Linux下编写C++服务器(HTTP服务器)
今天使用Makefile写一个HTTP的服务器，之前没有接触过Makefile，需要探索一下。
VS2015下测试Makefile
- 新建一个Makefile Project(Linux)，这里名为HTTPTest；
- 添加新建项， 添加C ++文件（.cpp）,名为main.cpp，
内容如下：
#pragma once
#pragma execution_character_set("utf-8")
#include - 在main.cpp的同级目录下创建一个Makefile的空文件，注意文件名的大小写，并添加到HTTPTest项目中，
写入如下内容：
build:
gcc -gdwarf-2 -o HTTPTest main.cpp
clean:
rm -rf HTTPTest
- 右键项目，选择属性，在General的Remote Build Root Directory中写入Linux上的项目目录，
在Remote Build四项中分别写入
cd $(RemoteRootDir)/$(ProjectName); make build
cd $(RemoteRootDir)/$(ProjectName); make clean build
cd $(RemoteRootDir)/$(ProjectName); make clean
$(RemoteRootDir)/$(ProjectName)/HTTPTest
如图：
- 在main.cpp的其中一行打上断点，按F5调试，测试成功了。
安装libevent
HTTP服务器我们选择libevent库实现。
- 把libevent下载到Linux虚拟机中，这里选择2.1.10版本，下载完成后对压缩包进行解压
tar xvf libevent-2.1.10-stable.tar.gz
- 输入如下命令，用于进入解压后的文件夹，并生成makefile，–prefix用来指定libevent的安装目录；
cd libevent-2.1.10-stable/
./configure --prefix=/usr/libevent
- 输入make编译；
- 输入make install开始安装，安装成功后，/usr/libevent生成了bin，include，lib文件夹。
配置环境
- 我们需要把上面生成的/usr/libevent/include复制一份到windows中，这里用到共享文件夹，
mkdir /mnt/hgfs/LinuxShare/libevent
cp -r /usr/libevent/include /mnt/hgfs/LinuxShare/libevent
windows出现了E:\LinuxShare\libevent\include目录，是我们需要的头文件；
- 右键项目->属性->C++->Include Search Path，输入
E:\LinuxShare\include;E:\LinuxShare\include\c++\4.8.2;E:\LinuxShare\libevent\include;，前两个是上一编配置的Linux头文件，最后一个是libevent头文件；
Makefile文件的build需要修改
gcc -gdwarf-2 -o HTTPTest main.cpp -I /usr/libevent/include/ -L /usr/libevent/lib/ -levent
按F5后编译通过，但无法运行，报错如下：
error while loading shared libraries: libevent-2.1.so.6: cannot open shared object file: No such file or directory，提示没有找到这个库，解决方法为在linux终端输入
ln -s /usr/libevent/lib/libevent-2.1.so.6 /usr/lib64/libevent-2.1.so.6
这样运行时就可以链接库。
封装HTTP
创建myhttpserver.h和myhttpserver.cpp，参考libevent实现http server，经历了不少bug后，实现了get和post方法。
myhttpserver.h
#pragma once
#include myhttpserver.cpp
#include %s ", dirname);
sprintf(buf + strlen(buf), "当前目录：%s
", dirname);
//添加目录内容
int num = scandir(dirname, &dirinfo, NULL, alphasort);
for (int i = 0; i<num; ++i) {
// 编码
strcpy(encoded_name, dirinfo[i]->d_name);
sprintf(path, "%s%s", dirname, dirinfo[i]->d_name);
printf("############# path = %s\n", path);
if (lstat(path, &sb) < 0) {
sprintf(buf + strlen(buf),
"%s %s/ %s %ld %s %s %ld
");
//bufferevent_write(bev, buf, strlen(buf));
evbuffer_add_printf(bev, buf);
printf(buf);
printf("################# Dir Read OK !!!!!!!!!!!!!!\n");
return 0;
}
int send_file_to_http(const char *filename, struct evbuffer* bev) {
int fd = open(filename, O_RDONLY);
int ret = 0;
char buf[4096] = { 0 };
//单次上限4096
//evbuffer_read(bev, fd, 30556);
while ((ret = read(fd, buf, sizeof(buf)))) {
if (ret < 0)
break;
//不能传\0
//evbuffer_add_printf(bev, buf);
//可以传\0
evbuffer_add(bev, buf, ret);
memset(buf, 0, 4096);
}
close(fd);
return 0;
}
//回调函数
void HttpGenericCallback(struct evhttp_request* request, void* arg)
{
const struct evhttp_uri* evhttp_uri = evhttp_request_get_evhttp_uri(request);
char url[8192];
memset(url, 0x00, sizeof(url));
evhttp_uri_join(const_cast<struct evhttp_uri*>(evhttp_uri), url, 8192);
printf("accept request url:%s\n", url);
if (request->kind == EVHTTP_REQUEST) {
//get
if (request->type == EVHTTP_REQ_GET) {
/*
http://foo.com/?q=test&s=some+thing
evhttp_request_uri: 解析HTTP请求中的ur，得到/?q=test&s=some+thing
evhttp_parse_query: 解析名值对，得到一个evkeyvalq结构，里面包含了key/value的数组.
*/
char* decode_uri = strdup((char*)evhttp_request_uri(request));
struct evkeyvalq http_query;
evhttp_parse_query(decode_uri, &http_query);
free(decode_uri);
//const char *request_value = evhttp_find_header(&http_query, "data");
//解码
//strcpy(url, evhttp_decode_uri(url));
char *pf = &url[1];
if (strcmp(url, "/") == 0 || strcmp(url, "/.") == 0) {
pf = "./";
}
printf("***** http Request Resource Path = %s, pf = %s\n", url, pf);
//退出服务器
if (strcmp(url, "/bye") == 0) {
closesign = true;
struct event_base* base = (struct event_base*)arg;
Myhttpserver::stop(base);
return;
}
struct stat sb;
struct evbuffer* evbuf = evbuffer_new();
if (!evbuf) {
printf("create evbuffer failed!\n");
return;
}
char dir[256] = { 0 }, filename[256] = { 0 };
snprintf(dir, sizeof(dir), "/home/aubin/projects/HTTPTest/%s", pf);
//打开文件
if (stat(dir, &sb) == 0 && (sb.st_mode & S_IFREG)) {
send_header(request, pf, sb.st_size, "close");
send_file_to_http(dir, evbuf);
evhttp_send_reply(request, HTTP_OK, "OK", evbuf);
evbuffer_free(evbuf);
return;
}
//打开子文件夹
else if (stat(dir, &sb) == 0 && (sb.st_mode & __S_IFDIR)) {
send_header(request, ".html", 0, "close");
send_dir(evbuf, dir);
evhttp_send_reply(request, HTTP_OK, "OK", evbuf);
evhttp_clear_headers(&http_query);
evbuffer_free(evbuf);
return;
}
//打开主文件夹
else {
send_header(request, ".html", 0, "close");
send_dir(evbuf, "/home/aubin/projects/HTTPTest");
evhttp_send_reply(request, HTTP_OK, "OK", evbuf);
evhttp_clear_headers(&http_query);
evbuffer_free(evbuf);
return;
}
}
//post
else if (request->type == EVHTTP_REQ_POST) {
char charadd1[10], charadd2[10];
struct evkeyvalq http_query_post;
char decode_post_uri[1024] = { 0 };
int buffer_data_len = EVBUFFER_LENGTH(request->input_buffer);
char *post_data = (char *)malloc(buffer_data_len + 1);
memset(post_data, 0, buffer_data_len + 1);
memcpy(post_data, EVBUFFER_DATA(request->input_buffer), buffer_data_len);
sprintf(decode_post_uri, "/?%s", post_data); //处理数据格式
evhttp_parse_query(decode_post_uri, &http_query_post);
strcpy(charadd1, evhttp_find_header(&http_query_post, "add1"));
strcpy(charadd2, evhttp_find_header(&http_query_post, "add2"));
int sum = atoi(charadd1) + atoi(charadd2);
struct evbuffer* evbuf = evbuffer_new();
if (!evbuf) {
printf("create evbuffer failed!\n");
return;
}
evbuffer_add_printf(evbuf, "\
\
\
\
(runoob.com) \
\
\
%d
\
\
", sum);
evhttp_send_reply(request, HTTP_OK, "OK", evbuf);
evbuffer_free(evbuf);
}
}
}
Myhttpserver::Myhttpserver()
{
}
Myhttpserver::~Myhttpserver()
{
}
bool Myhttpserver::inithttp()
{
event_init();
base = event_base_new();
if (!base)
{
sprintf(errmsg, "create event_base failed,error: %s(errno: %d)\n", strerror(errno), errno);
return false;
}
http = evhttp_new(base);
if (!http)
{
sprintf(errmsg, "create evhttp failed,error: %s(errno: %d)\n", strerror(errno), errno);
return false;
}
return true;
}
bool Myhttpserver::start(unsigned int port)
{
if (evhttp_bind_socket(http, "0.0.0.0", port) != 0)
{
sprintf(errmsg, "start evhttp failed,error: %s(errno: %d)\n", strerror(errno), errno);
return false;
}
evhttp_set_timeout(http, 120);
return true;
}
void Myhttpserver::set_gencb(void(*cb)(struct evhttp_request *, void *))
{
evhttp_set_gencb(http, cb, base);
}
void Myhttpserver::dispatch()
{
event_base_dispatch(base);
}
void Myhttpserver::stop(struct event_base* base)
{
event_base_loopbreak(base);
event_base_loopexit(base, 0);
return;
}
void Myhttpserver::free()
{
evhttp_free(http);
event_base_free(base);
}
char * Myhttpserver::geterrmsg()
{
return errmsg;
}
main.cpp
#pragma once
#pragma execution_character_set("utf-8")
#include Makefile的gcc需要改成g++，否则会出现下面的问题，include和lib就可以编译运行了。
Makefile
INCLUDEPATH=/usr/libevent/include
LIBPATH=/usr/libevent/lib
CC1=g++
build:main.o myhttpserver.o
$(CC1) -gdwarf-2 -o HTTPTest main.o myhttpserver.o -I $(INCLUDEPATH) -L $(LIBPATH) -levent
main.o:main.cpp myhttpserver.h
$(CC1) -gdwarf-2 -c main.cpp -I $(INCLUDEPATH) -L $(LIBPATH) -levent
myhttpserver.o:myhttpserver.cpp myhttpserver.h
$(CC1) -gdwarf-2 -c myhttpserver.cpp -I $(INCLUDEPATH) -L $(LIBPATH) -levent
clean:
rm *.o HTTPTest
运行展示
服务端的HTTPTest有这些文件。
index.html内容如下
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)title>
head>
<body>
<form name="input" action="/add" method="post">
add1: <input type="text" name="add1">
add2: <input type="text" name="add2">
<input type="submit" value="Submit">
form>
<p><b>注意：b> 表单本身是不可见的。并且注意一个文本字段的默认宽度是20个字符。p>
body>
html>
首页
普通文件展示
打开获取影音需要在html写入连接，不能像图片、gif一样直接打开，否则会跳出下载界面。
index页面
点击提交按钮
bye关闭服务器
