我正在尝试用C实现一个简单的HTTP服务器
- 读取请求
- 检查它是否是 GET 请求
- 从请求中读取 URL
- 检查文件是否在服务器上并尝试打开它
我正在使用strtok字符串标记，我认为它弄乱了文件路径。open并且fopen总是返回错误代码并且无法打开任何文件。
这是我的代码：
/*
** parser.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define MYPORT 3499 // the port users will be connecting to
#define BACKLOG 10 // how many pending connections queue will hold
#define MAXLEN 1024 //upper limit of the length of the string
int main(void)
{
char input[MAXLEN]; //the line that is read from the client
char * token1; //GET request
char * token2; //filepath
char tmpstring[MAXLEN]; //filesize
int sockfd, new_fd; // listen on sock_fd, new connection on new_fd, file open on file_fd
struct sockaddr_in my_addr; // my address information
struct sockaddr_in their_addr; // connector's address information
int sin_size;
int yes=1;
int n; //the amount of read characters from the client
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
perror("setsockopt");
exit(1);
}
my_addr.sin_family = AF_INET; // host byte order
my_addr.sin_port = htons(MYPORT); // short, network byte order
my_addr.sin_addr.s_addr = INADDR_ANY; // automatically fill with my IP
memset(&(my_addr.sin_zero), '\0', 8); // zero the rest of the struct
if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {
perror("bind");
exit(1);
}
if (listen(sockfd, BACKLOG) == -1) {
perror("listen");
exit(1);
}
while(1) { // main accept() loop
sin_size = sizeof(struct sockaddr_in);
if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) {
perror("accept");
continue;
}
printf("server: got connection from %s\n",inet_ntoa(their_addr.sin_addr));
n = readline(new_fd, input, MAXLEN); //n is the amount of read characters
if (n == -1) {
perror("Unable to read line");
}
//Check if it is a GET message
token1 = strtok(input," ");
if(strcmp(token1, "GET") != 0)
{
send(new_fd, "Bad request\n", 30, 0);
}
else
{
//Retrieve the file path
token2 = strtok(NULL, " ");
if(token2 == NULL)
{
send(new_fd, "File path not specified\n", 23, 0); //Check if filename is empty
}
send(new_fd, token2, strlen(token2), 0); //test
printf("%s", token2);
if(token2[0] == '/') //remove the initial slash
memmove(token2, token2 + 1, strlen(token2));
//char * path = "test.html"; //test line
//char * buff;
//int len = sprintf(buff, "1: %d 2: %d\n", strlen(token1), strlen(token2));
//send(new_fd, buff, len, 0);
//Check if file is on the server
if(open(token2, O_RDONLY) < 0) //Error opening file
{
if(errno == EACCES)
send(new_fd, "Access error\n", 30, 0);
else
send(new_fd, "Not existed\n", 30, 0);
}
else
{
FILE * requested_file = fopen(token2, "r");
if(requested_file == NULL) //
{
send(new_fd, "Error in fopen\n", 30, 0);
}
else
{
send(new_fd, "File found\n", 30, 0); //successful
}
fseek(requested_file, 0, SEEK_END); // move to the end of the file
int end= ftell(requested_file); // get the position of the end of file
int stringlen = sprintf(tmpstring, "file size: %d\n", end);
send(new_fd, tmpstring, stringlen, 0);
}
}
close(new_fd); //close connection
}
return 0;
}
//helper function for recieving text
int readline(int fd, char *buf, int maxlen)
{
int n, rc;
char c;
for (n = 1; n < maxlen; n++) {
if ((rc = read(fd, &c, 1)) == 1) {
*buf++ = c;
if (c == '\n')
break;
} else if (rc == 0) {
if (n == 1)
return 0; // EOF, no data read
else
break; // EOF, read some data
} else
return -1; // error
}
*buf = '\0'; // null-terminate
return n;
}
所以我将test.html放在与服务器相同的文件夹中。然后我远程登录到localhost和端口 3499。这是输入时的输出GET /test.html：
/test.html
Not existed
rError in fopen
Connection closed by foreign host.