Add HTTP support and update checking

code/cpp-httplib-0.19.0/example/one_time_request.cc

@@ -0,0 +1,56 @@
+#include <httplib.h>
+#include <iostream>
+
+using namespace httplib;
+
+const char *HOST = "localhost";
+const int PORT = 1234;
+
+void one_time_request_server(const char *label) {
+  std::thread th;
+  Server svr;
+
+  svr.Get("/hi", [&](const Request & /*req*/, Response &res) {
+    res.set_content(std::string("Hello from ") + label, "text/plain");
+
+    // Stop server
+    th = std::thread([&]() { svr.stop(); });
+  });
+
+  svr.listen(HOST, PORT);
+  th.join();
+
+  std::cout << label << " ended..." << std::endl;
+}
+
+void send_request(const char *label) {
+  Client cli(HOST, PORT);
+
+  std::cout << "Send " << label << " request" << std::endl;
+  auto res = cli.Get("/hi");
+
+  if (res) {
+    std::cout << res->body << std::endl;
+  } else {
+    std::cout << "Request error: " + to_string(res.error()) << std::endl;
+  }
+}
+
+int main(void) {
+  auto th1 = std::thread([&]() { one_time_request_server("Server #1"); });
+  auto th2 = std::thread([&]() { one_time_request_server("Server #2"); });
+
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+  send_request("1st");
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+  send_request("2nd");
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+  send_request("3rd");
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+  th1.join();
+  th2.join();
+}