//
// sse.cc
//
// Copyright (c) 2020 Yuji Hirose. All rights reserved.
// MIT License
//
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <httplib.h>
#include <iostream>
#include <mutex>
#include <sstream>
#include <thread>
using namespace httplib;
using namespace std;
class EventDispatcher {
public:
EventDispatcher() {
id_ = 0;
cid_ = -1;
}
void wait_event(DataSink *sink) {
unique_lock<mutex> lk(m_);
int id = id_;
cv_.wait(lk, [&] { return cid_ == id; });
if (sink->is_writable()) { sink->write(message_.data(), message_.size()); }
}
void send_event(const string &message) {
lock_guard<mutex> lk(m_);
cid_ = id_++;
message_ = message;
cv_.notify_all();
}
private:
mutex m_;
condition_variable cv_;
atomic_int id_;
atomic_int cid_;
string message_;
};
const auto html = R"(
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>SSE demo</title>
</head>
<body>
<script>
const ev1 = new EventSource("event1");
ev1.onmessage = function(e) {
console.log('ev1', e.data);
}
const ev2 = new EventSource("event2");
ev2.onmessage = function(e) {
console.log('ev2', e.data);
}
</script>
</body>
</html>
)";
int main(void) {
EventDispatcher ed;
Server svr;
svr.Get("/", [&](const Request & /*req*/, Response &res) {
res.set_content(html, "text/html");
});
svr.Get("/event1", [&](const Request & /*req*/, Response &res) {
cout << "connected to event1..." << endl;
res.set_chunked_content_provider("text/event-stream",
[&](size_t /*offset*/, DataSink &sink) {
ed.wait_event(&sink);
return true;
});
});
svr.Get("/event2", [&](const Request & /*req*/, Response &res) {
cout << "connected to event2..." << endl;
res.set_chunked_content_provider("text/event-stream",
[&](size_t /*offset*/, DataSink &sink) {
ed.wait_event(&sink);
return true;
});
});
thread t([&] {
int id = 0;
while (true) {
this_thread::sleep_for(chrono::seconds(1));
cout << "send event: " << id << std::endl;
std::stringstream ss;
ss << "data: " << id << "\n\n";
ed.send_event(ss.str());
id++;
}
});
svr.listen("localhost", 1234);
}