SSE client example

2025-05-15 01:08:27 +00:00 · 2020-07-25 11:20:57 -04:00 · 2020-07-25 11:20:57 -04:00 · 0e9cfd9f49
commit 0e9cfd9f49
parent 90da199aba
5 changed files with 42 additions and 20 deletions
--- a/example/ssesvr.cc
+++ b/example/ssesvr.cc
@ -0,0 +1,111 @@
+//
+//  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);
+}