我测试了以下Boost :: Asio最小HTTP服务器示例: (Minimal HTTP Server based on Boost:Asio)
我能够成功收集内容长度等标题信息,但是当我尝试阅读正文信息时,示例会挂起。以下是尝试读取Body信息的函数:
static void read_body(std::shared_ptr<session> pThis) {
info("read_body");
int nbuffer = pThis->headers.content_length();
std::shared_ptr<std::vector<char>> bufptr = std::make_shared<std::vector<char>>(nbuffer);
asio::async_read(pThis->socket, boost::asio::buffer(*bufptr, nbuffer),
[pThis](const error_code& e, std::size_t s)
{
info("read body complete");
});
}
我已经使用 libmicrohttpd 的解决方案成功阅读了相同的Body信息。
是否有更正确的方法可以使用Boost:ASIO读取Body(JSON)信息?
答案 0 :(得分:3)
问题的实质是双重的:
首先,有Undefined Behaviour,因为你无法在完成处理程序中捕获bufptr
,这意味着在系统调用写入时已经释放了向量...
其次,你是&#34; junking&#34;身体的第一部分,因为你在阅读标题时已经收到了它。您应该添加代码以保留已在read_next_line
。
真实的误导&#34;可能是在使用
asio::async_read_until(pThis->socket, pThis->buff, '\r', ...
好像它会以某种方式收到一行。套接字无法正常工作。您将收到一个数据包。 TCP堆栈决定什么构成数据包。 Asio只是承诺阅读&#34;直到&#34;数据包&gt;包含&lt;分隔符。它没有说它不会收到更多,它只是没有安排另一个接收操作。
所以,要真正解决它,你可能只是一次读取所有标题:
asio::async_read_until(pThis->socket, pThis->buff, "\r\n\r\n",
[pThis](const error_code &e, std::size_t s) {
if (e) { std::cerr << "Error:" << __LINE__ << " " << e.message() << "\n"; return; }
std::cout << __FILE__ << ":" << __LINE__ << " received:" << s << "\n";
std::istream is(&pThis->buff);
std::string line, ignore;
if (getline(is, line, '\r') && is.ignore(1, '\n'))
pThis->headers.on_read_request_line(line);
while (getline(is, line, '\r') && is.ignore(1, '\n') && !line.empty())
pThis->headers.on_read_header(line);
注意同样,重要的是不要假设标题末尾与数据包边界重合。因此,启动read_body()
并排除已收到的可用输入:
std::shared_ptr<std::vector<char> > bufptr = std::make_shared<std::vector<char> >(nbuffer);
auto partial = std::copy(
std::istreambuf_iterator<char>(&pThis->buff), {},
bufptr->begin());
std::size_t already_received = std::distance(bufptr->begin(), partial);
assert(nbuffer >= already_received);
nbuffer -= already_received;
<强> Live On Coliru 强>
#include <boost/asio.hpp>
#include <boost/algorithm/string/trim.hpp>
#include <string>
#include <memory>
#include <iostream>
#include <fstream>
using namespace boost;
using namespace boost::system;
using namespace boost::asio;
unsigned char *get_icon(int *pOutSize);
class session;
class http_headers {
std::string method;
std::string url;
std::string version;
std::map<std::string, std::string> headers;
public:
std::string get_response() {
std::stringstream ssOut;
if (url == "/favicon.ico") {
int nSize = 0;
unsigned char *data = get_icon(&nSize);
ssOut << "HTTP/1.1 200 OK" << std::endl;
ssOut << "content-type: image/vnd.microsoft.icon" << std::endl;
ssOut << "Content-Length: " << nSize << std::endl;
ssOut << std::endl;
ssOut.write((char *)data, nSize);
} else if (url == "/") {
std::string sHTML = "<html><body><h1>Hello World</h1><p>This is a test web server in c++</p></body></html>";
ssOut << "HTTP/1.1 200 OK" << std::endl;
ssOut << "Content-Type: text/html" << std::endl;
ssOut << "Content-Length: " << sHTML.length() << std::endl;
ssOut << std::endl;
ssOut << sHTML;
} else {
std::string sHTML = "<html><body><h1>404 Not Found</h1><p>There's nothing here.</p></body></html>";
ssOut << "HTTP/1.1 404 Not Found" << std::endl;
ssOut << "Content-Type: text/html" << std::endl;
ssOut << "Content-Length: " << sHTML.length() << std::endl;
ssOut << std::endl;
ssOut << sHTML;
}
return ssOut.str();
}
size_t content_length() {
auto request = headers.find("Content-Length");
if (request != headers.end()) {
std::stringstream ssLength(request->second);
size_t content_length;
ssLength >> content_length;
return content_length;
}
return 0;
}
void on_read_header(std::string line) {
std::cout << "header: '" << line << "'\n";
std::stringstream ssHeader(line);
std::string headerName;
std::getline(ssHeader, headerName, ':');
std::string value;
std::getline(ssHeader, value);
headers[headerName] = value;
}
void on_read_request_line(std::string line) {
std::stringstream ssRequestLine(line);
ssRequestLine >> method;
ssRequestLine >> url;
ssRequestLine >> version;
std::cout << "request for resource: " << url << std::endl;
}
};
namespace {
static void info(std::string s) { std::cout << "INFO:" << s << "\n"; }
}
class session {
asio::streambuf buff;
http_headers headers;
static void read_body(std::shared_ptr<session> pThis) {
info("read_body");
size_t nbuffer = pThis->headers.content_length();
std::cout << __FILE__ << ":" << __LINE__ << " nbuffer:" << nbuffer << "\n";
std::shared_ptr<std::vector<char> > bufptr = std::make_shared<std::vector<char> >(nbuffer);
auto partial = std::copy(
std::istreambuf_iterator<char>(&pThis->buff), {},
bufptr->begin());
std::size_t already_received = std::distance(bufptr->begin(), partial);
assert(nbuffer >= already_received);
nbuffer -= already_received;
asio::async_read(pThis->socket, boost::asio::buffer(&*bufptr->begin() + already_received, nbuffer),
[=](const error_code &e, std::size_t s) {
info("read body complete");
// EOF is to be expected on client disconnect
if (e && e != boost::asio::error::eof) {
std::cerr << "Error:" << __LINE__ << " " << e.message() << "\n"; return;
}
std::cout << __FILE__ << ":" << __LINE__ << " received:" << s << "/" << nbuffer << "\n";
std::string body(&*bufptr->begin(), already_received + s);
std::string::size_type p = 0;
for (int i = 0; i<2; ++i)
p = body.find_last_of("\r\n", p-1);
std::cout << "Tail: '" << body.substr(p+1) << "'\n";
{
std::ofstream ofs("debug.txt", std::ios::binary);
ofs << body;
ofs << "\n" << __FILE__ << ":" << __LINE__ << " received:" << s << "/" << nbuffer << "\n";
}
});
}
static void read_headers(std::shared_ptr<session> pThis) {
asio::async_read_until(pThis->socket, pThis->buff, "\r\n\r\n",
[pThis](const error_code &e, std::size_t s) {
if (e) { std::cerr << "Error:" << __LINE__ << " " << e.message() << "\n"; return; }
std::cout << __FILE__ << ":" << __LINE__ << " received:" << s << "\n";
std::istream is(&pThis->buff);
std::string line, ignore;
if (getline(is, line, '\r') && is.ignore(1, '\n'))
pThis->headers.on_read_request_line(line);
while (getline(is, line, '\r') && is.ignore(1, '\n') && !line.empty())
pThis->headers.on_read_header(line);
if (pThis->headers.content_length()) {
pThis->read_body(pThis);
auto str = std::make_shared<std::string>("HTTP/1.1 200 OK\r\nContent-Length: 0\r\n\r\n");
asio::async_write(
pThis->socket, boost::asio::buffer(*str),
[pThis, str](const error_code &e, std::size_t s) {
std::cout << "done" << std::endl;
});
} else {
std::shared_ptr<std::string> str = std::make_shared<std::string>(pThis->headers.get_response());
asio::async_write(
pThis->socket, boost::asio::buffer(*str),
[pThis, str](const error_code &e, std::size_t s) {
std::cout << "done" << std::endl;
});
}
});
}
public:
ip::tcp::socket socket;
session(io_service &io_service) : socket(io_service) {}
static void interact(std::shared_ptr<session> pThis) { read_headers(pThis); }
};
void accept_and_run(ip::tcp::acceptor &acceptor, io_service &io_service) {
std::shared_ptr<session> sesh = std::make_shared<session>(io_service);
acceptor.async_accept(sesh->socket, [sesh, &acceptor, &io_service](const error_code &accept_error) {
accept_and_run(acceptor, io_service);
if (accept_error) {
std::cerr << "Accept error: " << accept_error.message() << "\n";
} else {
session::interact(sesh);
}
});
}
int main() {
io_service io_service;
ip::tcp::endpoint endpoint{ ip::tcp::v4(), 8181 };
ip::tcp::acceptor acceptor{ io_service, endpoint };
acceptor.listen();
accept_and_run(acceptor, io_service);
io_service.run();
}
unsigned char icon_data[] = {
// reserved
0x00, 0x00,
// icon type (1 = icon)
0x01, 0x00,
// number of images (1)
0x01, 0x00,
// width, height (16x16)
0x10, 0x10,
// size of colour palette
0x00,
// reserved
0x00,
// colour planes (1)
0x01, 0x00,
// bits per pixel (32)
0x20, 0x00,
// size of data in bytes
0x28, 0x04, 0x00, 0x00,
// offset of bitmap data
0x16, 0x00, 0x00, 0x00,
// BEGIN BITMAPINFOHEADER
// bcsize
0x28, 0x00, 0x00, 0x00, // biSize
0x10, 0x00, 0x00, 0x00, // biWidth
0x20, 0x00, 0x00, 0x00, // biHeight (with both AND and XOR mask? wtf?)
0x01, 0x00, // biPlanes
0x20, 0x00, // biBitCount (32)
0x00, 0x00, 0x00, 0x00, // biCompression
0x00, 0x00, 0x00, 0x00, // biSizeImage
0x00, 0x00, 0x00, 0x00, // biXPelsPerMeter
0x00, 0x00, 0x00, 0x00, // biYPelsPerMeter
0x00, 0x00, 0x00, 0x00, // biClrUsed
0x00, 0x00, 0x00, 0x00, // biClrImportant
// END BITMAPINFOHEADER
// BITMAP DATA (4 bytes per pixel)
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF,
0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF,
0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF, 0x00, 0xFF
};
unsigned char *get_icon(int *pOut) {
*pOut = sizeof(icon_data);
return icon_data;
}