Add message queue and worker threads.

src/csoap/connection.cc

@@ -1,5 +1,9 @@
 #include "csoap/connection.h"
+
 #include <vector>
+#if CSOAP_ENABLE_OUTPUT
+#include <iostream>
+#endif
 
 #include "boost/asio/write.hpp"
 
@@ -42,7 +46,7 @@ void Connection::DoWrite() {
 }
 
 void Connection::HandleRead(boost::system::error_code ec,
-                            std::size_t bytes_transferred) {
+                            std::size_t length) {
   if (ec) {
     if (ec != boost::asio::error::operation_aborted) {
       connection_manager_.Stop(shared_from_this());
@@ -50,7 +54,7 @@ void Connection::HandleRead(boost::system::error_code ec,
     return;
   }
 
-  Error error = request_parser_.Parse(buffer_.data(), bytes_transferred);
+  Error error = request_parser_.Parse(buffer_.data(), length);
 
   if (error != kNoError) {
     // Bad request.
@@ -65,16 +69,23 @@ void Connection::HandleRead(boost::system::error_code ec,
     return;
   }
 
-  // Handle request.
-  // TODO: Time consuming
-  request_handler_.HandleRequest(request_, &response_);
-
-  // Send back the response.
-  DoWrite();
+  // Enqueue this connection.
+  // Some worker thread will handle it later.
+  // And DoWrite() will be called in the worker thread.
+  request_handler_.Enqueue(shared_from_this());
 }
 
+// NOTE:
+// This write handler will be called from main thread (the thread calling
+// io_context.run), even though DoWrite() is invoked by worker threads. This is
+// ensured by Asio.
 void Connection::HandleWrite(boost::system::error_code ec,
-                             size_t bytes_transferred) {
+                             size_t length) {
+#if CSOAP_ENABLE_OUTPUT
+  boost::thread::id thread_id = boost::this_thread::get_id();
+  std::cout << "Response has been sent back (thread: " << thread_id << ")\n";
+#endif
+
   if (!ec) {
     // Initiate graceful connection closure.
     boost::system::error_code ignored_ec;

src/csoap/connection.h

@@ -22,15 +22,15 @@ public:
   Connection(const Connection&) = delete;
   Connection& operator=(const Connection&) = delete;
 
+  friend class HttpRequestHandler;
+
   // Construct a connection with the given io_service.
   Connection(boost::asio::ip::tcp::socket socket,
              ConnectionManager& manager,
              HttpRequestHandler& handler);
 
-  // Start the first asynchronous operation for the connection.
   void Start();
 
-  // Stop all asynchronous operations associated with the connection.
   void Stop();
 
 private:
@@ -38,13 +38,11 @@ private:
 
   void DoWrite();
 
-  // Handle completion of a read operation.
   void HandleRead(boost::system::error_code ec,
-                  std::size_t bytes_transferred);
+                  std::size_t length);
 
-  // Handle completion of a write operation.
   void HandleWrite(boost::system::error_code ec,
-                   size_t bytes_transferred);
+                   std::size_t length);
 
 private:
   // Socket for the connection.
@@ -65,7 +63,7 @@ private:
   // The parser for the incoming request.
   HttpRequestParser request_parser_;
 
-  // The reply to be sent back to the client.
+  // The response to be sent back to the client.
   HttpResponse response_;
 };
 

src/csoap/http_request_handler.cc

@@ -1,48 +1,23 @@
 #include "csoap/http_request_handler.h"
 
 #include <sstream>
+#if CSOAP_ENABLE_OUTPUT
+#include <iostream>
+#endif
 
 #include "csoap/common.h"
 #include "csoap/http_request.h"
 #include "csoap/http_response.h"
 #include "csoap/soap_request.h"
 #include "csoap/soap_response.h"
-#include "csoap/soap_service.h"
 
 namespace csoap {
 
-#if 0
-// Perform URL-decoding on a string. Returns false if the encoding was invalid.
-static bool UrlDecode(const std::string& in, std::string& out) {
-  out.clear();
-  out.reserve(in.size());
-
-  for (std::size_t i = 0; i < in.size(); ++i) {
-    if (in[i] == '%') {
-      if (i + 3 <= in.size()) {
-        int value = 0;
-        std::istringstream is(in.substr(i + 1, 2));
-        if (is >> std::hex >> value) {
-          out += static_cast<char>(value);
-          i += 2;
-        } else {
-          return false;
-        }
-      } else {
-        return false;
-      }
-    } else if (in[i] == '+') {
-      out += ' ';
-    } else {
-      out += in[i];
-    }
-  }
-
-  return true;
-}
-#endif
-
 HttpRequestHandler::HttpRequestHandler() {
+  // Create worker threads.
+  for (std::size_t i = 0; i < 2; ++i) {
+    workers_.create_thread(std::bind(&HttpRequestHandler::WorkerRoutine, this));
+  }
 }
 
 bool HttpRequestHandler::RegisterService(SoapServicePtr soap_service) {
@@ -57,6 +32,7 @@ bool HttpRequestHandler::RegisterService(SoapServicePtr soap_service) {
   return true;
 }
 
+#if 0
 void HttpRequestHandler::HandleRequest(const HttpRequest& http_request,
                                        HttpResponse* http_response) {
   // Parse the SOAP request XML.
@@ -81,28 +57,69 @@ void HttpRequestHandler::HandleRequest(const HttpRequest& http_request,
   http_response->SetContentType(kTextXmlUtf8);
   http_response->SetContentLength(content.length());
   http_response->set_content(std::move(content));
+}
+#endif
 
-#if 0
-  // Decode URL to path.
-  std::string request_path;
-  if (!UrlDecode(request.uri, request_path)) {
-    reply = HttpReply::StockReply(HttpReply::BAD_REQUEST);
-    return;
-  }
+void HttpRequestHandler::Enqueue(ConnectionPtr conn) {
+  queue_.Put(conn);
+}
 
-  // Request path must be absolute and not contain "..".
-  if (request_path.empty() ||
-      request_path[0] != '/' ||
-      request_path.find("..") != std::string::npos) {
-    reply = HttpReply::StockReply(HttpReply::BAD_REQUEST);
-    return;
-  }
+void HttpRequestHandler::StopWorkers() {
+#if CSOAP_ENABLE_OUTPUT
+  std::cout << "Stopping workers...\n";
+#endif
 
-  // If path ends in slash (i.e. is a directory) then add "index.html".
-  if (request_path[request_path.size() - 1] == '/') {
-    request_path += "index.html";
-  }
+  // Enqueue an null connection to trigger the first worker to stop.
+  queue_.Put(ConnectionPtr());
+
+  workers_.join_all();
+
+#if CSOAP_ENABLE_OUTPUT
+  std::cout << "Workers have been stopped.\n";
+#endif
+}
+
+// TODO: How and when to exit?
+void HttpRequestHandler::WorkerRoutine() {
+  for (;;) {
+    ConnectionPtr conn = queue_.Get();
+
+    if (!conn) {
+#if CSOAP_ENABLE_OUTPUT
+      boost::thread::id thread_id = boost::this_thread::get_id();
+      std::cout << "Worker is going to stop (thread: " << thread_id << ")\n";
 #endif
+      // For stopping next worker.
+      queue_.Put(ConnectionPtr());
+      // Stop the worker.
+      break;
+    }
+
+    // Parse the SOAP request XML.
+    SoapRequest soap_request;
+    if (!soap_request.FromXml(conn->request_.content())) {
+      conn->response_.set_status(HttpStatus::BAD_REQUEST);
+      conn->DoWrite();  // TODO
+      continue;
+    }
+
+    SoapResponse soap_response;
+     
+    // TODO: Get service by URL.
+    for (SoapServicePtr& service : soap_services_) {
+      service->Handle(soap_request, &soap_response);
+    }
+
+    std::string content;
+    soap_response.ToXml(&content);
+
+    conn->response_.set_status(HttpStatus::OK);
+    conn->response_.SetContentType(kTextXmlUtf8);
+    conn->response_.SetContentLength(content.length());
+    conn->response_.set_content(std::move(content));
+
+    conn->DoWrite();
+  }
 }
 
 }  // namespace csoap

src/csoap/http_request_handler.h

@@ -1,7 +1,13 @@
 #ifndef CSOAP_HTTP_REQUEST_HANDLER_H_
 #define CSOAP_HTTP_REQUEST_HANDLER_H_
 
+#include <list>
 #include <vector>
+
+#include "boost/thread/thread.hpp"
+
+#include "csoap/connection.h"
+#include "csoap/queue.h"
 #include "csoap/soap_service.h"
 
 namespace csoap {
@@ -20,11 +26,25 @@ public:
   bool RegisterService(SoapServicePtr soap_service);
 
   // Handle a request and produce a response.
+#if 0
   void HandleRequest(const HttpRequest& http_request,
                      HttpResponse* http_response);
+#endif
+
+  // Put the connection into the queue.
+  void Enqueue(ConnectionPtr conn);
+
+  // Stop all worker threads.
+  void StopWorkers();
+
+private:
+  void WorkerRoutine();
 
 private:
   std::vector<SoapServicePtr> soap_services_;
+
+  Queue<ConnectionPtr> queue_;
+  boost::thread_group workers_;
 };
 
 }  // namespace csoap

src/csoap/http_server.cc

@@ -2,6 +2,10 @@
 
 #include <signal.h>
 
+#if CSOAP_ENABLE_OUTPUT
+#include <iostream>
+#endif
+
 #include "csoap/soap_service.h"
 #include "csoap/utility.h"
 
@@ -10,7 +14,7 @@ using tcp = boost::asio::ip::tcp;
 namespace csoap {
 
 HttpServer::HttpServer(unsigned short port)
-    : io_context_(1)  // TODO: concurrency_hint (threads)
+    : io_context_(1)
     , signals_(io_context_) {
 
   // Register to handle the signals that indicate when the server should exit.
@@ -43,6 +47,11 @@ bool HttpServer::RegisterService(SoapServicePtr soap_service) {
 }
 
 void HttpServer::Run() {
+#if CSOAP_ENABLE_OUTPUT
+  boost::thread::id thread_id = boost::this_thread::get_id();
+  std::cout << "Server main thread: " << thread_id << std::endl;
+#endif
+
   // The io_context::run() call will block until all asynchronous operations
   // have finished. While the server is running, there is always at least one
   // asynchronous operation outstanding: the asynchronous accept call waiting
@@ -53,30 +62,31 @@ void HttpServer::Run() {
 void HttpServer::DoAccept() {
   acceptor_->async_accept(
     [this](boost::system::error_code ec, tcp::socket socket) {
-    // Check whether the server was stopped by a signal before this
-    // completion handler had a chance to run.
-    if (!acceptor_->is_open()) {
-      return;
-    }
-
-    if (!ec) {
-      connection_manager_.Start(
-        std::make_shared<Connection>(std::move(socket),
-        connection_manager_,
-        request_handler_));
-    }
-
-    DoAccept();
-  });
+      // Check whether the server was stopped by a signal before this
+      // completion handler had a chance to run.
+      if (!acceptor_->is_open()) {
+        return;
+      }
+
+      if (!ec) {
+        connection_manager_.Start(
+            std::make_shared<Connection>(std::move(socket),
+                                         connection_manager_,
+                                         request_handler_));
+      }
+
+      DoAccept();
+    });
 }
 
 void HttpServer::DoAwaitStop() {
   signals_.async_wait(
     [this](boost::system::error_code /*ec*/, int /*signo*/) {
-    // The server is stopped by cancelling all outstanding asynchronous
+    // The server is stopped by canceling all outstanding asynchronous
     // operations. Once all operations have finished the io_context::run()
     // call will exit.
     acceptor_->close();
+    request_handler_.StopWorkers();
     connection_manager_.StopAll();
   });
 }

src/csoap/http_server.h

@@ -5,6 +5,8 @@
 #include <vector>
 
 #include "boost/scoped_ptr.hpp"
+#include "boost/thread/thread.hpp"
+
 #include "boost/asio/io_context.hpp"
 #include "boost/asio/signal_set.hpp"
 #include "boost/asio/ip/tcp.hpp"

src/csoap/queue.h

@@ -0,0 +1,49 @@
+#ifndef CSOAP_QUEUE_H_
+#define CSOAP_QUEUE_H_
+
+// A general message queue.
+
+#include <list>
+
+#include "boost/thread/condition_variable.hpp"
+#include "boost/thread/locks.hpp"
+#include "boost/thread/mutex.hpp"
+
+namespace csoap {
+
+template <typename T>
+class Queue {
+public:
+  Queue(const Queue& rhs) = delete;
+  Queue& operator=(const Queue& rhs) = delete;
+
+  Queue() = default;
+
+  T Get() {
+    boost::unique_lock<boost::mutex> lock(mutex_);
+
+    // Wait for a message.
+    not_empty_cv_.wait(lock, [=] { return !message_list_.empty(); });
+
+    T message = message_list_.front();
+    message_list_.pop_front();
+    return message;
+  }
+
+  void Put(const T& message) {
+    {
+      boost::lock_guard<boost::mutex> lock(mutex_);
+      message_list_.push_back(message);
+    }
+    not_empty_cv_.notify_one();
+  }
+
+private:
+  std::list<T> message_list_;
+  boost::mutex mutex_;
+  boost::condition_variable not_empty_cv_;
+};
+
+}  // namespace csoap
+
+#endif  // CSOAP_QUEUE_H_

src/demo/calculator_client/calculator_client.cc

@@ -24,7 +24,7 @@ bool CalculatorClient::Divide(double x, double y, double* result) {
 }
 
 // Set to 0 to test our own calculator server created with csoap.
-#define ACCESS_PARASOFT 1
+#define ACCESS_PARASOFT 0
 
 void CalculatorClient::Init() {
 #if ACCESS_PARASOFT

src/demo/calculator_server/main.cc

@@ -25,7 +25,7 @@ int main(int argc, char* argv[]) {
     server.Run();
 
   } catch (std::exception& e) {
-    std::cerr << "exception: " << e.what() << "\n";
+    std::cerr << "Exception: " << e.what() << std::endl;
     return 1;
   }