Switch from epee http client to boost::beast. All HTTP now non-blocking. (#150)

src/net/http/client.h

@@ -0,0 +1,72 @@
+// Copyright (c) 2024, The Monero Project
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. 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.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// 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.
+
+#pragma once
+
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/ssl/context.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/thread/mutex.hpp>
+#include <functional>
+#include <memory>
+#include <string>
+#include "byte_slice.h"    // monero/contrib/epee/include
+#include "common/expect.h" // monero/src
+#include "net/net_ssl.h"   // monero/contrib/epee/include
+
+namespace net { namespace http
+{
+  struct client_state;
+  using server_response_func = void(boost::system::error_code, std::string);
+
+  //! Primarily for webhooks, where the response is (basically) ignored.
+  class client
+  {
+    std::weak_ptr<client_state> state_;
+    std::shared_ptr<boost::asio::ssl::context> ssl_;
+    boost::mutex sync_;
+
+    expect<void> queue_async(boost::asio::io_context& io, std::string url, epee::byte_slice json_body, std::function<server_response_func> notifier);
+
+  public:
+    explicit client(epee::net_utils::ssl_verification_t verify);
+    explicit client(std::shared_ptr<boost::asio::ssl::context> ssl);
+    ~client();
+
+    const std::shared_ptr<boost::asio::ssl::context>& ssl_context() const noexcept
+    { return ssl_; }
+
+    //! Never blocks. Thread safe. \return `success()` if `url` is valid.
+    expect<void> post_async(boost::asio::io_context& io, std::string url, epee::byte_slice json_body);
+
+    /*! Never blocks. Thread safe. Calls `notifier` with server response iff
+      `success()` is returned.
+      \return `success()` if `url` is valid. */
+    expect<void> get_async(boost::asio::io_context& io, std::string url, std::function<server_response_func> notifier);
+  };
+}} // net // http
+