搭建简单的http服务器
开发语言C++,平台为Linux。
主要流程为：服务器获得请求–>响应并处理请求–>返回结果。
这里着重讲怎么处理请求。
主程序在获得一个请求后会开辟一个线程来处理请求
流程图如下。
hand_cgi函数流程图
cgi程序流程图。
代码：
#include"http.h"
int ret = 0;
void printf_log(string s){
//cout << s << endl;
}
int init_fd(int socketi, char* str){
sockaddr_in addr;
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(inet_addr(str));
addr.sin_port = htons(PORT);
int err = bind(socketi, (struct sockaddr*)&addr, sizeof(addr));
if (err < 0){
printf_log("bind error");
ret = -1;
}
int on = 0;
setsockopt( socketi, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on) );
err = listen(socketi, 5);
if (err < 0){
printf_log("listen error");
ret = -1;
}
return socketi;
}
static int get_line(int fd, char *buf){
char ch = 0;
char next = 0;
int i = 0;
int err = 0;
while (ch != '\n'){
int size = read(fd, &ch, 1);
if (size <= 0){
ch = '\n';
}
if (ch != '\n' && ch != '\r'){
buf[i++] = ch;
}
else{
if (ch == '\r'){
err = recv(fd, &next, 1, MSG_PEEK);
if (err < 0){
printf_log("recv error");
return -1;
}
if (next == '\n'){
err = read(fd, &ch, 1);
if (err < 0){
printf_log("recv error");
return -1;
}
}//if
ch = '\n';
}
}//else
}//while
buf[i] = 0;
return 1;
}
static void clean_header(int fd){
char ch[100] = {0};
get_line(fd, ch);
while (strlen(ch) != 0){
get_line(fd, ch);
}
}
static int hand_cgi(int fd, char* path, char * argument){
char line[SIZE/2] = {0};
char length[10] = {0};
int i_length = 0;
char method[10] = {0};
if (strlen(argument) == 0){
sprintf(method, "METHOD=POST");
while (get_line(fd, line) > 0){
if (strncmp(line, "Content-Length", 16) == 0){
i_length = atoi(line + 16);
break;
}
}//while
clean_header(fd);
sprintf(length, "Content-Length=%d", i_length);
putenv(length);
}//if
else{
sprintf(method, "METHOD=GET");
char str[100] = {0};
sprintf(str, "QESTRING=%s", argument);
if (putenv(str) < 0){
printf_log("she zhi huai jing cuo wu");
ret = -1;
}
clean_header(fd);
}//else
putenv(method);
//reponse
char request[] = "HTTP/1.0 200 OK\r\n";
write(fd, request, strlen(request));
int _std[2] = {0};
int _std2[2] = {0};
if (pipe(_std) < 0){
printf_log("pipe error");
ret = -1;
}
if (pipe(_std2) < 0){
printf_log("pipe2 error");
ret = -1;
}
pid_t pid = fork();
if (pid < 0){
printf_log("fork error");
ret = -1;
return 0;
}
if (pid == 0){
close(_std[0]);
close(_std2[1]);
dup2(_std[1], 1);
dup2(_std2[0], 0);
execl(path,path, NULL);
cout << "error" << endl;
}
else{
close(_std[1]);
close(_std2[0]);
int ch = 0;
char string[SIZE/2] = {0};
for (int i = 0; i < i_length; i++){
read(fd, &ch, 1);
string[i] = ch;
}
char buf[SIZE/2] = {0};
write(_std2[1], string, strlen(string));
read(_std[2], buf, SIZE/2);
//返回输出
write(fd, buf, strlen(buf));
}
close(_std[0]);
close(_std2[1]);
}
}
static void get(int fd){
char buf[2*SIZE];
char ch;
int i = 0;
while (read(fd, &ch, 1) > 0){
buf[i++] = ch;
}
// printf("%s\n", buf);
}
void *handler_in(void *arg){
pthread_detach(pthread_self());
char method[SIZE/2] = {0};
char buf[SIZE] = {0};
char line[SIZE/2] = {0};
char url[SIZE/2] = {0};
char goal[SIZE/2] = {0};
char argument[SIZE] = {0};
int err = 0;
int cgi = 0;
int i = 0;
char request[] = "HTTP/1.1 200 OK\r\n";
//cout << 123 << endl;
err = get_line((int)arg, line);
if (err < 0){
ret = 1;
goto end;
}
for (i = 0; line[i] != ' '; i++){
method[i] = line[i];
}
i++;
for (int j = 0; line[i] != ' '&&line[i] != '?'; i++){
url[j++] = line[i];
}
//printf("%s\n" ,method);
if (line[i] == '?'){
i++;
for (int j = 0; line[i] != ' '&&line[i] != '?'; i++){
argument[j++] = line[i];
}
}
if (strcasecmp(method, "POSE") != 0 && strcasecmp(method, "GET") != 0){
printf_log("method");
ret = 2;
goto end;
}
if (strcasecmp(method, "POSE") == 0)
cgi = 1;
if (strcasecmp(method, "GET") == 0 && argument[0] != 0)
cgi = 1;
if (strlen(url) == 1 && strcasecmp(url , "/") == 0)
sprintf(goal, "wwwroot/root.html");
else sprintf(goal, "wwwroot%s", url);
//判断文件
struct stat file;
err = stat(goal, &file);
if (err < 0){
ret = 3;
printf_log("file not found");
goto end;
}
if (file.st_mode & S_IFDIR){
//
}
if (file.st_mode & S_IXUSR || file.st_mode & S_IXGRP || file.st_mode & S_IXOTH){
if (0 == cgi){
ret = 4;
printf_log("文件类型与cgi不匹配");
goto end;
}
}
if (1 == cgi){
err = hand_cgi((int)arg, goal, argument);
}//cgi if
else{
clean_header((int)arg);
write((int)arg, request, strlen(request));
write((int)arg, "\r\n", 2);
int fd = open(goal, O_RDONLY);
err = sendfile((int)arg, fd, 0, file.st_size);
if (err < 0){
ret = 5;
printf_log("sendfile error");
printf("%d, %s\n", errno, strerror(errno));
}
}//cgi else
end: close((int)arg);
}
cgi程序示例（2数相加）：
#include %d + %d = %d
\r\n", num1, num2, num1+num2);
printf("\n");
}
int main(){
printf("Content-Type:text/html;charset=ISO-8859-1\n\n");
char *p = NULL;
int i_length = 0;
char query_string[SIZE/2] = {0};
char *length = NULL;
p = getenv("METHOD");
if (strcmp(p, "GET") == 0){
char *s = getenv("QESTRING");
memcpy(query_string, s, strlen(s));
}//if
else{
length = getenv("Content-Length");
i_length = atoi(length);
char ch = 0;
for (int i = 0; i < i_length; i++){
ch = getc(0);
query_string[i] = ch;
}
}
hand(query_string);
printf("\n");
return 0;
}
运行：
发送请求
返回结果：
此外，我们可再写一个可以连接mysql数据库的cgi程序，这样我们就可以远程管理数据库了。
cgi程序：
#include
mod表示操作，where是哪个·表，name是人名。
tbq这个表如下：
处理请求的结果：
前端知识知之甚少，勿怪啊。。
在这里一个简单的http服务器就搭建完成了，但是我们还可以做很多事。比如，当请求过多时效率太低怎么办？再者，我们可以写一个爬虫程序来提高。除此之外，我们可以在深入调研nginx服务器。
源码地址：https://github.com/fengasdf/-http-（由于整合了协程,python爬虫，以及其他程序，可能有点乱）
http服务器运用协程：
http://blog.csdn.net/fengasdfgh/article/details/76688440