src/app/c/ws_test_poll.cpp

// Copyright (c) 2013-2017, Matt Godbolt
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
//
// Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

// An extraordinarily simple test which presents a web page with some buttons.
// Clicking on the numbered button increments the number, which is visible to
// other connected clients.  WebSockets are used to do this: by the rather
// suspicious means of sending raw JavaScript commands to be executed on other
// clients.

// Same as ws_test, but uses the poll() method and a separate epoll set to
// demonstrate how Seasocks can be used with another polling system.

#include "seasocks/PrintfLogger.h"
#include "seasocks/Server.h"
#include "seasocks/StringUtil.h"
#include "seasocks/WebSocket.h"
#include "seasocks/util/Json.h"

#include <cstring>
#include <iostream>
#include <memory>
#include <set>
#include <sstream>
#include <string>
#include <fcntl.h>
#include <unistd.h>
#include <sys/epoll.h>

using namespace seasocks;

class MyHandler : public WebSocket::Handler {
public:
    explicit MyHandler(Server* server)
            : _server(server), _currentValue(0) {
        setValue(1);
    }

    virtual void onConnect(WebSocket* connection) override {
        _connections.insert(connection);
        connection->send(_currentSetValue.c_str());
        std::cout << "Connected: " << connection->getRequestUri()
                  << " : " << formatAddress(connection->getRemoteAddress())
                  << "\nCredentials: " << *(connection->credentials()) << "\n";
    }

    virtual void onData(WebSocket* connection, const char* data) override {
        if (0 == strcmp("die", data)) {
            _server->terminate();
            return;
        }
        if (0 == strcmp("close", data)) {
            std::cout << "Closing..\n";
            connection->close();
            std::cout << "Closed.\n";
            return;
        }

        const int value = std::stoi(data) + 1;
        if (value > _currentValue) {
            setValue(value);
            for (auto c : _connections) {
                c->send(_currentSetValue.c_str());
            }
        }
    }

    virtual void onDisconnect(WebSocket* connection) override {
        _connections.erase(connection);
        std::cout << "Disconnected: " << connection->getRequestUri()
                  << " : " << formatAddress(connection->getRemoteAddress()) << "\n";
    }

private:
    std::set<WebSocket*> _connections;
    Server* _server;
    int _currentValue;
    std::string _currentSetValue;

    void setValue(int value) {
        _currentValue = value;
        _currentSetValue = makeExecString("set", _currentValue);
    }
};

int main(int /*argc*/, const char* /*argv*/[]) {
    auto logger = std::make_shared<PrintfLogger>(Logger::Level::Debug);

    Server server(logger);

    auto handler = std::make_shared<MyHandler>(&server);
    server.addWebSocketHandler("/ws", handler);
    server.setStaticPath("src/ws_test_web");
    if (!server.startListening(9090)) {
        std::cerr << "couldn't start listening\n";
        return 1;
    }
    int myEpoll = epoll_create(10);
    epoll_event wakeSeasocks = {EPOLLIN | EPOLLOUT | EPOLLERR, {&server}};
    epoll_ctl(myEpoll, EPOLL_CTL_ADD, server.fd(), &wakeSeasocks);

    // Also poll stdin
    epoll_event wakeStdin = {EPOLLIN, {nullptr}};
    epoll_ctl(myEpoll, EPOLL_CTL_ADD, STDIN_FILENO, &wakeStdin);
    auto prevFlags = fcntl(STDIN_FILENO, F_GETFL, 0);
    fcntl(STDIN_FILENO, F_SETFL, prevFlags | O_NONBLOCK);

    std::cout << "Will echo anything typed in stdin: " << std::flush;
    while (true) {
        constexpr auto maxEvents = 2;
        epoll_event events[maxEvents];
        auto res = epoll_wait(myEpoll, events, maxEvents, -1);
        if (res < 0) {
            std::cerr << "epoll returned an error\n";
            return 1;
        }
        for (auto i = 0; i < res; ++i) {
            if (events[i].data.ptr == &server) {
                auto seasocksResult = server.poll(0);
                if (seasocksResult == Server::PollResult::Terminated)
                    return 0;
                if (seasocksResult == Server::PollResult::Error)
                    return 1;
            } else if (events[i].data.ptr == nullptr) {
                // Echo stdin to stdout to show we can read from that too.
                for (;;) {
                    char buf[1024];
                    auto numRead = ::read(STDIN_FILENO, buf, sizeof(buf));
                    if (numRead < 0) {
                        if (errno != EWOULDBLOCK && errno != EAGAIN) {
                            std::cerr << "Error reading stdin\n";
                            return 1;
                        }
                        break;
                    } else if (numRead > 0) {
                        auto written = write(STDOUT_FILENO, buf, numRead);
                        if (written != numRead) {
                            std::cerr << "Truncated write\n";
                        }
                    } else if (numRead == 0) {
                        std::cerr << "EOF on stdin\n";
                        return 0;
                    }
                }
            }
        }
    }
    return 0;
}