看到C++0x的lambda特性，随想到boost::asio，于是拿来练练手，的确很方便。但总有邪教的感觉。
以下代码的编译环境还是满苛刻的。
本人的编译环境为gcc 4.5.2 + boost 1.46。C++0x lambda则需要gcc 4.5以上版本
程序功能
命令：http-get 域名
功能：输出域名的首页，接收所有数据。因为是所有数据。所以有的数据会包含Chunk信息。
代码比较简单，都是最基本的应用，所以没啥注释。由于asio的handler全使用了lambda，代码整洁了许多，没有了长长的bind。
#include <string>
#include <iostream>
#include <algorithm>
#include <boost/asio.hpp>
using namespace std;
using namespace boost;
using boost::asio::ip::tcp;
#define CHECK_ERROR_CODE(code) if (code) { cerr << code.message() << endl; return; }
class HttpClient
{
asio::io_service &io_service_;
asio::streambuf buffer_;
tcp::socket socket_;
tcp::resolver resolver_;
string domain_;
public:
HttpClient(asio::io_service &io_service) : io_service_(io_service), socket_(io_service), resolver_(io_service)
{
}
void get(const string &domain)
{
resolve(domain);
}
void resolve(const string &domain)
{
domain_ = domain;
tcp::resolver::query query(domain, "http");
resolver_.async_resolve(query,
[this](const system::error_code &code, tcp::resolver::iterator iterator) {
CHECK_ERROR_CODE(code);
connect( iterator->endpoint() );
}
);
}
void connect(tcp::endpoint remote_endpoint)
{
socket_.async_connect(remote_endpoint,
[this](const system::error_code &code) {
CHECK_ERROR_CODE(code);
send_header();
}
);
}
void send_header()
{
string request_header("GET / HTTP/1.1\r\nHost: "+domain_+"\r\nConnection: close\r\n\r\n");
async_write(socket_, asio::buffer(request_header), asio::transfer_all(),
[this](const system::error_code &code, size_t n) {
CHECK_ERROR_CODE(code);
recv_any();
}
);
}
void recv_any()
{
async_read(socket_, buffer_, asio::transfer_at_least(1),
[this](const system::error_code &code, size_t n) {
size_t size = asio::buffer_size(buffer_.data());
if (size>0) {
const char *data = asio::buffer_cast<const char*>(buffer_.data());
cout.write(data, size);
buffer_.consume(size);
}
CHECK_ERROR_CODE(code);
recv_any();
}
);
}
};
int main(int argc, char *argv[])
{
if (argc<2) {
cerr << "http-get domain" << endl;
return 1;
}
asio::io_service io_service;
HttpClient client(io_service);
client.get(argv[1]);
io_service.run();
return 0;
}
另存为http-get.cc，编译并运行
$ g++ -std=c++0x -lboost_system -lboost_thread http-get.cc -o http-get $ ./http-get www.baidu.com HTTP/1.1 200 OK Date: Sun, 27 Mar 2011 20:36:51 GMT Server: BWS/1.0 Content-Length: 6759 Content-Type: text/html;charset=gb2312 Cache-Control: private Expires: Sun, 27 Mar 2011 20:36:51 GMT Set-Cookie: BAIDUID=83C77B5AA4FFE997F526519A3612F959:FG=1; expires=Sun, 27-Mar-41 20:36:51 GMT; path=/; domain=.baidu.com P3P: CP=" OTI DSP COR IVA OUR IND COM " Connection: Close <!doctype html><html><head>< ... ... </html><!--6a95ba0cdf1459cc--> End of file