[15] = '\0';
/* HTTP 请求的特点*/
if
(strcasecmp
(buf, "Content-Length:"
) == 0
)
content_length = atoi
(&
(buf[16]
));
numchars = get_line
(client, buf, sizeof
(buf
));
}
/*没有找到 content_length */
if
(content_length == -1
) {
/*错误请求*/
bad_request
(client);
return;
}
}
/* 正确，HTTP 状态码 200 */
sprintf
(buf, "HTTP/1.0 200 OK\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
/* 建立管道*/
if
(pipe
(cgi_output
) < 0
) {
/*错误处理*/
cannot_execute
(client);
return;
}
/*建立管道*/
if
(pipe
(cgi_input
) < 0
) {
/*错误处理*/
cannot_execute
(client);
return;
}
if
((pid = fork
()) < 0
) {
/*错误处理*/
cannot_execute
(client);
return;
}
if
(pid == 0
) /* child: CGI script */
{
char meth_env[255];
char query_env[255];
char length_env[255];
/* 把 STDOUT 重定向到 cgi_output 的写入端 */
dup2
(cgi_output[1], 1
);
/* 把 STDIN 重定向到 cgi_input 的读取端 */
dup2
(cgi_input[0], 0
);
/* 关闭 cgi_input 的写入端
和 cgi_output 的读取端 */
close
(cgi_output[0]
);
close
(cgi_input[1]
);
/*设置 request_method 的环境变量*/
sprintf
(meth_env, "REQUEST_METHOD=%s", method
);
putenv
(meth_env
);
if
(strcasecmp
(method, "GET"
) == 0
) {
/*设置 query_string 的环境变量*/
sprintf
(query_env, "QUERY_STRING=%s", query_string
);
putenv
(query_env
);
}
else { /* POST */
/*设置 content_length 的环境变量*/
sprintf
(length_env, "CONTENT_LENGTH=%d", content_length
);
putenv
(length_env
);
}
/*用 execl 运行 cgi 程序*/
execl
(path, path, NULL
);
exit
(0
);
} else { /* parent */
/* 关闭 cgi_input 的读取端
和 cgi_output 的写入端 */
close
(cgi_output[1]
);
close
(cgi_input[0]
);
if
(strcasecmp
(method, "POST"
) == 0
)
/*接收 POST 过来的数据*/
for
(i = 0; i < content_length; i++
) {
recv
(client, &c, 1, 0
);
/*把 POST 数据写入 cgi_input，现在重定向到 STDIN */
write
(cgi_input[1], &c, 1
);
}
/*读取 cgi_output 的管道输出到客户端，该管道输入是 STDOUT */
while
(read
(cgi_output[0], &c, 1
) > 0
)
send
(client, &c, 1, 0
);
/*关闭管道*/
close
(cgi_output[0]
);
close
(cgi_input[1]
);
/*等待子进程*/
waitpid
(pid, &status, 0
);
}
}
/**********************************************************************/
/* Get a line from a socket, whether the line ends in a newline,
* carriage return, or a CRLF combination. Terminates the string read
* with a null character. If no newline indicator is found before the
* end of the buffer, the string is terminated with a null. If any of
* the above three line terminators is read, the last character of the
* string will be a linefeed and the string will be terminated with a
* null character.
* Parameters: the socket descriptor
* the buffer to save the data in
* the size of the buffer
* Returns: the number of bytes stored
(excluding null
) */
/**********************************************************************/
int get_line
(int sock, char *buf, int size
)
{
printf
("get_line\n"
);
int i = 0;
char c = '\0';
int n;
/*把终止条件统一为 \n 换行符，标准化 buf 数组*/
while
((i < size - 1
) &&
(c != '\n'
))
{
/*一次仅接收一个字节*/
n = recv
(sock, &c, 1, 0
);
/* DEBUG printf
("%02X\n", c
); */
if
(n > 0
)
{
/*收到 \r 则继续接收下个字节，因为换行符可能是 \r\n */
if
(c == '\r'
)
{
/*使用 MSG_PEEK 标志使下一次读取依然可以得到这次读取的内容，可认为接收窗口不滑动*/
n = recv
(sock, &c, 1, MSG_PEEK
);
/* DEBUG printf
("%02X\n", c
); */
/*但如果是换行符则把它吸收掉*/
if
((n > 0
) &&
(c == '\n'
))
recv
(sock, &c, 1, 0
);
else
c = '\n';
}
/*存到缓冲区*/
buf[i] = c;
i++;
}
else
c = '\n';
}
buf[i] = '\0';
/*返回 buf 数组大小*/
return
(i
);
}
/**********************************************************************/
/* Return the informational HTTP headers about a file. */
/* Parameters: the socket to print the headers on
* the name of the file */
/**********************************************************************/
void headers
(int
client, const char *filename
)
{
printf
("headers\n"
);
char buf[65536];
(void
)filename; /* could use filename to determine file type */
/*正常的 HTTP header */
strcpy
(buf, "HTTP/1.0 200 OK\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
/*
服务器信息*/
strcpy
(buf,
SERVER_STRING
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "Content-Type: text/html\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
strcpy
(buf, "\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
}
/**********************************************************************/
/* Give a
client a 404 not found status message. */
/**********************************************************************/
void not_found
(int
client)
{
printf
("not_found\n"
);
char buf[65536];
/* 404 页面 */
sprintf
(buf, "HTTP/1.0 404 NOT FOUND\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
/*
服务器信息*/
sprintf
(buf,
SERVER_STRING
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "Content-Type: text/html\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "<HTML><TITLE>Not Found</TITLE>\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "<BODY><P>The
server could not fulfill\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "your request because the resource specified\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "is unavailable or nonexistent.\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "</BODY></HTML>\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
}
/**********************************************************************/
/* Send a regular file to the
client. Use headers, and report
* errors to
client if they occur.
* Parameters: a pointer to a file structure produced from the socket
* file descriptor
* the name of the file to
serve */
/**********************************************************************/
void
serve_file
(int
client, const char *filename
)
{
printf
("
serve_file\n"
);
FILE *resource = NULL;
int numchars = 1;
char buf[65536];
/*读取并丢弃 header */
buf[0] = 'A'; buf[1] = '\0';
while
((numchars > 0
) && strcmp
("\n", buf
)) /* read & discard headers */
numchars = get_line
(client, buf, sizeof
(buf
));
/*打开 sever 的文件*/
resource = fopen
(filename, "r"
);
if
(resource == NULL
)
not_found
(client);
else
{
/*写 HTTP header */
headers
(client, filename
);
/*复制文件*/
cat
(client, resource
);
}
fclose
(resource
);
}
/**********************************************************************/
/* This function starts the process of listening for
web connections
* on a specified port. If the port is 0, then dynamically allocate a
* port and modify the original port variable to reflect the actual
* port.
* Parameters: pointer to variable containing the port to connect on
* Returns: the socket */
/**********************************************************************/
int startup
(unsigned short *port
)
{
printf
("startup\n"
);
int httpd = 0;
struct sockaddr_in name;
/*建立 socket */
httpd = socket
(PF_INET, SOCK_STREAM, 0
);
if
(httpd == -1
)
error_die
("socket"
);
memset
(&name, 0, sizeof
(name
));
name.sin_family = AF_INET;
name.sin_port = htons
(*port
);
name.sin_addr.s_addr = htonl
(INADDR_ANY
);
if
(bind
(httpd,
(struct sockaddr *
)&name, sizeof
(name
)) < 0
)
error_die
("bind"
);
/*如果当前指定端口是 0，则动态随机分配一个端口*/
if
(*port == 0
) /* if dynamically allocating a port */
{
socklen_t namelen = sizeof
(name
);
if
(getsockname
(httpd,
(struct sockaddr *
)&name, &namelen
) == -1
)
error_die
("getsockname"
);
*port = ntohs
(name.sin_port
);
}
/*开始监听*/
if
(listen
(httpd, 5
) < 0
)
error_die
("listen"
);
/*返回 socket id */
return
(httpd
);
}
/**********************************************************************/
/* Inform the
client that the requested
web method has not been
* implemented.
* Parameter: the
client socket */
/**********************************************************************/
void unimplemented
(int
client)
{
printf
("unimplemented\n"
);
char buf[65536];
/* HTTP method 不被支持*/
sprintf
(buf, "HTTP/1.0 501 Method Not Implemented\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
/*
服务器信息*/
sprintf
(buf,
SERVER_STRING
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "Content-Type: text/html\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "<HTML><HEAD><TITLE>Method Not Implemented\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "</TITLE></HEAD>\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "<BODY><P>HTTP request method not supported.\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
sprintf
(buf, "</BODY></HTML>\r\n"
);
send
(client, buf, strlen
(buf
), 0
);
}
/**********************************************************************/
int main
(void
)
{
signal
(SIGPIPE, SIG_IGN
);
int
server_sock = -1;
unsigned short port = 8080;
int
client_sock = -1;
struct sockaddr_in
client_name;
socklen_t
client_name_len = sizeof
(client_name
);
pthread_t newthread;
/*在对应端口建立 httpd
服务*/
server_sock = startup
(&port
);
printf
("httpd running on port %d\n", port
);
while
(1
)
{
/*套接字收到客户端连接请求*/
client_sock = accept
(server_sock,
(struct sockaddr *
)&
client_name,&
client_name_len
);
if
(client_sock == -1
)
error_die
("accept"
);
/*派生新线程用 accept_request 函数处理新请求*/
/* accept_request
(client_sock
); */
if
(pthread_create
(&newthread , NULL, accept_request,
(void*
)&
client_sock
) != 0
)
perror
("pthread_create"
);
}
close
(server_sock
);
return
(0
);
}
以上是我的
webserver代码。我希望这个
webserver能够提供对.html，.css
和.js文件的响应，该修改哪些地方？
本文介绍了九十年代管理信息系统中的C/S技术，并对比了其与新兴B/S模式的区别。C/S模式采用请求/响应的方式进行交互，而B/S模式则通过Web服务器实现了更便捷的数据访问与动态信息发布。
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